Fix old clang: do not declare the defaulted document_data() noexcept

With the nested struct object_index, clang 4 (and, by the same bug, the clang 3.x of ci_test_compilers_clang) rejects the explicitly noexcept defaulted constructor: "default member initializer for 'indexes' needed within definition of enclosing class 'document_data' outside of member functions". Nothing depends on the constructor being noexcept, so let it take the implicit exception specification. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Fix CI: useless casts of the key hash of the view's object index
2026-09-30 19:50:34 +00:00 · 2026-09-30 21:02:01 +02:00 · 2026-09-30 21:02:00 +02:00 · 2026-09-30 21:01:59 +02:00 · 2026-09-30 21:01:58 +02:00 · 2026-09-30 21:01:58 +02:00
27 changed files with 1311 additions and 29 deletions
@@ -78,9 +78,11 @@ cc_library(
        "include/nlohmann/detail/view/materialize.hpp",
        "include/nlohmann/detail/view/node.hpp",
        "include/nlohmann/detail/view/number.hpp",
+        "include/nlohmann/detail/view/object_index.hpp",
        "include/nlohmann/detail/view/pointer.hpp",
        "include/nlohmann/detail/view/scan.hpp",
        "include/nlohmann/detail/view/serializer.hpp",
+        "include/nlohmann/detail/view/simd.hpp",
        "include/nlohmann/detail/view/string_ref.hpp",
        "include/nlohmann/detail/view/value.hpp",
        "include/nlohmann/json.hpp",
@@ -1405,6 +1405,7 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
 - The class contains parts of [Google Abseil](https://github.com/abseil/abseil-cpp) which is licensed under the [Apache 2.0 License](https://opensource.org/licenses/Apache-2.0).
 - The class contains an adapted version of the Eisel-Lemire algorithm, its table of powers of five, and its digit comparison for long numbers from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright &copy; 2021 The fast_float authors
 - The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
+- The view's parser (`<nlohmann/json_view.hpp>`) validates non-ASCII strings with the vector UTF-8 check of [simdjson](https://github.com/simdjson/simdjson) by Daniel Lemire, Geoff Langdale, John Keiser, and contributors (its "lookup4" algorithm and tables, after J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021), which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here) and the Apache 2.0 License. Copyright &copy; 2018-2025 The simdjson authors

 <img align="right" src="https://git.fsfe.org/reuse/reuse-ci/raw/branch/master/reuse-horizontal.png" alt="REUSE Software">

@@ -307,3 +307,5 @@ INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_SERIALIZE_ENUM'
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_MAJOR', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_MINOR', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_PATCH', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_VIEW_NO_SIMD', 'Macro', 'api/macros/json_view_no_simd/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_VIEW_USE_SSSE3', 'Macro', 'api/macros/json_view_use_ssse3/index.html');
@@ -74,6 +74,8 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
 1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
   another, in document order, stopping at the first match. Each comparison first checks the key's length --
   already known from the index, without reading the key bytes -- before comparing its content.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
 2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
   index (unlike `BasicJsonType`'s array, which is random-access).
 3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
@@ -35,6 +35,8 @@ No-throw guarantee: this function never throws exceptions.
 1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
   another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
   known from the index, without reading the key bytes -- before comparing its content.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
 2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
   that level or the index into the array -- as for [`operator[]`](operator[].md#complexity) and
   [`at`](at.md#complexity) with a JSON pointer.
@@ -26,6 +26,8 @@ No-throw guarantee: this function never throws exceptions.
 Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
 another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
 known from the index, without reading the key bytes -- before comparing its content.
+Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
+average.

 ## Notes

@@ -28,6 +28,8 @@ No-throw guarantee: this function never throws exceptions.
 Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
 another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
 known from the index, without reading the key bytes -- before comparing its content.
+Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
+average.

 ## Notes

@@ -76,6 +76,8 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
   another, in document order, stopping at the first match. Each comparison first checks the key's length --
   already known from the index, without reading the key bytes -- before comparing its content, so a key of a
   different length than `key` is rejected without touching the source text.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
 2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
   index (unlike `BasicJsonType`'s array, which is random-access).
 3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
@@ -70,6 +70,8 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
 1. Linear in the number of members: as for [`operator[]`](operator[].md#complexity), members are compared one after
   another, in document order, stopping at the first match. Plus the complexity of converting the found member to
   `T` (see [`get`](get.md)).
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
 2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
   that level or the index into the array -- as for the [`operator[]`](operator[].md#complexity) and
   [`at`](at.md#complexity) overloads that take a JSON pointer. Plus the complexity of converting the resolved value
@@ -34,6 +34,8 @@ header. See also the [macro overview page](../../features/macros.md).
 - [**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
+- [**JSON_VIEW_NO_SIMD**](json_view_no_simd.md) - use only portable code in the parser of `json_view.hpp`
+- [**JSON_VIEW_USE_SSSE3**](json_view_use_ssse3.md) - validate non-ASCII strings with SSSE3 in the parser of `json_view.hpp`

 ## Library version

@@ -0,0 +1,50 @@
+# JSON_VIEW_NO_SIMD
+
+```cpp
+#define JSON_VIEW_NO_SIMD
+```
+
+When defined, the parser of [`basic_json_document`](../basic_json_document/index.md) (`<nlohmann/json_view.hpp>`)
+uses only portable C++ to scan strings. By default, it scans long runs of string bytes 16 at a time with NEON on
+AArch64 (with GCC and Clang) and SSE2 on x86-64, which are part of the baseline instruction sets of these
+architectures, and validates non-ASCII text with NEON (or SSSE3, see
+[`JSON_VIEW_USE_SSSE3`](json_view_use_ssse3.md)).
+
+The same input is accepted or rejected either way, with the same values, and errors are reported the same way; only
+the speed differs. The macro exists for platforms whose compilers lack the intrinsics headers, and to test the portable
+code.
+
+!!! warning "Define consistently"
+
+    The macro selects between two definitions of the same inline functions. It must therefore be defined identically for
+    **every** translation unit that includes `<nlohmann/json_view.hpp>`; prefer a compile definition on the target.
+
+## Default definition
+
+By default, `#!cpp JSON_VIEW_NO_SIMD` is not defined, and the vector code is used where available.
+
+```cpp
+#undef JSON_VIEW_NO_SIMD
+```
+
+## Examples
+
+??? example
+
+    The code below uses the portable string scanning of the view.
+
+    ```cpp
+    #define JSON_VIEW_NO_SIMD
+    #include <nlohmann/json_view.hpp>
+
+    ...
+    ```
+
+## See also
+
+- [JSON_VIEW_USE_SSSE3](json_view_use_ssse3.md) - validate non-ASCII strings with SSSE3 on x86-64
+- [json_view](../../features/json_view.md) - the zero-copy view
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,49 @@
+# JSON_VIEW_USE_SSSE3
+
+```cpp
+#define JSON_VIEW_USE_SSSE3
+```
+
+When defined on x86-64, the parser of [`basic_json_document`](../basic_json_document/index.md)
+(`<nlohmann/json_view.hpp>`) validates non-ASCII text in strings with SSSE3, 16 bytes at a time, using the "lookup4"
+algorithm of [simdjson](https://github.com/simdjson/simdjson). Without it, non-ASCII text is validated one UTF-8
+sequence at a time on x86-64; on AArch64, the vector check uses NEON and is always on.
+
+SSSE3 is not part of the x86-64 baseline, so the code must be compiled for it: define the macro only together with a
+compiler option that enables SSSE3 (e.g. `-mssse3`, or `-march=` with a CPU that has it), and only for programs that
+run on such CPUs. The same input is accepted or rejected either way; only the speed of non-ASCII text differs.
+
+!!! warning "Define consistently"
+
+    The macro selects between two definitions of the same inline functions. It must therefore be defined identically,
+    with the same compiler options, for **every** translation unit that includes `<nlohmann/json_view.hpp>`; mixing
+    translation units that define it with ones that do not is an ODR violation. Prefer a compile definition on the
+    target.
+
+## Default definition
+
+By default, `#!cpp JSON_VIEW_USE_SSSE3` is not defined.
+
+```cpp
+#undef JSON_VIEW_USE_SSSE3
+```
+
+## Examples
+
+??? example
+
+    With CMake, for a program that only runs on CPUs with SSSE3:
+
+    ```cmake
+    target_compile_definitions(your_target PRIVATE JSON_VIEW_USE_SSSE3)
+    target_compile_options(your_target PRIVATE -mssse3)
+    ```
+
+## See also
+
+- [JSON_VIEW_NO_SIMD](json_view_no_simd.md) - use only portable code in the view's parser
+- [JSON_USE_SIMDUTF](json_use_simdutf.md) - validate UTF-8 with simdutf in `basic_json`'s parser
+
+## Version history
+
+- Added in version 3.13.0.
@@ -196,7 +196,7 @@ packet-beta
 |-------|---------|------------|-------------------------------------------------------------------------------------------------------------------------------|
 | 0     | `kind`  | `uint8_t`  | the type, numbered as [`value_t`](../api/basic_json/value_t.md): 0 null, 1 object, 2 array, 3 string, 4 boolean, 5 signed integer, 6 unsigned integer, 7 float |
 | 1     | `flags` | `uint8_t`  | bits 0-1: where a string's bytes are (0: the source text, 1: the buffer of decoded strings, for strings with escapes); bit 2: the value of a boolean |
-| 2-3   | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; otherwise 0                      |
+| 2-3   | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; objects: the number of their hash index (1-based), or 0; otherwise 0 |
 | 4-7   | `off`   | `uint32_t` | where the value starts: the first byte after a string's opening quote (or its position in the buffer of decoded strings), the first byte of a number or literal, the bracket of an array or object |
 | 8-11  | `len`   | `uint32_t` | strings: the length after decoding; floats and literals: the length of the token; arrays and objects: the number of elements |
 | 12-15 | `next`  | `uint32_t` | arrays and objects: the number of nodes of the subtree, including the node itself                                              |
@@ -211,6 +211,11 @@ packet-beta
  subtree is `next` nodes further for an array or object, and the next node otherwise (`document_data::after`). Views
  step from element to element this way and skip whole subtrees in constant time.
 - **Offsets** are 32 bits wide, so a document is limited to 4 GiB (`out_of_range.416`).
+- **Large objects** (128 members or more) get a hash index after parsing
+  ([`detail/view/object_index.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/view/object_index.hpp)):
+  an open-addressing table whose slots hold the distance from the object's node to a key's node, so that a lookup does
+  not compare every key. The object's `extra` holds the number of its table. Only 65,535 tables fit into `extra`;
+  objects beyond them are searched linearly.

 For example, `#!json {"a": [1, 2.5]}` becomes five nodes. Each node's elements follow it, and `next` leads from an
 array or object past its subtree:
@@ -23,3 +23,5 @@ The class contains a copy of [Hedley](https://nemequ.github.io/hedley/) from Eva
 The class contains an adapted version of the Eisel-Lemire algorithm, its table of powers of five, and its digit comparison for long numbers from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright &copy; 2021 The fast_float authors

 The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
+
+The view's parser (`<nlohmann/json_view.hpp>`) validates non-ASCII strings with the vector UTF-8 check of [simdjson](https://github.com/simdjson/simdjson) by Daniel Lemire, Geoff Langdale, John Keiser, and contributors (its "lookup4" algorithm and tables, after J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021), which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here) and the Apache 2.0 License. Copyright &copy; 2018-2025 The simdjson authors
@@ -369,6 +369,8 @@ nav:
          - '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
+          - 'JSON_VIEW_NO_SIMD': api/macros/json_view_no_simd.md
+          - 'JSON_VIEW_USE_SSSE3': api/macros/json_view_use_ssse3.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
@@ -116,6 +116,13 @@ class builder
    frame shallow[64]; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays): not initialized on purpose; filled as containers open
    std::vector<frame> deep{};

+    /// remember an object to index after parsing (out of line, so that the
+    /// parse loop only has a call for it)
+    NLOHMANN_VIEW_NOINLINE void note_large_object(std::uint32_t idx)
+    {
+        doc.large_objects.push_back(idx);
+    }
+
    NLOHMANN_VIEW_NOINLINE bool fail(error_code c, const unsigned char* at) noexcept
    {
        m_failure.code = c;
@@ -503,7 +510,7 @@ class builder
    switch (cur())                                                                              \
    {                                                                                           \
        case '"':                                                                               \
-            if (NLOHMANN_VIEW_UNLIKELY(!string())) { return false; }                      \
+            if (NLOHMANN_VIEW_UNLIKELY(!string<true>())) { return false; }                \
            goto NEXT;                                                                          \
        case '{':                                                                               \
            open(value_t::object);                                                              \
@@ -587,7 +594,7 @@ obj_key:
            {
                return fail(error_code::expected_key);
            }
-            if (NLOHMANN_VIEW_UNLIKELY(!string()))
+            if (NLOHMANN_VIEW_UNLIKELY(!string<false>()))
            {
                return false;
            }
@@ -628,19 +635,27 @@ obj_next:
                if (enabled(TrailingCommas) && cur() == '}')
                {
                    ++p;
-                    goto close_container;
+                    goto close_object;
                }
                goto obj_key;
            }
            if (cur() == '}')
            {
                ++p;
-                goto close_container;
+                goto close_object;
            }
            return fail(error_code::expected_object_end);

 #undef NLOHMANN_VIEW_VALUE

+close_object:
+            // a large object gets a hash index (objects only, so that closing
+            // an array pays nothing for this)
+            if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members))
+            {
+                cold.note_large_object(cur_idx);
+            }
+
 close_container:
            close();
            if (NLOHMANN_VIEW_UNLIKELY(depth == 0))
@@ -690,7 +705,7 @@ root_done:
            switch (cur())
            {
                case '"':
-                    return string();
+                    return string<true>();
                case 't':
                    return literal("true", 4, value_t::boolean, node_flags::is_true);
                case 'f':
@@ -977,12 +992,13 @@ indent_done:
            return true;
        }

-        /// a string (value or key) at p
+        /// a string at p: a value (Value) or a key
+        template<bool Value>
        NLOHMANN_VIEW_ALWAYS_INLINE bool string()
        {
            ++p; // opening quote
            const unsigned char* const s = p;
-            p = scan_string_run(p, e);
+            p = scan_string_run<Value>(p, e);
            if (NLOHMANN_VIEW_LIKELY(p != e && *p == '"'))
            {
                emit(value_t::string, 0, 0, static_cast<std::size_t>(s - b), static_cast<std::uint64_t>(p - s));
@@ -10,9 +10,11 @@

 #include <array> // array
 #include <cstddef> // size_t
+#include <cstdint> // uint32_t
 #include <cstring> // memcpy
 #include <new> // operator new, placement new
 #include <string> // string
+#include <vector> // vector

 #include <nlohmann/json.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
@@ -37,6 +39,17 @@ struct document_data
    std::size_t inline_cap = 0;
    std::string arena{}; ///< decoded strings that contained escapes // NOLINT(readability-redundant-member-init)
    std::string owned{}; ///< owned copy of the input, if any // NOLINT(readability-redundant-member-init)
+
+    // hash indexes of large objects (see object_index.hpp)
+    static constexpr std::uint32_t index_min_members = 128;
+    struct object_index
+    {
+        std::size_t start;  ///< first slot in index_slots
+        std::uint32_t mask; ///< slot count - 1 (a power of two minus one)
+    };
+    std::vector<object_index> indexes{}; // NOLINT(readability-redundant-member-init)
+    std::vector<std::uint32_t> index_slots{}; // NOLINT(readability-redundant-member-init)
+    std::vector<std::uint32_t> large_objects{}; ///< positions of the objects to index (noted while parsing) // NOLINT(readability-redundant-member-init)
    std::array<const char*, 4> base = {{nullptr, nullptr, nullptr, nullptr}}; ///< string bases: source, arena (indexed by flags & node_flags::storage)
    bool discarded = true;

@@ -64,7 +77,7 @@ struct document_data
        }
    };

-    document_data() noexcept = default;
+    document_data() = default;
    document_data(const document_data&) = delete;
    document_data(document_data&&) = delete;
    document_data& operator=(const document_data&) = delete;
@@ -16,6 +16,7 @@
 #include <nlohmann/detail/view/document_data.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
 #include <nlohmann/detail/view/node.hpp>
+#include <nlohmann/detail/view/object_index.hpp>

 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -85,6 +86,10 @@ class short_key
 /// nullptr; most keys are rejected by their length, from the index alone
 inline const node* find_member(const document_data& d, const node* object, const char* key, std::size_t n) noexcept
 {
+    if (NLOHMANN_VIEW_UNLIKELY(object->extra != 0))
+    {
+        return find_indexed(d, object, key, n); // a large object
+    }
    const node* const end = document_data::child_end(object);
    const auto* const k = reinterpret_cast<const unsigned char*>(key); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
    if (NLOHMANN_VIEW_LIKELY(n <= 16))
@@ -19,3 +19,8 @@
 #undef NLOHMANN_VIEW_THROW
 #undef NLOHMANN_VIEW_LITTLE_ENDIAN
 #undef NLOHMANN_VIEW_REPEAT16
+#undef NLOHMANN_VIEW_NEON
+#undef NLOHMANN_VIEW_SSE2
+#undef NLOHMANN_VIEW_SSSE3
+#undef NLOHMANN_VIEW_VECTOR
+#undef NLOHMANN_VIEW_VECTOR_UTF8
@@ -0,0 +1,131 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  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> // uint32_t, uint64_t
+#include <cstring> // memcmp
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/document_data.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/node.hpp>
+
+// Hash indexes of large objects, so that a lookup does not compare thousands
+// of keys (as Boost.JSON switches from a linear search to a hash table for
+// large objects). An object with document_data::index_min_members members or
+// more gets an open-addressing table after parsing; its node stores the
+// number of the table (1-based) in `extra`. A slot holds the offset of a key
+// node from its object node (0: empty). Of duplicate keys, the first is kept,
+// as for the linear search.
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+/// hash of a key: its bytes, eight at a time, in a fixed byte order
+inline std::uint64_t key_hash(const char* s, std::size_t n) noexcept
+{
+    std::uint64_t h = 0x9E3779B97F4A7C15u * (n + 1);
+    const auto* p = reinterpret_cast<const unsigned char*>(s); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    while (n >= 8)
+    {
+        h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
+        h ^= h >> 29u;
+        p += 8;
+        n -= 8;
+    }
+    std::uint64_t w = 0;
+    for (std::size_t i = 0; i < n; ++i)
+    {
+        w |= static_cast<std::uint64_t>(p[i]) << (8u * i);
+    }
+    h = (h ^ w) * 0x94D049BB133111EBu;
+    return h ^ (h >> 31u);
+}
+
+/// build the table of a large object
+inline void build_object_index(document_data& d, node* obj)
+{
+    if (d.indexes.size() >= 0xFFFFu)
+    {
+        return; // LCOV_EXCL_LINE (the number must fit `extra`; more large objects are searched linearly)
+    }
+    std::size_t cap = 16;
+    while (cap < 2 * static_cast<std::size_t>(obj->len))
+    {
+        cap *= 2;
+    }
+    const std::size_t start = d.index_slots.size();
+    d.index_slots.resize(start + cap, 0);
+    std::uint32_t* const slots = d.index_slots.data() + start;
+    const std::size_t mask = cap - 1;
+    for (const node* k = document_data::first_child(obj), *end = document_data::child_end(obj); k != end; k = document_data::after(k + 1))
+    {
+        const char* const key = d.str(*k);
+        const std::uint64_t hash = key_hash(key, k->len); // (a cast of the call would be useless where std::uint64_t is std::size_t)
+        std::size_t i = static_cast<std::size_t>(hash) & mask;
+        bool duplicate = false;
+        while (slots[i] != 0)
+        {
+            const node* const other = obj + slots[i];
+            if (other->len == k->len && (k->len == 0 || std::memcmp(d.str(*other), key, k->len) == 0))
+            {
+                duplicate = true; // keep the first
+                break;
+            }
+            i = (i + 1) & mask;
+        }
+        if (!duplicate)
+        {
+            slots[i] = static_cast<std::uint32_t>(k - obj);
+        }
+    }
+    d.indexes.push_back(document_data::object_index{start, static_cast<std::uint32_t>(mask)});
+    obj->extra = static_cast<std::uint16_t>(d.indexes.size());
+}
+
+/// build the tables of the large objects the parser noted
+inline void build_object_indexes(document_data& d)
+{
+    for (const std::uint32_t i : d.large_objects)
+    {
+        build_object_index(d, d.tape + i);
+    }
+}
+
+/// the key node of the first member with this key of an indexed object, or
+/// nullptr
+inline const node* find_indexed(const document_data& d, const node* obj, const char* key, std::size_t n) noexcept
+{
+    const document_data::object_index& ix = d.indexes[obj->extra - 1u];
+    const std::uint32_t* const slots = d.index_slots.data() + ix.start;
+    const std::uint64_t hash = key_hash(key, n); // (a cast of the call would be useless where std::uint64_t is std::size_t)
+    std::size_t i = static_cast<std::size_t>(hash) & ix.mask;
+    for (;;)
+    {
+        const std::uint32_t s = slots[i];
+        if (s == 0)
+        {
+            return nullptr;
+        }
+        const node* const k = obj + s;
+        if (k->len == n && (n == 0 || std::memcmp(d.str(*k), key, n) == 0))
+        {
+            return k;
+        }
+        i = (i + 1) & ix.mask;
+    }
+}
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END
@@ -16,6 +16,7 @@

 #include <nlohmann/json.hpp>
 #include <nlohmann/detail/view/macro_scope.hpp>
+#include <nlohmann/detail/view/simd.hpp>

 // Scanning primitives of the view's parser. The unrolled checks at fixed
 // offsets follow yyjson (https://github.com/ibireme/yyjson, MIT license): the
@@ -62,9 +63,12 @@ NLOHMANN_VIEW_ALWAYS_INLINE std::uint16_t load16(const unsigned char* p) noexcep

 /// Advance over plain string bytes and well-formed UTF-8. Stops at a quote,
 /// a backslash, a control character, ill-formed UTF-8, or the end. The first
-/// 16 bytes are checked one by one, so that the position advances by
-/// constants in predicted branches (most strings are short); longer runs
-/// continue eight bytes at a time.
+/// bytes are checked one by one, so that the position advances by constants
+/// in predicted branches: 16 for keys, whose lengths repeat from record to
+/// record, and 8 for string values (Value) where a vector loop follows, as
+/// their lengths vary more. Longer runs continue 16 bytes at a time with NEON
+/// or SSE2, else eight bytes at a time.
+template<bool Value = false>
 NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned char* p, const unsigned char* e) noexcept
 {
    const std::uint8_t* plain = string_plain();
@@ -73,9 +77,23 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
        if (e - p >= 16)
        {
 #define NLOHMANN_VIEW_STEP(i) if (NLOHMANN_VIEW_LIKELY(plain[p[i]] != 0)) {} else { p += (i); goto stop; }
-            NLOHMANN_VIEW_REPEAT16(NLOHMANN_VIEW_STEP)
+            NLOHMANN_VIEW_STEP(0) NLOHMANN_VIEW_STEP(1) NLOHMANN_VIEW_STEP(2) NLOHMANN_VIEW_STEP(3)
+            NLOHMANN_VIEW_STEP(4) NLOHMANN_VIEW_STEP(5) NLOHMANN_VIEW_STEP(6) NLOHMANN_VIEW_STEP(7)
+            if (!Value || !NLOHMANN_VIEW_VECTOR)
+            {
+                NLOHMANN_VIEW_STEP(8) NLOHMANN_VIEW_STEP(9) NLOHMANN_VIEW_STEP(10) NLOHMANN_VIEW_STEP(11)
+                NLOHMANN_VIEW_STEP(12) NLOHMANN_VIEW_STEP(13) NLOHMANN_VIEW_STEP(14) NLOHMANN_VIEW_STEP(15)
+                p += 8;
+            }
 #undef NLOHMANN_VIEW_STEP
-            p += 16;
+            p += 8;
+#if NLOHMANN_VIEW_VECTOR
+            p = vector_plain_run(p, e);
+            if (p != e && plain[*p] == 0)
+            {
+                goto stop;
+            }
+#else
            while (e - p >= 8)
            {
                const std::uint64_t special = swar_string_special(read_eight_bytes(p));
@@ -86,6 +104,7 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
                }
                p += 8;
            }
+#endif
            continue;
        }
        while (p != e && plain[*p] != 0)
@@ -101,6 +120,10 @@ stop:
        {
            return p; // quote, backslash, or control character
        }
+#if NLOHMANN_VIEW_VECTOR_UTF8
+        // non-ASCII: the vector check, out of line
+        return scan_string_vector(p, e, plain);
+#else
        // non-ASCII: a run of well-formed sequences (the library's check, so
        // that exactly what json::parse accepts is accepted)
        do
@@ -113,6 +136,7 @@ stop:
            p += n;
        }
        while (p != e && *p >= 0x80);
+#endif
    }
 }

@@ -0,0 +1,281 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-FileCopyrightText: 2018-2025 The simdjson authors <https://github.com/simdjson/simdjson>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <array> // array
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint64_t
+
+#include <nlohmann/json.hpp>
+#include <nlohmann/detail/view/macro_scope.hpp>
+
+// Vector code for long runs of string bytes. NEON (AArch64) and SSE2 (x86-64)
+// belong to the baseline instruction sets and are used by default. The vector
+// UTF-8 check needs NEON, or SSSE3 if JSON_VIEW_USE_SSSE3 is defined: SSSE3 is
+// not part of x86-64, so it must not depend on the flags of a translation unit
+// (two translation units with different flags would have different
+// definitions of the same inline functions). JSON_VIEW_NO_SIMD selects the
+// portable code.
+#if !defined(JSON_VIEW_NO_SIMD) && defined(__aarch64__) && (defined(__GNUC__) || defined(__clang__)) && NLOHMANN_VIEW_LITTLE_ENDIAN
+    #include <arm_neon.h>
+    #define NLOHMANN_VIEW_NEON 1
+#else
+    #define NLOHMANN_VIEW_NEON 0
+#endif
+#if !defined(JSON_VIEW_NO_SIMD) && !NLOHMANN_VIEW_NEON && (defined(__SSE2__) || defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+    #include <emmintrin.h>
+    #define NLOHMANN_VIEW_SSE2 1
+#else
+    #define NLOHMANN_VIEW_SSE2 0
+#endif
+#if NLOHMANN_VIEW_SSE2 && defined(JSON_VIEW_USE_SSSE3)
+    #include <tmmintrin.h>
+    #define NLOHMANN_VIEW_SSSE3 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
+#else
+    #define NLOHMANN_VIEW_SSSE3 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
+#endif
+#define NLOHMANN_VIEW_VECTOR (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSE2)
+#define NLOHMANN_VIEW_VECTOR_UTF8 (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSSE3)
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+#if NLOHMANN_VIEW_VECTOR
+/*!
+@brief the first byte of a string run that is a quote, a backslash, a control
+character, or not ASCII, 16 bytes per step
+
+Stops at such a byte, or where fewer than 16 bytes are left (the caller tells
+the two apart). A signed compare with 0x20 finds control characters and
+non-ASCII bytes at once.
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* vector_plain_run(const unsigned char* p, const unsigned char* e) noexcept
+{
+    while (e - p >= 16)
+    {
+#if NLOHMANN_VIEW_NEON
+        const uint8x16_t in = vld1q_u8(p);
+        const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))),
+                                            vcltq_s8(vreinterpretq_s8_u8(in), vdupq_n_s8(0x20)));
+        // one nibble per byte (the usual NEON replacement of x86's movemask, see
+        // D. Kutenin, "Porting x86 vector bitmask optimizations to Arm NEON", 2022)
+        const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
+        if (bits != 0)
+        {
+            return p + (count_trailing_zeros(bits) >> 2u);
+        }
+#else
+        const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p)));
+        const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
+                                             _mm_cmplt_epi8(in, _mm_set1_epi8(0x20)));
+        const auto bits = static_cast<std::uint64_t>(static_cast<unsigned>(_mm_movemask_epi8(special)));
+        if (bits != 0)
+        {
+            return p + count_trailing_zeros(bits);
+        }
+#endif
+        p += 16;
+    }
+    return p;
+}
+#endif
+
+#if NLOHMANN_VIEW_VECTOR_UTF8
+/// Tables of the UTF-8 check of J. Keiser and D. Lemire, "Validating UTF-8 In
+/// Less Than One Instruction Per Byte" (2021), as in simdjson ("lookup4"): each
+/// maps a nibble (high and low nibble of the previous byte, high nibble of the
+/// current byte) to the errors it allows; a byte pair is ill-formed if all
+/// three have an error bit in common.
+template<typename Dummy = void>
+struct utf8_lookup4
+{
+    static constexpr std::uint8_t too_short = 1u << 0u, too_long = 1u << 1u, overlong_3 = 1u << 2u, too_large = 1u << 3u;
+    static constexpr std::uint8_t surrogate = 1u << 4u, overlong_2 = 1u << 5u, too_large_1000 = 1u << 6u, overlong_4 = 1u << 6u;
+    static constexpr std::uint8_t two_conts = 1u << 7u, carry = too_short | too_long | two_conts;
+    static const std::array<std::uint8_t, 16> byte_1_high;
+    static const std::array<std::uint8_t, 16> byte_1_low;
+    static const std::array<std::uint8_t, 16> byte_2_high;
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_high =
+{
+    {
+        too_long, too_long, too_long, too_long, too_long, too_long, too_long, too_long,
+        two_conts, two_conts, two_conts, two_conts,
+        too_short | overlong_2, too_short, too_short | overlong_3 | surrogate, too_short | too_large | too_large_1000 | overlong_4
+    }
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_low =
+{
+    {
+        carry | overlong_3 | overlong_2 | overlong_4, carry | overlong_2, carry, carry,
+        carry | too_large, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
+        carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
+        carry | too_large | too_large_1000, carry | too_large | too_large_1000 | surrogate, carry | too_large | too_large_1000, carry | too_large | too_large_1000
+    }
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_2_high =
+{
+    {
+        too_short, too_short, too_short, too_short, too_short, too_short, too_short, too_short,
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large_1000 | overlong_4),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
+        too_short, too_short, too_short, too_short
+    }
+};
+
+/// the end of scan_string_vector from block, where the vector loop stopped
+/// (ill-formed UTF-8, or fewer than 16 bytes left): one byte or sequence at a
+/// time, from the start of a sequence that crosses into the block
+inline const unsigned char* scan_string_finish(const unsigned char* p, const unsigned char* block, const unsigned char* e, const std::uint8_t* plain) noexcept
+{
+    for (int i = 1; i <= 3 && block - i >= p; ++i)
+    {
+        const unsigned char c = block[-i];
+        if (c < 0x80)
+        {
+            break;
+        }
+        if (c >= 0xC0)
+        {
+            const int len = 2 + static_cast<int>(c >= 0xE0) + static_cast<int>(c >= 0xF0);
+            if (len > i)
+            {
+                block -= i;
+            }
+            break;
+        }
+    }
+    for (p = block; p != e;)
+    {
+        if (*p < 0x80)
+        {
+            if (plain[*p] == 0)
+            {
+                return p;
+            }
+            ++p;
+            continue;
+        }
+        const std::size_t n = validate_one_utf8(p, static_cast<std::size_t>(e - p));
+        if (n == 0)
+        {
+            return p;
+        }
+        p += n;
+    }
+    return p;
+}
+
+/*!
+@brief the rest of a string from p (a character boundary), 16 bytes per step
+
+The first quote, backslash, or control character is found with vector
+compares, and the UTF-8 check covers the bytes up to it. Returns where the
+string scan stops, like scan_string_run: before ill-formed UTF-8 and for the
+last bytes of the input, the bytes are checked one sequence at a time. Out of
+line, so that no constants of the check occupy registers in the parse loop.
+*/
+NLOHMANN_VIEW_NOINLINE inline const unsigned char* scan_string_vector(const unsigned char* p, const unsigned char* e, const std::uint8_t* plain) noexcept
+{
+    using lookup = utf8_lookup4<>;
+    const unsigned char* block = p;
+#if NLOHMANN_VIEW_NEON
+    const uint8x16_t t1h = vld1q_u8(lookup::byte_1_high.data());
+    const uint8x16_t t1l = vld1q_u8(lookup::byte_1_low.data());
+    const uint8x16_t t2h = vld1q_u8(lookup::byte_2_high.data());
+    uint8x16_t prev = vdupq_n_u8(0);
+    while (e - block >= 16)
+    {
+        const uint8x16_t in = vld1q_u8(block);
+        const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))), vcltq_u8(in, vdupq_n_u8(0x20)));
+        const uint8x16_t prev1 = vextq_u8(prev, in, 15);
+        const uint8x16_t sc = vandq_u8(vandq_u8(vqtbl1q_u8(t1h, vshrq_n_u8(prev1, 4)), vqtbl1q_u8(t1l, vandq_u8(prev1, vdupq_n_u8(0x0F)))), vqtbl1q_u8(t2h, vshrq_n_u8(in, 4)));
+        const uint8x16_t must23 = vorrq_u8(vqsubq_u8(vextq_u8(prev, in, 14), vdupq_n_u8(0xE0 - 0x80)), vqsubq_u8(vextq_u8(prev, in, 13), vdupq_n_u8(0xF0 - 0x80)));
+        const uint8x16_t err = veorq_u8(vandq_u8(must23, vdupq_n_u8(0x80)), sc);
+        const std::uint64_t special_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
+        const std::uint64_t err_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(vtstq_u8(err, err)), 4)), 0);
+        if (special_bits != 0)
+        {
+            // errors up to the special byte count (an incomplete sequence
+            // before a quote shows at the quote); the bytes after it do not
+            const unsigned k = static_cast<unsigned>(count_trailing_zeros(special_bits)) >> 2u;
+            const std::uint64_t upto = k == 15 ? ~std::uint64_t{0} :
+                                       (std::uint64_t{1} << (4u * (k + 1u))) - 1u;
+            if ((err_bits & upto) == 0)
+            {
+                return block + k;
+            }
+            break;
+        }
+        if (err_bits != 0)
+        {
+            break;
+        }
+        prev = in;
+        block += 16;
+    }
+#else
+    // the same with SSSE3 (pshufb for the table lookups; nibbles from 16-bit
+    // shifts, as there are no byte shifts)
+    const __m128i t1h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_high.data())));
+    const __m128i t1l = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_low.data())));
+    const __m128i t2h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_2_high.data())));
+    const __m128i nibble = _mm_set1_epi8(0x0F);
+    const __m128i zero = _mm_setzero_si128();
+    __m128i prev = zero;
+    while (e - block >= 16)
+    {
+        const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(block)));
+        const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
+                                             _mm_cmpeq_epi8(_mm_subs_epu8(in, _mm_set1_epi8(0x1F)), zero)); // in < 0x20
+        const __m128i prev1 = _mm_alignr_epi8(in, prev, 15);
+        const __m128i sc = _mm_and_si128(_mm_and_si128(_mm_shuffle_epi8(t1h, _mm_and_si128(_mm_srli_epi16(prev1, 4), nibble)),
+                                         _mm_shuffle_epi8(t1l, _mm_and_si128(prev1, nibble))),
+                                         _mm_shuffle_epi8(t2h, _mm_and_si128(_mm_srli_epi16(in, 4), nibble)));
+        const __m128i must23 = _mm_or_si128(_mm_subs_epu8(_mm_alignr_epi8(in, prev, 14), _mm_set1_epi8(0xE0 - 0x80)),
+                                            _mm_subs_epu8(_mm_alignr_epi8(in, prev, 13), _mm_set1_epi8(0xF0 - 0x80)));
+        const __m128i err = _mm_xor_si128(_mm_and_si128(must23, _mm_set1_epi8(static_cast<char>(-128))), sc);
+        const auto special_bits = static_cast<unsigned>(_mm_movemask_epi8(special));
+        const auto err_bits = ~static_cast<unsigned>(_mm_movemask_epi8(_mm_cmpeq_epi8(err, zero))) & 0xFFFFu;
+        if (special_bits != 0)
+        {
+            const unsigned k = static_cast<unsigned>(count_trailing_zeros(static_cast<std::uint64_t>(special_bits)));
+            if ((err_bits & ((2u << k) - 1u)) == 0)
+            {
+                return block + k;
+            }
+            break;
+        }
+        if (err_bits != 0)
+        {
+            break;
+        }
+        prev = in;
+        block += 16;
+    }
+#endif
+    return scan_string_finish(p, block, e, plain);
+}
+#endif
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END
@@ -25,6 +25,7 @@
 #define INCLUDE_NLOHMANN_JSON_VIEW_HPP_

 #include <cstddef> // size_t
+#include <cstdint> // uint32_t
 #include <cstring> // memcpy, strlen
 #include <iterator> // distance, input_iterator_tag, iterator_traits
 #include <map> // map
@@ -56,6 +57,7 @@
 #include <nlohmann/detail/view/macro_scope.hpp>
 #include <nlohmann/detail/view/materialize.hpp>
 #include <nlohmann/detail/view/node.hpp>
+#include <nlohmann/detail/view/object_index.hpp>
 #include <nlohmann/detail/view/pointer.hpp>
 #include <nlohmann/detail/view/serializer.hpp>
 #include <nlohmann/detail/view/string_ref.hpp>
@@ -925,7 +927,9 @@ class basic_json_document
        }
        return sizeof(document_data) + (m_data->inline_cap * sizeof(detail::view::node))
               + (m_data->tape != m_data->inline_tape ? m_data->tape_cap * sizeof(detail::view::node) : 0)
-               + m_data->arena.capacity() + m_data->owned.capacity();
+               + m_data->arena.capacity() + m_data->owned.capacity()
+               + (m_data->indexes.capacity() * sizeof(document_data::object_index)) + (m_data->index_slots.capacity() * sizeof(std::uint32_t))
+               + (m_data->large_objects.capacity() * sizeof(std::uint32_t));
    }

    /// release unused capacity of the index and the decoded strings; like
@@ -995,6 +999,9 @@ class basic_json_document
        d.size = size;
        d.tape_size = 0;
        d.arena.clear();
+        d.indexes.clear();
+        d.index_slots.clear();
+        d.large_objects.clear();
        d.discarded = true;
        detail::view::parse_failure failure;
        bool ok = false;
@@ -1010,6 +1017,7 @@ class basic_json_document
        {
            d.base[0] = d.src;
            d.base[1] = d.arena.data();
+            detail::view::build_object_indexes(d);
            d.discarded = false;
            return;
        }
@@ -25,6 +25,7 @@
 #define INCLUDE_NLOHMANN_JSON_VIEW_HPP_

 #include <cstddef> // size_t
+#include <cstdint> // uint32_t
 #include <cstring> // memcpy, strlen
 #include <iterator> // distance, input_iterator_tag, iterator_traits
 #include <map> // map
@@ -81,9 +82,11 @@

 #include <array> // array
 #include <cstddef> // size_t
+#include <cstdint> // uint32_t
 #include <cstring> // memcpy
 #include <new> // operator new, placement new
 #include <string> // string
+#include <vector> // vector

 // #include <nlohmann/json.hpp>
 // #include <nlohmann/detail/view/macro_scope.hpp>
@@ -279,6 +282,17 @@ struct document_data
    std::size_t inline_cap = 0;
    std::string arena{}; ///< decoded strings that contained escapes // NOLINT(readability-redundant-member-init)
    std::string owned{}; ///< owned copy of the input, if any // NOLINT(readability-redundant-member-init)
+
+    // hash indexes of large objects (see object_index.hpp)
+    static constexpr std::uint32_t index_min_members = 128;
+    struct object_index
+    {
+        std::size_t start;  ///< first slot in index_slots
+        std::uint32_t mask; ///< slot count - 1 (a power of two minus one)
+    };
+    std::vector<object_index> indexes{}; // NOLINT(readability-redundant-member-init)
+    std::vector<std::uint32_t> index_slots{}; // NOLINT(readability-redundant-member-init)
+    std::vector<std::uint32_t> large_objects{}; ///< positions of the objects to index (noted while parsing) // NOLINT(readability-redundant-member-init)
    std::array<const char*, 4> base = {{nullptr, nullptr, nullptr, nullptr}}; ///< string bases: source, arena (indexed by flags & node_flags::storage)
    bool discarded = true;

@@ -306,7 +320,7 @@ struct document_data
        }
    };

-    document_data() noexcept = default;
+    document_data() = default;
    document_data(const document_data&) = delete;
    document_data(document_data&&) = delete;
    document_data& operator=(const document_data&) = delete;
@@ -395,6 +409,290 @@ NLOHMANN_JSON_NAMESPACE_END
 // #include <nlohmann/json.hpp>
 // #include <nlohmann/detail/view/macro_scope.hpp>

+// #include <nlohmann/detail/view/simd.hpp>
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-FileCopyrightText: 2018-2025 The simdjson authors <https://github.com/simdjson/simdjson>
+// SPDX-License-Identifier: MIT
+
+
+
+#include <array> // array
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint64_t
+
+// #include <nlohmann/json.hpp>
+// #include <nlohmann/detail/view/macro_scope.hpp>
+
+
+// Vector code for long runs of string bytes. NEON (AArch64) and SSE2 (x86-64)
+// belong to the baseline instruction sets and are used by default. The vector
+// UTF-8 check needs NEON, or SSSE3 if JSON_VIEW_USE_SSSE3 is defined: SSSE3 is
+// not part of x86-64, so it must not depend on the flags of a translation unit
+// (two translation units with different flags would have different
+// definitions of the same inline functions). JSON_VIEW_NO_SIMD selects the
+// portable code.
+#if !defined(JSON_VIEW_NO_SIMD) && defined(__aarch64__) && (defined(__GNUC__) || defined(__clang__)) && NLOHMANN_VIEW_LITTLE_ENDIAN
+    #include <arm_neon.h>
+    #define NLOHMANN_VIEW_NEON 1
+#else
+    #define NLOHMANN_VIEW_NEON 0
+#endif
+#if !defined(JSON_VIEW_NO_SIMD) && !NLOHMANN_VIEW_NEON && (defined(__SSE2__) || defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
+    #include <emmintrin.h>
+    #define NLOHMANN_VIEW_SSE2 1
+#else
+    #define NLOHMANN_VIEW_SSE2 0
+#endif
+#if NLOHMANN_VIEW_SSE2 && defined(JSON_VIEW_USE_SSSE3)
+    #include <tmmintrin.h>
+    #define NLOHMANN_VIEW_SSSE3 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
+#else
+    #define NLOHMANN_VIEW_SSSE3 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
+#endif
+#define NLOHMANN_VIEW_VECTOR (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSE2)
+#define NLOHMANN_VIEW_VECTOR_UTF8 (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSSE3)
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+#if NLOHMANN_VIEW_VECTOR
+/*!
+@brief the first byte of a string run that is a quote, a backslash, a control
+character, or not ASCII, 16 bytes per step
+
+Stops at such a byte, or where fewer than 16 bytes are left (the caller tells
+the two apart). A signed compare with 0x20 finds control characters and
+non-ASCII bytes at once.
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* vector_plain_run(const unsigned char* p, const unsigned char* e) noexcept
+{
+    while (e - p >= 16)
+    {
+#if NLOHMANN_VIEW_NEON
+        const uint8x16_t in = vld1q_u8(p);
+        const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))),
+                                            vcltq_s8(vreinterpretq_s8_u8(in), vdupq_n_s8(0x20)));
+        // one nibble per byte (the usual NEON replacement of x86's movemask, see
+        // D. Kutenin, "Porting x86 vector bitmask optimizations to Arm NEON", 2022)
+        const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
+        if (bits != 0)
+        {
+            return p + (count_trailing_zeros(bits) >> 2u);
+        }
+#else
+        const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p)));
+        const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
+                                             _mm_cmplt_epi8(in, _mm_set1_epi8(0x20)));
+        const auto bits = static_cast<std::uint64_t>(static_cast<unsigned>(_mm_movemask_epi8(special)));
+        if (bits != 0)
+        {
+            return p + count_trailing_zeros(bits);
+        }
+#endif
+        p += 16;
+    }
+    return p;
+}
+#endif
+
+#if NLOHMANN_VIEW_VECTOR_UTF8
+/// Tables of the UTF-8 check of J. Keiser and D. Lemire, "Validating UTF-8 In
+/// Less Than One Instruction Per Byte" (2021), as in simdjson ("lookup4"): each
+/// maps a nibble (high and low nibble of the previous byte, high nibble of the
+/// current byte) to the errors it allows; a byte pair is ill-formed if all
+/// three have an error bit in common.
+template<typename Dummy = void>
+struct utf8_lookup4
+{
+    static constexpr std::uint8_t too_short = 1u << 0u, too_long = 1u << 1u, overlong_3 = 1u << 2u, too_large = 1u << 3u;
+    static constexpr std::uint8_t surrogate = 1u << 4u, overlong_2 = 1u << 5u, too_large_1000 = 1u << 6u, overlong_4 = 1u << 6u;
+    static constexpr std::uint8_t two_conts = 1u << 7u, carry = too_short | too_long | two_conts;
+    static const std::array<std::uint8_t, 16> byte_1_high;
+    static const std::array<std::uint8_t, 16> byte_1_low;
+    static const std::array<std::uint8_t, 16> byte_2_high;
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_high =
+{
+    {
+        too_long, too_long, too_long, too_long, too_long, too_long, too_long, too_long,
+        two_conts, two_conts, two_conts, two_conts,
+        too_short | overlong_2, too_short, too_short | overlong_3 | surrogate, too_short | too_large | too_large_1000 | overlong_4
+    }
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_low =
+{
+    {
+        carry | overlong_3 | overlong_2 | overlong_4, carry | overlong_2, carry, carry,
+        carry | too_large, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
+        carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
+        carry | too_large | too_large_1000, carry | too_large | too_large_1000 | surrogate, carry | too_large | too_large_1000, carry | too_large | too_large_1000
+    }
+};
+
+template<typename Dummy>
+const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_2_high =
+{
+    {
+        too_short, too_short, too_short, too_short, too_short, too_short, too_short, too_short,
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large_1000 | overlong_4),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
+        static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
+        too_short, too_short, too_short, too_short
+    }
+};
+
+/// the end of scan_string_vector from block, where the vector loop stopped
+/// (ill-formed UTF-8, or fewer than 16 bytes left): one byte or sequence at a
+/// time, from the start of a sequence that crosses into the block
+inline const unsigned char* scan_string_finish(const unsigned char* p, const unsigned char* block, const unsigned char* e, const std::uint8_t* plain) noexcept
+{
+    for (int i = 1; i <= 3 && block - i >= p; ++i)
+    {
+        const unsigned char c = block[-i];
+        if (c < 0x80)
+        {
+            break;
+        }
+        if (c >= 0xC0)
+        {
+            const int len = 2 + static_cast<int>(c >= 0xE0) + static_cast<int>(c >= 0xF0);
+            if (len > i)
+            {
+                block -= i;
+            }
+            break;
+        }
+    }
+    for (p = block; p != e;)
+    {
+        if (*p < 0x80)
+        {
+            if (plain[*p] == 0)
+            {
+                return p;
+            }
+            ++p;
+            continue;
+        }
+        const std::size_t n = validate_one_utf8(p, static_cast<std::size_t>(e - p));
+        if (n == 0)
+        {
+            return p;
+        }
+        p += n;
+    }
+    return p;
+}
+
+/*!
+@brief the rest of a string from p (a character boundary), 16 bytes per step
+
+The first quote, backslash, or control character is found with vector
+compares, and the UTF-8 check covers the bytes up to it. Returns where the
+string scan stops, like scan_string_run: before ill-formed UTF-8 and for the
+last bytes of the input, the bytes are checked one sequence at a time. Out of
+line, so that no constants of the check occupy registers in the parse loop.
+*/
+NLOHMANN_VIEW_NOINLINE inline const unsigned char* scan_string_vector(const unsigned char* p, const unsigned char* e, const std::uint8_t* plain) noexcept
+{
+    using lookup = utf8_lookup4<>;
+    const unsigned char* block = p;
+#if NLOHMANN_VIEW_NEON
+    const uint8x16_t t1h = vld1q_u8(lookup::byte_1_high.data());
+    const uint8x16_t t1l = vld1q_u8(lookup::byte_1_low.data());
+    const uint8x16_t t2h = vld1q_u8(lookup::byte_2_high.data());
+    uint8x16_t prev = vdupq_n_u8(0);
+    while (e - block >= 16)
+    {
+        const uint8x16_t in = vld1q_u8(block);
+        const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))), vcltq_u8(in, vdupq_n_u8(0x20)));
+        const uint8x16_t prev1 = vextq_u8(prev, in, 15);
+        const uint8x16_t sc = vandq_u8(vandq_u8(vqtbl1q_u8(t1h, vshrq_n_u8(prev1, 4)), vqtbl1q_u8(t1l, vandq_u8(prev1, vdupq_n_u8(0x0F)))), vqtbl1q_u8(t2h, vshrq_n_u8(in, 4)));
+        const uint8x16_t must23 = vorrq_u8(vqsubq_u8(vextq_u8(prev, in, 14), vdupq_n_u8(0xE0 - 0x80)), vqsubq_u8(vextq_u8(prev, in, 13), vdupq_n_u8(0xF0 - 0x80)));
+        const uint8x16_t err = veorq_u8(vandq_u8(must23, vdupq_n_u8(0x80)), sc);
+        const std::uint64_t special_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
+        const std::uint64_t err_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(vtstq_u8(err, err)), 4)), 0);
+        if (special_bits != 0)
+        {
+            // errors up to the special byte count (an incomplete sequence
+            // before a quote shows at the quote); the bytes after it do not
+            const unsigned k = static_cast<unsigned>(count_trailing_zeros(special_bits)) >> 2u;
+            const std::uint64_t upto = k == 15 ? ~std::uint64_t{0} :
+                                       (std::uint64_t{1} << (4u * (k + 1u))) - 1u;
+            if ((err_bits & upto) == 0)
+            {
+                return block + k;
+            }
+            break;
+        }
+        if (err_bits != 0)
+        {
+            break;
+        }
+        prev = in;
+        block += 16;
+    }
+#else
+    // the same with SSSE3 (pshufb for the table lookups; nibbles from 16-bit
+    // shifts, as there are no byte shifts)
+    const __m128i t1h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_high.data())));
+    const __m128i t1l = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_low.data())));
+    const __m128i t2h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_2_high.data())));
+    const __m128i nibble = _mm_set1_epi8(0x0F);
+    const __m128i zero = _mm_setzero_si128();
+    __m128i prev = zero;
+    while (e - block >= 16)
+    {
+        const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(block)));
+        const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
+                                             _mm_cmpeq_epi8(_mm_subs_epu8(in, _mm_set1_epi8(0x1F)), zero)); // in < 0x20
+        const __m128i prev1 = _mm_alignr_epi8(in, prev, 15);
+        const __m128i sc = _mm_and_si128(_mm_and_si128(_mm_shuffle_epi8(t1h, _mm_and_si128(_mm_srli_epi16(prev1, 4), nibble)),
+                                         _mm_shuffle_epi8(t1l, _mm_and_si128(prev1, nibble))),
+                                         _mm_shuffle_epi8(t2h, _mm_and_si128(_mm_srli_epi16(in, 4), nibble)));
+        const __m128i must23 = _mm_or_si128(_mm_subs_epu8(_mm_alignr_epi8(in, prev, 14), _mm_set1_epi8(0xE0 - 0x80)),
+                                            _mm_subs_epu8(_mm_alignr_epi8(in, prev, 13), _mm_set1_epi8(0xF0 - 0x80)));
+        const __m128i err = _mm_xor_si128(_mm_and_si128(must23, _mm_set1_epi8(static_cast<char>(-128))), sc);
+        const auto special_bits = static_cast<unsigned>(_mm_movemask_epi8(special));
+        const auto err_bits = ~static_cast<unsigned>(_mm_movemask_epi8(_mm_cmpeq_epi8(err, zero))) & 0xFFFFu;
+        if (special_bits != 0)
+        {
+            const unsigned k = static_cast<unsigned>(count_trailing_zeros(static_cast<std::uint64_t>(special_bits)));
+            if ((err_bits & ((2u << k) - 1u)) == 0)
+            {
+                return block + k;
+            }
+            break;
+        }
+        if (err_bits != 0)
+        {
+            break;
+        }
+        prev = in;
+        block += 16;
+    }
+#endif
+    return scan_string_finish(p, block, e, plain);
+}
+#endif
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END
+

 // Scanning primitives of the view's parser. The unrolled checks at fixed
 // offsets follow yyjson (https://github.com/ibireme/yyjson, MIT license): the
@@ -441,9 +739,12 @@ NLOHMANN_VIEW_ALWAYS_INLINE std::uint16_t load16(const unsigned char* p) noexcep

 /// Advance over plain string bytes and well-formed UTF-8. Stops at a quote,
 /// a backslash, a control character, ill-formed UTF-8, or the end. The first
-/// 16 bytes are checked one by one, so that the position advances by
-/// constants in predicted branches (most strings are short); longer runs
-/// continue eight bytes at a time.
+/// bytes are checked one by one, so that the position advances by constants
+/// in predicted branches: 16 for keys, whose lengths repeat from record to
+/// record, and 8 for string values (Value) where a vector loop follows, as
+/// their lengths vary more. Longer runs continue 16 bytes at a time with NEON
+/// or SSE2, else eight bytes at a time.
+template<bool Value = false>
 NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned char* p, const unsigned char* e) noexcept
 {
    const std::uint8_t* plain = string_plain();
@@ -452,9 +753,23 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
        if (e - p >= 16)
        {
 #define NLOHMANN_VIEW_STEP(i) if (NLOHMANN_VIEW_LIKELY(plain[p[i]] != 0)) {} else { p += (i); goto stop; }
-            NLOHMANN_VIEW_REPEAT16(NLOHMANN_VIEW_STEP)
+            NLOHMANN_VIEW_STEP(0) NLOHMANN_VIEW_STEP(1) NLOHMANN_VIEW_STEP(2) NLOHMANN_VIEW_STEP(3)
+            NLOHMANN_VIEW_STEP(4) NLOHMANN_VIEW_STEP(5) NLOHMANN_VIEW_STEP(6) NLOHMANN_VIEW_STEP(7)
+            if (!Value || !NLOHMANN_VIEW_VECTOR)
+            {
+                NLOHMANN_VIEW_STEP(8) NLOHMANN_VIEW_STEP(9) NLOHMANN_VIEW_STEP(10) NLOHMANN_VIEW_STEP(11)
+                NLOHMANN_VIEW_STEP(12) NLOHMANN_VIEW_STEP(13) NLOHMANN_VIEW_STEP(14) NLOHMANN_VIEW_STEP(15)
+                p += 8;
+            }
 #undef NLOHMANN_VIEW_STEP
-            p += 16;
+            p += 8;
+#if NLOHMANN_VIEW_VECTOR
+            p = vector_plain_run(p, e);
+            if (p != e && plain[*p] == 0)
+            {
+                goto stop;
+            }
+#else
            while (e - p >= 8)
            {
                const std::uint64_t special = swar_string_special(read_eight_bytes(p));
@@ -465,6 +780,7 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
                }
                p += 8;
            }
+#endif
            continue;
        }
        while (p != e && plain[*p] != 0)
@@ -480,6 +796,10 @@ stop:
        {
            return p; // quote, backslash, or control character
        }
+#if NLOHMANN_VIEW_VECTOR_UTF8
+        // non-ASCII: the vector check, out of line
+        return scan_string_vector(p, e, plain);
+#else
        // non-ASCII: a run of well-formed sequences (the library's check, so
        // that exactly what json::parse accepts is accepted)
        do
@@ -492,6 +812,7 @@ stop:
            p += n;
        }
        while (p != e && *p >= 0x80);
+#endif
    }
 }

@@ -660,6 +981,13 @@ class builder
    frame shallow[64]; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays): not initialized on purpose; filled as containers open
    std::vector<frame> deep{};

+    /// remember an object to index after parsing (out of line, so that the
+    /// parse loop only has a call for it)
+    NLOHMANN_VIEW_NOINLINE void note_large_object(std::uint32_t idx)
+    {
+        doc.large_objects.push_back(idx);
+    }
+
    NLOHMANN_VIEW_NOINLINE bool fail(error_code c, const unsigned char* at) noexcept
    {
        m_failure.code = c;
@@ -1047,7 +1375,7 @@ class builder
    switch (cur())                                                                              \
    {                                                                                           \
        case '"':                                                                               \
-            if (NLOHMANN_VIEW_UNLIKELY(!string())) { return false; }                      \
+            if (NLOHMANN_VIEW_UNLIKELY(!string<true>())) { return false; }                \
            goto NEXT;                                                                          \
        case '{':                                                                               \
            open(value_t::object);                                                              \
@@ -1131,7 +1459,7 @@ obj_key:
            {
                return fail(error_code::expected_key);
            }
-            if (NLOHMANN_VIEW_UNLIKELY(!string()))
+            if (NLOHMANN_VIEW_UNLIKELY(!string<false>()))
            {
                return false;
            }
@@ -1172,19 +1500,27 @@ obj_next:
                if (enabled(TrailingCommas) && cur() == '}')
                {
                    ++p;
-                    goto close_container;
+                    goto close_object;
                }
                goto obj_key;
            }
            if (cur() == '}')
            {
                ++p;
-                goto close_container;
+                goto close_object;
            }
            return fail(error_code::expected_object_end);

 #undef NLOHMANN_VIEW_VALUE

+close_object:
+            // a large object gets a hash index (objects only, so that closing
+            // an array pays nothing for this)
+            if (NLOHMANN_VIEW_UNLIKELY(cur_count >= document_data::index_min_members))
+            {
+                cold.note_large_object(cur_idx);
+            }
+
 close_container:
            close();
            if (NLOHMANN_VIEW_UNLIKELY(depth == 0))
@@ -1234,7 +1570,7 @@ root_done:
            switch (cur())
            {
                case '"':
-                    return string();
+                    return string<true>();
                case 't':
                    return literal("true", 4, value_t::boolean, node_flags::is_true);
                case 'f':
@@ -1521,12 +1857,13 @@ indent_done:
            return true;
        }

-        /// a string (value or key) at p
+        /// a string at p: a value (Value) or a key
+        template<bool Value>
        NLOHMANN_VIEW_ALWAYS_INLINE bool string()
        {
            ++p; // opening quote
            const unsigned char* const s = p;
-            p = scan_string_run(p, e);
+            p = scan_string_run<Value>(p, e);
            if (NLOHMANN_VIEW_LIKELY(p != e && *p == '"'))
            {
                emit(value_t::string, 0, 0, static_cast<std::size_t>(s - b), static_cast<std::uint64_t>(p - s));
@@ -2379,6 +2716,142 @@ NLOHMANN_JSON_NAMESPACE_END

 // #include <nlohmann/detail/view/node.hpp>

+// #include <nlohmann/detail/view/object_index.hpp>
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  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
+
+
+
+#include <cstddef> // size_t
+#include <cstdint> // uint32_t, uint64_t
+#include <cstring> // memcmp
+
+// #include <nlohmann/json.hpp>
+// #include <nlohmann/detail/view/document_data.hpp>
+
+// #include <nlohmann/detail/view/macro_scope.hpp>
+
+// #include <nlohmann/detail/view/node.hpp>
+
+
+// Hash indexes of large objects, so that a lookup does not compare thousands
+// of keys (as Boost.JSON switches from a linear search to a hash table for
+// large objects). An object with document_data::index_min_members members or
+// more gets an open-addressing table after parsing; its node stores the
+// number of the table (1-based) in `extra`. A slot holds the offset of a key
+// node from its object node (0: empty). Of duplicate keys, the first is kept,
+// as for the linear search.
+
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+namespace view
+{
+
+/// hash of a key: its bytes, eight at a time, in a fixed byte order
+inline std::uint64_t key_hash(const char* s, std::size_t n) noexcept
+{
+    std::uint64_t h = 0x9E3779B97F4A7C15u * (n + 1);
+    const auto* p = reinterpret_cast<const unsigned char*>(s); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    while (n >= 8)
+    {
+        h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
+        h ^= h >> 29u;
+        p += 8;
+        n -= 8;
+    }
+    std::uint64_t w = 0;
+    for (std::size_t i = 0; i < n; ++i)
+    {
+        w |= static_cast<std::uint64_t>(p[i]) << (8u * i);
+    }
+    h = (h ^ w) * 0x94D049BB133111EBu;
+    return h ^ (h >> 31u);
+}
+
+/// build the table of a large object
+inline void build_object_index(document_data& d, node* obj)
+{
+    if (d.indexes.size() >= 0xFFFFu)
+    {
+        return; // LCOV_EXCL_LINE (the number must fit `extra`; more large objects are searched linearly)
+    }
+    std::size_t cap = 16;
+    while (cap < 2 * static_cast<std::size_t>(obj->len))
+    {
+        cap *= 2;
+    }
+    const std::size_t start = d.index_slots.size();
+    d.index_slots.resize(start + cap, 0);
+    std::uint32_t* const slots = d.index_slots.data() + start;
+    const std::size_t mask = cap - 1;
+    for (const node* k = document_data::first_child(obj), *end = document_data::child_end(obj); k != end; k = document_data::after(k + 1))
+    {
+        const char* const key = d.str(*k);
+        const std::uint64_t hash = key_hash(key, k->len); // (a cast of the call would be useless where std::uint64_t is std::size_t)
+        std::size_t i = static_cast<std::size_t>(hash) & mask;
+        bool duplicate = false;
+        while (slots[i] != 0)
+        {
+            const node* const other = obj + slots[i];
+            if (other->len == k->len && (k->len == 0 || std::memcmp(d.str(*other), key, k->len) == 0))
+            {
+                duplicate = true; // keep the first
+                break;
+            }
+            i = (i + 1) & mask;
+        }
+        if (!duplicate)
+        {
+            slots[i] = static_cast<std::uint32_t>(k - obj);
+        }
+    }
+    d.indexes.push_back(document_data::object_index{start, static_cast<std::uint32_t>(mask)});
+    obj->extra = static_cast<std::uint16_t>(d.indexes.size());
+}
+
+/// build the tables of the large objects the parser noted
+inline void build_object_indexes(document_data& d)
+{
+    for (const std::uint32_t i : d.large_objects)
+    {
+        build_object_index(d, d.tape + i);
+    }
+}
+
+/// the key node of the first member with this key of an indexed object, or
+/// nullptr
+inline const node* find_indexed(const document_data& d, const node* obj, const char* key, std::size_t n) noexcept
+{
+    const document_data::object_index& ix = d.indexes[obj->extra - 1u];
+    const std::uint32_t* const slots = d.index_slots.data() + ix.start;
+    const std::uint64_t hash = key_hash(key, n); // (a cast of the call would be useless where std::uint64_t is std::size_t)
+    std::size_t i = static_cast<std::size_t>(hash) & ix.mask;
+    for (;;)
+    {
+        const std::uint32_t s = slots[i];
+        if (s == 0)
+        {
+            return nullptr;
+        }
+        const node* const k = obj + s;
+        if (k->len == n && (n == 0 || std::memcmp(d.str(*k), key, n) == 0))
+        {
+            return k;
+        }
+        i = (i + 1) & ix.mask;
+    }
+}
+
+}  // namespace view
+}  // namespace detail
+NLOHMANN_JSON_NAMESPACE_END
+

 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -2448,6 +2921,10 @@ class short_key
 /// nullptr; most keys are rejected by their length, from the index alone
 inline const node* find_member(const document_data& d, const node* object, const char* key, std::size_t n) noexcept
 {
+    if (NLOHMANN_VIEW_UNLIKELY(object->extra != 0))
+    {
+        return find_indexed(d, object, key, n); // a large object
+    }
    const node* const end = document_data::child_end(object);
    const auto* const k = reinterpret_cast<const unsigned char*>(key); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
    if (NLOHMANN_VIEW_LIKELY(n <= 16))
@@ -2807,6 +3284,8 @@ NLOHMANN_JSON_NAMESPACE_END

 // #include <nlohmann/detail/view/node.hpp>

+// #include <nlohmann/detail/view/object_index.hpp>
+
 // #include <nlohmann/detail/view/pointer.hpp>
 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
@@ -4501,7 +4980,9 @@ class basic_json_document
        }
        return sizeof(document_data) + (m_data->inline_cap * sizeof(detail::view::node))
               + (m_data->tape != m_data->inline_tape ? m_data->tape_cap * sizeof(detail::view::node) : 0)
-               + m_data->arena.capacity() + m_data->owned.capacity();
+               + m_data->arena.capacity() + m_data->owned.capacity()
+               + (m_data->indexes.capacity() * sizeof(document_data::object_index)) + (m_data->index_slots.capacity() * sizeof(std::uint32_t))
+               + (m_data->large_objects.capacity() * sizeof(std::uint32_t));
    }

    /// release unused capacity of the index and the decoded strings; like
@@ -4571,6 +5052,9 @@ class basic_json_document
        d.size = size;
        d.tape_size = 0;
        d.arena.clear();
+        d.indexes.clear();
+        d.index_slots.clear();
+        d.large_objects.clear();
        d.discarded = true;
        detail::view::parse_failure failure;
        bool ok = false;
@@ -4586,6 +5070,7 @@ class basic_json_document
        {
            d.base[0] = d.src;
            d.base[1] = d.arena.data();
+            detail::view::build_object_indexes(d);
            d.discarded = false;
            return;
        }
@@ -4751,6 +5236,11 @@ class tuple_element<N, ::nlohmann::detail::view::view_item<View>> // NOLINT(cert
 #undef NLOHMANN_VIEW_THROW
 #undef NLOHMANN_VIEW_LITTLE_ENDIAN
 #undef NLOHMANN_VIEW_REPEAT16
+#undef NLOHMANN_VIEW_NEON
+#undef NLOHMANN_VIEW_SSE2
+#undef NLOHMANN_VIEW_SSSE3
+#undef NLOHMANN_VIEW_VECTOR
+#undef NLOHMANN_VIEW_VECTOR_UTF8


 #endif  // INCLUDE_NLOHMANN_JSON_VIEW_HPP_
@@ -324,6 +324,26 @@ json_test_add_test_for(src/unit-diagnostic-positions.cpp
    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
 )

+# the json_view parser again with the portable string scanning instead of
+# NEON/SSE2, and on x86-64 with the SSSE3 UTF-8 check (JSON_VIEW_USE_SSSE3)
+json_test_set_test_options(test-json_view_builder_portable
+    COMPILE_DEFINITIONS JSON_VIEW_NO_SIMD
+)
+json_test_add_test_for(src/unit-json_view_builder.cpp
+    NAME test-json_view_builder_portable
+    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
+)
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^(x86_64|AMD64|amd64)$" AND NOT MSVC)
+    json_test_set_test_options(test-json_view_builder_ssse3
+        COMPILE_DEFINITIONS JSON_VIEW_USE_SSSE3
+        COMPILE_OPTIONS -mssse3
+    )
+    json_test_add_test_for(src/unit-json_view_builder.cpp
+        NAME test-json_view_builder_ssse3
+        MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
+    )
+endif()
+
 # *DO NOT* use json_test_set_test_options() below this line

 #############################################################################
@@ -1277,3 +1277,60 @@ TEST_CASE("json_view comparison")
        CHECK(a.root() != json_document::parse(other).root());
    }
 }
+
+TEST_CASE("json_view large objects")
+{
+    // objects with 128 members or more are looked up with a hash index
+    for (const std::size_t members :
+            {
+                127u, 128u, 129u, 10000u
+            })
+    {
+        CAPTURE(members);
+        std::string text = "{";
+        for (std::size_t i = 0; i < members; ++i)
+        {
+            text += (i != 0 ? ",\"" : "\"") + std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\\n" : "") + "\":" + std::to_string(i);
+        }
+        text += R"(,"":"empty key","k1":"a duplicate of an earlier key"})";
+        const json_document d = json_document::parse(text);
+        const json_view v = d.root();
+        const json j = json::parse(text);
+        for (std::size_t i = 0; i < members; ++i)
+        {
+            const std::string key = std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\n" : "");
+            CHECK(v[key].get<std::size_t>() == i);
+            CHECK(v.contains(key));
+            CHECK(v.find(key).key() == key);
+            CHECK(v.at(key).get<std::size_t>() == i);
+            CHECK(!v.contains(key + "x"));
+        }
+        CHECK(v[""].get_string() == "empty key");
+        CHECK(v["k1"].get<int>() == 1); // the first of duplicate keys, as for small objects
+        CHECK(!v.contains("missing"));
+        CHECK_THROWS_WITH_AS(v.at("missing"), "[json.exception.out_of_range.403] key 'missing' not found", json::out_of_range&);
+        CHECK(v == j);
+        CHECK(v.materialize() == j);
+    }
+
+    SECTION("nested, reused, and in arrays")
+    {
+        std::string inner = "{";
+        for (int i = 0; i < 300; ++i)
+        {
+            inner += (i != 0 ? ",\"m" : "\"m") + std::to_string(i) + "\":" + std::to_string(i);
+        }
+        inner += '}';
+        const std::string text = "[" + inner + ",{\"x\":" + inner + "}," + inner + "]";
+        json_document d = json_document::parse(text);
+        CHECK(d.root()[0]["m299"].get<int>() == 299);
+        CHECK(d.root()[1]["x"]["m150"].get<int>() == 150);
+        CHECK(d.root()[2]["m0"].get<int>() == 0);
+        const std::size_t with_index = d.memory_usage();
+        d.read(std::string("{\"small\": 1}"));
+        CHECK(d.root()["small"].get<int>() == 1);
+        d.read(text);
+        CHECK(d.root()[2]["m7"].get<int>() == 7);
+        CHECK(d.memory_usage() >= with_index / 2);
+    }
+}
@@ -17,6 +17,7 @@
 #endif
 using nlohmann::json;

+#include <array>
 #include <cstdint>
 #include <fstream>
 #include <map>
@@ -142,6 +143,32 @@ void check_same(const std::string& text)
    }
 }

+// a string value and a key must be accepted or rejected as json::parse does,
+// and give its value (cheaper than check_same: the options do not matter)
+void check_string(const std::string& content)
+{
+    for (const std::string& text :
+            {
+                "[\"" + content + "\"]", "{\"" + content + "\":1}"
+            })
+    {
+        const bool accepted = json::accept(text);
+        for (const bool sentinel :
+                {
+                    true, false
+                })
+        {
+            const built b = build(text, false, false, sentinel);
+            if (b.ok != accepted || (accepted && value_of(b) != json::parse(text)))
+            {
+                CAPTURE(text);
+                CHECK(b.ok == accepted);
+                CHECK((b.ok && accepted ? value_of(b) == json::parse(text) : true));
+            }
+        }
+    }
+}
+
 // a small deterministic generator of documents
 struct generator
 {
@@ -401,3 +428,81 @@ TEST_CASE("json_view builder")
        }
    }
 }
+
+TEST_CASE("json_view builder: strings across vector blocks")
+{
+    // Strings are scanned 8 or 16 bytes at a time (NEON, SSE2, or SWAR) and
+    // non-ASCII text with the vector UTF-8 check (NEON, SSSE3) or one sequence
+    // at a time. Sequences are placed so that they start at every offset
+    // around the block boundaries of keys (16, 32) and values (8, 24), with
+    // text of several lengths after them.
+    const std::array<std::size_t, 16> prefixes = {{0, 6, 7, 8, 13, 14, 15, 16, 21, 22, 23, 24, 29, 30, 31, 32}};
+    const std::array<std::size_t, 3> suffixes = {{0, 3, 17}};
+    const auto around = [&](const std::string & seq, std::size_t prefix, std::size_t suffix)
+    {
+        return std::string(prefix, 'a') + seq + std::string(suffix, 'b');
+    };
+
+    SECTION("every two-byte sequence")
+    {
+        for (unsigned lead = 0x80; lead <= 0xFF; ++lead)
+        {
+            for (unsigned second = 0; second <= 0xFF; ++second)
+            {
+                if (second == '"' || second == '\\')
+                {
+                    continue;
+                }
+                const std::string seq = {static_cast<char>(lead), static_cast<char>(second)};
+                check_string(around(seq, prefixes[(lead + second) % 16], suffixes[second % 3]));
+            }
+        }
+    }
+
+    SECTION("three- and four-byte sequences")
+    {
+        const std::array<unsigned, 8> conts = {{0x7F, 0x80, 0x8F, 0x90, 0x9F, 0xA0, 0xBF, 0xC0}};
+        for (unsigned lead = 0xE0; lead <= 0xF7; ++lead)
+        {
+            for (const unsigned b2 : conts)
+            {
+                for (const unsigned b3 : conts)
+                {
+                    for (const std::size_t prefix : prefixes)
+                    {
+                        std::string seq = {static_cast<char>(lead), static_cast<char>(b2), static_cast<char>(b3)};
+                        if (lead >= 0xF0)
+                        {
+                            seq += static_cast<char>(prefix % 2 == 0 ? 0x80 : 0xBF);
+                        }
+                        check_string(around(seq, prefix, suffixes[prefix % 3]));
+                        // cut short before the end of the string
+                        check_string(around(seq.substr(0, seq.size() - 1), prefix, suffixes[prefix % 3]));
+                    }
+                }
+            }
+        }
+    }
+
+    SECTION("long runs of text with one damaged byte")
+    {
+        const std::array<const char*, 7> chars = {{"a", "\xc3\xa9", "\xe3\x81\x82", "\xf0\x9f\x98\x80", "\xed\x9f\xbf", "\xef\xbf\xbf", "\xf4\x8f\xbf\xbf"}};
+        const std::array<char, 11> damage = {{'\x80', '\xbf', '\xc0', '\xc1', '\xe0', '\xed', '\xf5', '\xff', '\x1f', '"', '\\'}};
+        std::mt19937 rng(5295); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed): reproducible
+        for (int i = 0; i < 4000; ++i)
+        {
+            std::string text;
+            const auto n = rng() % 60;
+            for (unsigned k = 0; k < n; ++k)
+            {
+                text += chars[rng() % chars.size()];
+            }
+            check_string(text);
+            if (!text.empty())
+            {
+                text[rng() % text.size()] = damage[rng() % damage.size()];
+                check_string(text);
+            }
+        }
+    }
+}
Author	SHA1	Message	Date
Niels Lohmann	eede67ca92	Fix old clang: do not declare the defaulted document_data() noexcept With the nested struct object_index, clang 4 (and, by the same bug, the clang 3.x of ci_test_compilers_clang) rejects the explicitly noexcept defaulted constructor: "default member initializer for 'indexes' needed within definition of enclosing class 'document_data' outside of member functions". Nothing depends on the constructor being noexcept, so let it take the implicit exception specification. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:02:01 +02:00
Niels Lohmann	82b31f31b8	Fix CI: useless casts of the key hash of the view's object index GCC -Werror=useless-cast on Linux x86-64 rejects static_cast<std::size_t>(key_hash(...)): the call returns a std::uint64_t prvalue, the same type as std::size_t there, while the cast is needed where std::size_t is 32 bits wide. Store the hash in a variable and cast that, which GCC does not report. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:02:00 +02:00
Niels Lohmann	798f4c888a	Document the hash index of json_view on the architecture page The node index section says what extra holds for objects and how large objects are indexed. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:01:59 +02:00
Niels Lohmann	98258aa3af	Address the clang-tidy findings of the object index tests Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:01:58 +02:00
Niels Lohmann	904c8c6710	Index the large objects of json_view Lookups in objects are linear, as for ordered_json. Objects with 128 members or more now get a hash table after parsing (open addressing; the first of duplicate keys is kept, as for the linear search), so that operator[], at(), find(), contains(), count(), value(), and JSON pointers take constant time on average in them; the idea of switching to a hash table for large objects is Boost.JSON's. The parser notes such objects when it closes them (out of line, so that the parse loop only has a call for it), and the object node keeps the number of its table. Looking up each key of an object with 10,000 members: 59.8 ms -> 0.16 ms. Parsing (json_document::parse, best of 7, separate processes): most files within 1%; canada +5%, mesh.pretty +3%, citm +3%. Tests: objects with 127, 128, 129, and 10,000 members (escaped, empty, and duplicate keys, missing keys, comparisons), nested large objects, and documents reused with read(). Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:01:58 +02:00
Niels Lohmann	1f0c3be6f3	Address the clang-tidy findings of the SIMD scan Hold the UTF-8 lookup tables in std::array, compute the length of a sequence without nested conditionals, and use std::array in the tests. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:01:56 +02:00
Niels Lohmann	c3b51addbf	Scan the strings of json_view with NEON and SSE2 Long runs of string bytes are scanned 16 at a time with NEON (AArch64, with GCC and Clang) and SSE2 (x86-64): both belong to the baseline instruction sets. A signed compare with 0x20 finds control characters and non-ASCII bytes at once. Keys keep 16 table checks before the vector loop (their lengths repeat from record to record, so the branches predict well); string values have 8, as their lengths vary more. Non-ASCII text is validated 16 bytes at a time with the "lookup4" check of simdjson (J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021): with NEON, and on x86-64 with SSSE3 if JSON_VIEW_USE_SSSE3 is defined (SSSE3 is not part of x86-64, and the code must not depend on the flags of a translation unit). JSON_VIEW_NO_SIMD selects the portable code. The vector code sits in detail/view/simd.hpp; the same input is accepted either way. json_document::parse, best of 7 runs in separate processes (M1 Max): poet.json (CJK text) -72%, random.json -25%, twitter.json -22%, gsoc-2018.json -20%, semanticscholar -19%, github_events -11%, apache_builds -9.5%, canada/citm -5/-6%; lottie +4%, tree-pretty +2.5%. Tests: every two-byte sequence and three- and four-byte sequences with continuation bytes at the edges of their ranges, at every offset around the vector blocks of keys and values, cut short, and long runs of text with a damaged byte, against json::accept and json::parse. CMake builds the parser tests again with JSON_VIEW_NO_SIMD, and on x86-64 with JSON_VIEW_USE_SSSE3 and -mssse3; the macros are documented. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:01:55 +02:00