♻️ replace snprintf with stream

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

.github/workflows/ubuntu.yml

@@ -143,7 +143,7 @@ jobs:
     strategy:
       matrix:
         # older GCC docker images (4, 5, 6) fail to check out code
-        compiler: ['7', '8', '9', '10', '11', '12', '13', '14', '15', 'latest']
+        compiler: ['7', '8', '9', '10', '11', '12', '13', '14', 'latest']
     container: gcc:${{ matrix.compiler }}
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -221,21 +221,6 @@ jobs:
       - name: Build
         run: cmake --build build --target ci_cuda_example
 
-  ci_module_cpp20:
-    strategy:
-      matrix:
-        container: ['gcc:latest', 'silkeh/clang:latest']
-    runs-on: ubuntu-latest
-    container: ${{ matrix.container }}
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@57c20a23a6cac5b90f31864439996e5b206df9dc # v4.0.1
-      - name: Run CMake
-        run: cmake -S . -B build -DJSON_CI=On
-      - name: Build
-        run: cmake --build build --target ci_module_cpp20
-
   ci_icpc:
     runs-on: ubuntu-latest
     container: ghcr.io/nlohmann/json-ci:v2.2.0

.github/workflows/windows.yml

@@ -111,12 +111,3 @@ jobs:
         run: cmake --build build --config Debug --parallel 10
       - name: Test
         run: cd build ; ctest -j 10 -C Debug --exclude-regex "test-unicode" --output-on-failure
-
-  ci_module_cpp20:
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - name: Run CMake (Debug)
-        run: cmake -S . -B build -G "Visual Studio 17 2022" -DJSON_CI=ON -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8 /W4 /WX"
-      - name: Build
-        run: cmake --build build --config Debug --target ci_module_cpp20

cmake/ci.cmake

@@ -659,17 +659,6 @@ add_custom_target(ci_cuda_example
     COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_cuda_example
 )
 
-###############################################################################
-# C++ 20 modules
-###############################################################################
-
-add_custom_target(ci_module_cpp20
-    COMMAND ${CMAKE_COMMAND}
-        -DCMAKE_BUILD_TYPE=Debug -GNinja
-        -S${PROJECT_SOURCE_DIR}/tests/module_cpp20 -B${PROJECT_BINARY_DIR}/ci_module_cpp20
-    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/ci_module_cpp20
-)
-
 ###############################################################################
 # Intel C++ Compiler
 ###############################################################################

cmake/requirements/requirements-cppcheck.txt

@@ -1 +1 @@
-cppcheck==1.5.0
+cppcheck==1.5.1

docs/mkdocs/docs/community/quality_assurance.md

@@ -76,7 +76,6 @@ violations will result in a failed build.
         | GNU 13.3.0                                   | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | GNU 14.2.0                                   | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | GNU 14.2.0                                   | arm64        | Linux 6.1.100            | Cirrus CI |
-        | GNU 15.1.0                                   | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | icpc (ICC) 2021.5.0 20211109                 | x86_64       | Ubuntu 20.04.3 LTS       | GitHub    |
         | MSVC 19.0.24241.7                            | x86          | Windows 8.1              | AppVeyor  |
         | MSVC 19.16.27035.0                           | x86          | Windows-10 (Build 14393) | AppVeyor  |

include/nlohmann/detail/conversions/from_json.hpp

@@ -34,10 +34,6 @@
     #include <optional> // optional
 #endif
 
-#if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
-    #include <string_view> // u8string_view
-#endif
-
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
 {

include/nlohmann/detail/input/binary_reader.hpp

@@ -53,7 +53,7 @@ enum class cbor_tag_handler_t
 
 @note from https://stackoverflow.com/a/1001328/266378
 */
-inline bool little_endianness(int num = 1) noexcept
+static inline bool little_endianness(int num = 1) noexcept
 {
     return *reinterpret_cast<char*>(&num) == 1;
 }

include/nlohmann/detail/meta/type_traits.hpp

@@ -13,9 +13,7 @@
 #include <tuple> // tuple
 #include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
 #include <utility> // declval
-#if defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603L
+
-    #include <cstddef> // byte
-#endif
 #include <nlohmann/detail/iterators/iterator_traits.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/call_std/begin.hpp>
@@ -241,30 +239,6 @@ struct char_traits<signed char> : std::char_traits<char>
     }
 };
 
-#if defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603L
-template<>
-struct char_traits<std::byte> : std::char_traits<char>
-{
-    using char_type = std::byte;
-    using int_type = uint64_t;
-
-    static int_type to_int_type(char_type c) noexcept
-    {
-        return static_cast<int_type>(std::to_integer<unsigned char>(c));
-    }
-
-    static char_type to_char_type(int_type i) noexcept
-    {
-        return std::byte(static_cast<unsigned char>(i));
-    }
-
-    static constexpr int_type eof() noexcept
-    {
-        return static_cast<int_type>(std::char_traits<char>::eof());
-    }
-};
-#endif
-
 ///////////////////
 // is_ functions //
 ///////////////////

include/nlohmann/detail/output/serializer.hpp

@@ -17,6 +17,7 @@
 #include <cstdint> // uint8_t
 #include <cstdio> // snprintf
 #include <limits> // numeric_limits
+#include <sstream> // string_stream
 #include <string> // string, char_traits
 #include <iomanip> // setfill, setw
 #include <type_traits> // is_same
@@ -827,53 +828,13 @@ class serializer
 
     void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
     {
-        // get number of digits for a float -> text -> float round-trip
+        std::ostringstream oss;
-        static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;
+        oss.precision(std::numeric_limits<number_float_t>::max_digits10);
+        oss.imbue(std::locale::classic());
+        oss << std::defaultfloat << x;
 
-        // the actual conversion
+        const auto s = oss.str();
-        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        o->write_characters(s.c_str(), s.size());
-        std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
-
-        // negative value indicates an error
-        JSON_ASSERT(len > 0);
-        // check if buffer was large enough
-        JSON_ASSERT(static_cast<std::size_t>(len) < number_buffer.size());
-
-        // erase thousands separator
-        if (thousands_sep != '\0')
-        {
-            // NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::remove returns an iterator, see https://github.com/nlohmann/json/issues/3081
-            const auto end = std::remove(number_buffer.begin(), number_buffer.begin() + len, thousands_sep);
-            std::fill(end, number_buffer.end(), '\0');
-            JSON_ASSERT((end - number_buffer.begin()) <= len);
-            len = (end - number_buffer.begin());
-        }
-
-        // convert decimal point to '.'
-        if (decimal_point != '\0' && decimal_point != '.')
-        {
-            // NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::find returns an iterator, see https://github.com/nlohmann/json/issues/3081
-            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
-            if (dec_pos != number_buffer.end())
-            {
-                *dec_pos = '.';
-            }
-        }
-
-        o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
-
-        // determine if we need to append ".0"
-        const bool value_is_int_like =
-            std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
-                         [](char c)
-        {
-            return c == '.' || c == 'e';
-        });
-
-        if (value_is_int_like)
-        {
-            o->write_characters(".0", 2);
-        }
     }
 
     /*!

include/nlohmann/detail/string_escape.hpp

@@ -62,7 +62,7 @@ inline StringType escape(StringType s)
  * Note the order of escaping "~1" to "/" and "~0" to "~" is important.
  */
 template<typename StringType>
-inline void unescape(StringType& s)
+static void unescape(StringType& s)
 {
     replace_substring(s, StringType{"~1"}, StringType{"/"});
     replace_substring(s, StringType{"~0"}, StringType{"~"});

include/nlohmann/json.hpp

@@ -39,7 +39,6 @@
 #include <nlohmann/detail/hash.hpp>
 #include <nlohmann/detail/input/binary_reader.hpp>
 #include <nlohmann/detail/input/input_adapters.hpp>
-#include <nlohmann/detail/input/json_sax.hpp>
 #include <nlohmann/detail/input/lexer.hpp>
 #include <nlohmann/detail/input/parser.hpp>
 #include <nlohmann/detail/iterators/internal_iterator.hpp>

single_include/nlohmann/json.hpp

@@ -3126,7 +3126,7 @@ inline StringType escape(StringType s)
  * Note the order of escaping "~1" to "/" and "~0" to "~" is important.
  */
 template<typename StringType>
-inline void unescape(StringType& s)
+static void unescape(StringType& s)
 {
     replace_substring(s, StringType{"~1"}, StringType{"/"});
     replace_substring(s, StringType{"~0"}, StringType{"~"});
@@ -3367,9 +3367,7 @@ NLOHMANN_JSON_NAMESPACE_END
 #include <tuple> // tuple
 #include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
 #include <utility> // declval
-#if defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603L
+
-    #include <cstddef> // byte
-#endif
 // #include <nlohmann/detail/iterators/iterator_traits.hpp>
 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
@@ -3778,30 +3776,6 @@ struct char_traits<signed char> : std::char_traits<char>
     }
 };
 
-#if defined(__cpp_lib_byte) && __cpp_lib_byte >= 201603L
-template<>
-struct char_traits<std::byte> : std::char_traits<char>
-{
-    using char_type = std::byte;
-    using int_type = uint64_t;
-
-    static int_type to_int_type(char_type c) noexcept
-    {
-        return static_cast<int_type>(std::to_integer<unsigned char>(c));
-    }
-
-    static char_type to_char_type(int_type i) noexcept
-    {
-        return std::byte(static_cast<unsigned char>(i));
-    }
-
-    static constexpr int_type eof() noexcept
-    {
-        return static_cast<int_type>(std::char_traits<char>::eof());
-    }
-};
-#endif
-
 ///////////////////
 // is_ functions //
 ///////////////////
@@ -4845,10 +4819,6 @@ NLOHMANN_JSON_NAMESPACE_END
     #include <optional> // optional
 #endif
 
-#if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
-    #include <string_view> // u8string_view
-#endif
-
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
 {
@@ -9868,7 +9838,7 @@ enum class cbor_tag_handler_t
 
 @note from https://stackoverflow.com/a/1001328/266378
 */
-inline bool little_endianness(int num = 1) noexcept
+static inline bool little_endianness(int num = 1) noexcept
 {
     return *reinterpret_cast<char*>(&num) == 1;
 }
@@ -12889,8 +12859,6 @@ NLOHMANN_JSON_NAMESPACE_END
 
 // #include <nlohmann/detail/input/input_adapters.hpp>
 
-// #include <nlohmann/detail/input/json_sax.hpp>
-
 // #include <nlohmann/detail/input/lexer.hpp>
 
 // #include <nlohmann/detail/input/parser.hpp>
@@ -17657,6 +17625,7 @@ NLOHMANN_JSON_NAMESPACE_END
 #include <cstdint> // uint8_t
 #include <cstdio> // snprintf
 #include <limits> // numeric_limits
+#include <sstream> // string_stream
 #include <string> // string, char_traits
 #include <iomanip> // setfill, setw
 #include <type_traits> // is_same
@@ -19594,53 +19563,13 @@ class serializer
 
     void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
     {
-        // get number of digits for a float -> text -> float round-trip
+        std::ostringstream oss;
-        static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;
+        oss.precision(std::numeric_limits<number_float_t>::max_digits10);
+        oss.imbue(std::locale::classic());
+        oss << std::defaultfloat << x;
 
-        // the actual conversion
+        const auto s = oss.str();
-        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        o->write_characters(s.c_str(), s.size());
-        std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
-
-        // negative value indicates an error
-        JSON_ASSERT(len > 0);
-        // check if buffer was large enough
-        JSON_ASSERT(static_cast<std::size_t>(len) < number_buffer.size());
-
-        // erase thousands separator
-        if (thousands_sep != '\0')
-        {
-            // NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::remove returns an iterator, see https://github.com/nlohmann/json/issues/3081
-            const auto end = std::remove(number_buffer.begin(), number_buffer.begin() + len, thousands_sep);
-            std::fill(end, number_buffer.end(), '\0');
-            JSON_ASSERT((end - number_buffer.begin()) <= len);
-            len = (end - number_buffer.begin());
-        }
-
-        // convert decimal point to '.'
-        if (decimal_point != '\0' && decimal_point != '.')
-        {
-            // NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::find returns an iterator, see https://github.com/nlohmann/json/issues/3081
-            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
-            if (dec_pos != number_buffer.end())
-            {
-                *dec_pos = '.';
-            }
-        }
-
-        o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
-
-        // determine if we need to append ".0"
-        const bool value_is_int_like =
-            std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
-                         [](char c)
-        {
-            return c == '.' || c == 'e';
-        });
-
-        if (value_is_int_like)
-        {
-            o->write_characters(".0", 2);
-        }
     }
 
     /*!

tests/module_cpp20/CMakeLists.txt

@@ -1,12 +0,0 @@
-cmake_minimum_required(VERSION 3.28)
-
-project(json_test CXX)
-
-add_executable(json_test)
-
-target_sources(json_test
-    PRIVATE main.cpp
-    PUBLIC FILE_SET cxx_modules TYPE CXX_MODULES FILES json.cpp)
-
-target_compile_features(json_test PUBLIC cxx_std_20)
-target_include_directories(json_test PRIVATE ../../include)

tests/module_cpp20/json.cpp

@@ -1,17 +0,0 @@
-module;
-#include <nlohmann/json.hpp>
-export module json;
-
-export namespace nlohmann
-{
-using ::nlohmann::adl_serializer;
-
-using ::nlohmann::basic_json;
-using ::nlohmann::json_pointer;
-
-using ::nlohmann::json;
-using ::nlohmann::ordered_json;
-using ::nlohmann::ordered_map;
-
-using ::nlohmann::json_pointer;
-}  // namespace nlohmann

tests/module_cpp20/main.cpp

@@ -1,6 +0,0 @@
-import json;
-
-int main()
-{
-    nlohmann::json j;
-}

tests/src/unit-msgpack.cpp

@@ -1880,82 +1880,3 @@ TEST_CASE("MessagePack roundtrips" * doctest::skip())
         }
     }
 }
-
-#ifdef JSON_HAS_CPP_17
-// Test suite for verifying MessagePack handling with std::byte input
-TEST_CASE("MessagePack with std::byte")
-{
-
-    SECTION("std::byte compatibility")
-    {
-        SECTION("vector roundtrip")
-        {
-            json original =
-            {
-                {"name", "test"},
-                {"value", 42},
-                {"array", {1, 2, 3}}
-            };
-
-            std::vector<uint8_t> temp = json::to_msgpack(original);
-            // Convert the uint8_t vector to std::byte vector
-            std::vector<std::byte> msgpack_data(temp.size());
-            for (size_t i = 0; i < temp.size(); ++i)
-            {
-                msgpack_data[i] = std::byte(temp[i]);
-            }
-            // Deserialize from std::byte vector back to JSON
-            json from_bytes;
-            CHECK_NOTHROW(from_bytes = json::from_msgpack(msgpack_data));
-
-            CHECK(from_bytes == original);
-        }
-
-        SECTION("empty vector")
-        {
-            const std::vector<std::byte> empty_data;
-            CHECK_THROWS_WITH_AS([&]()
-            {
-                [[maybe_unused]] auto result = json::from_msgpack(empty_data);
-                return true;
-            }
-            (),
-            "[json.exception.parse_error.110] parse error at byte 1: syntax error while parsing MessagePack value: unexpected end of input",
-            json::parse_error&);
-        }
-
-        SECTION("comparison with workaround")
-        {
-            json original =
-            {
-                {"string", "hello"},
-                {"integer", 42},
-                {"float", 3.14},
-                {"boolean", true},
-                {"null", nullptr},
-                {"array", {1, 2, 3}},
-                {"object", {{"key", "value"}}}
-            };
-
-            std::vector<uint8_t> temp = json::to_msgpack(original);
-
-            std::vector<std::byte> msgpack_data(temp.size());
-            for (size_t i = 0; i < temp.size(); ++i)
-            {
-                msgpack_data[i] = std::byte(temp[i]);
-            }
-            // Attempt direct deserialization using std::byte input
-            json direct_result = json::from_msgpack(msgpack_data);
-
-            // Test the workaround approach: reinterpret as unsigned char* and use iterator range
-            const auto* const char_start = reinterpret_cast<unsigned char const*>(msgpack_data.data());
-            const auto* const char_end = char_start + msgpack_data.size();
-            json workaround_result = json::from_msgpack(char_start, char_end);
-
-            // Verify that the final deserialized JSON matches the original JSON
-            CHECK(direct_result == workaround_result);
-            CHECK(direct_result == original);
-        }
-    }
-}
-#endif

tests/src/unit-regression2.cpp

@@ -396,7 +396,7 @@ struct Example_3810
     Example_3810() = default;
 };
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(Example_3810, bla) // NOLINT(misc-use-internal-linkage)
+NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(Example_3810, bla); // NOLINT(misc-use-internal-linkage)
 
 /////////////////////////////////////////////////////////////////////
 // for #4740

tests/src/unit-user_defined_input.cpp

@@ -60,12 +60,12 @@ TEST_CASE("Custom container member begin/end")
     {
         const char* data;
 
-        const char* begin() const noexcept
+        const char* begin() const
         {
             return data;
         }
 
-        const char* end() const noexcept
+        const char* end() const
         {
             return data + strlen(data); // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
         }