Use the shared descent bookkeeping rather than a second set

Comparing kept a thread_local count, a limit and a guard of its own beside
the ones copying already had, all three the same thing under a different
name. They are gone; the shared count, limit and guard do the work.

The guard grows a second constructor here, because the comparison
operators are written as a macro and a macro cannot use the preprocessor:
it cannot look the count up behind an #ifdef the way copy_structured does,
so the guard looks it up for it. nesting_depth_exhausted() arrives for the
same reason - whether an operator descends at all is a constant at every
call site, and testing it there is what MSVC reports as C4127.

Also say in compare_leaves what happens to a pair that is an array on one
side and an object on the other, since the answer is not obvious from the
code: an operator only descends into two values of the same type, so such
a pair is told apart by its types alone - unequal, and ordered the way the
types are - exactly as it is above the bound.

And record what the explicit stack costs: the comparison operators are
noexcept and the container comparison this replaces allocated nothing, so
running out of memory here ends the process instead of throwing. It takes
a value nested past the bound and an exhausted heap to reach, and the same
comparison used to exhaust the call stack, but it is a new way to fail.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/CONTRIBUTING.md

@@ -108,9 +108,9 @@ The tests are located in [`tests/src/unit-*.cpp`](https://github.com/nlohmann/js
 are structured along the features of the library or the nature of the tests. Usually, it should be clear from the
 context which existing file needs to be extended, and only very few cases require creating new test files.
 
-When fixing a bug, edit `unit-regression3.cpp` and add a section referencing the fixed issue.
-`unit-regression2.cpp` holds the older tests; the two files exist because a single one grew large enough for the
-MinGW linker to fail relocating it, so please keep adding to the smaller file rather than growing the larger one.
+When fixing a bug, edit `unit-regression3.cpp` and add a test case referencing the fixed issue. Its predecessors
+`unit-regression1.cpp` and `unit-regression2.cpp` stay as they are: the MinGW linker fails on the object a file this
+size produces, which is why the tests are spread over several files in the first place.
 
 #### Exceptions
 

.github/workflows/ubuntu.yml

@@ -100,7 +100,7 @@ jobs:
     container: ubuntu:focal
     strategy:
       matrix:
-        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls, ci_test_simdutf]
+        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls, ci_test_no_thread_local]
     steps:
       - name: Install build-essential
         run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev

.github/workflows/windows.yml

@@ -158,6 +158,10 @@ jobs:
       # to fit: IMAGE_REL_AMD64_SECREL against `.debug_line'" because the
       # MinGW linker cannot relocate the debug sections this test produces.
       # The tests are only built and run here, so the debug info is not used.
+      # Do not add -O1 here to shrink the objects further: it does make them
+      # link, but the binaries clang 11.0.1 and clang 18.1.8 then produce crash
+      # before doctest prints its first line - 39 of 102 tests on clang 18.
+      # Keep the objects small by splitting the test files instead.
       - name: Run CMake
         run: cmake -S . -B build ^
              -DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" ^

cmake/ci.cmake

@@ -212,24 +212,6 @@ add_custom_target(ci_test_legacycomparison
     COMMENT "Compile and test with legacy discarded value comparison enabled"
 )
 
-###############################################################################
-# Validate UTF-8 with simdutf.
-###############################################################################
-
-add_custom_target(ci_test_simdutf
-    COMMAND ${CMAKE_COMMAND}
-    -DCMAKE_BUILD_TYPE=Debug -GNinja
-    -DJSON_BuildTests=ON -DJSON_TestSimdutf=ON
-    # simdutf needs C++17, so the library falls back to its scalar validator
-    # below that: build the suite at C++11 to cover the fallback with the macro
-    # defined, and at C++17 to run every test against simdutf itself
-    "-DJSON_TestStandards=11\;17"
-    -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_simdutf
-    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_simdutf
-    COMMAND cd ${PROJECT_BINARY_DIR}/build_simdutf && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
-    COMMENT "Compile and test with simdutf UTF-8 validation enabled"
-)
-
 ###############################################################################
 # Enable brace-init copy semantics.
 ###############################################################################
@@ -260,6 +242,25 @@ add_custom_target(ci_test_noglobaludls
     COMMENT "Compile and test with global UDLs disabled"
 )
 
+###############################################################################
+# Disable thread-local storage.
+###############################################################################
+
+# Without thread-local storage, copying and comparing cannot bound their
+# descent and handle every object and array without the call stack. Those paths
+# are otherwise only reached by values nested deeper than the bound, so this
+# target is what runs the whole test suite through them.
+add_custom_target(ci_test_no_thread_local
+    COMMAND ${CMAKE_COMMAND}
+    -DCMAKE_BUILD_TYPE=Debug -GNinja
+    -DJSON_BuildTests=ON
+    -DCMAKE_CXX_FLAGS=-DJSON_NO_THREAD_LOCAL
+    -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_no_thread_local
+    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_no_thread_local
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_no_thread_local && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
+    COMMENT "Compile and test without thread-local storage"
+)
+
 ###############################################################################
 # Coverage.
 ###############################################################################

docs/mkdocs/docs/api/macros/index.md

@@ -22,9 +22,9 @@ header. See also the [macro overview page](../../features/macros.md).
 - [**JSON_HAS_STD_FORMAT**](json_has_std_format.md) - control `std::format`/`std::formatter` support
 - [**JSON_HAS_THREE_WAY_COMPARISON**](json_has_three_way_comparison.md) - control 3-way comparison support
 - [**JSON_NO_IO**](json_no_io.md) - switch off functions relying on certain C++ I/O headers
+- [**JSON_NO_THREAD_LOCAL**](json_no_thread_local.md) - switch off the use of `thread_local` storage
 - [**JSON_SKIP_UNSUPPORTED_COMPILER_CHECK**](json_skip_unsupported_compiler_check.md) - do not warn about unsupported compilers
 - [**JSON_USE_GLOBAL_UDLS**](json_use_global_udls.md) - place user-defined string literals (UDLs) into the global namespace
-- [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
 
 ## Library version
 

docs/mkdocs/docs/api/macros/json_no_thread_local.md

@@ -0,0 +1,48 @@
+# JSON_NO_THREAD_LOCAL
+
+```cpp
+#define JSON_NO_THREAD_LOCAL
+```
+
+When defined, the library does not use `#!cpp thread_local` storage. This is relevant for the few environments whose
+toolchain does not support it.
+
+Copying a value and comparing two values both descend into the first levels by letting the containers copy or compare
+themselves, and finish whatever is nested deeper than that without the call stack, so that neither can exhaust the stack
+however deeply the values are nested. Each counts the levels it has descended into in a `#!cpp thread_local` variable, as
+a counter shared between threads would be raced.
+
+Without those counters, no descent can be bounded safely, so objects and arrays are copied and compared without the call
+stack right away. Both keep working exactly as they do otherwise - the same values come out, the same comparisons hold,
+and deeply nested values are handled just as safely - but both are slower, because the containers no longer copy or
+compare themselves. Copying the benchmark documents takes 9% (`canada.json`) to 34% (`twitter.json`) longer, and
+comparing two equal ones 10% (`citm_catalog.json`) to 90% (`canada.json`) longer.
+
+## Default definition
+
+By default, `#!cpp JSON_NO_THREAD_LOCAL` is not defined.
+
+```cpp
+#undef JSON_NO_THREAD_LOCAL
+```
+
+The library defines it by itself for Clang targeting MinGW, which does not survive the `#!cpp thread_local` storage:
+copying a value segfaults there, with both old and current Clang versions, while GCC targeting MinGW is unaffected.
+Copying and comparing fall back to working without the call stack there, as they do whenever the macro is defined.
+
+## Examples
+
+??? example
+
+    The code below forces the library not to use `#!cpp thread_local` storage.
+
+    ```cpp
+    #define JSON_NO_THREAD_LOCAL 1
+    #include <nlohmann/json.hpp>
+
+    ...
+    ```
+
+## Version history
+
+- Added in version 3.12.1.

docs/mkdocs/docs/api/macros/json_use_simdutf.md

@@ -1,71 +0,0 @@
-# JSON_USE_SIMDUTF
-
-```cpp
-#define JSON_USE_SIMDUTF
-```
-
-When defined, the parser validates the UTF-8 content of JSON strings that come from a **contiguous byte input**
-(`std::string`, `std::vector<char>`/`<std::uint8_t>`, string literals, `const char*` ranges, …) using the
-[simdutf](https://github.com/simdutf/simdutf) library instead of the built-in scalar validator. On text with many
-non-ASCII characters (e.g. CJK or emoji) this can validate several times faster.
-
-This is an **opt-in external dependency**. The library itself remains header-only and its behavior is unchanged: the
-same input is accepted or rejected either way, and every parse error is reported at the same position with the same
-message (simdutf is only used to fast-path *valid* runs; anything it flags falls back to the scalar path so the exact
-diagnostic is preserved). Streaming inputs (files, `std::istream`, wide strings, user-defined adapters) always use the
-scalar path.
-
-When `JSON_USE_SIMDUTF` is defined you must make the `simdutf.h` header available on the include path and link the
-simdutf library. When it is not defined, no simdutf header is included and there is no dependency.
-
-!!! note "Requires C++17"
-
-    simdutf requires C++17 and its header rejects older standards with an `#!cpp #error`. The backend is therefore only
-    compiled in from C++17 on. In C++11 and C++14 the macro has no effect and the scalar validator is used, which
-    accepts and rejects exactly the same input -- only throughput differs. Setting the macro project-wide is therefore
-    safe even when some translation units are built with an older standard.
-
-!!! warning "Define consistently"
-
-    The macro selects between two definitions of the same inline validation function. It must therefore be defined
-    identically for **every** translation unit that includes the library; mixing translation units that define it with
-    ones that do not is an ODR violation. Prefer setting it as a compile definition on the target rather than with
-    `#!cpp #define` in individual source files.
-
-## Default definition
-
-By default, `#!cpp JSON_USE_SIMDUTF` is not defined and the portable C++11 scalar validator is used.
-
-```cpp
-#undef JSON_USE_SIMDUTF
-```
-
-## Examples
-
-??? example
-
-    The code below enables the simdutf backend for UTF-8 validation.
-
-    ```cpp
-    #define JSON_USE_SIMDUTF 1
-    #include <nlohmann/json.hpp>
-
-    ...
-    ```
-
-    The project must also link against simdutf, e.g. with CMake:
-
-    ```cmake
-    target_compile_definitions(your_target PRIVATE JSON_USE_SIMDUTF)
-    target_link_libraries(your_target PRIVATE simdutf::simdutf)
-    ```
-
-!!! hint "Testing this configuration"
-
-    The unit tests can be built against the simdutf backend with the CMake option `JSON_TestSimdutf` (`OFF` by
-    default), which fetches simdutf and defines `JSON_USE_SIMDUTF` for every test target. The `ci_test_simdutf` target
-    runs the whole test suite in that configuration.
-
-## Version history
-
-- Added in version 3.13.0.

docs/mkdocs/docs/features/binary_formats/ubjson.md

@@ -69,13 +69,6 @@ The library uses the following mapping from JSON values types to UBJSON types ac
     Note that `use_size = true` alone may result in larger representations - the benefit of this parameter is that the
     receiving side is immediately informed on the number of elements of the container.
 
-    An array whose type marker is `Z` (null), `T` (true) or `F` (false) stores no payload at all, because the marker
-    already is the value. Its declared count is therefore the only thing that decides how much memory the receiving side
-    allocates, and a handful of bytes can describe billions of elements. `from_ubjson` rejects such an array with
-    [`out_of_range.408`](../../home/exceptions.md#jsonexceptionout_of_range408) when the count exceeds 1,048,576
-    (`1 << 20`), and `to_ubjson` writes longer arrays of these types without the annotation, so any value it produces
-    can be read back.
-
 !!! info "Binary values"
 
     If the JSON data contains the binary type, the value stored is a list of integers, as suggested by the UBJSON

docs/mkdocs/docs/features/macros.md

@@ -91,6 +91,14 @@ security reasons (e.g., Intel Software Guard Extensions (SGX)).
 
 See [full documentation of `JSON_NO_IO`](../api/macros/json_no_io.md).
 
+## `JSON_NO_THREAD_LOCAL`
+
+When defined, the library does not use `#!cpp thread_local` storage. Copying a value and comparing two values then
+always avoid the call stack rather than descending into a bounded number of levels first, which is slower but yields the
+same values and the same comparisons.
+
+See [full documentation of `JSON_NO_THREAD_LOCAL`](../api/macros/json_no_thread_local.md).
+
 ## `JSON_SKIP_LIBRARY_VERSION_CHECK`
 
 When defined, the library will not create a compiler warning when a different version of the library was already
@@ -137,14 +145,6 @@ behavior is deprecated and switched off (`0`) by default.
 
 See [full documentation of `JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../api/macros/json_use_legacy_discarded_value_comparison.md).
 
-## `JSON_USE_SIMDUTF`
-
-When defined, UTF-8 validation of JSON strings read from contiguous byte input is delegated to the
-[simdutf](https://github.com/simdutf/simdutf) library instead of the built-in scalar validator. This is an opt-in
-external dependency and is not defined by default.
-
-See [full documentation of `JSON_USE_SIMDUTF`](../api/macros/json_use_simdutf.md).
-
 ## `NLOHMANN_DEFINE_TYPE_*(...)`, `NLOHMANN_DEFINE_DERIVED_TYPE_*(...)`
 
 The library defines 12 macros to simplify the serialization/deserialization of types. See the page on

docs/mkdocs/docs/home/exceptions.md

@@ -868,12 +868,6 @@ The size of an array or object in a [binary format](../features/binary_formats/i
 the size following `#` for [UBJSON](../features/binary_formats/ubjson.md)/[BJData](../features/binary_formats/bjdata.md),
 or the encoded length for [CBOR](../features/binary_formats/cbor.md).
 
-The exception is also thrown for a [UBJSON](../features/binary_formats/ubjson.md) array of a type that is encoded by its
-marker alone (`Z`, `T` or `F`) whose declared count exceeds 1,048,576 (`1 << 20`). Such an array has no payload, so its
-count alone decides how much memory is allocated, and a handful of bytes would otherwise describe billions of values.
-[`to_ubjson`](../api/basic_json/to_ubjson.md) writes longer arrays of these types without the size and type annotation,
-so any value it produces can still be read back.
-
 !!! failure "Example messages"
 
     ```
@@ -885,9 +879,6 @@ so any value it produces can still be read back.
     ```
     [json.exception.out_of_range.408] syntax error while parsing CBOR size: excessive map size
     ```
-    ```
-    [json.exception.out_of_range.408] syntax error while parsing UBJSON size: excessive array size
-    ```
 
 ### json.exception.out_of_range.409
 

docs/mkdocs/mkdocs.yml

@@ -291,12 +291,12 @@ nav:
           - 'JSON_HAS_THREE_WAY_COMPARISON': api/macros/json_has_three_way_comparison.md
           - 'JSON_NOEXCEPTION': api/macros/json_noexception.md
           - 'JSON_NO_IO': api/macros/json_no_io.md
+          - 'JSON_NO_THREAD_LOCAL': api/macros/json_no_thread_local.md
           - 'JSON_SKIP_LIBRARY_VERSION_CHECK': api/macros/json_skip_library_version_check.md
           - 'JSON_SKIP_UNSUPPORTED_COMPILER_CHECK': api/macros/json_skip_unsupported_compiler_check.md
           - 'JSON_USE_GLOBAL_UDLS': api/macros/json_use_global_udls.md
           - 'JSON_USE_IMPLICIT_CONVERSIONS': api/macros/json_use_implicit_conversions.md
           - 'JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON': api/macros/json_use_legacy_discarded_value_comparison.md
-          - 'JSON_USE_SIMDUTF': api/macros/json_use_simdutf.md
           - 'NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_derived_type.md
           - 'NLOHMANN_DEFINE_TYPE_INTRUSIVE, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_type_intrusive.md
           - 'NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_type_non_intrusive.md

include/nlohmann/detail/input/input_adapters.hpp

@@ -155,31 +155,11 @@ class input_stream_adapter
 
 // General-purpose iterator-based adapter. It might not be as fast as
 // theoretically possible for some containers, but it is extremely versatile.
-// SentinelType defaults to IteratorType for backward compatibility, but may be
-// a different type, e.g. a C++20 sentinel such as std::default_sentinel_t when
-// IteratorType is a std::counted_iterator.
+// SentinelType defaults to IteratorType for backward compatibility, but may
+// be a different type (e.g., a C++20 sentinel or counted_iterator).
 template<typename IteratorType, typename SentinelType = IteratorType>
 class iterator_input_adapter
 {
-    // Whether the number of elements between two positions can be computed in
-    // O(1): either the iterator and the sentinel have the same type (plain
-    // std::distance) or, in C++20, the sentinel is a sized sentinel for the
-    // iterator (std::ranges::distance), e.g. std::default_sentinel_t paired
-    // with std::counted_iterator.
-    //
-    // JSON_HAS_RANGES gates the C++20 branch: on standard libraries with an
-    // incomplete <ranges> (libstdc++ < 11, see #4440) evaluating
-    // std::contiguous_iterator on a std::counted_iterator is a hard error
-    // instead of yielding false, and these traits are instantiated for every
-    // adapter. Such toolchains fall back to the pointer-only test and simply
-    // use the byte-at-a-time scanner.
-    static constexpr bool sentinel_is_sized =
-#if JSON_HAS_RANGES && defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
-        std::is_same<IteratorType, SentinelType>::value || std::sized_sentinel_for<SentinelType, IteratorType>;
-#else
-        std::is_same<IteratorType, SentinelType>::value;
-#endif
-
   public:
     using char_type = typename std::iterator_traits<IteratorType>::value_type;
 
@@ -191,7 +171,7 @@ class iterator_input_adapter
     // in wide_string_input_adapter, which does not expose this).
     static constexpr bool supports_seek =
         std::is_same<typename std::iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value
-        && sentinel_is_sized
+        && std::is_same<IteratorType, SentinelType>::value
         && sizeof(char_type) == 1;
 
     iterator_input_adapter(IteratorType first, SentinelType last)
@@ -239,60 +219,30 @@ class iterator_input_adapter
   private:
     // whether IteratorType refers to a contiguous range and therefore supports
     // a std::memcpy fast path (pointers always do; in C++20 we can also detect
-    // library iterators such as those of std::vector and std::string). The
-    // available element count must also be computable in O(1), hence
-    // sentinel_is_sized.
-    static constexpr bool iterator_is_contiguous = sentinel_is_sized &&
-#if JSON_HAS_RANGES && defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
-        (std::contiguous_iterator<IteratorType> || std::is_pointer<IteratorType>::value);
+    // library iterators such as those of std::vector and std::string).
+    // Computing the available element count needs either same-type iterators
+    // (plain std::distance) or, in C++20, a sized sentinel (std::ranges::distance),
+    // e.g. std::counted_iterator paired with std::default_sentinel_t.
+    static constexpr bool iterator_is_contiguous =
+#if defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
+        (std::is_same<IteratorType, SentinelType>::value || std::sized_sentinel_for<SentinelType, IteratorType>)
+        && (std::contiguous_iterator<IteratorType> || std::is_pointer<IteratorType>::value);
 #else
-        std::is_pointer<IteratorType>::value;
+        std::is_same<IteratorType, SentinelType>::value && std::is_pointer<IteratorType>::value;
 #endif
 
-    // number of unread elements in [current, end)
-    std::size_t remaining_count() const
-    {
-#if JSON_HAS_RANGES && defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
-        // std::ranges::distance also supports sized sentinels of a different
-        // type (e.g. std::counted_iterator + std::default_sentinel_t)
-        return static_cast<std::size_t>(std::ranges::distance(current, end));
-#else
-        return static_cast<std::size_t>(std::distance(current, end));
-#endif
-    }
-
-  public:
-    // Whether the remaining input is a single contiguous block of 1-byte
-    // elements that the lexer can inspect directly (used for the SWAR string
-    // fast path).
-    static constexpr bool supports_bulk_scan =
-        iterator_is_contiguous && sizeof(char_type) == 1;
-
-    // Pointer to the next unread element; only valid when bulk_remaining() > 0.
-    const char_type* bulk_data() const
-    {
-        return &*current;
-    }
-
-    // Number of unread elements available as one contiguous block.
-    std::size_t bulk_remaining() const
-    {
-        return remaining_count();
-    }
-
-    // Consume @a n elements previously inspected via bulk_data().
-    void bulk_skip(std::size_t n)
-    {
-        std::advance(current, static_cast<typename std::iterator_traits<IteratorType>::difference_type>(n));
-    }
-
-  private:
     // contiguous fast path: bulk copy the remaining range with std::memcpy
     template<class T>
     std::size_t get_elements_impl(T* dest, std::size_t count, std::true_type /*contiguous*/)
     {
         const std::size_t wanted = count * sizeof(T);
-        const std::size_t available = remaining_count() * sizeof(char_type);
+#if defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
+        // std::ranges::distance also supports sized sentinels of a different
+        // type (e.g. std::counted_iterator + std::default_sentinel_t)
+        const std::size_t available = static_cast<std::size_t>(std::ranges::distance(current, end)) * sizeof(char_type);
+#else
+        const std::size_t available = static_cast<std::size_t>(std::distance(current, end)) * sizeof(char_type);
+#endif
         const std::size_t copied = (std::min)(wanted, available);
         if (JSON_HEDLEY_LIKELY(copied != 0))
         {
@@ -620,46 +570,6 @@ typename iterator_input_adapter_factory<IteratorType, SentinelType>::adapter_typ
     return factory_type::create(first, last);
 }
 
-// The element type a container's data() points at, cv-qualifiers removed.
-// Ill-formed - and therefore SFINAE-friendly - for types without data().
-template<typename ContainerType>
-using container_data_t = typename std::remove_cv<typename std::remove_pointer <
-                         decltype(std::declval<const ContainerType&>().data()) >::type >::type;
-
-// The container's own element type, cv-qualifiers removed. It is looked up on
-// the bare type so it is also found when ContainerType is deduced as a
-// reference by the forwarding-reference overload below.
-template<typename ContainerType>
-using container_value_t = typename std::remove_cv <
-                          typename std::remove_cv<typename std::remove_reference<ContainerType>::type>::type::value_type >::type;
-
-// Detect a container that stores its elements contiguously as single bytes
-// (std::string, std::vector<char/unsigned char>, std::array<char, N>,
-// std::string_view, ...). Such inputs are wrapped in a pointer-based adapter so
-// they benefit from the contiguous fast paths (bulk string scanning, memcpy for
-// binary formats) in every C++ standard - not only in C++20, where the standard
-// library iterators model std::contiguous_iterator and are detected directly.
-//
-// data() and size() on their own would be duck typing: they say nothing about
-// size() counting the units data() points at, and reading [data(), data() +
-// size()) as bytes would be wrong for a type where it does not. Requiring the
-// container's own value_type to be that same single-byte element ties the two
-// together; every contiguous standard container satisfies it. Anything else
-// keeps the iterator-based adapter, which is always correct - only slower.
-template<typename ContainerType, typename = void>
-struct is_contiguous_byte_container : std::false_type {};
-
-template<typename ContainerType>
-struct is_contiguous_byte_container < ContainerType, void_t <
-    container_data_t<ContainerType>,
-    container_value_t<ContainerType>,
-decltype(std::declval<const ContainerType&>().size()) >>
-            : std::integral_constant < bool,
-        std::is_pointer<decltype(std::declval<const ContainerType&>().data())>::value&&
-        std::is_integral<container_data_t<ContainerType>>::value&&
-        sizeof(container_data_t<ContainerType>) == 1 &&
-        std::is_same<container_data_t<ContainerType>, container_value_t<ContainerType>>::value > {};
-
 // Convenience shorthand from container to iterator
 // Enables ADL on begin(container) and end(container)
 // Encloses the using declarations in namespace for not to leak them to outside scope
@@ -687,32 +597,12 @@ struct container_input_adapter_factory< ContainerType,
 
 }  // namespace container_input_adapter_factory_impl
 
-// General container path (iterator-based). Contiguous single-byte containers
-// are excluded here and routed through the pointer-based overload below.
-template < typename ContainerType,
-           enable_if_t < !is_contiguous_byte_container<ContainerType>::value, int > = 0 >
-typename container_input_adapter_factory_impl::container_input_adapter_factory<ContainerType>::adapter_type input_adapter(ContainerType && container)
+template<typename ContainerType>
+typename container_input_adapter_factory_impl::container_input_adapter_factory<ContainerType>::adapter_type input_adapter(ContainerType&& container)
 {
     return container_input_adapter_factory_impl::container_input_adapter_factory<ContainerType>::create(std::forward<ContainerType>(container));
 }
 
-// Contiguous single-byte containers (std::string, std::vector<char>, ...) are
-// wrapped in a pointer-based adapter so the contiguous fast paths apply in every
-// standard. The pointer keeps the container's own element type (const char* for
-// std::string, const std::uint8_t* for std::vector<std::uint8_t>, ...), so the
-// resulting char_type - and therefore the parsing behavior - is byte-for-byte
-// identical to the iterator-based path; only the raw pointer additionally
-// enables the bulk fast paths. The container outlives the adapter for the whole
-// parse (temporaries live until the end of the full expression), exactly as the
-// iterators it replaces did.
-template < typename ContainerType,
-           enable_if_t < is_contiguous_byte_container<ContainerType>::value, int > = 0 >
-auto input_adapter(const ContainerType& container)
--> decltype(input_adapter(container.data(), container.data() + container.size()))
-{
-    return input_adapter(container.data(), container.data() + container.size());
-}
-
 // specialization for std::string
 using string_input_adapter_type = decltype(input_adapter(std::declval<std::string>()));
 

include/nlohmann/detail/input/json_sax.hpp

@@ -222,16 +222,12 @@ class json_sax_dom_parser
 
     bool string(string_t& val)
     {
-        // json_sax documents that the passed value may be moved from,
-        // so hand the buffer over instead of copying it
-        handle_value(std::move(val));
+        handle_value(val);
         return true;
     }
 
     bool binary(binary_t& val)
     {
-        // json_sax documents that the passed value may be moved from,
-        // so hand the buffer over instead of copying it
         handle_value(std::move(val));
         return true;
     }
@@ -536,16 +532,12 @@ class json_sax_dom_callback_parser
 
     bool string(string_t& val)
     {
-        // json_sax documents that the passed value may be moved from,
-        // so hand the buffer over instead of copying it
-        handle_value(std::move(val));
+        handle_value(val);
         return true;
     }
 
     bool binary(binary_t& val)
     {
-        // json_sax documents that the passed value may be moved from,
-        // so hand the buffer over instead of copying it
         handle_value(std::move(val));
         return true;
     }
@@ -556,11 +548,6 @@ class json_sax_dom_callback_parser
         const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::object_start, discarded);
         keep_stack.push_back(keep);
 
-        // the key this object will be stored under, read before handle_value()
-        // may consume it; kept in lockstep with ref_stack so end_object() can
-        // find the object in its parent again
-        container_key_stack.push_back(current_key());
-
         auto val = handle_value(BasicJsonType::value_t::object, true);
         ref_stack.push_back(val.second);
 
@@ -594,9 +581,6 @@ class json_sax_dom_callback_parser
         // check callback for the key
         const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::key, k);
         key_keep_stack.push_back(keep);
-        // remember the key so a rejected value can be erased without searching
-        // the object for it (kept in lockstep with key_keep_stack)
-        key_stack.push_back(val);
 
         // add discarded value at the given key and store the reference for later
         if (keep && ref_stack.back())
@@ -638,16 +622,13 @@ class json_sax_dom_callback_parser
 
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(!keep_stack.empty());
-        JSON_ASSERT(!container_key_stack.empty());
         ref_stack.pop_back();
         keep_stack.pop_back();
-        const string_t object_key = std::move(container_key_stack.back());
-        container_key_stack.pop_back();
 
         if (!ref_stack.empty() && ref_stack.back() && ref_stack.back()->is_structured())
         {
             // remove discarded value
-            remove_discarded_value(*ref_stack.back(), object_key);
+            remove_discarded_value(*ref_stack.back());
         }
 
         return true;
@@ -658,9 +639,6 @@ class json_sax_dom_callback_parser
         const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::array_start, discarded);
         keep_stack.push_back(keep);
 
-        // see start_object()
-        container_key_stack.push_back(current_key());
-
         auto val = handle_value(BasicJsonType::value_t::array, true);
         ref_stack.push_back(val.second);
 
@@ -723,11 +701,8 @@ class json_sax_dom_callback_parser
 
         JSON_ASSERT(!ref_stack.empty());
         JSON_ASSERT(!keep_stack.empty());
-        JSON_ASSERT(!container_key_stack.empty());
         ref_stack.pop_back();
         keep_stack.pop_back();
-        const string_t object_key = std::move(container_key_stack.back());
-        container_key_stack.pop_back();
 
         // remove discarded value
         if (!ref_stack.empty() && ref_stack.back())
@@ -741,7 +716,7 @@ class json_sax_dom_callback_parser
                 // the array is either still stored under its key or was never
                 // stored, leaving the placeholder key() wrote; both show up as
                 // a discarded member of the parent object
-                remove_discarded_value(*ref_stack.back(), object_key);
+                remove_discarded_value(*ref_stack.back());
             }
         }
 
@@ -834,56 +809,15 @@ class json_sax_dom_callback_parser
     }
 #endif
 
-    /*!
-    @brief the key the value now being handled will be stored under
-
-    Empty unless the enclosing container is an object, in which case it is the
-    key of the pending key() event. Read before handle_value() consumes that
-    key, so it is also correct when the value never reaches its parent.
-    */
-    string_t current_key() const
+    /// remove the discarded value the callback rejected from its parent
+    static void remove_discarded_value(BasicJsonType& parent)
     {
-        if (!ref_stack.empty() && ref_stack.back() && ref_stack.back()->is_object()
-                && !key_stack.empty())
+        for (auto it = parent.begin(); it != parent.end(); ++it)
         {
-            return key_stack.back();
-        }
-        return string_t{};
-    }
-
-    /*!
-    @brief remove the discarded value the callback rejected from its parent
-
-    A rejected value can only ever be the one most recently added to @a parent:
-    the last element of an array, or the placeholder key() stored under @a key
-    in an object. Looking there directly makes this O(1) resp. O(log n), where
-    searching @a parent for it made a filtering parse quadratic in the number of
-    members of a single container.
-
-    Finding no discarded value there means none was stored in the first place -
-    the callback rejected the value before it reached its parent - so there is
-    nothing to remove.
-
-    @param[in,out] parent  the container to remove the rejected value from
-    @param[in] key  the key the value was stored under; unused for arrays
-    */
-    static void remove_discarded_value(BasicJsonType& parent, const string_t& key)
+            if (it->is_discarded())
             {
-        if (parent.is_array())
-        {
-            auto& array = *parent.m_data.m_value.array;
-            if (!array.empty() && array.back().is_discarded())
-            {
-                array.pop_back();
-            }
-        }
-        else if (parent.is_object())
-        {
-            auto& object = *parent.m_data.m_value.object;
-            const auto it = object.find(key);
-            if (it != object.end() && it->second.is_discarded())
-            {
-                object.erase(it);
+                parent.erase(it);
+                break;
             }
         }
     }
@@ -933,14 +867,11 @@ class json_sax_dom_callback_parser
             if (!ref_stack.empty() && ref_stack.back() && ref_stack.back()->is_object())
             {
                 JSON_ASSERT(!key_keep_stack.empty());
-                JSON_ASSERT(!key_stack.empty());
                 const bool placeholder_stored = key_keep_stack.back();
                 key_keep_stack.pop_back();
-                const string_t key = std::move(key_stack.back());
-                key_stack.pop_back();
                 if (placeholder_stored)
                 {
-                    remove_discarded_value(*ref_stack.back(), key);
+                    remove_discarded_value(*ref_stack.back());
                 }
             }
             return {false, nullptr};
@@ -973,10 +904,8 @@ class json_sax_dom_callback_parser
         JSON_ASSERT(ref_stack.back()->is_object());
         // check if we should store an element for the current key
         JSON_ASSERT(!key_keep_stack.empty());
-        JSON_ASSERT(!key_stack.empty());
         const bool store_element = key_keep_stack.back();
         key_keep_stack.pop_back();
-        key_stack.pop_back();
 
         if (!store_element)
         {
@@ -996,12 +925,6 @@ class json_sax_dom_callback_parser
     std::vector<bool> keep_stack {}; // NOLINT(readability-redundant-member-init)
     /// stack to manage which object keys to keep
     std::vector<bool> key_keep_stack {}; // NOLINT(readability-redundant-member-init)
-    /// the keys key() stored a placeholder for, in lockstep with key_keep_stack
-    std::vector<string_t> key_stack {}; // NOLINT(readability-redundant-member-init)
-    /// for each open container, the key it is stored under in its parent
-    /// object, in lockstep with ref_stack; unused where the parent is not an
-    /// object
-    std::vector<string_t> container_key_stack {}; // NOLINT(readability-redundant-member-init)
     /// helper to hold the reference for the next object element
     BasicJsonType* object_element = nullptr;
     /// whether a syntax error occurred

include/nlohmann/detail/input/lexer.hpp

@@ -19,9 +19,7 @@
 #include <vector> // vector
 
 #include <nlohmann/detail/input/input_adapters.hpp>
-#include <nlohmann/detail/input/number_parse.hpp>
 #include <nlohmann/detail/input/position_t.hpp>
-#include <nlohmann/detail/input/string_scan.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>
 
@@ -127,25 +125,6 @@ constexpr bool input_adapter_supports_seek(std::false_type /*detected*/)
     return false;
 }
 
-// Detect whether an input adapter exposes a contiguous byte block that the
-// lexer can scan directly (see iterator_input_adapter::supports_bulk_scan).
-// Adapters without the flag - file, stream, wide-string, user-defined - fall
-// back to the character-at-a-time string scanner.
-template<typename InputAdapterType>
-using detect_supports_bulk_scan = decltype(InputAdapterType::supports_bulk_scan);
-
-template<typename InputAdapterType>
-constexpr bool input_adapter_supports_bulk_scan(std::true_type /*detected*/)
-{
-    return InputAdapterType::supports_bulk_scan;
-}
-
-template<typename InputAdapterType>
-constexpr bool input_adapter_supports_bulk_scan(std::false_type /*detected*/)
-{
-    return false;
-}
-
 /*!
 @brief lexical analysis
 
@@ -167,14 +146,6 @@ class lexer : public lexer_base<BasicJsonType>
     static constexpr bool lazy_token_string =
         input_adapter_supports_seek<InputAdapterType>(is_detected<detect_supports_seek, InputAdapterType> {});
 
-    /// whether string scanning may bulk-consume runs of ordinary characters
-    /// directly from a contiguous input buffer (SWAR fast path). This requires
-    /// the token to be reconstructible lazily (lazy_token_string), so bypassing
-    /// the per-character capture in get() cannot lose error diagnostics.
-    static constexpr bool bulk_scan =
-        lazy_token_string
-        && input_adapter_supports_bulk_scan<InputAdapterType>(is_detected<detect_supports_bulk_scan, InputAdapterType> {});
-
   public:
     using token_type = typename lexer_base<BasicJsonType>::token_type;
 
@@ -295,40 +266,6 @@ class lexer : public lexer_base<BasicJsonType>
         return true;
     }
 
-    /// contiguous input: bulk-append the run of ordinary characters and complete
-    /// well-formed UTF-8 sequences starting at the current read position, leaving
-    /// the first byte that needs individual handling (the closing quote, an
-    /// escape, a control character, or an ill-formed UTF-8 byte) for get()
-    void scan_string_bulk(std::true_type /*bulk*/)
-    {
-        // a pending unget must be consumed through the normal path first
-        if (next_unget)
-        {
-            return;
-        }
-        const std::size_t remaining = ia.bulk_remaining();
-        if (remaining == 0)
-        {
-            return;
-        }
-        const auto* const data = reinterpret_cast<const unsigned char*>(ia.bulk_data());
-
-        const std::size_t pos = string_bulk_run(data, remaining);
-        if (pos == 0)
-        {
-            return;
-        }
-        token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(data), pos);
-        ia.bulk_skip(pos);
-        // the run contains no newline (all bytes < 0x20 are treated as special),
-        // so only the flat character counters advance
-        position.chars_read_total += pos;
-        position.chars_read_current_line += pos;
-    }
-
-    /// streaming input: no bulk fast path
-    void scan_string_bulk(std::false_type /*bulk*/) const noexcept {}
-
     /*!
     @brief scan a string literal
 
@@ -354,10 +291,6 @@ class lexer : public lexer_base<BasicJsonType>
 
         while (true)
         {
-            // bulk-consume ordinary characters from contiguous input, then
-            // handle the next special byte through the switch below
-            scan_string_bulk(std::integral_constant<bool, bulk_scan> {});
-
             // get the next character
             switch (get())
             {
@@ -1076,12 +1009,6 @@ class lexer : public lexer_base<BasicJsonType>
         // changed if minus sign, decimal point, or exponent is read
         token_type number_type = token_type::value_unsigned;
 
-        // offset just past the last mantissa byte in token_buffer (i.e. the
-        // index of 'e'/'E', or the whole token when there is no exponent).
-        // convert_number() uses it to count significant digits; npos means
-        // "not seen an exponent yet" and is resolved at scan_number_done
-        std::size_t mantissa_end = std::string::npos;
-
         // state (init): we just found out we need to scan a number
         switch (current)
         {
@@ -1267,9 +1194,6 @@ scan_number_decimal2:
 scan_number_exponent:
         // we just parsed an exponent
         number_type = token_type::value_float;
-        // this label is reached only right after the 'e'/'E' was appended (from
-        // the zero, any1, and decimal2 states), so the mantissa ends before it
-        mantissa_end = token_buffer.size() - 1;
         switch (get())
         {
             case '+':
@@ -1356,116 +1280,6 @@ scan_number_done:
         // we are done scanning a number)
         unget();
 
-        // no exponent was scanned: the mantissa spans the whole token
-        if (mantissa_end == std::string::npos)
-        {
-            mantissa_end = token_buffer.size();
-        }
-
-        return convert_number(number_type, mantissa_end);
-    }
-
-    /*!
-    @brief convert an already-validated integer token to its value
-
-    The digit sequence in [first, last) has been validated by the caller, so a
-    dedicated parser can avoid the locale/errno overhead of std::strtoull.
-
-    @return the token type on success; token_type::uninitialized if @a
-            number_type is not an integer type or the value does not fit, in
-            which case the caller falls back to the floating-point conversion
-            (matching the previous std::strtoull/std::strtoll behavior)
-    */
-    token_type convert_integer(token_type number_type, const char* first, const char* last)
-    {
-        if (number_type == token_type::value_unsigned)
-        {
-            if (parse_integer_unsigned(first, last, value_unsigned))
-            {
-                return token_type::value_unsigned;
-            }
-        }
-        else if (number_type == token_type::value_integer)
-        {
-            if (parse_integer_signed(first, last, value_integer))
-            {
-                return token_type::value_integer;
-            }
-        }
-
-        return token_type::uninitialized;
-    }
-
-    /*!
-    @brief check whether Clinger's fast path can still succeed for this token
-
-    parse_float_fast() needs a significand below 2^53. A mantissa with 17 or
-    more significant digits is at least 10^16 and therefore always exceeds it,
-    so calling the fast path would walk the token one extra time only to
-    decline before strtod has to run anyway.
-
-    Significant digits are the mantissa's digits from the first nonzero one on;
-    the sign, the decimal point, leading zeros, and the exponent do not count.
-    The answer is derived from indices - the digits are not scanned again - so
-    this stays off the hot path of the number scanners.
-
-    @param[in] mantissa_end  offset just past the last mantissa byte in
-                             token_buffer
-    @return false if parse_float_fast() is guaranteed to decline
-    */
-    bool mantissa_fits_clinger(std::size_t mantissa_end) const
-    {
-        // 10^16 already exceeds 2^53, so 17 digits can never fit
-        constexpr std::size_t limit = 17;
-
-        const std::size_t neg = (!token_buffer.empty() && token_buffer[0] == '-') ? 1u : 0u;
-        const std::size_t has_dot = (decimal_point_position != std::string::npos) ? 1u : 0u;
-        // the JSON grammar restricts the integer part to "0" or [1-9][0-9]*, so
-        // a leading zero can only be a lone "0", which is not significant
-        const std::size_t lead_zero = (token_buffer[neg] == '0') ? 1u : 0u;
-        JSON_ASSERT(mantissa_end >= neg + has_dot + lead_zero);
-        std::size_t digits = mantissa_end - neg - has_dot - lead_zero;
-
-        if (JSON_HEDLEY_LIKELY(digits < limit))
-        {
-            return true;
-        }
-
-        // Only a number below 1 can carry further insignificant zeros, and only
-        // while the count stays at the limit does removing them change the
-        // answer - so this loop is skipped for all but a few tokens. Note
-        // token_buffer holds the locale's decimal point, so the fraction is
-        // located through decimal_point_position rather than by searching '.'.
-        if (lead_zero != 0)
-        {
-            JSON_ASSERT(has_dot != 0); // an integer "0" cannot reach the limit
-            for (std::size_t i = decimal_point_position + 1;
-                    digits >= limit && i < mantissa_end && token_buffer[i] == '0'; ++i)
-            {
-                --digits;
-            }
-        }
-
-        return digits < limit;
-    }
-
-    /*!
-    @brief convert the number text in token_buffer to its value and token type
-
-    The digit sequence in token_buffer has already been validated (by the
-    scan_number() state machine or by the contiguous fast path) and holds the
-    locale decimal point in place of '.'. Integers are parsed first and fall
-    back to floating point on overflow. This is shared so both scanners produce
-    identical results.
-
-    @param[in] mantissa_end  offset just past the last mantissa byte in
-                             token_buffer (the index of 'e'/'E', or
-                             token_buffer.size() when there is no exponent);
-                             used to skip Clinger's fast path when it cannot
-                             possibly succeed - see mantissa_fits_clinger()
-    */
-    token_type convert_number(token_type number_type, std::size_t mantissa_end)
-    {
         // If the caller does not need the converted value (only whether the
         // input is syntactically valid; see json_sax_acceptor/accept()), an
         // unsigned/integer token can be reported without calling
@@ -1518,37 +1332,45 @@ scan_number_done:
             }
         }
 
-        const char* const num_begin = token_buffer.data();
-        const char* const num_end = num_begin + token_buffer.size();
+        char* endptr = nullptr; // NOLINT(misc-const-correctness,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        errno = 0;
 
-        if (number_type != token_type::value_float)
+        // try to parse integers first and fall back to floats
+        if (number_type == token_type::value_unsigned)
         {
-            const token_type integer_result = convert_integer(number_type, num_begin, num_end);
-            if (integer_result != token_type::uninitialized)
+            const auto x = std::strtoull(token_buffer.data(), &endptr, 10);
+
+            // we checked the number format before
+            JSON_ASSERT(endptr == token_buffer.data() + token_buffer.size());
+
+            if (errno != ERANGE)
             {
-                return integer_result;
+                value_unsigned = static_cast<number_unsigned_t>(x);
+                if (value_unsigned == x)
+                {
+                    return token_type::value_unsigned;
+                }
+            }
+        }
+        else if (number_type == token_type::value_integer)
+        {
+            const auto x = std::strtoll(token_buffer.data(), &endptr, 10);
+
+            // we checked the number format before
+            JSON_ASSERT(endptr == token_buffer.data() + token_buffer.size());
+
+            if (errno != ERANGE)
+            {
+                value_integer = static_cast<number_integer_t>(x);
+                if (value_integer == x)
+                {
+                    return token_type::value_integer;
+                }
             }
         }
 
         // this code is reached if we parse a floating-point number or if an
-        // integer conversion above overflowed. Prefer std::from_chars
-        // (Eisel-Lemire, locale-independent, correctly rounded) when available;
-        // otherwise the exact Clinger fast path (double only); otherwise the
-        // locale-aware strtof/strtod.
-        if (parse_float_from_chars(num_begin, num_end, value_float))
-        {
-            return token_type::value_float;
-        }
-        // Skipping a fast path that cannot succeed is lossless and saves a full
-        // extra pass over the token's bytes, which otherwise shows up on
-        // high-precision inputs such as canada.json
-        if (mantissa_fits_clinger(mantissa_end)
-                && parse_float_fast(num_begin, num_end, decimal_point_char, value_float))
-        {
-            return token_type::value_float;
-        }
-
-        char* endptr = nullptr; // NOLINT(misc-const-correctness,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        // integer conversion above failed
         strtof(value_float, token_buffer.data(), &endptr);
 
         // we checked the number format before
@@ -1557,158 +1379,6 @@ scan_number_done:
         return token_type::value_float;
     }
 
-    /*!
-    @brief contiguous fast path for scanning a number
-
-    Parses the whole number token straight from the input buffer, avoiding the
-    per-character get()/add() of scan_number(). On success it fills token_buffer
-    (with the locale decimal point substituted, as scan_number() does) and
-    returns the token type. On anything it does not fully recognize as a
-    well-formed number it makes no state change and returns
-    token_type::uninitialized, so the caller falls back to scan_number(), which
-    then produces the exact diagnostic. @a current is the first digit or the
-    leading minus (already read); the remaining bytes are taken from the adapter.
-    */
-    token_type scan_number_bulk_contiguous()
-    {
-        // a pending unget offsets the buffer position from current; fall back
-        if (next_unget)
-        {
-            return token_type::uninitialized;
-        }
-        const std::size_t rem = ia.bulk_remaining();
-        if (rem == 0)
-        {
-            // the first digit is the last input byte; let scan_number() finish
-            return token_type::uninitialized;
-        }
-        // the byte before the next unread one is current (contiguous input)
-        const char* const data = reinterpret_cast<const char*>(ia.bulk_data()) - 1;
-        const std::size_t avail = rem + 1;
-
-        // validate + classify the number extent (mirrors scan_number()'s grammar)
-        std::size_t i = 0;
-        std::size_t dot_index = std::string::npos;
-        token_type number_type = token_type::value_unsigned;
-        if (data[0] == '-')
-        {
-            number_type = token_type::value_integer;
-            i = 1;
-            if (i >= avail)
-            {
-                return token_type::uninitialized;
-            }
-        }
-        if (data[i] == '0')
-        {
-            ++i;
-        }
-        else if (data[i] >= '1' && data[i] <= '9')
-        {
-            ++i;
-            while (i < avail && data[i] >= '0' && data[i] <= '9')
-            {
-                ++i;
-            }
-        }
-        else
-        {
-            return token_type::uninitialized;
-        }
-        if (i < avail && data[i] == '.')
-        {
-            number_type = token_type::value_float;
-            dot_index = i;
-            ++i;
-            if (i >= avail || !(data[i] >= '0' && data[i] <= '9'))
-            {
-                return token_type::uninitialized;
-            }
-            while (i < avail && data[i] >= '0' && data[i] <= '9')
-            {
-                ++i;
-            }
-        }
-        // the mantissa ends here, whether or not an exponent part follows
-        const std::size_t mantissa_end = i;
-        if (i < avail && (data[i] == 'e' || data[i] == 'E'))
-        {
-            number_type = token_type::value_float;
-            ++i;
-            if (i < avail && (data[i] == '+' || data[i] == '-'))
-            {
-                ++i;
-            }
-            if (i >= avail || !(data[i] >= '0' && data[i] <= '9'))
-            {
-                return token_type::uninitialized;
-            }
-            while (i < avail && data[i] >= '0' && data[i] <= '9')
-            {
-                ++i;
-            }
-        }
-        const std::size_t len = i;
-
-        // reset() records where this token starts (for diagnostics), so it has
-        // to run before the input position advances below
-        reset();
-
-        // An integer token needs no token_buffer: the SAX callbacks for
-        // number_integer/number_unsigned take only the value, and the overflow
-        // diagnostic rebuilds the text from the input. Convert straight from the
-        // input buffer and leave token_buffer empty. (JSON_DIAGNOSTIC_POSITIONS
-        // derives a number's start position from get_string().size(), so there
-        // the token still has to be materialized.)
-#if !JSON_DIAGNOSTIC_POSITIONS
-        if (number_type != token_type::value_float)
-        {
-            const token_type integer_result = convert_integer(number_type, data, data + len);
-            if (JSON_HEDLEY_LIKELY(integer_result != token_type::uninitialized))
-            {
-                ia.bulk_skip(len - 1);
-                position.chars_read_total += (len - 1);
-                position.chars_read_current_line += (len - 1);
-                return integer_result;
-            }
-            // The value does not fit an integer, so this token converts as a
-            // float. Recording that here keeps convert_number() below from
-            // repeating the integer attempt that just failed.
-            number_type = token_type::value_float;
-        }
-#endif
-
-        // materialize the token exactly as scan_number() would, substituting the
-        // locale decimal point so convert_number()'s strtof fallback stays valid.
-        // reset() already cleared token_buffer, so append() fills it (assign() is
-        // avoided because custom string_t types need not provide it)
-        token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(data), len);
-        if (dot_index != std::string::npos)
-        {
-            token_buffer[dot_index] = static_cast<typename string_t::value_type>(decimal_point_char);
-            decimal_point_position = dot_index;
-        }
-
-        ia.bulk_skip(len - 1);
-        position.chars_read_total += (len - 1);
-        position.chars_read_current_line += (len - 1);
-
-        return convert_number(number_type, mantissa_end);
-    }
-
-    /// contiguous input: try the number fast path, else the byte-path scanner
-    token_type scan_number_dispatch(std::true_type /*bulk*/)
-    {
-        const token_type t = scan_number_bulk_contiguous();
-        return (t != token_type::uninitialized) ? t : scan_number();
-    }
-
-    /// streaming input: always use the byte-path scanner
-    token_type scan_number_dispatch(std::false_type /*bulk*/)
-    {
-        return scan_number();
-    }
-
     /*!
     @param[in] literal_text  the literal text to expect
     @param[in] length        the length of the passed literal text
@@ -1812,9 +1482,6 @@ scan_number_done:
         if (current == '\n')
         {
             ++position.lines_read;
-            // remember the column the newline was read at: chars_read_current_line
-            // is about to be cleared, and a matching unget() cannot reconstruct it
-            chars_read_before_newline = position.chars_read_current_line;
             position.chars_read_current_line = 0;
         }
 
@@ -1871,20 +1538,12 @@ scan_number_done:
         --position.chars_read_total;
 
         // in case we "unget" a newline, we have to also decrement the lines_read
-        // and restore the column that get() cleared when it saw the newline;
-        // chars_read_current_line == 0 can only mean the last get() read one
         if (position.chars_read_current_line == 0)
         {
             if (position.lines_read > 0)
             {
                 --position.lines_read;
             }
-
-            // chars_read_before_newline counts the newline itself, which is the
-            // character being ungotten, hence the -1
-            position.chars_read_current_line = (chars_read_before_newline > 0)
-                                               ? chars_read_before_newline - 1
-                                               : 0;
         }
         else
         {
@@ -2151,7 +1810,7 @@ scan_number_done:
             case '7':
             case '8':
             case '9':
-                return scan_number_dispatch(std::integral_constant<bool, bulk_scan> {});
+                return scan_number();
 
             // end of input (the null byte is needed when parsing from
             // string literals)
@@ -2182,10 +1841,6 @@ scan_number_done:
     /// the start position of the current token
     position_t position {};
 
-    /// the value chars_read_current_line had when the last newline was read, so
-    /// that unget() can restore the column instead of leaving it at 0
-    std::size_t chars_read_before_newline = 0;
-
     /// raw input token string for error messages; only populated for streaming
     /// adapters (seekable adapters reconstruct it lazily via token_string_start)
     std::vector<char_type> token_string {};

include/nlohmann/detail/input/number_parse.hpp

@@ -1,302 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#pragma once
-
-#include <array> // array
-#include <cfloat> // FLT_EVAL_METHOD
-#include <cstddef> // size_t
-#include <cstdint> // int64_t, uint64_t
-#include <limits> // numeric_limits
-
-#include <nlohmann/detail/macro_scope.hpp>
-
-// std::from_chars lives in <charconv>, but being in C++17 mode does not
-// guarantee the header exists: GCC 7 sets __cplusplus to C++17 yet ships no
-// <charconv> (added in GCC 8; floating-point support in GCC 11). Guard the
-// include with __has_include so such toolchains fall back to the scalar path.
-#if defined(JSON_HAS_CPP_17) && defined(__has_include)
-    #if __has_include(<charconv>)
-        #include <charconv> // from_chars (only used when __cpp_lib_to_chars is defined)
-        #include <system_error> // errc
-    #endif
-#endif
-
-// This file contains the value-conversion helpers used by the lexer to turn an
-// already-validated number token into a value, without the locale/errno
-// overhead of std::strtoull/std::strtod. They are free functions so the lexer
-// stays focused on scanning; see lexer::convert_number().
-
-NLOHMANN_JSON_NAMESPACE_BEGIN
-namespace detail
-{
-
-/*!
-@brief fast integer parser for an already-validated unsigned integer
-
-The number scanner has already checked that [first, last) is a valid JSON
-integer, so this only needs to accumulate the digits and detect overflow. This
-avoids the locale/errno machinery of std::strtoull, which dominates
-integer-heavy inputs.
-
-@param[in]  first   pointer to the first character (a digit)
-@param[in]  last    pointer past the last character
-@param[out] value   the parsed value on success
-@return true if the value fit into @a NumberUnsignedType; false on overflow, in
-        which case the caller falls back to floating-point parsing (matching the
-        previous std::strtoull behavior)
-*/
-template<typename NumberUnsignedType>
-bool parse_integer_unsigned(const char* first, const char* last, NumberUnsignedType& value) noexcept
-{
-    // accumulate in the widest unsigned type used by the previous strtoull
-    // path so the overflow behavior is unchanged for custom number types
-    std::uint64_t x = 0;
-    constexpr std::uint64_t cutoff = (std::numeric_limits<std::uint64_t>::max)() / 10u;
-    constexpr std::uint64_t cutlim = (std::numeric_limits<std::uint64_t>::max)() % 10u;
-    for (const char* p = first; p != last; ++p)
-    {
-        const auto digit = static_cast<std::uint64_t>(static_cast<unsigned char>(*p) - static_cast<unsigned char>('0'));
-        if (JSON_HEDLEY_UNLIKELY(x > cutoff || (x == cutoff && digit > cutlim)))
-        {
-            return false;
-        }
-        x = (x * 10u) + digit;
-    }
-    value = static_cast<NumberUnsignedType>(x);
-    // reject values that do not round-trip into a narrower NumberUnsignedType
-    return static_cast<std::uint64_t>(value) == x;
-}
-
-/*!
-@brief fast integer parser for an already-validated negative integer
-
-@param[in]  first   pointer to the leading '-'
-@param[in]  last    pointer past the last character
-@param[out] value   the parsed (negative) value on success
-@return true on success; false on overflow (caller falls back to float)
-*/
-template<typename NumberIntegerType>
-bool parse_integer_signed(const char* first, const char* last, NumberIntegerType& value) noexcept
-{
-    // the state machine only reaches the signed path via a leading '-'
-    JSON_ASSERT(first != last && *first == '-');
-    std::uint64_t magnitude = 0;
-    // |INT64_MIN| == INT64_MAX + 1; this is the largest admissible magnitude
-    constexpr std::uint64_t limit = static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()) + 1u;
-    for (const char* p = first + 1; p != last; ++p)
-    {
-        const auto digit = static_cast<std::uint64_t>(static_cast<unsigned char>(*p) - static_cast<unsigned char>('0'));
-        if (JSON_HEDLEY_UNLIKELY(magnitude > (limit - digit) / 10u))
-        {
-            return false;
-        }
-        magnitude = (magnitude * 10u) + digit;
-    }
-    const std::int64_t x = (magnitude == limit)
-                           ? (std::numeric_limits<std::int64_t>::min)()
-                           : -static_cast<std::int64_t>(magnitude);
-    value = static_cast<NumberIntegerType>(x);
-    // reject values that do not round-trip into a narrower NumberIntegerType
-    return static_cast<std::int64_t>(value) == x;
-}
-
-/*!
-@brief exact fast path for parsing a `double` (Clinger's algorithm)
-
-For the common case - at most 19 significant digits, a decimal exponent in
-[-22, 22], and a significand below 2^53 - the value equals significand *
-10^exp computed in IEEE-754 double arithmetic, which is exact under
-round-to-nearest because both operands are exactly representable. This is the
-same fast path used by fast_float/simdjson; the general cases are left to
-std::strtod. The parser only activates for number_float_t == double; float and
-long double keep the std::strtof/std::strtold paths (see the templated overload
-below).
-
-@param[in]  first          pointer to the first character of the number
-@param[in]  last           pointer past the last character
-@param[in]  decimal_point  the (locale-dependent) decimal point character
-@param[out] out            the parsed value on success
-@return true if the value was parsed exactly; false to fall back to strtod
-*/
-template<typename DecimalPointType>
-bool parse_float_fast(const char* first, const char* last, DecimalPointType decimal_point, double& out) noexcept
-{
-#if defined(FLT_EVAL_METHOD) && FLT_EVAL_METHOD != 0
-    // Clinger's fast path is only exact when double operations are evaluated in
-    // true double precision. On platforms that keep intermediates in extended
-    // precision (e.g. the x87 FPU on 32-bit x86, where FLT_EVAL_METHOD == 2) the
-    // single significand * 10^scale step is double-rounded and can be 1 ULP off,
-    // so decline and let the caller fall back to the correctly-rounded
-    // std::from_chars / std::strtod path.
-    static_cast<void>(first);
-    static_cast<void>(last);
-    static_cast<void>(decimal_point);
-    static_cast<void>(out);
-    return false;
-#else
-    static const std::array<double, 23> powers_of_ten =
-    {
-        {
-            1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10, 1e11,
-            1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, 1e20, 1e21, 1e22
-        }
-    };
-
-    const char* p = first;
-    bool negative = false;
-    if (p != last && (*p == '-' || *p == '+'))
-    {
-        negative = (*p == '-');
-        ++p;
-    }
-
-    std::uint64_t significand = 0;
-    int num_digits = 0;
-    int fractional_digits = 0;
-    bool seen_dot = false;
-    bool any_digit = false;
-    for (; p != last; ++p)
-    {
-        const char c = *p;
-        if (c >= '0' && c <= '9')
-        {
-            any_digit = true;
-            if (JSON_HEDLEY_UNLIKELY(num_digits >= 19))
-            {
-                return false; // significand may not fit into uint64_t
-            }
-            significand = (significand * 10u) + static_cast<std::uint64_t>(c - '0');
-            ++num_digits;
-            fractional_digits += static_cast<int>(seen_dot);
-        }
-        else if (static_cast<DecimalPointType>(c) == decimal_point)
-        {
-            if (JSON_HEDLEY_UNLIKELY(seen_dot))
-            {
-                return false;
-            }
-            seen_dot = true;
-        }
-        else if (c == 'e' || c == 'E')
-        {
-            ++p;
-            break;
-        }
-        else
-        {
-            return false;
-        }
-    }
-    if (JSON_HEDLEY_UNLIKELY(!any_digit))
-    {
-        return false;
-    }
-
-    int exponent = 0;
-    if (p != last) // an exponent part remains
-    {
-        bool exp_negative = false;
-        if (p != last && (*p == '-' || *p == '+'))
-        {
-            exp_negative = (*p == '-');
-            ++p;
-        }
-        bool any_exp_digit = false;
-        for (; p != last; ++p)
-        {
-            if (JSON_HEDLEY_UNLIKELY(*p < '0' || *p > '9'))
-            {
-                return false;
-            }
-            exponent = (exponent * 10) + (*p - '0');
-            any_exp_digit = true;
-            if (JSON_HEDLEY_UNLIKELY(exponent > 9999))
-            {
-                return false;
-            }
-        }
-        if (JSON_HEDLEY_UNLIKELY(!any_exp_digit))
-        {
-            return false;
-        }
-        if (exp_negative)
-        {
-            exponent = -exponent;
-        }
-    }
-
-    const int scale = exponent - fractional_digits;
-    if (JSON_HEDLEY_UNLIKELY(significand >= (static_cast<std::uint64_t>(1) << 53)))
-    {
-        return false; // significand not exactly representable as double
-    }
-
-    auto result = static_cast<double>(significand);
-    if (scale >= 0)
-    {
-        if (JSON_HEDLEY_UNLIKELY(scale > 22))
-        {
-            return false;
-        }
-        result *= powers_of_ten[static_cast<std::size_t>(scale)];
-    }
-    else
-    {
-        if (JSON_HEDLEY_UNLIKELY(-scale > 22))
-        {
-            return false;
-        }
-        result /= powers_of_ten[static_cast<std::size_t>(-scale)];
-    }
-    out = negative ? -result : result;
-    return true;
-#endif
-}
-
-/// fast float path is only exact for `double`; decline for float/long double
-template<typename DecimalPointType, typename FloatType>
-bool parse_float_fast(const char* /*first*/, const char* /*last*/, DecimalPointType /*decimal_point*/, FloatType& /*out*/) noexcept
-{
-    return false;
-}
-
-/*!
-@brief parse a float with std::from_chars (Eisel-Lemire) when available
-
-std::from_chars is locale-independent, correctly rounded, and - via the
-Eisel-Lemire algorithm in modern standard libraries - much faster than strtod
-over the whole value range (not just the Clinger subset). It is used only when
-__cpp_lib_to_chars indicates full floating-point support and only when it
-consumes the entire token ([first, last)); a partial parse means the buffer
-uses a non-'.' locale decimal point, in which case the caller falls back to the
-locale-aware path. An under-/overflow (result_out_of_range) also declines, so
-the caller's strtod fallback supplies the well-defined ±inf/0 result the parser
-expects (side-stepping the P4168 divergence between implementations).
-
-@return true if the value was parsed exactly and fully; false to fall back
-*/
-template<typename FloatType>
-bool parse_float_from_chars(const char* first, const char* last, FloatType& out) noexcept
-{
-    // JSON_HAS_CPP_17 must gate the use as well as the <charconv> include above:
-    // some standard libraries (e.g. libstdc++ 15) define __cpp_lib_to_chars even
-    // in C++14 mode, where <charconv> is not included.
-#if defined(JSON_HAS_CPP_17) && defined(__cpp_lib_to_chars)
-    const auto result = std::from_chars(first, last, out);
-    return result.ec == std::errc() && result.ptr == last;
-#else
-    static_cast<void>(first);
-    static_cast<void>(last);
-    static_cast<void>(out);
-    return false;
-#endif
-}
-
-}  // namespace detail
-NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/input/string_scan.hpp

@@ -1,287 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#pragma once
-
-#include <cstddef> // size_t
-#include <cstdint> // uint64_t
-#include <cstring> // memcpy
-
-#include <nlohmann/detail/macro_scope.hpp>
-
-// Optional SIMD backend for bulk UTF-8 validation. This is an opt-in external
-// dependency: nlohmann/json itself stays header-only and the C++11 scalar
-// validator below is always available; defining JSON_USE_SIMDUTF additionally
-// requires the simdutf headers on the include path and linking the simdutf
-// library. See string_bulk_run().
-//
-// simdutf.h itself requires C++17 - it rejects older standards with an #error -
-// so the backend is only compiled in from C++17 on. Below that the macro has no
-// effect and the scalar validator is used; it accepts and rejects exactly the
-// same input, so only throughput differs. macro_scope.hpp is included above to
-// have JSON_HAS_CPP_17 available for this test.
-#if defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17)
-    #include <simdutf.h>
-#endif
-
-// This file contains the byte-level string-scanning helpers used by the lexer's
-// contiguous fast path. They operate purely on raw bytes (no dependency on the
-// lexer's template parameters) so they are free functions, keeping the lexer
-// itself focused on the state machine; see lexer::scan_string_bulk().
-
-NLOHMANN_JSON_NAMESPACE_BEGIN
-namespace detail
-{
-
-// classify a single byte as needing individual string handling: the closing
-// quote, an escape, a control character, or a non-ASCII (UTF-8)
-// lead/continuation byte. Ordinary bytes (0x20..0x7F except '"' and '\\') are
-// copied verbatim, which the bulk scanner does 8 bytes at a time.
-inline bool is_string_special(unsigned char c) noexcept
-{
-    return c == '\"' || c == '\\' || c < 0x20u || c >= 0x80u;
-}
-
-// SWAR helper: return a word whose high bit is set in every byte of @a v that
-// is_string_special(); zero if the 8 bytes are all ordinary.
-inline std::uint64_t swar_string_special(std::uint64_t v) noexcept
-{
-    constexpr std::uint64_t ones = 0x0101010101010101ull;
-    constexpr std::uint64_t high = 0x8080808080808080ull;
-    const std::uint64_t q = v ^ 0x2222222222222222ull; // '"'  (0x22)
-    const std::uint64_t b = v ^ 0x5C5C5C5C5C5C5C5Cull; // '\\' (0x5C)
-    const std::uint64_t has_quote     = (q - ones) & ~q & high;
-    const std::uint64_t has_backslash = (b - ones) & ~b & high;
-    const std::uint64_t has_control   = (v - 0x2020202020202020ull) & ~v & high; // < 0x20
-    const std::uint64_t has_non_ascii = v & high;                                // >= 0x80
-    return has_quote | has_backslash | has_control | has_non_ascii;
-}
-
-// return the index of the first is_string_special() byte in [data, data+n), or
-// n if every byte is ordinary; scans 8 bytes at a time
-inline std::size_t find_string_special(const unsigned char* data, std::size_t n) noexcept
-{
-    std::size_t i = 0;
-    for (; i + 8 <= n; i += 8)
-    {
-        std::uint64_t word = 0;
-        std::memcpy(&word, data + i, sizeof(word));
-        if (swar_string_special(word) != 0)
-        {
-            // a special byte is in this word; locate it (endian-agnostic)
-            for (std::size_t j = 0; j < 8; ++j)
-            {
-                if (is_string_special(data[i + j]))
-                {
-                    return i + j;
-                }
-            }
-        }
-    }
-    for (; i < n; ++i)
-    {
-        if (is_string_special(data[i]))
-        {
-            return i;
-        }
-    }
-    return n;
-}
-
-// classify a byte as one the serializer must NOT copy verbatim when
-// ensure_ascii is requested: the closing quote, an escape, a control character
-// (< 0x20), DEL (0x7F), or any non-ASCII byte (>= 0x80). Everything else -
-// printable ASCII except '"' and '\\' - is emitted unchanged. Note this differs
-// from is_string_special() only in that 0x7F is also a stop (it is escaped as
-// \u007f under ensure_ascii).
-inline bool is_ascii_copyable(unsigned char c) noexcept
-{
-    return c >= 0x20u && c < 0x7Fu && c != '"' && c != '\\';
-}
-
-// return the index of the first byte in [data, data+n) that is NOT
-// is_ascii_copyable(), or n if every byte can be copied verbatim; scans 8 bytes
-// at a time. Used by the serializer's ensure_ascii fast path.
-inline std::size_t find_ascii_copyable_run(const unsigned char* data, std::size_t n) noexcept
-{
-    constexpr std::uint64_t ones = 0x0101010101010101ull;
-    constexpr std::uint64_t high = 0x8080808080808080ull;
-    std::size_t i = 0;
-    for (; i + 8 <= n; i += 8)
-    {
-        std::uint64_t v = 0;
-        std::memcpy(&v, data + i, sizeof(v));
-        const std::uint64_t q = v ^ 0x2222222222222222ull; // '"'  (0x22)
-        const std::uint64_t b = v ^ 0x5C5C5C5C5C5C5C5Cull; // '\\' (0x5C)
-        const std::uint64_t d = v ^ 0x7F7F7F7F7F7F7F7Full; // DEL  (0x7F)
-        const std::uint64_t stop = ((q - ones) & ~q & high)   // == '"'
-                                   | ((b - ones) & ~b & high)  // == '\\'
-                                   | ((d - ones) & ~d & high)  // == 0x7F
-                                   | ((v - 0x2020202020202020ull) & ~v & high) // < 0x20
-                                   | (v & high);               // >= 0x80
-        if (stop != 0)
-        {
-            break;
-        }
-    }
-    for (; i < n; ++i)
-    {
-        if (!is_ascii_copyable(data[i]))
-        {
-            return i;
-        }
-    }
-    return n;
-}
-
-// Validate one UTF-8 sequence at the front of [data, data+avail). Returns its
-// length (2..4) only when the bytes form a *well-formed* sequence using exactly
-// the same ranges as scan_string()'s per-byte switch, so the bulk path accepts
-// precisely what the byte path accepts. Returns 0 for anything that is invalid,
-// incomplete, or that the byte path must diagnose (the caller then defers to
-// that path, keeping error messages unchanged). Lead bytes < 0x80 are handled
-// by the caller and never passed here.
-inline std::size_t validate_one_utf8(const unsigned char* data, std::size_t avail) noexcept
-{
-    const unsigned char c0 = data[0];
-    if (c0 >= 0xC2 && c0 <= 0xDF)  // U+0080..U+07FF
-    {
-        if (avail >= 2 && data[1] >= 0x80 && data[1] <= 0xBF)
-        {
-            return 2;
-        }
-    }
-    else if (c0 == 0xE0)  // U+0800..U+0FFF
-    {
-        if (avail >= 3 && data[1] >= 0xA0 && data[1] <= 0xBF && data[2] >= 0x80 && data[2] <= 0xBF)
-        {
-            return 3;
-        }
-    }
-    else if ((c0 >= 0xE1 && c0 <= 0xEC) || c0 == 0xEE || c0 == 0xEF)  // U+1000..U+CFFF, U+E000..U+FFFF
-    {
-        if (avail >= 3 && data[1] >= 0x80 && data[1] <= 0xBF && data[2] >= 0x80 && data[2] <= 0xBF)
-        {
-            return 3;
-        }
-    }
-    else if (c0 == 0xED)  // U+D000..U+D7FF (excludes surrogates)
-    {
-        if (avail >= 3 && data[1] >= 0x80 && data[1] <= 0x9F && data[2] >= 0x80 && data[2] <= 0xBF)
-        {
-            return 3;
-        }
-    }
-    else if (c0 == 0xF0)  // U+10000..U+3FFFF
-    {
-        if (avail >= 4 && data[1] >= 0x90 && data[1] <= 0xBF && data[2] >= 0x80 && data[2] <= 0xBF && data[3] >= 0x80 && data[3] <= 0xBF)
-        {
-            return 4;
-        }
-    }
-    else if (c0 >= 0xF1 && c0 <= 0xF3)  // U+40000..U+FFFFF
-    {
-        if (avail >= 4 && data[1] >= 0x80 && data[1] <= 0xBF && data[2] >= 0x80 && data[2] <= 0xBF && data[3] >= 0x80 && data[3] <= 0xBF)
-        {
-            return 4;
-        }
-    }
-    else if (c0 == 0xF4)  // U+100000..U+10FFFF
-    {
-        if (avail >= 4 && data[1] >= 0x80 && data[1] <= 0x8F && data[2] >= 0x80 && data[2] <= 0xBF && data[3] >= 0x80 && data[3] <= 0xBF)
-        {
-            return 4;
-        }
-    }
-    return 0; // invalid, incomplete, or must be diagnosed by the byte path
-}
-
-// Scalar (C++11) computation of the bulk run length: the number of leading
-// bytes in [data, data+n) that are ordinary ASCII or complete well-formed UTF-8
-// sequences, stopping before the first byte that needs individual handling (the
-// closing quote, an escape, a control character, or an ill-formed/truncated
-// sequence). ASCII is skipped 8 bytes at a time.
-inline std::size_t scalar_string_bulk_run(const unsigned char* data, std::size_t n) noexcept
-{
-    std::size_t pos = 0;
-    while (pos < n)
-    {
-        pos += find_string_special(data + pos, n - pos);
-        if (pos >= n || data[pos] < 0x80u)
-        {
-            break; // end of buffer, or a quote/escape/control byte
-        }
-        const std::size_t seq = validate_one_utf8(data + pos, n - pos);
-        if (seq == 0)
-        {
-            break; // ill-formed or truncated: let the byte path diagnose it
-        }
-        pos += seq;
-    }
-    return pos;
-}
-
-#if defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17)
-// Index of the first quote/escape/control byte in [data, data+n) (non-ASCII
-// bytes are *not* stops here - the whole run is handed to simdutf), or n.
-inline std::size_t find_string_delimiter(const unsigned char* data, std::size_t n) noexcept
-{
-    constexpr std::uint64_t ones = 0x0101010101010101ull;
-    constexpr std::uint64_t high = 0x8080808080808080ull;
-    std::size_t i = 0;
-    for (; i + 8 <= n; i += 8)
-    {
-        std::uint64_t v = 0;
-        std::memcpy(&v, data + i, sizeof(v));
-        const std::uint64_t q = v ^ 0x2222222222222222ull;
-        const std::uint64_t b = v ^ 0x5C5C5C5C5C5C5C5Cull;
-        const std::uint64_t hit = ((q - ones) & ~q & high)
-                                  | ((b - ones) & ~b & high)
-                                  | ((v - 0x2020202020202020ull) & ~v & high);
-        if (hit != 0)
-        {
-            for (std::size_t j = 0; j < 8; ++j)
-            {
-                const unsigned char c = data[i + j];
-                if (c == '\"' || c == '\\' || c < 0x20u)
-                {
-                    return i + j;
-                }
-            }
-        }
-    }
-    for (; i < n; ++i)
-    {
-        const unsigned char c = data[i];
-        if (c == '\"' || c == '\\' || c < 0x20u)
-        {
-            return i;
-        }
-    }
-    return n;
-}
-#endif
-
-// Backend-dispatched bulk run length. With JSON_USE_SIMDUTF the run up to the
-// next delimiter is validated in one shot by simdutf; on the rare failure the
-// scalar helper recomputes the exact valid prefix so the byte path still
-// produces the precise diagnostic. Without it, the pure scalar path is used.
-inline std::size_t string_bulk_run(const unsigned char* data, std::size_t n) noexcept
-{
-#if defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17)
-    const std::size_t run = find_string_delimiter(data, n);
-    if (run != 0 && simdutf::validate_utf8(reinterpret_cast<const char*>(data), run))
-    {
-        return run;
-    }
-#endif
-    return scalar_string_bulk_run(data, n);
-}
-
-}  // namespace detail
-NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/macro_scope.hpp

@@ -186,6 +186,15 @@
     #define JSON_NO_UNIQUE_ADDRESS
 #endif
 
+// Clang targeting MinGW does not survive the thread_local storage the copy
+// constructor uses to bound its descent: every test that copies a value
+// segfaults with clang 11.0.1 and clang 18.1.8, while the same tests pass with
+// GCC targeting MinGW and with every other toolchain the library is tested on.
+// Copying works the same way without the counter, only more slowly.
+#if !defined(JSON_NO_THREAD_LOCAL) && defined(__clang__) && defined(__MINGW32__)
+    #define JSON_NO_THREAD_LOCAL 1
+#endif
+
 // disable documentation warnings on clang
 #if defined(__clang__)
     #pragma clang diagnostic push

include/nlohmann/detail/output/binary_writer.hpp

@@ -826,17 +826,7 @@ class binary_writer
 
                     std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
 
-                    // an optimized array of a valueless type carries no payload, so a
-                    // reader has nothing but the declared count to bound the allocation
-                    // by and refuses an excessive one. Write the unoptimized form for
-                    // those, at one byte per element, so the result can be read back.
-                    // Objects are not affected: every element is preceded by its key.
-                    const bool valueless_type = (first_prefix == 'Z' || first_prefix == 'T' || first_prefix == 'F');
-                    const bool excessive_valueless = valueless_type
-                                                     && j.m_data.m_value.array->size() > detail::max_valueless_container_size;
-
-                    if (same_prefix && !excessive_valueless
-                            && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));
@@ -1657,20 +1647,6 @@ class binary_writer
         return 'D';  // float 64
     }
 
-    /*!
-    @brief checks whether a JSON number fits into @a TargetType
-    @param[in] el a JSON number of either the signed or unsigned integer kind
-    @return whether @a el's value can be represented by @a TargetType without
-            wrapping, regardless of which of the two kinds it is stored as
-    */
-    template<typename TargetType>
-    static bool bjdata_ndarray_value_in_range(const BasicJsonType& el)
-    {
-        return el.is_number_unsigned()
-               ? value_in_range_of<TargetType>(el.template get<std::uint64_t>())
-               : value_in_range_of<TargetType>(el.template get<std::int64_t>());
-    }
-
     /*!
     @return false if the object is successfully converted to a bjdata ndarray, true if the type or size is invalid
     */
@@ -1755,60 +1731,6 @@ class binary_writer
             }
         }
 
-        // every element is cast to the (possibly narrower) C++ type matching
-        // dtype below; a value that does not fit that type would silently
-        // wrap (integers) or overflow to infinity (the "single" precision
-        // float) instead of being reported, so such an object falls back to
-        // a plain object encoding as well
-        for (const auto& el : value.at(key))
-        {
-            bool in_range = true;
-            switch (dtype)
-            {
-                case 'U':
-                case 'C':
-                case 'B':
-                    in_range = bjdata_ndarray_value_in_range<std::uint8_t>(el);
-                    break;
-                case 'i':
-                    in_range = bjdata_ndarray_value_in_range<std::int8_t>(el);
-                    break;
-                case 'u':
-                    in_range = bjdata_ndarray_value_in_range<std::uint16_t>(el);
-                    break;
-                case 'I':
-                    in_range = bjdata_ndarray_value_in_range<std::int16_t>(el);
-                    break;
-                case 'm':
-                    in_range = bjdata_ndarray_value_in_range<std::uint32_t>(el);
-                    break;
-                case 'l':
-                    in_range = bjdata_ndarray_value_in_range<std::int32_t>(el);
-                    break;
-                case 'M':
-                    in_range = bjdata_ndarray_value_in_range<std::uint64_t>(el);
-                    break;
-                case 'L':
-                    in_range = bjdata_ndarray_value_in_range<std::int64_t>(el);
-                    break;
-                case 'd':
-                {
-                    const auto dval = el.template get<double>();
-                    in_range = !std::isfinite(dval) ||
-                               (dval >= static_cast<double>(std::numeric_limits<float>::lowest()) &&
-                                dval <= static_cast<double>((std::numeric_limits<float>::max)()));
-                    break;
-                }
-                default:
-                    // 'D' (double) already spans the full range of number_float_t
-                    break;
-            }
-            if (!in_range)
-            {
-                return true;
-            }
-        }
-
         oa->write_character('[');
         oa->write_character('$');
         oa->write_character(dtype);

tests/CMakeLists.txt

@@ -2,9 +2,6 @@ cmake_minimum_required(VERSION 3.13...4.0)
 
 option(JSON_Valgrind    "Execute test suite with Valgrind." OFF)
 option(JSON_FastTests   "Skip expensive/slow tests." OFF)
-option(JSON_TestSimdutf "Build the unit tests against the simdutf UTF-8 validation backend." OFF)
-
-set(JSON_SIMDUTF_VERSION 9.1.0 CACHE STRING "The simdutf version used by JSON_TestSimdutf.")
 
 set(JSON_32bitTest     AUTO CACHE STRING "Enable the 32bit unit test (ON/OFF/AUTO/ONLY).")
 set(JSON_TestStandards "" CACHE STRING "The list of standards to test explicitly.")
@@ -75,7 +72,12 @@ target_compile_options(test_main PUBLIC
     #                              is annotated JSON_HEDLEY_NO_RETURN (it always throws), which
     #                              makes MSVC flag the code following its call in binary_reader.hpp
     #                              as unreachable for that instantiation, in both Debug and Release
-    $<$<CXX_COMPILER_ID:MSVC>:/W4;/wd4566;/wd4996;/wd4702>
+    #       Disable warning C4503: decorated name length exceeded, name was truncated; the deep
+    #                              copy support added for #5387 pushes the mangled name of
+    #                              std::allocator_traits<...>::construct for the custom-base-class
+    #                              test's map type past VS2015's limit. The name is only used for
+    #                              debug info, so truncation does not affect the build.
+    $<$<CXX_COMPILER_ID:MSVC>:/W4;/wd4566;/wd4996;/wd4702;/wd4503>
     # https://github.com/nlohmann/json/issues/1114
     $<$<CXX_COMPILER_ID:MSVC>:/bigobj> $<$<BOOL:${MINGW}>:-Wa,-mbig-obj>
 
@@ -197,71 +199,6 @@ if(test_force)
 endif()
 message(STATUS "${msg}")
 
-#############################################################################
-# optionally validate UTF-8 with simdutf (JSON_USE_SIMDUTF)
-#############################################################################
-
-# The simdutf backend is opt-in and not vendored, so it is fetched here rather
-# than being a checked-in dependency. Everything below hangs off test_main,
-# whose usage requirements every test target inherits; the library target and
-# the installed CMake package are deliberately left untouched.
-if (JSON_TestSimdutf)
-    # simdutf requires C++17, both to compile itself and to be reachable from
-    # the library, which keeps its scalar validator below that. Find a tested
-    # standard that satisfies it.
-    set(simdutf_standard "")
-    foreach(cxx_standard ${test_cxx_standards})
-        if(NOT cxx_standard LESS 17 AND compiler_supports_cpp_${cxx_standard})
-            set(simdutf_standard ${cxx_standard})
-            break()
-        endif()
-    endforeach()
-
-    if("${simdutf_standard}" STREQUAL "")
-        # Building simdutf would fail outright without a C++17 compiler, and
-        # even with one it would go unused if no C++17-or-later standard is
-        # tested. Say so and fall back to the scalar validator rather than
-        # failing the build.
-        if(NOT compiler_supports_cpp_17)
-            set(simdutf_reason "the compiler does not support C++17")
-        else()
-            set(simdutf_reason "no tested standard is C++17 or later (testing ${msg_standards})")
-        endif()
-        message(WARNING
-            "JSON_TestSimdutf is enabled, but ${simdutf_reason}. simdutf requires C++17, so it "
-            "is not fetched and JSON_USE_SIMDUTF is not defined: the tests run against the "
-            "built-in scalar UTF-8 validator instead. Set JSON_TestStandards to include 17 or "
-            "later, or build with a compiler that supports C++17.")
-    else()
-        if (CMAKE_VERSION VERSION_LESS 3.18)
-            message(FATAL_ERROR "JSON_TestSimdutf requires CMake 3.18 or later (simdutf's minimum).")
-        endif()
-
-        include(FetchContent)
-
-        # simdutf builds its tests and tools by default, and its tests pull
-        # further dependencies of their own; only the library is needed here
-        set(SIMDUTF_TESTS OFF CACHE BOOL "" FORCE)
-        set(SIMDUTF_TOOLS OFF CACHE BOOL "" FORCE)
-        set(SIMDUTF_BENCHMARKS OFF CACHE BOOL "" FORCE)
-        set(SIMDUTF_ICONV OFF CACHE BOOL "" FORCE)
-
-        FetchContent_Declare(simdutf
-            URL https://github.com/simdutf/simdutf/archive/refs/tags/v${JSON_SIMDUTF_VERSION}.tar.gz
-            DOWNLOAD_EXTRACT_TIMESTAMP TRUE
-        )
-        FetchContent_MakeAvailable(simdutf)
-
-        target_compile_definitions(test_main PUBLIC JSON_USE_SIMDUTF)
-        target_link_libraries(test_main PUBLIC simdutf::simdutf)
-
-        # simdutf.h requires C++17; below that the library keeps its scalar
-        # validator, so any C++11/14 test targets exercise the fallback and the
-        # C++17-and-later ones exercise simdutf. Both must agree.
-        message(STATUS "UTF-8 validation delegated to simdutf ${JSON_SIMDUTF_VERSION} for C++17 and later (JSON_USE_SIMDUTF)")
-    endif()
-endif()
-
 # *DO* use json_test_set_test_options() above this line
 
 json_test_should_build_32bit_test(json_32bit_test json_32bit_test_only "${JSON_32bitTest}")
@@ -298,24 +235,6 @@ json_test_add_test_for(src/unit-comparison.cpp
     MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
 )
 
-# test the parser again with JSON_DIAGNOSTIC_POSITIONS enabled
-json_test_set_test_options(test-class_parser_diagnostic_positions
-    COMPILE_DEFINITIONS JSON_DIAGNOSTIC_POSITIONS=1
-)
-json_test_add_test_for(src/unit-class_parser.cpp
-    NAME test-class_parser_diagnostic_positions
-    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
-)
-
-# test diagnostic positions again without regular diagnostics (JSON pointer paths)
-json_test_set_test_options(test-diagnostic-positions_only
-    COMPILE_DEFINITIONS JSON_DIAGNOSTICS=0
-)
-json_test_add_test_for(src/unit-diagnostic-positions.cpp
-    NAME test-diagnostic-positions_only
-    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
-)
-
 # *DO NOT* use json_test_set_test_options() below this line
 
 #############################################################################

tests/benchmarks/src/benchmarks.cpp

@@ -81,44 +81,6 @@ BENCHMARK_CAPTURE(ParseString, signed_ints,       TEST_DATA_DIRECTORY "/regressi
 BENCHMARK_CAPTURE(ParseString, unsigned_ints,     TEST_DATA_DIRECTORY "/regression/unsigned_ints.json");
 BENCHMARK_CAPTURE(ParseString, small_signed_ints, TEST_DATA_DIRECTORY "/regression/small_signed_ints.json");
 
-//////////////////////////////////////////////////////////////////////////////
-// parse pretty-printed JSON from string
-//
-// Every file in the corpus above is minified or only lightly spaced, so none of
-// them exercise the lexer's whitespace handling. Real-world JSON is frequently
-// indented - configuration files, pretty-printed API responses, anything kept
-// under version control - where insignificant whitespace can outweigh the data.
-// Re-serializing a document with an indentation and parsing that keeps the
-// content identical to the ParseString row above, so the pair isolates the cost
-// of the whitespace alone.
-//////////////////////////////////////////////////////////////////////////////
-
-static void ParseIndented(benchmark::State& state, const char* filename, int indent)
-{
-    std::ifstream f(filename);
-    std::string str((std::istreambuf_iterator<char>(f)), std::istreambuf_iterator<char>());
-    const std::string indented = json::parse(str).dump(indent);
-
-    while (state.KeepRunning())
-    {
-        state.PauseTiming();
-        auto* j = new json();
-        state.ResumeTiming();
-
-        *j = json::parse(indented);
-
-        state.PauseTiming();
-        delete j;
-        state.ResumeTiming();
-    }
-
-    state.SetBytesProcessed(state.iterations() * indented.size());
-}
-BENCHMARK_CAPTURE(ParseIndented, jeopardy / 4,     TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json",                 4);
-BENCHMARK_CAPTURE(ParseIndented, canada / 4,       TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json",       4);
-BENCHMARK_CAPTURE(ParseIndented, citm_catalog / 4, TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", 4);
-BENCHMARK_CAPTURE(ParseIndented, twitter / 4,      TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json",      4);
-
 //////////////////////////////////////////////////////////////////////////////
 // serialize JSON
 //////////////////////////////////////////////////////////////////////////////
@@ -252,323 +214,4 @@ static void BinaryToCbor(benchmark::State& state)
 }
 BENCHMARK(BinaryToCbor)->RangeMultiplier(2)->Range(8, 8 << 12);
 
-//////////////////////////////////////////////////////////////////////////////
-// parse binary formats
-//////////////////////////////////////////////////////////////////////////////
-
-// Only MessagePack had a read benchmark (FromMsgpack above, left untouched so
-// its numbers stay comparable across releases). The benchmarks below cover the
-// other formats, and read from a contiguous buffer as well as from a FILE*:
-// most callers pass a container, and the two adapters compile to different
-// code. The test data repository ships JSON only, so the input for each is
-// derived at setup time by serializing a parsed test file.
-
-/// binary format to benchmark; the _optimized variants add UBJSON/BJData size
-/// and type annotations, which the readers handle in a separate code path
-enum class binary_format
-{
-    cbor,
-    msgpack,
-    ubjson,
-    ubjson_optimized,
-    bjdata,
-    bjdata_optimized,
-    bson
-};
-
-static std::vector<std::uint8_t> to_binary(const json& j, const binary_format format)
-{
-    switch (format)
-    {
-        case binary_format::cbor:
-            return json::to_cbor(j);
-        case binary_format::msgpack:
-            return json::to_msgpack(j);
-        case binary_format::ubjson:
-            return json::to_ubjson(j);
-        case binary_format::ubjson_optimized:
-            return json::to_ubjson(j, true, true);
-        case binary_format::bjdata:
-            return json::to_bjdata(j);
-        case binary_format::bjdata_optimized:
-            return json::to_bjdata(j, true, true);
-        case binary_format::bson:
-        default:
-            return json::to_bson(j);
-    }
-}
-
-static json from_binary(const std::vector<std::uint8_t>& bytes, const binary_format format)
-{
-    switch (format)
-    {
-        case binary_format::cbor:
-            return json::from_cbor(bytes);
-        case binary_format::msgpack:
-            return json::from_msgpack(bytes);
-        case binary_format::ubjson:
-        case binary_format::ubjson_optimized:
-            return json::from_ubjson(bytes);
-        case binary_format::bjdata:
-        case binary_format::bjdata_optimized:
-            return json::from_bjdata(bytes);
-        case binary_format::bson:
-        default:
-            return json::from_bson(bytes);
-    }
-}
-
-static json from_binary(std::FILE* file, const binary_format format)
-{
-    switch (format)
-    {
-        case binary_format::cbor:
-            return json::from_cbor(file);
-        case binary_format::msgpack:
-            return json::from_msgpack(file);
-        case binary_format::ubjson:
-        case binary_format::ubjson_optimized:
-            return json::from_ubjson(file);
-        case binary_format::bjdata:
-        case binary_format::bjdata_optimized:
-            return json::from_bjdata(file);
-        case binary_format::bson:
-        default:
-            return json::from_bson(file);
-    }
-}
-
-/*!
-@brief serialize a parsed test file to @a format
-
-Returns an empty vector and marks the benchmark as skipped if the file cannot
-be represented in the format, rather than letting the exception escape: BSON
-requires an object at the top level, and several test files are arrays.
-*/
-static std::vector<std::uint8_t> binary_input(benchmark::State& state, const char* filename, const binary_format format)
-{
-    std::ifstream f(filename);
-    std::string const str((std::istreambuf_iterator<char>(f)), std::istreambuf_iterator<char>());
-    const json j = json::parse(str);
-
-    if (format == binary_format::bson && !j.is_object())
-    {
-        state.SkipWithError("BSON requires an object at the top level");
-        return {};
-    }
-
-    return to_binary(j, format);
-}
-
-static void FromBinaryBuffer(benchmark::State& state, const char* filename, const binary_format format)
-{
-    const std::vector<std::uint8_t> bytes = binary_input(state, filename, format);
-    if (bytes.empty())
-    {
-        return;
-    }
-
-    for (auto _ : state)
-    {
-        // the value is destroyed outside the timed section, because destroying
-        // a large DOM is not what this benchmark measures
-        state.PauseTiming();
-        auto* j = new json();
-        state.ResumeTiming();
-
-        *j = from_binary(bytes, format);
-
-        state.PauseTiming();
-        delete j;
-        state.ResumeTiming();
-    }
-
-    state.SetBytesProcessed(state.iterations() * bytes.size());
-}
-
-BENCHMARK_CAPTURE(FromBinaryBuffer, cbor / jeopardy, TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryBuffer, cbor / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryBuffer, cbor / citm_catalog, TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryBuffer, cbor / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryBuffer, cbor / floats, TEST_DATA_DIRECTORY "/regression/floats.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryBuffer, cbor / signed_ints, TEST_DATA_DIRECTORY "/regression/signed_ints.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryBuffer, msgpack / jeopardy, TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json", binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryBuffer, msgpack / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryBuffer, msgpack / citm_catalog, TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryBuffer, msgpack / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryBuffer, ubjson / jeopardy, TEST_DATA_DIRECTORY "/jeopardy/jeopardy.json", binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryBuffer, ubjson / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryBuffer, ubjson / citm_catalog, TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryBuffer, ubjson / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryBuffer, ubjson_optimized / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::ubjson_optimized);
-BENCHMARK_CAPTURE(FromBinaryBuffer, ubjson_optimized / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::ubjson_optimized);
-BENCHMARK_CAPTURE(FromBinaryBuffer, bjdata / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::bjdata);
-BENCHMARK_CAPTURE(FromBinaryBuffer, bjdata / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::bjdata);
-BENCHMARK_CAPTURE(FromBinaryBuffer, bjdata_optimized / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::bjdata_optimized);
-BENCHMARK_CAPTURE(FromBinaryBuffer, bjdata_optimized / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::bjdata_optimized);
-// BSON requires an object at the top level, so the array-rooted test files
-// (jeopardy and the regression files) cannot be captured here
-BENCHMARK_CAPTURE(FromBinaryBuffer, bson / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::bson);
-BENCHMARK_CAPTURE(FromBinaryBuffer, bson / citm_catalog, TEST_DATA_DIRECTORY "/nativejson-benchmark/citm_catalog.json", binary_format::bson);
-BENCHMARK_CAPTURE(FromBinaryBuffer, bson / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::bson);
-
-static void FromBinaryFile(benchmark::State& state, const char* filename, const binary_format format)
-{
-    const std::vector<std::uint8_t> bytes = binary_input(state, filename, format);
-    if (bytes.empty())
-    {
-        return;
-    }
-
-    const char* tmp = "benchmark_input.bin";
-    std::ofstream o(tmp, std::ios::binary);
-    o.write(reinterpret_cast<const char*>(bytes.data()), static_cast<std::streamsize>(bytes.size()));
-    o.flush();
-    o.close();
-
-    for (auto _ : state)
-    {
-        state.PauseTiming();
-        auto* j = new json();
-        auto* file = std::fopen(tmp, "rb");
-        state.ResumeTiming();
-
-        *j = from_binary(file, format);
-
-        state.PauseTiming();
-        std::fclose(file);
-        delete j;
-        state.ResumeTiming();
-    }
-
-    state.SetBytesProcessed(state.iterations() * bytes.size());
-}
-
-BENCHMARK_CAPTURE(FromBinaryFile, cbor / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryFile, cbor / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryFile, ubjson / canada, TEST_DATA_DIRECTORY "/nativejson-benchmark/canada.json", binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryFile, ubjson / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryFile, bjdata / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::bjdata);
-BENCHMARK_CAPTURE(FromBinaryFile, bson / twitter, TEST_DATA_DIRECTORY "/nativejson-benchmark/twitter.json", binary_format::bson);
-
-//////////////////////////////////////////////////////////////////////////////
-// parse binary formats: value shapes
-//////////////////////////////////////////////////////////////////////////////
-
-// The test files above are wide and shallow, but the readers' cost is per
-// container, so these cover the shapes that stress the container handling
-// itself. Every shape is wrapped in an object so that BSON, which requires an
-// object at the top level, measures the same value as the other formats.
-
-/// deeply nested arrays: one container per level, no other work
-static json make_nested()
-{
-    json nested = json::array();
-    json* p = &nested;
-    for (std::size_t i = 1; i < 1000; ++i)
-    {
-        p->push_back(json::array());
-        p = &p->operator[](0);
-    }
-
-    json j = json::object();
-    j["data"] = std::move(nested);
-    return j;
-}
-
-/// many sibling containers: maximum container churn, minimum nesting
-static json make_containers()
-{
-    json data = json::array();
-    for (std::size_t i = 0; i < 100000; ++i)
-    {
-        data.push_back(json::array({1, 2}));
-    }
-
-    json j = json::object();
-    j["data"] = std::move(data);
-    return j;
-}
-
-/// one flat array of numbers: the scalar decoding path, which must not move
-static json make_scalars()
-{
-    json data = json::array();
-    for (std::size_t i = 0; i < 1000000; ++i)
-    {
-        data.push_back(i);
-    }
-
-    json j = json::object();
-    j["data"] = std::move(data);
-    return j;
-}
-
-static void FromBinaryShape(benchmark::State& state, json (*build)(), const binary_format format)
-{
-    const std::vector<std::uint8_t> bytes = to_binary(build(), format);
-
-    for (auto _ : state)
-    {
-        state.PauseTiming();
-        auto* j = new json();
-        state.ResumeTiming();
-
-        *j = from_binary(bytes, format);
-
-        state.PauseTiming();
-        delete j;
-        state.ResumeTiming();
-    }
-
-    state.SetBytesProcessed(state.iterations() * bytes.size());
-}
-
-BENCHMARK_CAPTURE(FromBinaryShape, nested / cbor, make_nested, binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryShape, nested / msgpack, make_nested, binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryShape, nested / ubjson, make_nested, binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryShape, nested / bjdata, make_nested, binary_format::bjdata);
-BENCHMARK_CAPTURE(FromBinaryShape, nested / bson, make_nested, binary_format::bson);
-BENCHMARK_CAPTURE(FromBinaryShape, containers / cbor, make_containers, binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryShape, containers / msgpack, make_containers, binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryShape, containers / ubjson, make_containers, binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryShape, containers / ubjson_optimized, make_containers, binary_format::ubjson_optimized);
-BENCHMARK_CAPTURE(FromBinaryShape, containers / bjdata, make_containers, binary_format::bjdata);
-BENCHMARK_CAPTURE(FromBinaryShape, containers / bson, make_containers, binary_format::bson);
-// BSON names every array element, so a large array measures key generation
-// rather than scalar decoding and is left out here
-BENCHMARK_CAPTURE(FromBinaryShape, scalars / cbor, make_scalars, binary_format::cbor);
-BENCHMARK_CAPTURE(FromBinaryShape, scalars / msgpack, make_scalars, binary_format::msgpack);
-BENCHMARK_CAPTURE(FromBinaryShape, scalars / ubjson, make_scalars, binary_format::ubjson);
-BENCHMARK_CAPTURE(FromBinaryShape, scalars / bjdata, make_scalars, binary_format::bjdata);
-
-/*!
-@brief parse an indefinite-length CBOR string
-
-The writer never emits this form, so the input is assembled by hand: 0x7F
-opens the string, each chunk is a one-character string, and 0xFF closes it.
-*/
-static void FromCborChunkedString(benchmark::State& state, const std::size_t chunks)
-{
-    std::vector<std::uint8_t> bytes;
-    bytes.reserve(2 * chunks + 2);
-    bytes.push_back(0x7F);
-    for (std::size_t i = 0; i < chunks; ++i)
-    {
-        bytes.push_back(0x61); // string of length 1
-        bytes.push_back(0x61); // 'a'
-    }
-    bytes.push_back(0xFF);
-
-    for (auto _ : state)
-    {
-        json j = json::from_cbor(bytes);
-        benchmark::DoNotOptimize(j);
-    }
-
-    state.SetBytesProcessed(state.iterations() * bytes.size());
-}
-
-BENCHMARK_CAPTURE(FromCborChunkedString, 10000 chunks, 10000);
-
 BENCHMARK_MAIN();

tests/src/unit-allocator.cpp

@@ -216,6 +216,57 @@ TEST_CASE("controlled bad_alloc")
             CHECK_THROWS_AS(my_json(s), std::bad_alloc&);
             next_construct_fails = false;
         }
+
+        SECTION("basic_json(const basic_json&) of a deeply nested value (#5387)")
+        {
+            // Copying a value nested deeper than the descent bound builds the
+            // copy from the top down: every value whose own copy has not been
+            // made yet stays a null value until it is. Failing an allocation
+            // part-way through is what proves such a half-built copy can still
+            // be destroyed.
+            //
+            // Which path the failure lands in depends on the build: the first
+            // allocation of a copy belongs to the outermost level, so here it
+            // is the descending one. Built with JSON_NO_THREAD_LOCAL - as the
+            // ci_test_no_thread_local target builds the whole suite - no
+            // descent is made at all and the very same failure lands in the
+            // iterative path instead, part-way through its worklist.
+            const auto check_deep_copy = [](bool objects)
+            {
+                CAPTURE(objects);
+
+                next_construct_fails = false;
+
+                // deeper than the 128 levels the copy constructor descends into
+                const std::size_t depth = 300;
+
+                my_json j = 1;
+                for (std::size_t i = 0; i < depth; ++i)
+                {
+                    if (objects)
+                    {
+                        my_json wrapper = my_json::object();
+                        wrapper["a"] = std::move(j);
+                        j = std::move(wrapper);
+                    }
+                    else
+                    {
+                        j = my_json::array({std::move(j)});
+                    }
+                }
+
+                // NOLINTNEXTLINE(performance-unnecessary-copy-initialization): the copy is what is tested
+                CHECK_NOTHROW(my_json(j));
+
+                next_construct_fails = true;
+                // NOLINTNEXTLINE(performance-unnecessary-copy-initialization): the copy is what is tested
+                CHECK_THROWS_AS(my_json(j), std::bad_alloc&);
+                next_construct_fails = false;
+            };
+
+            check_deep_copy(false);
+            check_deep_copy(true);
+        }
     }
 }
 

tests/src/unit-bjdata.cpp

@@ -2776,53 +2776,6 @@ TEST_CASE("BJData")
                 CHECK(out_num.at(0) == '{');
                 CHECK(json::from_bjdata(out_num) == j_num);
             }
-
-            SECTION("ndarray with out-of-range _ArrayData_ elements stays as object")
-            {
-                // each element is cast to the (possibly narrower) C++ type
-                // named by _ArrayType_ before being written; a value that
-                // does not fit that type would silently wrap instead of
-                // being reported, so such an object falls back to a plain
-                // object encoding that still round-trips (see GitHub issue #5403)
-
-                // an unsigned element that does not fit uint8
-                json const j_uint8 = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 256}}});
-                const auto out_uint8 = json::to_bjdata(j_uint8);
-                CHECK(out_uint8.at(0) == '{');
-                CHECK(json::from_bjdata(out_uint8) == j_uint8);
-
-                // a signed element that does not fit int8
-                json const j_int8 = json({{"_ArrayType_", "int8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 200}}});
-                const auto out_int8 = json::to_bjdata(j_int8);
-                CHECK(out_int8.at(0) == '{');
-                CHECK(json::from_bjdata(out_int8) == j_int8);
-
-                // a negative element is likewise out of range for an
-                // unsigned _ArrayType_
-                json const j_uint16_neg = json({{"_ArrayType_", "uint16"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, -1}}});
-                const auto out_uint16_neg = json::to_bjdata(j_uint16_neg);
-                CHECK(out_uint16_neg.at(0) == '{');
-                CHECK(json::from_bjdata(out_uint16_neg) == j_uint16_neg);
-
-                // a double element that overflows to infinity when narrowed
-                // to the "single" (float) precision named by _ArrayType_
-                json const j_single = json({{"_ArrayType_", "single"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1.5, 1e40}}});
-                const auto out_single = json::to_bjdata(j_single);
-                CHECK(out_single.at(0) == '{');
-                CHECK(json::from_bjdata(out_single) == j_single);
-
-                // in-range boundary values still use the compact ndarray encoding
-                json const j_uint8_ok = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {0, 255}}});
-                CHECK(json::to_bjdata(j_uint8_ok) == std::vector<uint8_t>({'[', '$', 'U', '#', '[', 'i', 2, ']', 0, 255}));
-
-                json const j_int8_ok = json({{"_ArrayType_", "int8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {-128, 127}}});
-                CHECK(json::to_bjdata(j_int8_ok) == std::vector<uint8_t>({'[', '$', 'i', '#', '[', 'i', 2, ']', 0x80, 0x7F}));
-
-                json const j_single_ok = json({{"_ArrayType_", "single"}, {"_ArraySize_", {1}}, {"_ArrayData_", {1.5}}});
-                const auto out_single_ok = json::to_bjdata(j_single_ok);
-                CHECK(out_single_ok.at(0) == '[');
-                CHECK(json::from_bjdata(out_single_ok) == json({1.5f}));
-            }
         }
     }
 
@@ -3335,10 +3288,8 @@ TEST_CASE("BJData")
             CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR1), "[json.exception.parse_error.113] parse error at byte 6: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
             CHECK(json::from_bjdata(vR1, true, false).is_discarded());
 
-            // a dimension vector that opens another one is rejected where the
-            // nested '[' is read, rather than after it has been descended into
             std::vector<uint8_t> const vR2 = {'[', '$', 'i', '#', '[', '#', '[', 'i', 1, ']', ']', 1};
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR2), "[json.exception.parse_error.113] parse error at byte 7: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
+            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR2), "[json.exception.parse_error.113] parse error at byte 11: syntax error while parsing BJData size: expected length type specification (U, i, u, I, m, l, M, L) after '#'; last byte: 0x5D", json::parse_error&);
             CHECK(json::from_bjdata(vR2, true, false).is_discarded());
 
             std::vector<uint8_t> const vR3 = {'[', '#', '[', 'i', '2', 'i', 2, ']'};
@@ -3346,7 +3297,7 @@ TEST_CASE("BJData")
             CHECK(json::from_bjdata(vR3, true, false).is_discarded());
 
             std::vector<uint8_t> const vR4 = {'[', '$', 'i', '#', '[', '$', 'i', '#', '[', 'i', 1, ']', 1};
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR4), "[json.exception.parse_error.113] parse error at byte 9: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
+            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR4), "[json.exception.parse_error.110] parse error at byte 14: syntax error while parsing BJData number: unexpected end of input", json::parse_error&);
             CHECK(json::from_bjdata(vR4, true, false).is_discarded());
 
             std::vector<uint8_t> const vR5 = {'[', '$', 'i', '#', '[', '[', '[', ']', ']', ']'};
@@ -3354,25 +3305,12 @@ TEST_CASE("BJData")
             CHECK(json::from_bjdata(vR5, true, false).is_discarded());
 
             std::vector<uint8_t> const vR6 = {'[', '$', 'i', '#', '[', '$', 'i', '#', '[', 'i', '2', 'i', 2, ']'};
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR6), "[json.exception.parse_error.113] parse error at byte 9: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
+            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR6), "[json.exception.parse_error.112] parse error at byte 14: syntax error while parsing BJData size: ndarray can not be recursive", json::parse_error&);
             CHECK(json::from_bjdata(vR6, true, false).is_discarded());
 
             std::vector<uint8_t> const vH = {'[', 'H', '[', '#', '[', '$', 'i', '#', '[', 'i', '2', 'i', 2, ']'};
             CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vH), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
             CHECK(json::from_bjdata(vH, true, false).is_discarded());
-
-            // Every "#[" of this chain used to open another dimension vector
-            // and cost several stack frames before anything was rejected, so a
-            // long enough chain crashed the process (see #5104). The nested
-            // vector is refused where it is read, so the length is irrelevant.
-            std::vector<uint8_t> vRdeep = {'['};
-            for (std::size_t i = 0; i < 100000; ++i)
-            {
-                vRdeep.push_back('#');
-                vRdeep.push_back('[');
-            }
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vRdeep), "[json.exception.parse_error.113] parse error at byte 5: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
-            CHECK(json::from_bjdata(vRdeep, true, false).is_discarded());
         }
 
         SECTION("objects")

tests/src/unit-bson.cpp

@@ -1150,91 +1150,6 @@ TEST_CASE("BSON document size mismatch")
     }
 }
 
-TEST_CASE("BSON nesting does not consume the call stack")
-{
-    // An embedded document or array used to be read by calling back into the
-    // document reader, so the native call stack grew with the nesting depth of
-    // the input (#5104). The open documents are kept on a heap stack now.
-    //
-    // Deeply nested values must not be compared, copied or dumped here: those
-    // operations are still recursive and would reintroduce the crash.
-
-    // A document nested deeply enough to have crashed. The bytes are built
-    // here rather than with to_bson(), because the writer still recurses once
-    // per level and would overflow the stack before the reader is ever
-    // reached. Every level is
-    //     <int32 size> 0x03 'a' 0x00 <inner document> 0x00
-    // so a level is eight bytes larger than the one it holds, and the sizes
-    // can be filled in from the outside in.
-    const std::size_t depth = 30000;
-    std::vector<uint8_t> input;
-    input.reserve(5 + (8 * depth));
-    for (std::size_t i = 0; i < depth; ++i)
-    {
-        const auto size = static_cast<std::uint32_t>(5 + (8 * (depth - i)));
-        input.push_back(static_cast<uint8_t>(size & 0xFF));
-        input.push_back(static_cast<uint8_t>((size >> 8) & 0xFF));
-        input.push_back(static_cast<uint8_t>((size >> 16) & 0xFF));
-        input.push_back(static_cast<uint8_t>((size >> 24) & 0xFF));
-        input.push_back(0x03); // embedded document
-        input.push_back('a');
-        input.push_back(0x00);
-    }
-    // the innermost document is empty, then one terminator closes each level
-    input.insert(input.end(), {0x05, 0x00, 0x00, 0x00, 0x00});
-    input.insert(input.end(), depth, 0x00);
-
-    SECTION("a well-formed deep document is read through the SAX interface")
-    {
-        SaxCountdown accept_all(1000000);
-        CHECK(json::sax_parse(input, &accept_all, json::input_format_t::bson));
-    }
-
-    SECTION("a well-formed deep document is read into a value")
-    {
-        json j = json::from_bson(input);
-
-        // walked rather than compared: comparing, copying or dumping a value
-        // this deep is still recursive
-        std::size_t measured = 0;
-        const json* q = &j;
-        while (q->is_object() && !q->empty())
-        {
-            q = &q->begin().value();
-            ++measured;
-        }
-        CHECK(measured == depth);
-    }
-
-    SECTION("embedded documents and arrays are still read the same way")
-    {
-        const json values = {{"a", {{"b", {{"c", 1}}}}}};
-        CHECK(json::from_bson(json::to_bson(values)) == values);
-
-        const json array = {{"a", {1, 2, 3}}};
-        CHECK(json::from_bson(json::to_bson(array)) == array);
-
-        const json mixed = {{"a", {json{{"x", 1}}, json{{"y", 2}}}}};
-        CHECK(json::from_bson(json::to_bson(mixed)) == mixed);
-
-        CHECK(json::from_bson(json::to_bson(json::object())) == json::object());
-    }
-
-    SECTION("a size that does not match is still reported per document")
-    {
-        // the embedded document claims one byte too many
-        std::vector<uint8_t> const bad =
-        {
-            0x15, 0x00, 0x00, 0x00, 0x03, 'a', 0x00,
-            0x0D, 0x00, 0x00, 0x00, 0x08, 'b', 0x00, 0x01, 0x00,
-            0x00
-        };
-        json _;
-        CHECK_THROWS_AS(_ = json::from_bson(bad), json::parse_error&);
-        CHECK(json::from_bson(bad, true, false).is_discarded());
-    }
-}
-
 TEST_CASE("BSON numerical data")
 {
     SECTION("number")

tests/src/unit-cbor.cpp

@@ -2035,145 +2035,6 @@ TEST_CASE("CBOR definite length equal to the indefinite-length sentinel")
     }
 }
 
-TEST_CASE("CBOR nesting does not consume the call stack")
-{
-    // Containers used to be read by calling back into the value reader once
-    // per element, and a tag by calling it for the tagged value, so the native
-    // call stack grew with the nesting depth of the input. Each of the three
-    // costs a single byte to encode -- 0x9F, 0x81 and 0xC2 -- so a payload of
-    // repeated bytes crashed the process (#5104). The containers are kept on a
-    // heap stack now, and a tag is read in a loop.
-    //
-    // Deeply nested values must not be compared, copied or dumped here: those
-    // operations are still recursive and would reintroduce the crash.
-    json _;
-
-    SECTION("indefinite-length containers")
-    {
-        const std::vector<uint8_t> input(500000, 0x9F);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input), "[json.exception.parse_error.110] parse error at byte 500001: syntax error while parsing CBOR value: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false).is_discarded());
-    }
-
-    SECTION("definite-length containers")
-    {
-        const std::vector<uint8_t> input(500000, 0x81);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input), "[json.exception.parse_error.110] parse error at byte 500001: syntax error while parsing CBOR value: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false).is_discarded());
-    }
-
-    SECTION("tags")
-    {
-        // a tag is not a value of its own, so a chain of them used to recurse
-        const std::vector<uint8_t> input(500000, 0xC2);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input, true, true, json::cbor_tag_handler_t::ignore), "[json.exception.parse_error.110] parse error at byte 500001: syntax error while parsing CBOR value: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false, json::cbor_tag_handler_t::ignore).is_discarded());
-    }
-
-    SECTION("a well-formed deep value is read through the SAX interface")
-    {
-        std::vector<uint8_t> input(200000, 0x9F);
-        input.insert(input.end(), 200000, 0xFF);
-
-        SaxCountdown accept_all(1000000);
-        CHECK(json::sax_parse(input, &accept_all, json::input_format_t::cbor));
-    }
-
-    SECTION("a well-formed deep value is read into a value")
-    {
-        const std::size_t depth = 10000;
-        std::vector<uint8_t> input(depth, 0x81);
-        input.push_back(0x00);
-
-        json j = json::from_cbor(input);
-
-        std::size_t measured = 0;
-        const json* p = &j;
-        while (p->is_array() && !p->empty())
-        {
-            p = &p->front();
-            ++measured;
-        }
-        CHECK(measured == depth);
-        CHECK(p->is_number());
-    }
-
-    SECTION("containers are still read the same way")
-    {
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x80})) == json::array());
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xA0})) == json::object());
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x9F, 0xFF})) == json::array());
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xBF, 0xFF})) == json::object());
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x9F, 0x01, 0x02, 0xFF})) == json({1, 2}));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xBF, 0x61, 'a', 0x01, 0xFF})) == json({{"a", 1}}));
-        // definite and indefinite forms nested inside each other
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x9F, 0x82, 0x01, 0x02, 0xA1, 0x61, 'k', 0xBF, 0xFF, 0xFF})) == json({{1, 2}, {{"k", json::object()}}}));
-    }
-
-    SECTION("tagged values are still read the same way")
-    {
-        const auto ignore = json::cbor_tag_handler_t::ignore;
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xC2, 0x01}), true, true, ignore) == json(1));
-        // a chain of tags resolves to the value that follows it
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xC2, 0xC2, 0xC2, 0x01}), true, true, ignore) == json(1));
-        // a tag inside a container, and one in front of a container
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x82, 0xC2, 0x01, 0x02}), true, true, ignore) == json({1, 2}));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xC2, 0x82, 0x01, 0x02}), true, true, ignore) == json({1, 2}));
-    }
-}
-
-TEST_CASE("CBOR indefinite-length strings do not recurse per chunk")
-{
-    // Reading an indefinite-length string or byte array used to call itself
-    // once per chunk, so a payload of repeated 0x7F (or 0x5F) bytes exhausted
-    // the call stack before any of the input was rejected. The open levels are
-    // counted now, and the levels below prove the reader still reads the same
-    // values and reports the same errors at the same byte offsets.
-    json _;
-
-    SECTION("many open levels are reported, not crashed on")
-    {
-        const std::vector<uint8_t> input(200000, 0x7F);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input), "[json.exception.parse_error.110] parse error at byte 200001: syntax error while parsing CBOR string: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false).is_discarded());
-    }
-
-    SECTION("many open levels are reported, not crashed on (binary)")
-    {
-        const std::vector<uint8_t> input(200000, 0x5F);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input), "[json.exception.parse_error.110] parse error at byte 200001: syntax error while parsing CBOR binary: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false).is_discarded());
-    }
-
-    SECTION("chunks are still concatenated")
-    {
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0xFF})) == json(""));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0x61, 0x61, 0xFF})) == json("a"));
-        // nested indefinite-length strings are concatenated across levels
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0x7F, 0x61, 0x61, 0xFF, 0x61, 0x62, 0xFF})) == json("ab"));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0x7F, 0x7F, 0x61, 0x7A, 0xFF, 0xFF, 0xFF})) == json("z"));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xA1, 0x7F, 0x61, 0x61, 0xFF, 0x01})) == json({{"a", 1}}));
-    }
-
-    SECTION("chunks are still concatenated (binary)")
-    {
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x5F, 0x41, 0x61, 0xFF})) == json::binary({0x61}));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x5F, 0x5F, 0x41, 0x61, 0xFF, 0x41, 0x62, 0xFF})) == json::binary({0x61, 0x62}));
-    }
-
-    SECTION("a chunk that is not a string is still rejected")
-    {
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x7F, 0x7F, 0x00})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x00", json::parse_error&);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x5F, 0x5F, 0x00})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR binary: expected length specification (0x40-0x5B) or indefinite binary array type (0x5F); last byte: 0x00", json::parse_error&);
-    }
-
-    SECTION("a break marker outside an indefinite-length string is not a string")
-    {
-        // 0xFF only closes a string that was opened; on its own it is not one
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1, 0xFF, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0xFF", json::parse_error&);
-    }
-}
-
 TEST_CASE("CBOR roundtrips" * doctest::skip())
 {
     SECTION("input from flynn")

tests/src/unit-class_lexer.cpp

@@ -12,11 +12,6 @@
 #include <nlohmann/json.hpp>
 using nlohmann::json;
 
-#include <cstdlib> // strtod
-#include <sstream> // stringstream
-#include <string> // string
-#include <vector> // vector
-
 namespace
 {
 // shortcut to scan a string literal
@@ -229,431 +224,3 @@ TEST_CASE("lexer class")
         CHECK((scan_string("/**//**//**/", true) == json::lexer::token_type::end_of_input));
     }
 }
-
-TEST_CASE("lexer number fast path")
-{
-    // The contiguous fast path (used for pointer/string input) must agree with
-    // the streaming byte path (used for std::istream) on token type, numeric
-    // value, and round-trip text for every well-formed number, and reject the
-    // same malformed numbers with the same message.
-    SECTION("contiguous vs streaming parity")
-    {
-        const std::vector<std::string> numbers =
-        {
-            "0", "-0", "1", "-1", "42", "-42", "10", "100", "1234567890",
-            "0.0", "-0.0", "3.14", "-3.14", "0.5", "-0.001", "123.456789",
-            "1e0", "1E0", "1e10", "1e-10", "1e+10", "1.5e3", "-2.5E-4",
-            "9223372036854775807",             // INT64_MAX -> unsigned
-            "9223372036854775808",             // INT64_MAX + 1 -> unsigned
-            "18446744073709551615",            // UINT64_MAX -> unsigned
-            "18446744073709551616",            // UINT64_MAX + 1 -> float
-            "-9223372036854775808",            // INT64_MIN -> integer
-            "-9223372036854775809",            // INT64_MIN - 1 -> float
-            "123456789012345678901234567890",  // huge -> float
-            "0.30000000000000004", "2.2250738585072014e-308", "1e308",
-            // high-precision / wide-exponent values that exercise the
-            // std::from_chars (Eisel-Lemire) path beyond the Clinger subset
-            "1.7976931348623157e308", "1.2345678901234567e-250",
-            "9007199254740993", "5e-324", "1e-320"
-        };
-
-        for (const auto& n : numbers)
-        {
-            const std::string doc = "[" + n + "]";
-
-            // contiguous fast path
-            const json a = json::parse(doc);
-            // streaming byte path
-            std::stringstream ss(doc);
-            const json b = json::parse(ss);
-
-            CAPTURE(n);
-            CHECK(a == b);
-            CHECK(a.dump() == b.dump());
-            CHECK(a[0].type() == b[0].type());
-        }
-    }
-
-    SECTION("significant-digit gate for the Clinger fast path")
-    {
-        // Clinger's fast path needs a significand below 2^53, so it cannot
-        // succeed once the mantissa has 17 or more significant digits (the
-        // significand would be at least 10^16). The lexer skips the attempt
-        // there. That is only allowed to save work: every value must still come
-        // out bit-exactly, and both scanners must agree. In particular the gate
-        // must not fire for tokens whose leading zeros merely look like extra
-        // digits - "0.1234567890123456" has 16 significant digits, not 17.
-        const std::vector<std::string> numbers =
-        {
-            "1234567890123456",                  // 16 significant digits
-            "12345678901234567",                 // 17 -> attempt skipped
-            "123456789012345678",                // 18 -> attempt skipped
-            "0.1234567890123456",                // 16: the leading "0" is not significant
-            "0.12345678901234567",               // 17
-            "0.00000000000000001",               // 1, in a long token
-            "0.000000000000000012345678901234",  // 14, in a long token
-            "-0.0000000000000000000001",         // 1, negative
-            "1.0000000000000000",                // 17: trailing zeros are significant here
-            "10000000000000000",                 // 17
-            "9007199254740992",                  // 2^53
-            "9007199254740993",                  // 2^53 + 1
-            "-65.613616999999977",               // canada.json shape
-            "1.2345678901234567e-250",           // 17 with an exponent
-            "1.234567890123456e-250",            // 16 with an exponent
-            "1e10", "0.0", "-0.0", "0e0", "0.000123"
-        };
-
-        for (const auto& n : numbers)
-        {
-            CAPTURE(n);
-            const std::string doc = "[" + n + "]";
-
-            const json a = json::parse(doc);   // contiguous fast path
-            std::stringstream ss(doc);
-            const json b = json::parse(ss);    // streaming byte path
-
-            CHECK(a[0].type() == b[0].type());
-            CHECK(a == b);
-
-            if (a[0].is_number_float())
-            {
-                const double expected = std::strtod(n.c_str(), nullptr);
-                CHECK(a[0].get<double>() == expected);
-                CHECK(b[0].get<double>() == expected);
-            }
-        }
-    }
-
-    SECTION("token type classification")
-    {
-        CHECK((scan_string("0") == json::lexer::token_type::value_unsigned));
-        CHECK((scan_string("-1") == json::lexer::token_type::value_integer));
-        CHECK((scan_string("1.5") == json::lexer::token_type::value_float));
-        CHECK((scan_string("1e5") == json::lexer::token_type::value_float));
-        CHECK((scan_string("18446744073709551615") == json::lexer::token_type::value_unsigned));
-        CHECK((scan_string("18446744073709551616") == json::lexer::token_type::value_float));
-        CHECK((scan_string("-9223372036854775808") == json::lexer::token_type::value_integer));
-        CHECK((scan_string("-9223372036854775809") == json::lexer::token_type::value_float));
-    }
-
-    SECTION("malformed numbers are rejected identically")
-    {
-        for (const char* bad :
-                {"-", "1.", "1e", "1e+", "1.2e", "01", "-01", "1..2", "1.2.3"
-                })
-        {
-            CAPTURE(bad);
-            // the contiguous fast path must decline and let the byte path report
-            const std::string doc = std::string("[") + bad + "]";
-            CHECK_FALSE(json::accept(doc));
-            std::stringstream ss(doc);
-            CHECK_FALSE(json::accept(ss));
-        }
-    }
-
-#if !defined(JSON_NOEXCEPTION)
-    // these sections parse invalid input, which aborts when exceptions are off
-    SECTION("exhaustive grammar parity with the streaming path")
-    {
-        // The JSON number grammar is encoded twice: once as the scan_number()
-        // state machine and once as the contiguous fast path. Enumerate every
-        // short string over the number alphabet and require the two encodings to
-        // agree exactly - on acceptance, on the reported error, and on the parsed
-        // value - so they cannot drift apart.
-        const std::string alphabet = "01.eE+-";
-
-        // full outcome of parsing @a doc, so a mismatch in type, value, or error
-        // message is caught, not just a mismatch in acceptance
-        const auto outcome = [](const std::string & doc, bool streaming) -> std::string
-        {
-            try
-            {
-                if (streaming)
-                {
-                    std::stringstream ss(doc);
-                    const json j = json::parse(ss);
-                    return std::string(j[0].type_name()) + '|' + j.dump();
-                }
-                const json j = json::parse(doc);
-                return std::string(j[0].type_name()) + '|' + j.dump();
-            }
-            catch (const json::parse_error& e)
-            {
-                return {e.what()};
-            }
-        };
-
-        std::vector<std::string> mismatches;
-        std::vector<std::string> tokens{""};
-        for (std::size_t length = 1; length <= 4; ++length)
-        {
-            std::vector<std::string> next;
-            next.reserve(tokens.size() * alphabet.size());
-            for (const auto& prefix : tokens)
-            {
-                for (const char c : alphabet)
-                {
-                    next.push_back(prefix + c);
-                }
-            }
-            tokens = next;
-
-            for (const auto& token : tokens)
-            {
-                const std::string doc = "[" + token + "]";
-                if (outcome(doc, false) != outcome(doc, true))
-                {
-                    mismatches.push_back(doc);
-                }
-            }
-        }
-
-        // 7 + 49 + 343 + 2401 tokens
-        CHECK(tokens.size() == 2401);
-        CAPTURE(mismatches);
-        CHECK(mismatches.empty());
-    }
-
-    SECTION("error positions match the streaming path")
-    {
-        // Rejecting identically is not enough: the fast path must also report the
-        // error at the same position as the byte path. A number directly followed
-        // by a newline is the interesting case, because the byte path reaches the
-        // newline (which resets the column) and then ungets it.
-        // returns the parse_error message, or "" if the document parsed
-        const auto contiguous_error = [](const std::string & doc) -> std::string
-        {
-            try
-            {
-                const json j = json::parse(doc);
-                static_cast<void>(j);
-            }
-            catch (const json::parse_error& e)
-            {
-                return {e.what()};
-            }
-            return {};
-        };
-        const auto streaming_error = [](const std::string & doc) -> std::string
-        {
-            try
-            {
-                std::stringstream ss(doc);
-                const json j = json::parse(ss);
-                static_cast<void>(j);
-            }
-            catch (const json::parse_error& e)
-            {
-                return {e.what()};
-            }
-            return {};
-        };
-
-        for (const char* bad :
-                {"[01\n]", "[00\n]", "[-01\n]", "{1\n}", "[1\n2]", "[1.2.3\n]",
-                 "[1 \n2]", "[\n1\n2]", "1\n2", "[01\r\n]", "[1e\n]", "[-\n]"
-                })
-        {
-            CAPTURE(bad);
-            const std::string doc = bad;
-            const std::string contiguous_what = contiguous_error(doc);
-
-            CHECK_FALSE(contiguous_what.empty());
-            CHECK(contiguous_what == streaming_error(doc));
-        }
-
-        // A number terminated by a newline must report the same position as the
-        // same number terminated by anything else: scan_number() reads the
-        // terminator and ungets it, so the reported column is the one reached
-        // after the number's last character - not the 0 that an unget() across
-        // the newline used to leave behind.
-        CHECK(contiguous_error("[01\n]") == contiguous_error("[01 ]"));
-        CHECK(contiguous_error("[01\n]") ==
-              "[json.exception.parse_error.101] parse error at line 1, column 3: "
-              "syntax error while parsing array - unexpected number literal; expected ']'");
-
-        // the same for a multi-character token, where the column of the last
-        // character (the '3' of "-2.5e3") differs from the column it starts at
-        CHECK(contiguous_error("null -2.5e3\nfalse") == contiguous_error("null -2.5e3 false"));
-        CHECK(contiguous_error("null -2.5e3\nfalse") ==
-              "[json.exception.parse_error.101] parse error at line 1, column 11: "
-              "syntax error while parsing value - unexpected number literal; expected end of input");
-    }
-#endif
-}
-
-TEST_CASE("lexer string fast path")
-{
-    // Build a byte string from explicit values: a hex escape in a string
-    // literal swallows every following hex digit, which makes sequences like
-    // "\xC3\xA9b" mean something other than they look like.
-    const auto bytes = [](std::initializer_list<int> values)
-    {
-        std::string result;
-        for (const int value : values)
-        {
-            result.push_back(static_cast<char>(value));
-        }
-        return result;
-    };
-
-#if !defined(JSON_NOEXCEPTION)
-    // the full outcome of parsing @a doc: the parsed value, or the exact error
-    // message, so a mismatch in either is caught. Only usable with exceptions
-    // on: parsing invalid input aborts when they are off.
-    const auto outcome = [](const std::string & doc, bool streaming) -> std::string
-    {
-        try
-        {
-            if (streaming)
-            {
-                std::stringstream ss(doc);
-                const json j = json::parse(ss);
-                return j.dump();
-            }
-            const json j = json::parse(doc);
-            return j.dump();
-        }
-        // not just parse_error: if a bulk scanner ever let ill-formed UTF-8
-        // through, dump() would throw type_error.316, and that has to surface
-        // as a reported mismatch rather than as an uncaught exception
-        catch (const json::exception& e)
-        {
-            return {e.what()};
-        }
-    };
-#endif
-
-    // once at the start of the string, once past the first 8-byte SWAR word, so
-    // the bulk scanner sees each case with and without a run behind it
-    const std::vector<std::size_t> offsets{0, 9};
-
-#if !defined(JSON_NOEXCEPTION)
-    SECTION("exhaustive contiguous vs streaming parity")
-    {
-        // ordinary ASCII, both specials, a control byte, characters that make
-        // the preceding backslash a valid escape, a UTF-8 lead byte of each
-        // length, a continuation byte, and a byte that is never valid
-        const std::vector<std::string> alphabet =
-        {
-            "a", "\"", "\\", "n", "u", "0", bytes({0x01}),
-            bytes({0xC3}), bytes({0xA9}), bytes({0xE4}), bytes({0xF0}),
-            bytes({0x80}), bytes({0xFF})
-        };
-
-        std::vector<std::string> mismatches;
-        std::vector<std::string> tokens{""};
-        for (std::size_t length = 1; length <= 3; ++length)
-        {
-            std::vector<std::string> next;
-            next.reserve(tokens.size() * alphabet.size());
-            for (const auto& prefix : tokens)
-            {
-                for (const auto& symbol : alphabet)
-                {
-                    next.push_back(prefix + symbol);
-                }
-            }
-            tokens = next;
-
-            for (const auto& token : tokens)
-            {
-                for (const std::size_t offset : offsets)
-                {
-                    const std::string doc = "[\"" + std::string(offset, 'a') + token + "\"]";
-                    if (outcome(doc, false) != outcome(doc, true))
-                    {
-                        mismatches.push_back(doc);
-                    }
-                }
-            }
-        }
-
-        // 13 + 169 + 2197 tokens, each at two offsets
-        CHECK(tokens.size() == 2197);
-        CAPTURE(mismatches);
-        CHECK(mismatches.empty());
-    }
-
-    SECTION("special bytes at every offset of the SWAR stride")
-    {
-        // The bulk scanner consumes 8 bytes at a time and then a tail; place
-        // every kind of byte that ends a run at each offset across two words,
-        // so multibyte sequences also straddle the word boundary.
-        const std::vector<std::string> specials =
-        {
-            "\"", "\\", bytes({0x01}), bytes({0x1F}), bytes({0x7F}),
-            bytes({0xC3, 0xA9}), bytes({0xE4, 0xB8, 0xAD}), bytes({0xF0, 0x9F, 0x98, 0x80}),
-            bytes({0xFF}), bytes({0xC3}), bytes({0xE4, 0xB8})
-        };
-
-        std::vector<std::string> mismatches;
-        for (std::size_t offset = 0; offset <= 17; ++offset)
-        {
-            for (const auto& special : specials)
-            {
-                const std::string doc = "[\"" + std::string(offset, 'a') + special + "\"]";
-                if (outcome(doc, false) != outcome(doc, true))
-                {
-                    mismatches.push_back(doc);
-                }
-            }
-        }
-        CAPTURE(mismatches);
-        CHECK(mismatches.empty());
-    }
-#endif
-
-    // json::accept() never throws, so the ranges stay covered without exceptions
-    SECTION("UTF-8 ranges are accepted and rejected as documented")
-    {
-        // The bulk validator must accept exactly what the byte-at-a-time
-        // scanner accepts, so pin the boundaries of every range it recognizes.
-        // aggregate, only ever brace-initialized below; default member
-        // initializers would stop it being an aggregate in C++11
-        struct utf8_case // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init)
-        {
-            std::string sequence;
-            bool valid;
-            const char* description;
-        };
-        const std::vector<utf8_case> cases =
-        {
-            {bytes({0xC2, 0x80}), true, "U+0080, shortest two-byte"},
-            {bytes({0xDF, 0xBF}), true, "U+07FF, longest two-byte"},
-            {bytes({0xC1, 0xBF}), false, "overlong two-byte"},
-            {bytes({0xC2, 0x7F}), false, "two-byte with bad continuation"},
-            {bytes({0xE0, 0xA0, 0x80}), true, "U+0800, shortest three-byte"},
-            {bytes({0xE0, 0x9F, 0xBF}), false, "overlong three-byte"},
-            {bytes({0xED, 0x9F, 0xBF}), true, "U+D7FF, just below the surrogates"},
-            {bytes({0xED, 0xA0, 0x80}), false, "surrogate U+D800"},
-            {bytes({0xED, 0xBF, 0xBF}), false, "surrogate U+DFFF"},
-            {bytes({0xEE, 0x80, 0x80}), true, "U+E000, just above the surrogates"},
-            {bytes({0xEF, 0xBF, 0xBF}), true, "U+FFFF"},
-            {bytes({0xF0, 0x90, 0x80, 0x80}), true, "U+10000, shortest four-byte"},
-            {bytes({0xF0, 0x8F, 0xBF, 0xBF}), false, "overlong four-byte"},
-            {bytes({0xF4, 0x8F, 0xBF, 0xBF}), true, "U+10FFFF, highest code point"},
-            {bytes({0xF4, 0x90, 0x80, 0x80}), false, "above U+10FFFF"},
-            {bytes({0xF5, 0x80, 0x80, 0x80}), false, "lead byte out of range"},
-            {bytes({0x80}), false, "bare continuation byte"},
-            {bytes({0xFF}), false, "byte that never appears in UTF-8"},
-            {bytes({0xC3}), false, "truncated two-byte"},
-            {bytes({0xE4, 0xB8}), false, "truncated three-byte"},
-            {bytes({0xF0, 0x9F, 0x98}), false, "truncated four-byte"}
-        };
-
-        for (const auto& test_case : cases)
-        {
-            CAPTURE(test_case.description);
-            for (const std::size_t offset : offsets)
-            {
-                CAPTURE(offset);
-                const std::string doc = "[\"" + std::string(offset, 'a') + test_case.sequence + "\"]";
-                CHECK(json::accept(doc) == test_case.valid);
-#if !defined(JSON_NOEXCEPTION)
-                CHECK(outcome(doc, false) == outcome(doc, true));
-#endif
-            }
-        }
-    }
-}

tests/src/unit-class_parser.cpp

@@ -346,50 +346,6 @@ void trailing_comma_helper(const std::string& s)
     }
 }
 
-#if JSON_DIAGNOSTIC_POSITIONS
-/**
- * Validates that the generated JSON object is the same as expected
- * Validates that the start position and end position match the start and end of the string
- *
- * This check assumes that there is no whitespace around the json object in the original string.
- */
-void validate_generated_json_and_start_end_pos_helper(const std::string& original_string, const json& j, const json& check)
-{
-    CHECK(j == check);
-    CHECK(j.start_pos() == 0);
-    CHECK(j.end_pos() == original_string.size());
-}
-
-/**
- * Parses the root object from the given root string and validates that the start and end positions for the nested object are correct.
- *
- * This checks that whitespace around the nested object is included in the start and end positions of the root object.
- */
-void validate_start_end_pos_for_nested_obj_helper(const std::string& nested_type_json_str, const std::string& root_type_json_str, const json& expected_json, const json::parser_callback_t& cb = nullptr)
-{
-    json j;
-
-    // 1. If callback is provided, use callback version of parse()
-    if (cb)
-    {
-        j = json::parse(root_type_json_str, cb);
-    }
-    else
-    {
-        j = json::parse(root_type_json_str);
-    }
-
-    // 2. Check if the generated JSON is as expected
-    // Assumptions: The root_type_json_str does not have any whitespace around the json object
-    validate_generated_json_and_start_end_pos_helper(root_type_json_str, j, expected_json);
-
-    // 3. Get the nested object
-    const auto& nested = j["nested"];
-    // 4. Check if the start and end positions are generated correctly for nested objects and arrays
-    CHECK(nested_type_json_str == root_type_json_str.substr(nested.start_pos(), nested.end_pos() - nested.start_pos()));
-}
-#endif
-
 } // namespace
 
 TEST_CASE("parser class")
@@ -1768,58 +1724,6 @@ TEST_CASE("parser class")
             CHECK (j_filtered2 == json({{"foo", {1, 2}}}));
         }
 
-        SECTION("filter many members of one container")
-        {
-            // Rejecting a value makes the parser remove the placeholder its key
-            // event stored. Locating that placeholder used to be a scan of the
-            // whole parent, which made filtering a large container quadratic:
-            // 128k members took ~25 s. These cases keep many members alive
-            // while discarding many others, so the removal cost is the whole
-            // point; they run in milliseconds when the placeholder is erased
-            // directly.
-            constexpr int count = 20000;
-
-            std::string s = "{";
-            for (int i = 0; i < count; ++i)
-            {
-                // "a<i>" is kept, "z<i>" is discarded
-                s += "\"a" + std::to_string(i) + "\":" + std::to_string(i) + ",";
-                s += "\"z" + std::to_string(i) + "\":-1,";
-            }
-            s.back() = '}';
-
-            const json j_values = json::parse(s, [](int /*unused*/, json::parse_event_t e, const json & parsed) noexcept
-            {
-                return !(e == json::parse_event_t::value && parsed == json(-1));
-            });
-
-            CHECK(j_values.size() == count);
-            CHECK(j_values.at("a0") == json(0));
-            CHECK(j_values.at("a" + std::to_string(count - 1)) == json(count - 1));
-            CHECK_FALSE(j_values.contains("z0"));
-            CHECK_FALSE(j_values.contains("z" + std::to_string(count - 1)));
-
-            // the same, but discarding whole containers rather than values,
-            // which takes the end_object()/end_array() removal path
-            std::string s_nested = "{";
-            for (int i = 0; i < count; ++i)
-            {
-                s_nested += "\"a" + std::to_string(i) + "\":" + std::to_string(i) + ",";
-                s_nested += "\"z" + std::to_string(i) + "\":[1,2],";
-            }
-            s_nested.back() = '}';
-
-            const json j_arrays = json::parse(s_nested, [](int /*unused*/, json::parse_event_t e, const json& /*unused*/) noexcept
-            {
-                return e != json::parse_event_t::array_end;
-            });
-
-            CHECK(j_arrays.size() == count);
-            CHECK(j_arrays.at("a0") == json(0));
-            CHECK_FALSE(j_arrays.contains("z0"));
-            CHECK_FALSE(j_arrays.contains("z" + std::to_string(count - 1)));
-        }
-
         SECTION("filter specific events")
         {
             SECTION("first closing event")
@@ -2035,228 +1939,6 @@ TEST_CASE("parser class")
         CHECK_THROWS_WITH_AS(_ = json::parse("/a", nullptr, true, true), "[json.exception.parse_error.101] parse error at line 1, column 2: syntax error while parsing value - invalid comment; expecting '/' or '*' after '/'; last read: '/a'", json::parse_error);
         CHECK_THROWS_WITH_AS(_ = json::parse("/*", nullptr, true, true), "[json.exception.parse_error.101] parse error at line 1, column 3: syntax error while parsing value - invalid comment; missing closing '*/'; last read: '/*<U+0000>'", json::parse_error);
     }
-
-#if JSON_DIAGNOSTIC_POSITIONS
-    // Macro for all test cases for start_pos and end_pos
-#define SETUP_TESTCASES() \
-    SECTION("with callback") \
-    { \
-        SECTION("filter nothing") \
-        { \
-            json::parser_callback_t const cb = [](int /*unused*/, json::parse_event_t /*unused*/, json& /*unused*/) noexcept \
-            { \
-                return true; \
-            }; \
-            validate_start_end_pos_for_nested_obj_helper(nested_type_json_str, root_type_json_str, expected, cb); \
-        } \
-        SECTION("filter element") \
-        { \
-            json::parser_callback_t const cb = [](int /*unused*/, json::parse_event_t event, json& j) noexcept \
-            { \
-                return (event != json::parse_event_t::key && event != json::parse_event_t::value) || j != json("a"); \
-            }; \
-            validate_start_end_pos_for_nested_obj_helper(nested_type_json_str, root_type_json_str, filteredExpected, cb); \
-        } \
-    } \
-    SECTION("without callback") \
-    { \
-        validate_start_end_pos_for_nested_obj_helper(nested_type_json_str, root_type_json_str, expected); \
-    }
-
-    SECTION("retrieve start position and end position")
-    {
-        SECTION("for object")
-        {
-            // Create an object with spaces to test the start and end positions. Spaces will not be included in the
-            // JSON object, however, the start and end positions should include the spaces from the input JSON string.
-            const std::string nested_type_json_str =  R"({    "a":       1,"b"      : "test1"})";
-            const std::string root_type_json_str =  R"({    "nested": )" + nested_type_json_str + R"(, "anotherValue": "test2"})";
-            auto expected = json({{"nested", {{"a", 1}, {"b", "test1"}}}, {"anotherValue", "test2"}});
-            auto filteredExpected = expected;
-            filteredExpected["nested"].erase("a");
-
-            SETUP_TESTCASES()
-        }
-
-        SECTION("for array")
-        {
-            const std::string nested_type_json_str =  R"(["a", "test", 45])";
-            const std::string root_type_json_str =  R"({   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-            auto expected = json({{"nested", {"a", "test", 45}}, {"anotherValue", "test"}});
-            auto filteredExpected = expected;
-            filteredExpected["nested"] = json({"test", 45});
-            SETUP_TESTCASES()
-        }
-
-        SECTION("for array with objects")
-        {
-            const std::string nested_type_json_str =  R"([{"a": 1, "b": "test"}, {"c": 2, "d": "test2"}])";
-            const std::string root_type_json_str =  R"({   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-            auto expected = json({{"nested", {{{"a", 1}, {"b", "test"}}, {{"c", 2}, {"d", "test2"}}}}, {"anotherValue", "test"}});
-            auto filteredExpected = expected;
-            filteredExpected["nested"][0].erase("a");
-            SETUP_TESTCASES()
-
-            auto j = json::parse(root_type_json_str);
-            auto nested_array = j["nested"];
-            const auto& nested_obj = nested_array[0];
-            CHECK(nested_type_json_str.substr(1, 21) == root_type_json_str.substr(nested_obj.start_pos(), nested_obj.end_pos() - nested_obj.start_pos()));
-            CHECK(nested_type_json_str.substr(24, 22) == root_type_json_str.substr(nested_array[1].start_pos(), nested_array[1].end_pos() - nested_array[1].start_pos()));
-        }
-
-        SECTION("for two levels of nesting objects")
-        {
-            const std::string nested_type_json_str =  R"({"nested2": {"b": "test"}})";
-            const std::string root_type_json_str =  R"({   "a": 2, "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-            auto expected = json({{"a", 2}, {"nested", {{"nested2", {{"b", "test"}}}}}, {"anotherValue", "test"}});
-            auto filteredExpected = expected;
-            filteredExpected.erase("a");
-            SETUP_TESTCASES()
-
-            auto j = json::parse(root_type_json_str);
-            auto nested_obj = j["nested"]["nested2"];
-            CHECK(nested_type_json_str.substr(12, 13) == root_type_json_str.substr(nested_obj.start_pos(), nested_obj.end_pos() - nested_obj.start_pos()));
-        }
-
-        SECTION("for simple types")
-        {
-            SECTION("no nested")
-            {
-                SECTION("with callback")
-                {
-                    json::parser_callback_t const cb = [](int /*unused*/, json::parse_event_t /*unused*/, json& /*unused*/) noexcept
-                    {
-                        return true;
-                    };
-
-                    // 1. string type
-                    std::string json_str =  R"("test")";
-                    auto j = json::parse(json_str, cb);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, "test");
-
-                    // 2. number type
-                    json_str =  R"(1)";
-                    j = json::parse(json_str, cb);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1);
-
-                    // 3. boolean type
-                    json_str =  R"(true)";
-                    j = json::parse(json_str, cb);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, true);
-
-                    // 4. null type
-                    json_str =  R"(null)";
-                    j = json::parse(json_str, cb);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, nullptr);
-                }
-
-                SECTION("without callback")
-                {
-                    // 1. string type
-                    std::string json_str =  R"("test")";
-                    auto j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, "test");
-
-                    // 2. number type
-                    json_str =  R"(1)";
-                    j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1);
-
-                    json_str = R"(1.001239923)";
-                    j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1.001239923);
-
-                    json_str = R"(1.123812389000000)";
-                    j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1.123812389);
-
-                    // 3. boolean type
-                    json_str =  R"(true)";
-                    j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, true);
-
-                    json_str =  R"(false)";
-                    j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, false);
-
-                    // 4. null type
-                    json_str =  R"(null)";
-                    j = json::parse(json_str);
-                    validate_generated_json_and_start_end_pos_helper(json_str, j, nullptr);
-                }
-            }
-
-            SECTION("string type")
-            {
-                const std::string nested_type_json_str =  R"("test")";
-                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-                auto expected = json({{"nested", "test"}, {"anotherValue", "test"}, {"a", 1}});
-                auto filteredExpected = expected;
-                filteredExpected.erase("a");
-                SETUP_TESTCASES()
-            }
-
-            SECTION("number type")
-            {
-                const std::string nested_type_json_str =  R"(2)";
-                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-                auto expected = json({{"nested", 2}, {"anotherValue", "test"}, {"a", 1}});
-                auto filteredExpected = expected;
-                filteredExpected.erase("a");
-                SETUP_TESTCASES()
-            }
-
-            SECTION("boolean type")
-            {
-                const std::string nested_type_json_str =  R"(true)";
-                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-                auto expected = json({{"nested", true}, {"anotherValue", "test"}, {"a", 1}});
-                auto filteredExpected = expected;
-                filteredExpected.erase("a");
-                SETUP_TESTCASES()
-            }
-
-            SECTION("null type")
-            {
-                const std::string nested_type_json_str =  R"(null)";
-                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
-                auto expected = json({{"nested", nullptr}, {"anotherValue", "test"}, {"a", 1}});
-                auto filteredExpected = expected;
-                filteredExpected.erase("a");
-                SETUP_TESTCASES()
-            }
-        }
-        SECTION("with leading whitespace and newlines around root JSON")
-        {
-            const std::string initial_whitespace = R"(
-                
-            )";
-            const std::string nested_type_json_str = R"({
-                "a": 1,
-                "nested": {
-                    "b": "test"
-                },
-                "anotherValue": "test"
-            })";
-            const std::string end_whitespace = R"(
-                
-            )";
-            const std::string root_type_json_str = initial_whitespace + nested_type_json_str + end_whitespace;
-
-            auto expected = json({{"a", 1}, {"nested", {{"b", "test"}}}, {"anotherValue", "test"}});
-
-            auto j = json::parse(root_type_json_str);
-
-            // 2. Check if the generated JSON is as expected
-            CHECK(j == expected);
-
-            // 3. Check if the start and end positions do not include the surrounding whitespace
-            CHECK(j.start_pos() == initial_whitespace.size());
-            CHECK(j.end_pos() == root_type_json_str.size() - end_whitespace.size());
-        }
-    }
-#undef SETUP_TESTCASES
-#endif
 }
 
 // this test relies on parse errors being thrown, so it is skipped when

tests/src/unit-convenience.cpp

@@ -98,10 +98,8 @@ void check_escaped(const char* original, const char* escaped = "", bool ensure_a
 void check_escaped(const char* original, const char* escaped, const bool ensure_ascii)
 {
     std::stringstream ss;
-    nlohmann::detail::output_stream_adapter<char> adapter(ss);
-    json::serializer s(adapter, ' ', false, ensure_ascii);
-    s.dump_escaped(original);
-    s.flush(); // dump_escaped writes into the serializer's internal buffer
+    json::serializer s(nlohmann::detail::output_adapter<char>(ss), ' ');
+    s.dump_escaped(original, ensure_ascii);
     CHECK(ss.str() == escaped);
 }
 } // namespace

tests/src/unit-diagnostic-positions-only.cpp

@@ -0,0 +1,44 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#include "doctest_compatibility.h"
+
+#ifdef JSON_DIAGNOSTICS
+    #undef JSON_DIAGNOSTICS
+#endif
+
+#define JSON_DIAGNOSTICS 0
+#define JSON_DIAGNOSTIC_POSITIONS 1
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+TEST_CASE("Better diagnostics with positions only")
+{
+    SECTION("invalid type")
+    {
+        const std::string json_invalid_string = R"(
+        {
+            "address": {
+                "street": "Fake Street",
+                "housenumber": "1"
+            }
+        }
+        )";
+        json j = json::parse(json_invalid_string);
+        CHECK_THROWS_WITH_AS(j.at("address").at("housenumber").get<int>(),
+                             "[json.exception.type_error.302] (bytes 108-111) type must be number, but is string", json::type_error);
+    }
+
+    SECTION("invalid type without positions")
+    {
+        const json j = "foo";
+        CHECK_THROWS_WITH_AS(j.get<int>(),
+                             "[json.exception.type_error.302] type must be number, but is string", json::type_error);
+    }
+}

tests/src/unit-diagnostic-positions.cpp

@@ -8,9 +8,7 @@
 
 #include "doctest_compatibility.h"
 
-#ifndef JSON_DIAGNOSTICS
-    #define JSON_DIAGNOSTICS 1
-#endif
+#define JSON_DIAGNOSTICS 1
 #define JSON_DIAGNOSTIC_POSITIONS 1
 #include <nlohmann/json.hpp>
 
@@ -29,13 +27,8 @@ TEST_CASE("Better diagnostics with positions")
         }
         )";
         json j = json::parse(json_invalid_string);
-#if JSON_DIAGNOSTICS
         CHECK_THROWS_WITH_AS(j.at("address").at("housenumber").get<int>(),
                              "[json.exception.type_error.302] (/address/housenumber) (bytes 108-111) type must be number, but is string", json::type_error);
-#else
-        CHECK_THROWS_WITH_AS(j.at("address").at("housenumber").get<int>(),
-                             "[json.exception.type_error.302] (bytes 108-111) type must be number, but is string", json::type_error);
-#endif
     }
 
     SECTION("invalid type without positions")
@@ -75,18 +68,79 @@ TEST_CASE("Better diagnostics with positions")
         CHECK(j.end_pos() == root.size());
     }
 
+    SECTION("copying keeps the positions of nested values (#5387)")
+    {
+        // Values nested deeper than the copy constructor's descent bound are
+        // copied without the call stack, on a path that has to carry the
+        // positions over itself; shallower ones copy their containers, which
+        // bring the positions along. Both sides of the bound are checked here.
+        const auto check_copy = [](std::size_t depth, bool objects)
+        {
+            CAPTURE(depth)
+            CAPTURE(objects)
+
+            const std::string opening = objects ? R"({"a":)" : "[";
+            const std::string closing = objects ? "}" : "]";
+
+            std::string text;
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                text += opening;
+            }
+            text += "12";
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                text += closing;
+            }
+
+            const json original = json::parse(text);
+            const json copy(original); // NOLINT(performance-unnecessary-copy-initialization)
+
+            const json* o = &original;
+            const json* c = &copy;
+            for (std::size_t level = 0; level <= depth; ++level)
+            {
+                CAPTURE(level)
+                REQUIRE(c->start_pos() == o->start_pos());
+                REQUIRE(c->end_pos() == o->end_pos());
+
+                if (level < depth)
+                {
+                    o = objects ? &o->at("a") : &o->at(0);
+                    c = objects ? &c->at("a") : &c->at(0);
+                }
+            }
+        };
+
+        const auto check_arrays = [&check_copy](std::size_t depth)
+        {
+            check_copy(depth, false);
+        };
+        const auto check_objects = [&check_copy](std::size_t depth)
+        {
+            check_copy(depth, true);
+        };
+
+        check_arrays(1);
+        check_arrays(127);
+        check_arrays(128);
+        check_arrays(129);
+        check_arrays(300);
+
+        check_objects(1);
+        check_objects(127);
+        check_objects(128);
+        check_objects(129);
+        check_objects(300);
+    }
+
     SECTION("JSON patch add to primitive parent (#4292)")
     {
         // the JSON Patch "add" target /foo/bar/baz has a string parent
         // (/foo/bar); the position of that parent is reported in the message
         const json doc = json::parse(R"({"foo":{"bar":"a string"}})");
         const json patch = json::parse(R"([{"op":"add","path":"/foo/bar/baz","value":1}])");
-#if JSON_DIAGNOSTICS
         CHECK_THROWS_WITH_AS(doc.patch(patch),
                              "[json.exception.out_of_range.411] (/foo/bar) (bytes 14-24) cannot add value: the JSON Patch 'add' target's parent is of type string, but must be an object or array", json::out_of_range);
-#else
-        CHECK_THROWS_WITH_AS(doc.patch(patch),
-                             "[json.exception.out_of_range.411] (bytes 14-24) cannot add value: the JSON Patch 'add' target's parent is of type string, but must be an object or array", json::out_of_range);
-#endif
     }
 }

tests/src/unit-diagnostics.cpp

@@ -274,34 +274,60 @@ TEST_CASE("Regression tests for extended diagnostics")
         CHECK(j1["string"] == "t");
     }
 
-    SECTION("Regression test - swap(array_t&)/swap(object_t&) must update JSON_DIAGNOSTICS parent pointers")
+    SECTION("Regression test for issue #5387 - copying keeps the parents of nested values")
     {
-        // swap(array_t&)
+        // A value nested deeper than the copy constructor's descent bound is
+        // copied without the call stack. Every container that path creates has
+        // to have the parents of its children set, or the JSON Pointer in the
+        // diagnostic is cut short.
+        const std::size_t depth = 300;
+
+        SECTION("objects")
         {
-            json j = json::array();
-            json::array_t arr = {json::array({1})};
-            j.swap(arr);
-
-            // parent pointers of the moved-in elements must point into j, not
-            // into the now-defunct free-standing array_t
-            CHECK_THROWS_WITH_AS(j[0][0].get<std::string>(), "[json.exception.type_error.302] (/0/0) type must be string, but is number", json::type_error);
-
-            // must not trigger assert_invariant() in a debug/assert-enabled build
-            json const k = j;
-            CHECK(k == j);
+            json j = "not a number";
+            std::string pointer;
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                j = json{{"a", j}};
+                pointer += "/a";
             }
 
-        // swap(object_t&)
+            json const copy(j); // NOLINT(performance-unnecessary-copy-initialization)
+
+            const json* inner = &copy;
+            for (std::size_t i = 0; i < depth; ++i)
             {
-            json o = json::object();
-            json::object_t obj = {{"a", json::array({1})}};
-            o.swap(obj);
+                inner = &inner->at("a");
+            }
 
-            CHECK_THROWS_WITH_AS(o["a"][0].get<std::string>(), "[json.exception.type_error.302] (/a/0) type must be string, but is number", json::type_error);
+            std::string const expected = "[json.exception.type_error.302] (" + pointer + ") type must be number, but is string";
+            int i = 0;
+            CHECK_THROWS_WITH_AS(i = inner->get<int>(), expected.c_str(), json::type_error);
+            CHECK(i == 0);
+        }
 
-            // must not trigger assert_invariant() in a debug/assert-enabled build
-            json const p = o;
-            CHECK(p == o);
+        SECTION("arrays")
+        {
+            json j = "not a number";
+            std::string pointer;
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                j = json::array({j});
+                pointer += "/0";
+            }
+
+            json const copy(j); // NOLINT(performance-unnecessary-copy-initialization)
+
+            const json* inner = &copy;
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                inner = &inner->at(0);
+            }
+
+            std::string const expected = "[json.exception.type_error.302] (" + pointer + ") type must be number, but is string";
+            int i = 0;
+            CHECK_THROWS_WITH_AS(i = inner->get<int>(), expected.c_str(), json::type_error);
+            CHECK(i == 0);
         }
     }
 }

tests/src/unit-large_json.cpp

@@ -12,6 +12,7 @@
 using nlohmann::json;
 
 #include <algorithm>
+#include <string>
 
 TEST_CASE("tests on very large JSONs")
 {
@@ -27,3 +28,201 @@ TEST_CASE("tests on very large JSONs")
     }
 }
 
+namespace
+{
+
+// Descend a chain of single-element containers and return the value at its end,
+// reporting the number of levels traversed in @a depth.
+//
+// The values in the test case below are nested far deeper than the call stack
+// can follow, so they must not be inspected with operator== or dump(): both are
+// still recursive and would overflow the stack themselves.
+const json* innermost_value(const json& j, std::size_t& depth)
+{
+    const json* current = &j;
+    depth = 0;
+
+    while ((current->is_array() || current->is_object()) && !current->empty())
+    {
+        current = current->is_array()
+                  ? &current->front()
+                  : &current->begin().value();
+        ++depth;
+    }
+
+    return current;
+}
+
+} // namespace
+
+TEST_CASE("tests on deeply nested JSONs")
+{
+    // deep enough to exhaust the call stack, but small enough to stay cheap:
+    // parsing is iterative, so building the values below costs little
+    const std::size_t depth = 100000;
+
+    SECTION("issue #5387 - stack overflow in the copy constructor")
+    {
+        SECTION("array")
+        {
+            const json j = json::parse(std::string(depth, '[') + '0' + std::string(depth, ']'));
+
+            const json copy(j); // NOLINT(performance-unnecessary-copy-initialization): the copy is what is tested
+
+            std::size_t copy_depth = 0;
+            CHECK(*innermost_value(copy, copy_depth) == 0);
+            CHECK(copy_depth == depth);
+        }
+
+        SECTION("object")
+        {
+            std::string s;
+            s.reserve((6 * depth) + 1);
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                s += "{\"a\":";
+            }
+            s += '1';
+            s.append(depth, '}');
+
+            const json j = json::parse(s);
+
+            const json copy(j); // NOLINT(performance-unnecessary-copy-initialization): the copy is what is tested
+
+            std::size_t copy_depth = 0;
+            CHECK(*innermost_value(copy, copy_depth) == 1);
+            CHECK(copy_depth == depth);
+        }
+
+        SECTION("copy assignment")
+        {
+            // operator=(basic_json) takes its argument by value, so the deep
+            // copy happens in the copy constructor
+            const json j = json::parse(std::string(depth, '[') + '0' + std::string(depth, ']'));
+
+            json target;
+            target = j;
+
+            std::size_t target_depth = 0;
+            CHECK(*innermost_value(target, target_depth) == 0);
+            CHECK(target_depth == depth);
+        }
+
+        SECTION("depths around the bound of the recursive descent")
+        {
+            // The copy constructor descends into a bounded number of levels and
+            // completes whatever is below that without the call stack. Cover
+            // every depth around that bound, so that the two ways of copying
+            // are known to meet cleanly - wherever the bound is set.
+            for (std::size_t d = 1; d <= 300; ++d)
+            {
+                CAPTURE(d);
+
+                const json array = json::parse(std::string(d, '[') + '0' + std::string(d, ']'));
+                const json array_copy(array); // NOLINT(performance-unnecessary-copy-initialization): the copy is what is tested
+                std::size_t array_depth = 0;
+                CHECK(*innermost_value(array_copy, array_depth) == 0);
+                CHECK(array_depth == d);
+
+                std::string object_text;
+                for (std::size_t i = 0; i < d; ++i)
+                {
+                    object_text += "{\"a\":";
+                }
+                object_text += '1';
+                object_text.append(d, '}');
+
+                const json object = json::parse(object_text);
+                const json object_copy(object); // NOLINT(performance-unnecessary-copy-initialization): the copy is what is tested
+                std::size_t object_depth = 0;
+                CHECK(*innermost_value(object_copy, object_depth) == 1);
+                CHECK(object_depth == d);
+            }
+        }
+
+        SECTION("a value that is deep in one place only")
+        {
+            json j = json::object();
+            j["shallow"] = 1;
+            j["deep"] = json::parse(std::string(depth, '[') + '0' + std::string(depth, ']'));
+            j["also_shallow"] = json::array({1, 2, 3});
+
+            const json copy(j);
+
+            CHECK(copy["shallow"] == 1);
+            CHECK(copy["also_shallow"] == json::array({1, 2, 3}));
+
+            std::size_t deep_depth = 0;
+            CHECK(*innermost_value(copy["deep"], deep_depth) == 0);
+            CHECK(deep_depth == depth);
+        }
+
+        SECTION("comparing")
+        {
+            // Comparing used to descend once per level, and an ordered
+            // comparison used to compare every pair of elements twice, once in
+            // each direction, which took exponentially long in the nesting
+            // depth. Both are gone: these finish in milliseconds, where the
+            // second used to take longer than anyone would wait even for a
+            // value nested only a few dozen levels deep.
+            const std::string text = std::string(depth, '[') + '0' + std::string(depth, ']');
+            const json j = json::parse(text);
+            const json same = json::parse(text);
+            const json larger = json::parse(std::string(depth, '[') + '1' + std::string(depth, ']'));
+
+            CHECK(j == same);
+            CHECK_FALSE(j == larger);
+            CHECK(j != larger);
+
+            CHECK(j < larger);
+            CHECK_FALSE(larger < j);
+            CHECK(larger > j);
+            CHECK(j <= same);
+            CHECK(j >= same);
+
+            // a value that ends earlier is the smaller one
+            const json shorter = json::parse(std::string(depth - 1, '[') + '0' + std::string(depth - 1, ']'));
+            CHECK_FALSE(j == shorter);
+        }
+
+        SECTION("comparing objects")
+        {
+            std::string text;
+            text.reserve((6 * depth) + 1);
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                text += "{\"a\":";
+            }
+            text += '1';
+            text.append(depth, '}');
+
+            const json j = json::parse(text);
+            const json same = json::parse(text);
+
+            CHECK(j == same);
+            CHECK_FALSE(j != same);
+            CHECK(j <= same);
+            CHECK(j >= same);
+        }
+
+        SECTION("the copy is independent of the original")
+        {
+            const json j = json::parse(std::string(depth, '[') + '0' + std::string(depth, ']'));
+
+            json copy(j);
+
+            // reach the innermost value without recursing and replace it
+            json* current = &copy;
+            while (current->is_array() && !current->empty())
+            {
+                current = &current->front();
+            }
+            *current = 42;
+
+            std::size_t unused = 0;
+            CHECK(*innermost_value(copy, unused) == 42);
+            CHECK(*innermost_value(j, unused) == 0);
+        }
+    }
+}
+

tests/src/unit-msgpack.cpp

@@ -1598,67 +1598,6 @@ TEST_CASE("MessagePack")
 }
 
 // use this testcase outside [hide] to run it with Valgrind
-TEST_CASE("MessagePack nesting does not consume the call stack")
-{
-    // Reading a container used to call back into the value reader once per
-    // element, so the native call stack grew with the nesting depth of the
-    // input: one frame per byte for repeated 0x91 (a one-element array), which
-    // crashes the process long before the input is exhausted (#5104). The
-    // containers are kept on a heap stack now.
-    //
-    // Note that deeply nested values must not be compared, copied or dumped
-    // here: those operations are still recursive, and would reintroduce the
-    // very crash this checks for. Depth is measured by descending instead.
-
-    SECTION("an unterminated chain is reported, not crashed on")
-    {
-        json _;
-        const std::vector<uint8_t> input(300000, 0x91);
-        CHECK_THROWS_WITH_AS(_ = json::from_msgpack(input), "[json.exception.parse_error.110] parse error at byte 300001: syntax error while parsing MessagePack value: unexpected end of input", json::parse_error&);
-        CHECK(json::from_msgpack(input, true, false).is_discarded());
-    }
-
-    SECTION("a well-formed deep value is read through the SAX interface")
-    {
-        std::vector<uint8_t> input(300000, 0x91);
-        input.push_back(0x01); // innermost value
-
-        SaxCountdown accept_all(600001);
-        CHECK(json::sax_parse(input, &accept_all, json::input_format_t::msgpack));
-    }
-
-    SECTION("a well-formed deep value is read into a value")
-    {
-        const std::size_t depth = 10000;
-        std::vector<uint8_t> input(depth, 0x91);
-        input.push_back(0x01);
-
-        json j = json::from_msgpack(input);
-
-        std::size_t measured = 0;
-        const json* p = &j;
-        while (p->is_array() && !p->empty())
-        {
-            p = &p->front();
-            ++measured;
-        }
-        CHECK(measured == depth);
-        CHECK(p->is_number());
-    }
-
-    SECTION("containers are still read the same way")
-    {
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0x90})) == json::array());
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0x80})) == json::object());
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0x92, 0x90, 0x80})) == json({json::array(), json::object()}));
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0x91, 0x91, 0x91, 0x90})) == json({{{json::array()}}}));
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0x81, 0xA1, 'a', 0x81, 0xA1, 'b', 0x92, 0x01, 0x02})) == json({{"a", {{"b", {1, 2}}}}}));
-        // array 16 and map 32, i.e. the counted forms
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0xDC, 0x00, 0x02, 0x01, 0x02})) == json({1, 2}));
-        CHECK(json::from_msgpack(std::vector<uint8_t>({0xDF, 0x00, 0x00, 0x00, 0x01, 0xA1, 'k', 0xC3})) == json({{"k", true}}));
-    }
-}
-
 TEST_CASE("single MessagePack roundtrip")
 {
     SECTION("sample.json")

tests/src/unit-ordered_json.cpp

@@ -82,83 +82,36 @@ TEST_CASE("regression test for issue #3732 - iteration_proxy_value<iter_impl<ord
     static_cast<void>(fn);
 }
 
-TEST_CASE("regression test - diff() must account for ordered_json member order")
+TEST_CASE("copying an ordered_json with nested values")
 {
-    SECTION("pure reorder, no value changes")
+    // ordered_map is backed by a vector, so copying an object that has
+    // structured values takes a different route than copying a std::map-backed
+    // one; see https://github.com/nlohmann/json/issues/5387
+    ordered_json oj;
+    oj["z"] = 1;
+    oj["a"]["y"] = 2;
+    oj["a"]["b"]["x"] = 3;
+    oj["m"] = {1, 2, {{"w", 4}}};
+
+    const ordered_json copy(oj);
+
+    SECTION("the copy is equal to the original")
     {
-        ordered_json a = {{"a", 1}, {"b", 2}};
-        ordered_json b = {{"b", 2}, {"a", 1}};
-        CHECK(a != b); // order-sensitive equality
-        CHECK(a.patch(ordered_json::diff(a, b)) == b);
+        CHECK(copy == oj);
+        CHECK(copy.dump() == oj.dump());
     }
 
-    SECTION("new key must land at the front")
+    SECTION("the key order is preserved at every level")
     {
-        ordered_json c = {{"b", 2}};
-        ordered_json e = {{"a", 1}, {"b", 2}};
-        CHECK(c.patch(ordered_json::diff(c, e)) == e);
+        CHECK(copy.dump() == R"({"z":1,"a":{"y":2,"b":{"x":3}},"m":[1,2,{"w":4}]})");
     }
 
-    SECTION("reorder plus a value change on one of the reordered keys")
+    SECTION("the copy is independent of the original")
     {
-        ordered_json a = {{"a", 1}, {"b", 2}};
-        ordered_json b = {{"b", 20}, {"a", 1}};
-        CHECK(a != b);
-        CHECK(a.patch(ordered_json::diff(a, b)) == b);
-    }
+        ordered_json mutated(oj);
+        mutated["a"]["b"]["x"] = 99;
 
-    SECTION("reorder plus a deleted key")
-    {
-        ordered_json a = {{"a", 1}, {"b", 2}, {"c", 3}};
-        ordered_json b = {{"b", 2}, {"a", 1}};
-        CHECK(a != b);
-        CHECK(a.patch(ordered_json::diff(a, b)) == b);
-    }
-
-    SECTION("reorder plus a nested value that itself needs a recursive diff")
-    {
-        ordered_json a = {{"a", {{"x", 1}, {"y", 2}}}, {"b", 2}};
-        ordered_json b = {{"b", 2}, {"a", {{"x", 1}, {"y", 99}}}};
-        CHECK(a != b);
-        CHECK(a.patch(ordered_json::diff(a, b)) == b);
-    }
-
-    SECTION("three or more keys shuffled into a different order")
-    {
-        ordered_json a = {{"a", 1}, {"b", 2}, {"c", 3}, {"d", 4}};
-        ordered_json b = {{"d", 4}, {"b", 2}, {"a", 1}, {"c", 3}};
-        CHECK(a != b);
-        CHECK(a.patch(ordered_json::diff(a, b)) == b);
-    }
-
-    SECTION("matching order still produces a minimal patch (fast path unaffected)")
-    {
-        ordered_json a = {{"a", 1}, {"b", 2}, {"c", 3}};
-        ordered_json b = {{"a", 1}, {"b", 20}, {"c", 3}};
-        auto p = ordered_json::diff(a, b);
-        // only the changed value should be touched, not a wholesale remove+add
-        CHECK(p.size() == 1);
-        CHECK(p[0]["op"] == "replace");
-        CHECK(p[0]["path"] == "/b");
-        CHECK(a.patch(p) == b);
-    }
-
-    SECTION("plain json (std::map-backed) is unaffected by same-key-different-insertion-order")
-    {
-        json a;
-        a["b"] = 2;
-        a["a"] = 1;
-
-        json b;
-        b["a"] = 1;
-        b["b"] = 2;
-
-        // std::map iteration is always sorted by key, so a == b regardless of
-        // insertion order, and diff() must still produce the same minimal
-        // (empty) result as before this fix
-        CHECK(a == b);
-        auto p = json::diff(a, b);
-        CHECK(p.empty());
-        CHECK(a.patch(p) == b);
+        CHECK(oj["a"]["b"]["x"] == 3);
+        CHECK(mutated["a"]["b"]["x"] == 99);
     }
 }

tests/src/unit-regression2.cpp

@@ -44,22 +44,6 @@ using ordered_json = nlohmann::ordered_json;
     #elif __has_include(<experimental/optional>)
         #include <experimental/optional>
     #endif
-
-    /////////////////////////////////////////////////////////////////////
-    // for #4804
-    /////////////////////////////////////////////////////////////////////
-    using json_4804 = nlohmann::basic_json<std::map,        // ObjectType
-    std::vector,     // ArrayType
-    std::string,     // StringType
-    bool,            // BooleanType
-    std::int64_t,    // NumberIntegerType
-    std::uint64_t,   // NumberUnsignedType
-    double,          // NumberFloatType
-    std::allocator,  // AllocatorType
-    nlohmann::adl_serializer,  // JSONSerializer
-    std::vector<std::byte>,    // BinaryType
-    void                       // CustomBaseClass
-    >;
 #endif
 
 #ifdef JSON_HAS_CPP_20
@@ -175,71 +159,6 @@ struct NotSerializableData
     float myfloat;
 };
 
-/////////////////////////////////////////////////////////////////////
-// for #2574
-/////////////////////////////////////////////////////////////////////
-
-struct NonDefaultConstructible
-{
-    explicit NonDefaultConstructible(int a)
-        : x(a)
-    {}
-    int x;
-};
-
-namespace nlohmann
-{
-template<>
-struct adl_serializer<NonDefaultConstructible>
-{
-    static NonDefaultConstructible from_json(json const& j)
-    {
-        return NonDefaultConstructible(j.get<int>());
-    }
-};
-}  // namespace nlohmann
-
-/////////////////////////////////////////////////////////////////////
-// for #2824
-/////////////////////////////////////////////////////////////////////
-
-class sax_no_exception : public nlohmann::detail::json_sax_dom_parser<json, nlohmann::detail::string_input_adapter_type>
-{
-  public:
-    explicit sax_no_exception(json& j)
-        : nlohmann::detail::json_sax_dom_parser<json, nlohmann::detail::string_input_adapter_type>(j, false)
-    {}
-
-    static bool parse_error(std::size_t /*position*/, const std::string& /*last_token*/, const json::exception& ex)
-    {
-        error_string = new std::string(ex.what());  // NOLINT(cppcoreguidelines-owning-memory)
-        return false;
-    }
-
-    static std::string* error_string;
-};
-
-std::string* sax_no_exception::error_string = nullptr;
-
-/////////////////////////////////////////////////////////////////////
-// for #2982
-/////////////////////////////////////////////////////////////////////
-
-template<class T>
-class my_allocator : public std::allocator<T>
-{
-  public:
-    using std::allocator<T>::allocator;
-
-    my_allocator() = default;
-    template<class U> my_allocator(const my_allocator<U>& /*unused*/) { }
-
-    template <class U>
-    struct rebind
-    {
-        using other = my_allocator<U>;
-    };
-};
 
 TEST_CASE("regression tests 2")
 {
@@ -527,240 +446,6 @@ TEST_CASE("regression tests 2")
         CHECK(result.dump() == R"([{"op":"add","path":"/foo/-","value":"3"}])");
     }
 
-    SECTION("issue #2067 - cannot serialize binary data to text JSON")
-    {
-        const std::array<unsigned char, 23> data = {{0x81, 0xA4, 0x64, 0x61, 0x74, 0x61, 0xC4, 0x0F, 0x33, 0x30, 0x30, 0x32, 0x33, 0x34, 0x30, 0x31, 0x30, 0x37, 0x30, 0x35, 0x30, 0x31, 0x30}};
-        const json j = json::from_msgpack(data.data(), data.size());
-        // dump() is nodiscard; this only checks that dumping does not throw
-        CHECK_NOTHROW(
-            utils::ignore_return_value(
-                j.dump(4,                             // Indent
-                       ' ',                           // Indent char
-                       false,                         // Ensure ascii
-                       json::error_handler_t::strict  // Error
-                      )));
-    }
-
-    SECTION("PR #2181 - regression bug with lvalue")
-    {
-        // see https://github.com/nlohmann/json/pull/2181#issuecomment-653326060
-        const json j{{"x", "test"}};
-        const std::string defval = "default value";
-        auto val = j.value("x", defval); // NOLINT(bugprone-unused-local-non-trivial-variable)
-        auto val2 = j.value("y", defval); // NOLINT(bugprone-unused-local-non-trivial-variable)
-    }
-
-    SECTION("issue #2293 - eof doesn't cause parsing to stop")
-    {
-        const std::vector<uint8_t> data =
-        {
-            0x7B,
-            0x6F,
-            0x62,
-            0x6A,
-            0x65,
-            0x63,
-            0x74,
-            0x20,
-            0x4F,
-            0x42
-        };
-        const json result = json::from_cbor(data, true, false);
-        CHECK(result.is_discarded());
-    }
-
-    SECTION("issue #2315 - json.update and vector<pair>does not work with ordered_json")
-    {
-        nlohmann::ordered_json jsonAnimals = {{"animal", "dog"}};
-        const nlohmann::ordered_json jsonCat = {{"animal", "cat"}};
-        jsonAnimals.update(jsonCat);
-        CHECK(jsonAnimals["animal"] == "cat");
-
-        auto jsonAnimals_parsed = nlohmann::ordered_json::parse(jsonAnimals.dump());
-        CHECK(jsonAnimals == jsonAnimals_parsed);
-
-        const std::vector<std::pair<std::string, int64_t>> intData = {std::make_pair("aaaa", 11),
-                                                                      std::make_pair("bbb", 222)
-                                                                     };
-        nlohmann::ordered_json jsonObj;
-        for (const auto& data : intData)
-        {
-            jsonObj[data.first] = data.second;
-        }
-        CHECK(jsonObj["aaaa"] == 11);
-        CHECK(jsonObj["bbb"] == 222);
-    }
-
-    SECTION("issue #2330 - ignore_comment=true fails on multiple consecutive lines starting with comments")
-    {
-        const std::string ss = "//\n//\n{\n}\n";
-        const json j = json::parse(ss, nullptr, true, true);
-        CHECK(j.dump() == "{}");
-    }
-
-#ifdef JSON_HAS_CPP_20
-#ifndef _LIBCPP_VERSION // see https://github.com/nlohmann/json/issues/4490
-    // classic Intel ICC reports <span> as includable but cannot actually compile
-    // std::span/std::as_bytes usage below
-#if __has_include(<span>) && !defined(__ICC) && !defined(__INTEL_COMPILER)
-    SECTION("issue #2546 - parsing containers of std::byte")
-    {
-        const char DATA[] = R"("Hello, world!")"; // NOLINT(misc-const-correctness,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
-        const auto s = std::as_bytes(std::span(DATA));
-        const json j = json::parse(s);
-        CHECK(j.dump() == "\"Hello, world!\"");
-    }
-#endif
-#endif
-#endif
-
-    SECTION("issue #2574 - Deserialization to std::array, std::pair, and std::tuple with non-default constructable types fails")
-    {
-        SECTION("std::array")
-        {
-            {
-                const json j = {7, 4};
-                auto arr = j.get<std::array<NonDefaultConstructible, 2>>();
-                CHECK(arr[0].x == 7);
-                CHECK(arr[1].x == 4);
-            }
-
-            {
-                const json j = 7;
-                CHECK_THROWS_AS((j.get<std::array<NonDefaultConstructible, 1>>()), json::type_error);
-            }
-        }
-
-        SECTION("std::pair")
-        {
-            {
-                const json j = {3, 8};
-                auto p = j.get<std::pair<NonDefaultConstructible, NonDefaultConstructible>>();
-                CHECK(p.first.x == 3);
-                CHECK(p.second.x == 8);
-            }
-
-            {
-                const json j = {4, 1};
-                auto p = j.get<std::pair<int, NonDefaultConstructible>>();
-                CHECK(p.first == 4);
-                CHECK(p.second.x == 1);
-            }
-
-            {
-                const json j = {6, 7};
-                auto p = j.get<std::pair<NonDefaultConstructible, int>>();
-                CHECK(p.first.x == 6);
-                CHECK(p.second == 7);
-            }
-
-            {
-                const json j = 7;
-                CHECK_THROWS_AS((j.get<std::pair<NonDefaultConstructible, int>>()), json::type_error);
-            }
-        }
-
-        SECTION("std::tuple")
-        {
-            {
-                const json j = {9};
-                auto t = j.get<std::tuple<NonDefaultConstructible>>();
-                CHECK(std::get<0>(t).x == 9);
-            }
-
-            {
-                const json j = {9, 8, 7};
-                auto t = j.get<std::tuple<NonDefaultConstructible, int, NonDefaultConstructible>>();
-                CHECK(std::get<0>(t).x == 9);
-                CHECK(std::get<1>(t) == 8);
-                CHECK(std::get<2>(t).x == 7);
-            }
-
-            {
-                const json j = 7;
-                CHECK_THROWS_AS((j.get<std::tuple<NonDefaultConstructible>>()), json::type_error);
-            }
-        }
-    }
-
-    SECTION("issue #4530 - Serialization of empty tuple")
-    {
-        const auto source_tuple = std::tuple<>();
-        const nlohmann::json j = source_tuple;
-
-        CHECK(j.get<decltype(source_tuple)>() == source_tuple);
-        CHECK("[]" == j.dump());
-    }
-
-    SECTION("issue #2865 - ASAN detects memory leaks")
-    {
-        // the code below is expected to not leak memory
-        {
-            nlohmann::json o;
-            const std::string s = "bar";
-
-            nlohmann::to_json(o["foo"], s);
-
-            nlohmann::json p = o;
-
-            // call to_json with a non-null JSON value
-            nlohmann::to_json(p["foo"], s);
-        }
-
-        {
-            nlohmann::json o;
-            const std::string s = "bar";
-
-            nlohmann::to_json(o["foo"], s);
-
-            // call to_json with a non-null JSON value
-            nlohmann::to_json(o["foo"], s);
-        }
-    }
-
-    SECTION("issue #2824 - encoding of json::exception::what()")
-    {
-        json j;
-        sax_no_exception sax(j);
-
-        CHECK(!json::sax_parse("xyz", &sax));
-        CHECK(*sax_no_exception::error_string == "[json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - invalid literal; last read: 'x'");
-        delete sax_no_exception::error_string;  // NOLINT(cppcoreguidelines-owning-memory)
-    }
-
-    SECTION("issue #2825 - Properly constrain the basic_json conversion operator")
-    {
-        static_assert(std::is_copy_assignable<nlohmann::ordered_json>::value, "ordered_json must be copy assignable");
-    }
-
-    SECTION("issue #2958 - Inserting in unordered json using a pointer retains the leading slash")
-    {
-        const std::string p = "/root";
-
-        json test1;
-        test1[json::json_pointer(p)] = json::object();
-        CHECK(test1.dump() == "{\"root\":{}}");
-
-        ordered_json test2;
-        test2[ordered_json::json_pointer(p)] = json::object();
-        CHECK(test2.dump() == "{\"root\":{}}");
-
-        // json::json_pointer and ordered_json::json_pointer are the same type; behave as above
-        ordered_json test3;
-        test3[json::json_pointer(p)] = json::object();
-        CHECK(std::is_same<json::json_pointer::string_t, ordered_json::json_pointer::string_t>::value);
-        CHECK(test3.dump() == "{\"root\":{}}");
-    }
-
-    SECTION("issue #2982 - to_{binary format} does not provide a mechanism for specifying a custom allocator for the returned type")
-    {
-        std::vector<std::uint8_t, my_allocator<std::uint8_t>> my_vector;
-        const json j = {1, 2, 3, 4};
-        json::to_cbor(j, my_vector);
-        json k = json::from_cbor(my_vector);
-        CHECK(j == k);
-    }
-
 }
 
 DOCTEST_CLANG_SUPPRESS_WARNING_POP

tests/src/unit-serialization.cpp

@@ -387,232 +387,3 @@ TEST_CASE("dump for basic_json with long double number_float_t")
         check_same(100.0L,  100.0);
     }
 }
-
-TEST_CASE("serialization of strings (bulk fast path)")
-{
-    // These cases exercise the SWAR bulk-copy fast path in dump_escaped and the
-    // internal write buffer: long runs, escapes interrupting runs, 0x7F/DEL,
-    // multibyte UTF-8 under both ensure_ascii settings, and payloads larger than
-    // the write buffer.
-
-    SECTION("long unescaped ASCII exceeds the write buffer")
-    {
-        const std::string big(3000, 'a');
-        const json j = big;
-        CHECK(j.dump() == '"' + big + '"');
-        CHECK(j.dump(-1, ' ', true) == '"' + big + '"');
-        // round-trips
-        CHECK(json::parse(j.dump()) == j);
-    }
-
-    SECTION("runs interrupted by escapes")
-    {
-        const json j = std::string(500, 'x') + "\n\"\\" + std::string(500, 'y');
-        const std::string out = j.dump();
-        CHECK(out == '"' + std::string(500, 'x') + "\\n\\\"\\\\" + std::string(500, 'y') + '"');
-        CHECK(json::parse(out) == j);
-    }
-
-    SECTION("DEL (0x7F) depends on ensure_ascii")
-    {
-        const json j = std::string("a\x7f" "b");
-        CHECK(j.dump(-1, ' ', false) == "\"a\x7f" "b\"");   // copied verbatim
-        CHECK(j.dump(-1, ' ', true) == "\"a\\u007fb\"");    // escaped
-    }
-
-    SECTION("multibyte UTF-8 under both ensure_ascii settings")
-    {
-        const json j = std::string("A\xc3\xa9\xe4\xbd\xa0\xf0\x9f\x98\x80Z"); // A é 你 😀 Z
-        // not escaping non-ASCII: bytes are copied through the bulk validator
-        CHECK(j.dump(-1, ' ', false) == "\"A\xc3\xa9\xe4\xbd\xa0\xf0\x9f\x98\x80Z\"");
-        // ensure_ascii: escaped (with a surrogate pair for the emoji)
-        CHECK(j.dump(-1, ' ', true) == "\"A\\u00e9\\u4f60\\ud83d\\ude00Z\"");
-        CHECK(json::parse(j.dump(-1, ' ', true)) == j);
-    }
-
-    SECTION("many small structural writes exceed the write buffer")
-    {
-        json arr = json::array();
-        for (int i = 0; i < 2000; ++i)
-        {
-            arr.push_back(i);
-        }
-        const std::string out = arr.dump();
-        CHECK(out.front() == '[');
-        CHECK(out.back() == ']');
-        CHECK(json::parse(out) == arr);
-
-        json obj = json::object();
-        for (int i = 0; i < 500; ++i)
-        {
-            obj["key" + std::to_string(i)] = i;
-        }
-        CHECK(json::parse(obj.dump()) == obj);
-        CHECK(json::parse(obj.dump(2)) == obj);
-
-        // an array of many empty strings emits a long run of single-character
-        // writes ('"', '"', ',') at shallow nesting depth, so the write buffer
-        // fills and flushes mid-run without the deep recursion that would
-        // overflow the stack on some debug builds
-        json many_empty = json::array();
-        for (int i = 0; i < 500; ++i)
-        {
-            many_empty.push_back("");
-        }
-        const std::string out2 = many_empty.dump();
-        CHECK(out2.size() > 1024); // spans multiple write-buffer flushes
-        CHECK(out2.front() == '[');
-        CHECK(out2.back() == ']');
-        CHECK(json::parse(out2) == many_empty);
-    }
-
-    SECTION("invalid UTF-8 handling is unaffected by the fast path")
-    {
-        const json j = std::string("valid\xff" "more");
-        CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump()), "[json.exception.type_error.316] invalid UTF-8 byte at index 5: 0xFF", json::type_error&);
-        CHECK(j.dump(-1, ' ', false, json::error_handler_t::replace) == "\"valid\xef\xbf\xbd" "more\"");
-        CHECK(j.dump(-1, ' ', true, json::error_handler_t::replace) == "\"valid\\ufffdmore\"");
-        CHECK(j.dump(-1, ' ', false, json::error_handler_t::ignore) == "\"validmore\"");
-    }
-}
-
-TEST_CASE("indentation is written straight into the write buffer")
-{
-    // put_indent() memsets the indentation into the write buffer instead of
-    // copying it out of a pre-grown indentation string. These cases cover an
-    // indentation wider than the buffer, a non-space indentation character, and
-    // nesting deep enough that the accumulated indentation spans several
-    // buffer-fulls - the situations the old grow-a-string approach got wrong.
-
-    SECTION("indent_step wider than the write buffer")
-    {
-        const json j = {{"a", 1}};
-        // 2000 > the 1024-byte write buffer, and > the 512 the indentation
-        // string used to start at
-        CHECK(j.dump(2000) == "{\n" + std::string(2000, ' ') + "\"a\": 1\n}");
-        // several whole buffer-fulls, so the buffer is refilled once and then
-        // flushed repeatedly
-        CHECK(j.dump(5000) == "{\n" + std::string(5000, ' ') + "\"a\": 1\n}");
-        CHECK(j.dump(5000, '\t') == "{\n" + std::string(5000, '\t') + "\"a\": 1\n}");
-        // an exact multiple of the buffer size
-        CHECK(j.dump(4096) == "{\n" + std::string(4096, ' ') + "\"a\": 1\n}");
-    }
-
-    SECTION("a non-space indentation character is used throughout")
-    {
-        const json j = {{"a", 1}};
-        // 600 is past the point where the indentation used to be grown, which
-        // is where a hard-coded space would have shown up
-        CHECK(j.dump(600, '\t') == "{\n" + std::string(600, '\t') + "\"a\": 1\n}");
-        CHECK(j.dump(3, '.') == "{\n...\"a\": 1\n}");
-    }
-
-    SECTION("accumulated indentation spans several buffer-fulls")
-    {
-        // five levels deep at 400 per level: the innermost value is indented by
-        // 2000 characters, reached in steps that each straddle the buffer end
-        json j = json::array({1});
-        for (int i = 0; i < 4; ++i)
-        {
-            j = json::array({j});
-        }
-
-        const std::string out = j.dump(400);
-        CHECK(out.find(std::string("\n") + std::string(2000, ' ') + "1\n") != std::string::npos);
-        CHECK(json::parse(out) == j);
-    }
-
-    SECTION("indentation is unchanged for ordinary widths")
-    {
-        const json j = {{"a", {1, 2}}, {"b", nullptr}};
-        CHECK(j.dump(2) == "{\n  \"a\": [\n    1,\n    2\n  ],\n  \"b\": null\n}");
-        CHECK(j.dump(0) == "{\n\"a\": [\n1,\n2\n],\n\"b\": null\n}");
-    }
-}
-
-TEST_CASE("serialization of deeply nested values")
-{
-    // dump() descends into a bounded number of levels and writes out whatever
-    // is nested deeper than that without the call stack; see
-    // https://github.com/nlohmann/json/issues/5387
-
-    SECTION("nested deeper than the call stack could follow")
-    {
-        // parsing is iterative, so building these costs little
-        const std::size_t depth = 100000;
-
-        const std::string array_text = std::string(depth, '[') + '0' + std::string(depth, ']');
-        CHECK(json::parse(array_text).dump() == array_text);
-
-        std::string object_text;
-        object_text.reserve((6 * depth) + 1);
-        for (std::size_t i = 0; i < depth; ++i)
-        {
-            object_text += "{\"a\":";
-        }
-        object_text += '1';
-        object_text.append(depth, '}');
-        CHECK(json::parse(object_text).dump() == object_text);
-    }
-
-    SECTION("depths around the bound of the descent")
-    {
-        // Cover every depth around the bound, so that the two ways of writing a
-        // value are known to meet cleanly - wherever the bound is set.
-        for (std::size_t d = 1; d <= 300; ++d)
-        {
-            CAPTURE(d);
-
-            const std::string array_text = std::string(d, '[') + '7' + std::string(d, ']');
-            CHECK(json::parse(array_text).dump() == array_text);
-
-            std::string object_text;
-            for (std::size_t i = 0; i < d; ++i)
-            {
-                object_text += "{\"k\":";
-            }
-            object_text += '7';
-            object_text.append(d, '}');
-            CHECK(json::parse(object_text).dump() == object_text);
-        }
-    }
-
-    SECTION("pretty-printing across the bound")
-    {
-        for (std::size_t d = 120; d <= 140; ++d)
-        {
-            CAPTURE(d);
-
-            const json j = json::parse(std::string(d, '[') + '7' + std::string(d, ']'));
-
-            std::string expected;
-            for (std::size_t i = 0; i < d; ++i)
-            {
-                expected += std::string(2 * i, ' ') + "[\n";
-            }
-            expected += std::string(2 * d, ' ') + '7';
-            for (std::size_t i = d; i > 0; --i)
-            {
-                expected += '\n' + std::string(2 * (i - 1), ' ') + ']';
-            }
-
-            CHECK(j.dump(2) == expected);
-        }
-    }
-
-    SECTION("an empty container below the bound")
-    {
-        // an empty container is written out in full and never descended into,
-        // so it must not gain a newline when it is reached iteratively
-        for (std::size_t d = 125; d <= 135; ++d)
-        {
-            CAPTURE(d);
-
-            const std::string compact = std::string(d, '[') + "[]" + std::string(d, ']');
-            CHECK(json::parse(compact).dump() == compact);
-
-            const std::string with_object = std::string(d, '[') + "{}" + std::string(d, ']');
-            CHECK(json::parse(with_object).dump() == with_object);
-        }
-    }
-}

tests/src/unit-ubjson.cpp

@@ -2149,172 +2149,6 @@ TEST_CASE("UBJSON")
     }
 }
 
-TEST_CASE("UBJSON nesting does not consume the call stack")
-{
-    // Containers used to be read by calling back into the value reader once
-    // per element, so the native call stack grew with the nesting depth of the
-    // input. '[' alone opens a container, so a payload of repeated '[' crashed
-    // the process (#5104), as did the optimized forms, which reach the same
-    // path through a type or size annotation. The containers are kept on a
-    // heap stack now.
-    //
-    // Deeply nested values must not be compared, copied or dumped here: those
-    // operations are still recursive and would reintroduce the crash.
-    json _;
-
-    SECTION("containers that end at a marker")
-    {
-        const std::vector<uint8_t> input(500000, '[');
-        CHECK_THROWS_WITH_AS(_ = json::from_ubjson(input), "[json.exception.parse_error.110] parse error at byte 500001: syntax error while parsing UBJSON value: unexpected end of input", json::parse_error&);
-        CHECK(json::from_ubjson(input, true, false).is_discarded());
-    }
-
-    SECTION("containers with a size")
-    {
-        std::vector<uint8_t> input;
-        for (std::size_t i = 0; i < 100000; ++i)
-        {
-            input.push_back('[');
-            input.push_back('#');
-            input.push_back('i');
-            input.push_back(1);
-        }
-        CHECK_THROWS_AS(_ = json::from_ubjson(input), json::parse_error&);
-        CHECK(json::from_ubjson(input, true, false).is_discarded());
-    }
-
-    SECTION("containers with a type and a size")
-    {
-        // '[' is a permitted optimized type in UBJSON, so each element of such
-        // a container is itself a container, read without a marker of its own
-        std::vector<uint8_t> input;
-        for (std::size_t i = 0; i < 100000; ++i)
-        {
-            const std::vector<uint8_t> level = {'[', '$', '[', '#', 'i', 1};
-            input.insert(input.end(), level.begin(), level.end());
-        }
-        CHECK_THROWS_AS(_ = json::from_ubjson(input), json::parse_error&);
-        CHECK(json::from_ubjson(input, true, false).is_discarded());
-    }
-
-    SECTION("a well-formed deep value is read through the SAX interface")
-    {
-        std::vector<uint8_t> input(100000, '[');
-        input.insert(input.end(), 100000, ']');
-
-        SaxCountdown accept_all(1000000);
-        CHECK(json::sax_parse(input, &accept_all, json::input_format_t::ubjson));
-    }
-
-    SECTION("a well-formed deep value is read into a value")
-    {
-        const std::size_t depth = 10000;
-        std::vector<uint8_t> input(depth, '[');
-        input.insert(input.end(), depth, ']');
-
-        json j = json::from_ubjson(input);
-
-        std::size_t measured = 0;
-        const json* p = &j;
-        while (p->is_array() && !p->empty())
-        {
-            p = &p->front();
-            ++measured;
-        }
-        // the innermost array is empty, so the descent stops one level short
-        CHECK(measured == depth - 1);
-    }
-
-    SECTION("containers are still read the same way")
-    {
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', ']'})) == json::array());
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'{', '}'})) == json::object());
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '#', 'i', 0})) == json::array());
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'{', '#', 'i', 0})) == json::object());
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'i', '#', 'i', 2, 1, 2})) == json({1, 2}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '#', 'i', 2, 'i', 1, 'i', 2})) == json({1, 2}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'{', '$', 'i', '#', 'i', 1, 'i', 1, 'a', 1})) == json({{"a", 1}}));
-        // a no-op is not a value, so a container of them holds none
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'N', '#', 'i', 2})) == json::array());
-        // sized and unsized forms nested inside one another
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '[', '#', 'i', 2, 'i', 1, 'i', 2, ']'})) == json({{1, 2}}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '#', 'i', 1, '[', 'i', 1, ']'})) == json({{1}}));
-        // an optimized container of containers
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', '[', '#', 'i', 2, 'i', 1, ']', 'i', 2, ']'})) == json({{1}, {2}}));
-    }
-
-    SECTION("BJData containers are still read the same way")
-    {
-        // the ND-array wrapper and the binary shortcut are complete values,
-        // not containers the reader descends into
-        CHECK(json::from_bjdata(std::vector<uint8_t>({'[', '$', 'U', '#', '[', '$', 'i', '#', 'i', 2, 2, 3, 1, 2, 3, 4, 5, 6})) ==
-        json({{"_ArrayType_", "uint8"}, {"_ArraySize_", {2, 3}}, {"_ArrayData_", {1, 2, 3, 4, 5, 6}}}));
-        CHECK(json::from_bjdata(std::vector<uint8_t>({'[', '$', 'i', '#', 'i', 2, 1, 2})) == json({1, 2}));
-        CHECK(json::from_bjdata(std::vector<uint8_t>({'[', '[', 'i', 1, ']', ']'})) == json({{1}}));
-    }
-}
-
-TEST_CASE("UBJSON optimized arrays of a valueless type are bounded")
-{
-    // An element of type 'Z', 'T' or 'F' is encoded by its marker alone, so an
-    // optimized array of one of those has no payload and the declared count is
-    // the only thing deciding how much is allocated. Ten bytes used to produce
-    // billions of values (#2793); every other type costs at least one byte per
-    // element and is bounded by the end of the input.
-    json _;
-
-    SECTION("an excessive count is rejected")
-    {
-        // 'l' is a big-endian int32: 0x7FFFFFFF elements, about 34 GB of value
-        for (const auto marker :
-                {'Z', 'T', 'F'
-                })
-        {
-            const std::vector<uint8_t> input = {'[', '$', static_cast<uint8_t>(marker), '#', 'l', 0x7F, 0xFF, 0xFF, 0xFF};
-            CHECK_THROWS_WITH_AS(_ = json::from_ubjson(input), "[json.exception.out_of_range.408] syntax error while parsing UBJSON size: excessive array size", json::out_of_range&);
-            CHECK(json::from_ubjson(input, true, false).is_discarded());
-        }
-    }
-
-    SECTION("ordinary counts are unaffected")
-    {
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'Z', '#', 'i', 3})) == json({nullptr, nullptr, nullptr}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'T', '#', 'i', 2})) == json({true, true}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'F', '#', 'i', 2})) == json({false, false}));
-        // 'N' is a no-op rather than a value, and still yields an empty array
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'N', '#', 'i', 2})) == json::array());
-    }
-
-    SECTION("a type with a payload is unaffected")
-    {
-        // A count past the limit is not rejected for 'U', which costs a byte
-        // per element and is bounded by the end of the input instead. The
-        // count is kept just past the limit rather than made huge, because a
-        // count that also exceeds the array's max_size() is reported as
-        // out_of_range before the input runs out, and max_size() depends on
-        // the width of std::size_t.
-        const std::vector<uint8_t> input = {'[', '$', 'U', '#', 'l', 0x00, 0x10, 0x00, 0x01};
-        CHECK_THROWS_WITH_AS(_ = json::from_ubjson(input), "[json.exception.parse_error.110] parse error at byte 10: syntax error while parsing UBJSON number: unexpected end of input", json::parse_error&);
-        CHECK(json::from_ubjson(input, true, false).is_discarded());
-    }
-
-    SECTION("the writer stays within what the reader accepts")
-    {
-        // below the limit the optimized form is used and is tiny; above it the
-        // writer falls back so that the result can still be read back
-        json const at_limit(1048576, nullptr);
-        const auto v_at_limit = json::to_ubjson(at_limit, true, true);
-        CHECK(v_at_limit.size() == 9);
-        CHECK(v_at_limit.at(1) == '$');
-        CHECK(json::from_ubjson(v_at_limit) == at_limit);
-
-        json const above_limit(1048577, nullptr);
-        const auto v_above_limit = json::to_ubjson(above_limit, true, true);
-        CHECK(v_above_limit.at(1) != '$');
-        CHECK(json::from_ubjson(v_above_limit) == above_limit);
-    }
-}
-
 TEST_CASE("Universal Binary JSON Specification Examples 1")
 {
     SECTION("Null Value")

tests/src/unit-user_defined_input.cpp

@@ -18,12 +18,7 @@
 #include <nlohmann/json.hpp>
 using nlohmann::json;
 
-#include <array> // array
-#include <cstddef> // size_t
-#include <cstdint> // uint8_t
 #include <list>
-#include <string> // string
-#include <vector> // vector
 
 #if defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
     #include <iterator>
@@ -217,66 +212,6 @@ TEST_CASE("Parse with heterogeneous iterator and sentinel types")
     CHECK(j2.at(0) == 1);
 }
 
-// A type whose data() hands out raw bytes but whose size() counts something
-// else - here fixed-size records. Reading [data(), data() + size()) as bytes
-// would silently truncate the input, so data() and size() alone must not be
-// taken as evidence of contiguous byte storage.
-struct record_buffer
-{
-    using value_type = std::array<char, 4>;
-
-    std::string bytes;
-
-    const char* data() const noexcept
-    {
-        return bytes.data();
-    }
-    std::size_t size() const noexcept
-    {
-        return bytes.size() / sizeof(value_type);
-    }
-    const char* begin() const noexcept
-    {
-        return bytes.data();
-    }
-    const char* end() const noexcept
-    {
-        return bytes.data() + bytes.size();
-    }
-};
-
-TEST_CASE("Contiguous byte containers take the pointer adapter")
-{
-    // Containers with contiguous single-byte storage are routed through the
-    // pointer-based adapter so the bulk fast paths apply in every standard, not
-    // only in C++20 where the library iterators model std::contiguous_iterator.
-    CHECK(nlohmann::detail::is_contiguous_byte_container<std::string>::value);
-    CHECK(nlohmann::detail::is_contiguous_byte_container<std::vector<char>>::value);
-    CHECK(nlohmann::detail::is_contiguous_byte_container<std::vector<std::uint8_t>>::value);
-    CHECK(nlohmann::detail::is_contiguous_byte_container<std::array<char, 4>>::value);
-
-    // input_adapter() takes its container by forwarding reference, so the trait
-    // is also asked about reference types
-    CHECK(nlohmann::detail::is_contiguous_byte_container<std::string&>::value);
-    CHECK(nlohmann::detail::is_contiguous_byte_container<const std::string&>::value);
-
-    // everything else keeps the iterator-based adapter
-    CHECK_FALSE(nlohmann::detail::is_contiguous_byte_container<std::list<char>>::value);
-    CHECK_FALSE(nlohmann::detail::is_contiguous_byte_container<std::vector<int>>::value);
-    CHECK_FALSE(nlohmann::detail::is_contiguous_byte_container<const char*>::value);
-
-    // including a type that has data() and size() but whose size() does not
-    // count the units data() points at: its value_type says so
-    CHECK_FALSE(nlohmann::detail::is_contiguous_byte_container<record_buffer>::value);
-
-    // and such a container still parses through its iterators, in full - taking
-    // it for a byte container would stop after data() + size() bytes
-    const record_buffer buffer{"[1,2,3,4,5]"};
-    CHECK(buffer.data() == buffer.bytes.data());
-    CHECK(buffer.size() * sizeof(record_buffer::value_type) < buffer.bytes.size());
-    CHECK(json::parse(buffer) == json({1, 2, 3, 4, 5}));
-}
-
 #if defined(__cpp_lib_concepts) && defined(JSON_HAS_CPP_20)
 // JSON_HAS_CPP_20 (do not remove; see note at top of file)
 TEST_CASE("Parse with std::counted_iterator and std::default_sentinel_t")
@@ -293,180 +228,6 @@ TEST_CASE("Parse with std::counted_iterator and std::default_sentinel_t")
     const std::counted_iterator<iterator_type> first2(json_str.begin(), len);
     CHECK(json::accept(first2, std::default_sentinel));
 }
-
-TEST_CASE("std::counted_iterator reaches the contiguous fast paths")
-{
-    // A sized sentinel makes the remaining element count computable in O(1), so
-    // std::counted_iterator over a contiguous iterator must reach the same bulk
-    // string/number scanners as a plain pointer - not just the byte-at-a-time
-    // fallback (see #5268 for the equivalent memcpy fast path).
-#if JSON_HAS_RANGES
-    // JSON_HAS_RANGES is 0 on standard libraries with an incomplete <ranges>
-    // (libstdc++ < 11, libc++ < 16), where the adapter deliberately falls back
-    // to the byte-at-a-time scanner; everything below still has to work there.
-    using adapter_type = nlohmann::detail::iterator_input_adapter<std::counted_iterator<const char*>, std::default_sentinel_t>;
-    CHECK(adapter_type::supports_bulk_scan);
-    CHECK(adapter_type::supports_seek);
-#endif
-
-    // exercise every fast path: long ASCII run, multibyte UTF-8, escapes, and
-    // integer/floating-point numbers
-    const std::string json_str =
-        R"({"ascii":"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",)"
-        "\"utf8\":\"\xe4\xb8\xad\xe6\x96\x87\xf0\x9f\x98\x80\xc3\xa9\","
-        R"("escaped":"aéb\n\\","ints":[0,-1,18446744073709551615,-9223372036854775808],)"
-        R"("floats":[1.5,-2.25e3,0.30000000000000004]})";
-    const auto len = static_cast<std::iter_difference_t<const char*>>(json_str.size());
-
-    const std::counted_iterator<const char*> first(json_str.data(), len);
-    const json j = json::parse(first, std::default_sentinel);
-
-    // parsing through the pointer adapter must give exactly the same result
-    CHECK(j == json::parse(json_str));
-
-#if !defined(JSON_NOEXCEPTION)
-    // Diagnostics that quote the offending token are reconstructed from the
-    // already-consumed input (supports_seek), a path a sized sentinel only
-    // reaches now; check a few that include the "last read" text. Parsing
-    // invalid input aborts when exceptions are off, hence the guard.
-    // Raw strings and explicit bytes: an escaped literal and two literals
-    // written next to each other both read as mistakes to static analysis.
-    const auto byte = [](int value)
-    {
-        return std::string(1, static_cast<char>(value));
-    };
-    const std::vector<std::string> diagnostic_docs =
-    {
-        "1\nx",
-        "truX",
-        "[tru]",
-        R"("abc)",
-        R"(["\ud834"])",
-        R"(["a)" + byte(0x01) + R"(b"])",
-        R"([")" + byte(0xC3) + byte(0x28) + R"("])",
-        "[1e]",
-        R"(["aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaX)"
-    };
-
-    for (const auto& text : diagnostic_docs)
-    {
-        CAPTURE(text);
-        const std::counted_iterator<const char*> it(text.data(), static_cast<std::iter_difference_t<const char*>>(text.size()));
-        std::string counted_message;
-        std::string string_message;
-        try
-        {
-            const json counted_result = json::parse(it, std::default_sentinel);
-            static_cast<void>(counted_result);
-        }
-        catch (const json::parse_error& e)
-        {
-            counted_message = e.what();
-        }
-        try
-        {
-            const json string_result = json::parse(text);
-            static_cast<void>(string_result);
-        }
-        catch (const json::parse_error& e)
-        {
-            string_message = e.what();
-        }
-        CHECK_FALSE(counted_message.empty());
-        CHECK(counted_message == string_message);
-    }
-
-    // and errors must still be reported identically
-    const std::string bad = "[01\n]";
-    const std::counted_iterator<const char*> bad_first(bad.data(), static_cast<std::iter_difference_t<const char*>>(bad.size()));
-    std::string counted_what;
-    std::string string_what;
-    try
-    {
-        const json counted_result = json::parse(bad_first, std::default_sentinel);
-        static_cast<void>(counted_result);
-    }
-    catch (const json::parse_error& e)
-    {
-        counted_what = e.what();
-    }
-    try
-    {
-        const json string_result = json::parse(bad);
-        static_cast<void>(string_result);
-    }
-    catch (const json::parse_error& e)
-    {
-        string_what = e.what();
-    }
-    CHECK_FALSE(counted_what.empty());
-    CHECK(counted_what == string_what);
-#endif
-}
-
-#if !defined(JSON_NOEXCEPTION)
-// several cases below are truncated on purpose, and parsing invalid input
-// aborts when exceptions are off
-TEST_CASE("std::counted_iterator bulk scanning stops at the counted end")
-{
-    // The count, not the size of the underlying buffer, is the end of the
-    // input: the bulk scanners must never look at the bytes behind it, even
-    // though they are readable. Each case is compared against parsing the
-    // equivalent prefix as a std::string.
-    const auto via_counted = [](const std::string & buf, std::size_t n) -> std::string
-    {
-        const std::counted_iterator<const char*> first(buf.data(), static_cast<std::iter_difference_t<const char*>>(n));
-        try
-        {
-            const json j = json::parse(first, std::default_sentinel);
-            return "OK|" + j.dump();
-        }
-        catch (const json::parse_error& e)
-        {
-            return {e.what()};
-        }
-    };
-    const auto via_prefix = [](const std::string & buf, std::size_t n) -> std::string
-    {
-        try
-        {
-            const json j = json::parse(buf.substr(0, n));
-            return "OK|" + j.dump();
-        }
-        catch (const json::parse_error& e)
-        {
-            return {e.what()};
-        }
-    };
-
-    struct testcase // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init)
-    {
-        const char* buffer;
-        std::size_t count;
-    };
-    const std::vector<testcase> cases =
-    {
-        {"[\"abc\"]____TRAILING____", 7},                    // exact fit, tail hidden
-        {"[\"abcdefghijklmnop\"]____", 8},                   // cut inside a string
-        {"[\"abc\"]____", 6},                                // cut just before the closing quote
-        {"[12345]xxxxx", 4},                                 // cut inside a number
-        {"[123]999999", 5},                                  // number ends exactly at the count
-        {"[\"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\"]", 12},        // closing quote only behind the count
-        {"[\"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\"]", 19},      // cut inside an 8-byte SWAR stride
-        {"[\"\xe4\xb8\xad\xe6\x96\x87\"]", 5},               // cut inside a UTF-8 sequence
-        {"[\"\xe4\xb8\xad\xe6\x96\x87\"]____", 10},          // complete UTF-8, tail hidden
-        {"[1.25e3]TRAILINGDIGITS999", 7},                    // number token reaches the count
-    };
-
-    for (const auto& tc : cases)
-    {
-        CAPTURE(tc.buffer);
-        CAPTURE(tc.count);
-        const std::string buffer = tc.buffer;
-        CHECK(via_counted(buffer, tc.count) == via_prefix(buffer, tc.count));
-    }
-}
-#endif
 #endif
 
 } // namespace