include/nlohmann/detail/view/simd.hpp - third_party/json - Git at Google


            
            //     __ _____ _____ _____

            
            //  __|  |   __|     |   | |  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 <atomic> // atomic

            
            #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. SSSE3 is not part of x86-64, and the code

            
            // 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): the check is compiled for SSSE3 with a function attribute and

            
            // used where the CPU has SSSE3 (all x86-64 CPUs since about 2011), else the

            
            // portable check. JSON_VIEW_USE_SSSE3 skips the CPU check (for code compiled

            
            // for SSSE3 anyway); JSON_VIEW_NO_SIMD selects the portable code.

            
            // NLOHMANN_VIEW_NO_TARGET_ATTRIBUTE (set by the GCC module interface, where GCC

            
            // ignores the target attribute and then rejects the SSSE3 intrinsics) keeps the

            
            // check portable without disabling the SSE2 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

            
            // (x86 only: other targets can define __SSE2__ as well, e.g., WebAssembly with -msse2, but have no <cpuid.h>)

            
            #if !defined(JSON_VIEW_NO_SIMD) && !NLOHMANN_VIEW_NEON && (defined(__x86_64__) || defined(__i386__) || defined(_M_X64) || defined(_M_IX86)) && (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

            
            #if NLOHMANN_VIEW_SSE2 && !NLOHMANN_VIEW_SSSE3 && !defined(NLOHMANN_VIEW_NO_TARGET_ATTRIBUTE) && ((defined(__clang__) && __clang_major__ >= 4) || (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9))))

            
                // (GCC before 4.9 has no SSSE3 intrinsics without -mssse3)

            
                // <cpuid.h> of GCC before 11 has no include guard, and json.hpp and

            
                // json_view.hpp both include it

            
                #ifndef NLOHMANN_JSON_CPUID_INCLUDED

            
                    #define NLOHMANN_JSON_CPUID_INCLUDED

            
                    #include <cpuid.h>

            
                #endif

            
                #include <tmmintrin.h>

            
                #define NLOHMANN_VIEW_SSSE3_DISPATCH 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)

            
                #define NLOHMANN_VIEW_SSSE3_TARGET __attribute__((target("ssse3")))

            
            #elif NLOHMANN_VIEW_SSE2 && !NLOHMANN_VIEW_SSSE3 && defined(_MSC_VER)

            
                // (MSVC compiles intrinsics of any instruction set)

            
                #include <intrin.h>

            
                #include <tmmintrin.h>

            
                #define NLOHMANN_VIEW_SSSE3_DISPATCH 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)

            
                #define NLOHMANN_VIEW_SSSE3_TARGET

            
            #else

            
                #define NLOHMANN_VIEW_SSSE3_DISPATCH 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)

            
                #define NLOHMANN_VIEW_SSSE3_TARGET

            
            #endif

            
            #define NLOHMANN_VIEW_VECTOR (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSE2)

            
            #define NLOHMANN_VIEW_VECTOR_UTF8 (NLOHMANN_VIEW_NEON || NLOHMANN_VIEW_SSSE3 || NLOHMANN_VIEW_SSSE3_DISPATCH)


            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))); // NOLINT(bugprone-casting-through-void)

            
                    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;

            
            }


            /*!

            
            @brief copy 16 bytes from p to w, and find the first quote, backslash,

            
            control character, or non-ASCII byte among them


            The bytes are copied whether or not they are all plain (the caller has room

            
            for 16 bytes and keeps only the plain ones).


            @return the offset of that byte, or 16 if there is none

            
            */

            
            NLOHMANN_VIEW_ALWAYS_INLINE unsigned copy_plain_run16(const unsigned char* p, char* w) noexcept

            
            {

            
            #if NLOHMANN_VIEW_NEON

            
                const uint8x16_t in = vld1q_u8(p);

            
                vst1q_u8(reinterpret_cast<std::uint8_t*>(w), in); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)

            
                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)));

            
                const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);

            
                return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits) >> 2u) : 16u;

            
            #else

            
                const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p))); // NOLINT(bugprone-casting-through-void)

            
                _mm_storeu_si128(static_cast<__m128i*>(static_cast<void*>(w)), in); // NOLINT(bugprone-casting-through-void)

            
                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)));

            
                return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits)) : 16u;

            
            #endif

            
            }

            
            #endif


            #if NLOHMANN_VIEW_SSSE3_DISPATCH

            
            /// whether the CPU has SSSE3 (CPUID leaf 1, ECX bit 9)

            
            inline bool cpu_ssse3() noexcept

            
            {

            
            #if defined(_MSC_VER) && !defined(__clang__)

            
                std::array<int, 4> regs {{}};

            
                __cpuid(regs.data(), 1);

            
                return (static_cast<unsigned>(regs[2]) & (1u << 9u)) != 0;

            
            #else

            
                unsigned eax = 0;

            
                unsigned ebx = 0;

            
                unsigned ecx = 0;

            
                unsigned edx = 0;

            
                return __get_cpuid(1, &eax, &ebx, &ecx, &edx) != 0 && (ecx & (1u << 9u)) != 0;

            
            #endif

            
            }


            /// whether the CPU has SSSE3, asked once: the answer is kept in an atomic

            
            /// that is initialized at compile time, so that neither a guard of a local

            
            /// static nor a global constructor is needed (threads that ask at the same

            
            /// time all store the same answer)

            
            NLOHMANN_VIEW_ALWAYS_INLINE bool cpu_has_ssse3() noexcept

            
            {

            
                static std::atomic<int> known{0}; // 0: not asked yet, 1: no, 2: yes

            
                int state = known.load(std::memory_order_relaxed);

            
                if (NLOHMANN_VIEW_UNLIKELY(state == 0))

            
                {

            
                    state = cpu_ssse3() ? 2 : 1;

            
                    known.store(state, std::memory_order_relaxed);

            
                }

            
                return state == 2;

            
            }

            
            #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.

            
            On x86-64, it is compiled for SSSE3 (see cpu_has_ssse3()).

            
            */

            
            NLOHMANN_VIEW_SSSE3_TARGET 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()))); // NOLINT(bugprone-casting-through-void)

            
                const __m128i t1l = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_low.data()))); // NOLINT(bugprone-casting-through-void)

            
                const __m128i t2h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_2_high.data()))); // NOLINT(bugprone-casting-through-void)

            
                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))); // NOLINT(bugprone-casting-through-void)

            
                    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 auto 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
	// __ _____ _____ _____
	// __\| \| __\| \| \| \| 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 <atomic> // atomic
	#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. SSSE3 is not part of x86-64, and the code
	// 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): the check is compiled for SSSE3 with a function attribute and
	// used where the CPU has SSSE3 (all x86-64 CPUs since about 2011), else the
	// portable check. JSON_VIEW_USE_SSSE3 skips the CPU check (for code compiled
	// for SSSE3 anyway); JSON_VIEW_NO_SIMD selects the portable code.
	// NLOHMANN_VIEW_NO_TARGET_ATTRIBUTE (set by the GCC module interface, where GCC
	// ignores the target attribute and then rejects the SSSE3 intrinsics) keeps the
	// check portable without disabling the SSE2 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
	// (x86 only: other targets can define __SSE2__ as well, e.g., WebAssembly with -msse2, but have no <cpuid.h>)
	#if !defined(JSON_VIEW_NO_SIMD) && !NLOHMANN_VIEW_NEON && (defined(__x86_64__) \|\| defined(__i386__) \|\| defined(_M_X64) \|\| defined(_M_IX86)) && (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
	#if NLOHMANN_VIEW_SSE2 && !NLOHMANN_VIEW_SSSE3 && !defined(NLOHMANN_VIEW_NO_TARGET_ATTRIBUTE) && ((defined(__clang__) && __clang_major__ >= 4) \|\| (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 9))))
	// (GCC before 4.9 has no SSSE3 intrinsics without -mssse3)
	// <cpuid.h> of GCC before 11 has no include guard, and json.hpp and
	// json_view.hpp both include it
	#ifndef NLOHMANN_JSON_CPUID_INCLUDED
	#define NLOHMANN_JSON_CPUID_INCLUDED
	#include <cpuid.h>
	#endif
	#include <tmmintrin.h>
	#define NLOHMANN_VIEW_SSSE3_DISPATCH 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
	#define NLOHMANN_VIEW_SSSE3_TARGET __attribute__((target("ssse3")))
	#elif NLOHMANN_VIEW_SSE2 && !NLOHMANN_VIEW_SSSE3 && defined(_MSC_VER)
	// (MSVC compiles intrinsics of any instruction set)
	#include <intrin.h>
	#include <tmmintrin.h>
	#define NLOHMANN_VIEW_SSSE3_DISPATCH 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
	#define NLOHMANN_VIEW_SSSE3_TARGET
	#else
	#define NLOHMANN_VIEW_SSSE3_DISPATCH 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
	#define NLOHMANN_VIEW_SSSE3_TARGET
	#endif
	#define NLOHMANN_VIEW_VECTOR (NLOHMANN_VIEW_NEON \|\| NLOHMANN_VIEW_SSE2)
	#define NLOHMANN_VIEW_VECTOR_UTF8 (NLOHMANN_VIEW_NEON \|\| NLOHMANN_VIEW_SSSE3 \|\| NLOHMANN_VIEW_SSSE3_DISPATCH)

	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))); // NOLINT(bugprone-casting-through-void)
	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;
	}

	/*!
	@brief copy 16 bytes from p to w, and find the first quote, backslash,
	control character, or non-ASCII byte among them

	The bytes are copied whether or not they are all plain (the caller has room
	for 16 bytes and keeps only the plain ones).

	@return the offset of that byte, or 16 if there is none
	*/
	NLOHMANN_VIEW_ALWAYS_INLINE unsigned copy_plain_run16(const unsigned char* p, char* w) noexcept
	{
	#if NLOHMANN_VIEW_NEON
	const uint8x16_t in = vld1q_u8(p);
	vst1q_u8(reinterpret_cast<std::uint8_t*>(w), in); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
	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)));
	const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
	return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits) >> 2u) : 16u;
	#else
	const __m128i in = _mm_loadu_si128(static_cast<const __m128i>(static_cast<const void>(p))); // NOLINT(bugprone-casting-through-void)
	_mm_storeu_si128(static_cast<__m128i>(static_cast<void>(w)), in); // NOLINT(bugprone-casting-through-void)
	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)));
	return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits)) : 16u;
	#endif
	}
	#endif

	#if NLOHMANN_VIEW_SSSE3_DISPATCH
	/// whether the CPU has SSSE3 (CPUID leaf 1, ECX bit 9)
	inline bool cpu_ssse3() noexcept
	{
	#if defined(_MSC_VER) && !defined(__clang__)
	std::array<int, 4> regs {{}};
	__cpuid(regs.data(), 1);
	return (static_cast<unsigned>(regs[2]) & (1u << 9u)) != 0;
	#else
	unsigned eax = 0;
	unsigned ebx = 0;
	unsigned ecx = 0;
	unsigned edx = 0;
	return __get_cpuid(1, &eax, &ebx, &ecx, &edx) != 0 && (ecx & (1u << 9u)) != 0;
	#endif
	}

	/// whether the CPU has SSSE3, asked once: the answer is kept in an atomic
	/// that is initialized at compile time, so that neither a guard of a local
	/// static nor a global constructor is needed (threads that ask at the same
	/// time all store the same answer)
	NLOHMANN_VIEW_ALWAYS_INLINE bool cpu_has_ssse3() noexcept
	{
	static std::atomic<int> known{0}; // 0: not asked yet, 1: no, 2: yes
	int state = known.load(std::memory_order_relaxed);
	if (NLOHMANN_VIEW_UNLIKELY(state == 0))
	{
	state = cpu_ssse3() ? 2 : 1;
	known.store(state, std::memory_order_relaxed);
	}
	return state == 2;
	}
	#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.
	On x86-64, it is compiled for SSSE3 (see cpu_has_ssse3()).
	*/
	NLOHMANN_VIEW_SSSE3_TARGET 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()))); // NOLINT(bugprone-casting-through-void)
	const __m128i t1l = _mm_loadu_si128(static_cast<const __m128i>(static_cast<const void>(lookup::byte_1_low.data()))); // NOLINT(bugprone-casting-through-void)
	const __m128i t2h = _mm_loadu_si128(static_cast<const __m128i>(static_cast<const void>(lookup::byte_2_high.data()))); // NOLINT(bugprone-casting-through-void)
	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))); // NOLINT(bugprone-casting-through-void)
	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 auto 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