xxhash.c

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#ifdef EXTRA_CHECKS

//**************************************
// Tuning parameters
//**************************************
// Unaligned memory access is automatically enabled for "common" CPU, such as x86.
// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected.
// If you know your target CPU supports unaligned memory access, you want to force this option manually to improve performance.
// You can also enable this parameter if you know your input data will always be aligned (boundaries of 4, for U32).
#if defined(__ARM_FEATURE_UNALIGNED) || defined(__i386) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_X64)
#define XXH_USE_UNALIGNED_ACCESS 1
#endif

// XXH_ACCEPT_NULL_INPUT_POINTER :
// If the input pointer is a null pointer, xxHash default behavior is to trigger a memory access error, since it is a bad pointer.
// When this option is enabled, xxHash output for null input pointers will be the same as a null-length input.
// This option has a very small performance cost (only measurable on small inputs).
// By default, this option is disabled. To enable it, uncomment below define :
// #define XXH_ACCEPT_NULL_INPUT_POINTER 1

// XXH_FORCE_NATIVE_FORMAT :
// By default, xxHash library provides endian-independant Hash values, based on little-endian convention.
// Results are therefore identical for little-endian and big-endian CPU.
// This comes at a performance cost for big-endian CPU, since some swapping is required to emulate little-endian format.
// Should endian-independance be of no importance for your application, you may set the #define below to 1.
// It will improve speed for Big-endian CPU.
// This option has no impact on Little_Endian CPU.
#define XXH_FORCE_NATIVE_FORMAT 0

//**************************************
// Compiler Specific Options
//**************************************
// Disable some Visual warning messages
#ifdef _MSC_VER         // Visual Studio
#pragma warning(disable : 4127) // disable: C4127: conditional expression is constant
#endif

#ifdef _MSC_VER         // Visual Studio
#define FORCE_INLINE static __forceinline
#else
#ifdef __GNUC__
#define FORCE_INLINE static inline __attribute__((always_inline))
#else
#define FORCE_INLINE static inline
#endif
#endif

//**************************************
// Includes & Memory related functions
//**************************************
#include "xxhash.h"

//**************************************
// Basic Types
//**************************************
#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   // C99
#include <stdint.h>
typedef uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
typedef int32_t S32;
typedef uint64_t U64;
#else
typedef unsigned char BYTE;
typedef unsigned short U16;
typedef unsigned int U32;
typedef signed int S32;
typedef unsigned long long U64;
#endif

#if defined(__GNUC__)  && !defined(XXH_USE_UNALIGNED_ACCESS)
#define _PACKED __attribute__ ((packed))
#else
#define _PACKED
#endif

#if !defined(XXH_USE_UNALIGNED_ACCESS) && !defined(__GNUC__)
#ifdef __IBMC__
#pragma pack(1)
#else
#pragma pack(push, 1)
#endif
#endif

typedef struct _U32_S {
    U32 v;
} _PACKED U32_S;
typedef struct _U64_S {
    U64 v;
} _PACKED U64_S;

#if !defined(XXH_USE_UNALIGNED_ACCESS) && !defined(__GNUC__)
#pragma pack(pop)
#endif

#define A32(x) (((U32_S *)(x))->v)
#define A64(x) (((U64_S *)(x))->v)

//***************************************
// Compiler-specific Functions and Macros
//***************************************
#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)

// Note : although _rotl exists for minGW (GCC under windows), performance seems poor
#if defined(_MSC_VER)
#define XXH_rotl32(x,r) _rotl(x,r)
#define XXH_rotl64(x,r) _rotl64(x,r)
#else
#define XXH_rotl32(x,r) ((x << r) | (x >> (32 - r)))
#define XXH_rotl64(x,r) ((x << r) | (x >> (64 - r)))
#endif

#if defined(_MSC_VER)       // Visual Studio
#define XXH_swap32 _byteswap_ulong
#define XXH_swap64 _byteswap_uint64
#elif GCC_VERSION >= 403
#define XXH_swap32 __builtin_bswap32
#define XXH_swap64 __builtin_bswap64
#else
static inline U32 XXH_swap32(U32 x)
{
    return ((x << 24) & 0xff000000) |
        ((x << 8) & 0x00ff0000) |
        ((x >> 8) & 0x0000ff00) | ((x >> 24) & 0x000000ff);
}

static inline U64 XXH_swap64(U64 x)
{
    return ((x << 56) & 0xff00000000000000ULL) |
        ((x << 40) & 0x00ff000000000000ULL) |
        ((x << 24) & 0x0000ff0000000000ULL) |
        ((x << 8) & 0x000000ff00000000ULL) |
        ((x >> 8) & 0x00000000ff000000ULL) |
        ((x >> 24) & 0x0000000000ff0000ULL) |
        ((x >> 40) & 0x000000000000ff00ULL) |
        ((x >> 56) & 0x00000000000000ffULL);
}
#endif

//**************************************
// Constants
//**************************************
#define PRIME32_1   2654435761U
#define PRIME32_2   2246822519U
#define PRIME32_3   3266489917U
#define PRIME32_4    668265263U
#define PRIME32_5    374761393U

#define PRIME64_1 11400714785074694791ULL
#define PRIME64_2 14029467366897019727ULL
#define PRIME64_3  1609587929392839161ULL
#define PRIME64_4  9650029242287828579ULL
#define PRIME64_5  2870177450012600261ULL

//**************************************
// Architecture Macros
//**************************************
typedef enum { XXH_bigEndian = 0, XXH_littleEndian = 1 } XXH_endianess;
#ifndef XXH_CPU_LITTLE_ENDIAN   // It is possible to define XXH_CPU_LITTLE_ENDIAN externally, for example using a compiler switch
static const int one = 1;
#define XXH_CPU_LITTLE_ENDIAN   (*(char*)(&one))
#endif

//**************************************
// Macros
//**************************************
#define XXH_STATIC_ASSERT(c)   { enum { XXH_static_assert = 1/(!!(c)) }; }  // use only *after* variable declarations

//****************************
// Memory reads
//****************************
typedef enum { XXH_aligned, XXH_unaligned } XXH_alignment;

FORCE_INLINE U32 XXH_readLE32_align(const void *ptr, XXH_endianess endian,
                    XXH_alignment align)
{
    if (align == XXH_unaligned)
        return endian ==
            XXH_littleEndian ? A32(ptr) : XXH_swap32(A32(ptr));
    else
        return endian ==
            XXH_littleEndian ? *(U32 *) ptr : XXH_swap32(*(U32 *) ptr);
}

FORCE_INLINE U32 XXH_readLE32(const void *ptr, XXH_endianess endian)
{
    return XXH_readLE32_align(ptr, endian, XXH_unaligned);
}

FORCE_INLINE U64 XXH_readLE64_align(const void *ptr, XXH_endianess endian,
                    XXH_alignment align)
{
    if (align == XXH_unaligned)
        return endian ==
            XXH_littleEndian ? A64(ptr) : XXH_swap64(A64(ptr));
    else
        return endian ==
            XXH_littleEndian ? *(U64 *) ptr : XXH_swap64(*(U64 *) ptr);
}

FORCE_INLINE U64 XXH_readLE64(const void *ptr, XXH_endianess endian)
{
    return XXH_readLE64_align(ptr, endian, XXH_unaligned);
}

//****************************
// Simple Hash Functions
//****************************
FORCE_INLINE U32 XXH32_endian_align(const void *input, size_t len, U32 seed,
                    XXH_endianess endian, XXH_alignment align)
{
    const BYTE *p = (const BYTE *)input;
    const BYTE *bEnd = p + len;
    U32 h32;
#define XXH_get32bits(p) XXH_readLE32_align(p, endian, align)

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (p == NULL) {
        len = 0;
        bEnd = p = (const BYTE *)(size_t)16;
    }
#endif

    if (len >= 16) {
        const BYTE *const limit = bEnd - 16;
        U32 v1 = seed + PRIME32_1 + PRIME32_2;
        U32 v2 = seed + PRIME32_2;
        U32 v3 = seed + 0;
        U32 v4 = seed - PRIME32_1;

        do {
            v1 += XXH_get32bits(p) * PRIME32_2;
            v1 = XXH_rotl32(v1, 13);
            v1 *= PRIME32_1;
            p += 4;
            v2 += XXH_get32bits(p) * PRIME32_2;
            v2 = XXH_rotl32(v2, 13);
            v2 *= PRIME32_1;
            p += 4;
            v3 += XXH_get32bits(p) * PRIME32_2;
            v3 = XXH_rotl32(v3, 13);
            v3 *= PRIME32_1;
            p += 4;
            v4 += XXH_get32bits(p) * PRIME32_2;
            v4 = XXH_rotl32(v4, 13);
            v4 *= PRIME32_1;
            p += 4;
        }
        while (p <= limit);

        h32 =
            XXH_rotl32(v1, 1) + XXH_rotl32(v2, 7) + XXH_rotl32(v3,
                                       12) +
            XXH_rotl32(v4, 18);
    } else {
        h32 = seed + PRIME32_5;
    }

    h32 += (U32) len;

    while (p + 4 <= bEnd) {
        h32 += XXH_get32bits(p) * PRIME32_3;
        h32 = XXH_rotl32(h32, 17) * PRIME32_4;
        p += 4;
    }

    while (p < bEnd) {
        h32 += (*p) * PRIME32_5;
        h32 = XXH_rotl32(h32, 11) * PRIME32_1;
        p++;
    }

    h32 ^= h32 >> 15;
    h32 *= PRIME32_2;
    h32 ^= h32 >> 13;
    h32 *= PRIME32_3;
    h32 ^= h32 >> 16;

    return h32;
}

unsigned int XXH32(const void *input, size_t len, unsigned seed)
{
#if 0
    // Simple version, good for code maintenance, but unfortunately slow for small inputs
    XXH32_state_t state;
    XXH32_reset(&state, seed);
    XXH32_update(&state, input, len);
    return XXH32_digest(&state);
#else
    XXH_endianess endian_detected = (XXH_endianess) XXH_CPU_LITTLE_ENDIAN;

#if !defined(XXH_USE_UNALIGNED_ACCESS)
    if ((((size_t)input) & 3) == 0) // Input is aligned, let's leverage the speed advantage
    {
        if ((endian_detected == XXH_littleEndian)
            || XXH_FORCE_NATIVE_FORMAT)
            return XXH32_endian_align(input, len, seed,
                          XXH_littleEndian,
                          XXH_aligned);
        else
            return XXH32_endian_align(input, len, seed,
                          XXH_bigEndian, XXH_aligned);
    }
#endif

    if ((endian_detected == XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH32_endian_align(input, len, seed, XXH_littleEndian,
                      XXH_unaligned);
    else
        return XXH32_endian_align(input, len, seed, XXH_bigEndian,
                      XXH_unaligned);
#endif
}

FORCE_INLINE U64 XXH64_endian_align(const void *input, size_t len, U64 seed,
                    XXH_endianess endian, XXH_alignment align)
{
    const BYTE *p = (const BYTE *)input;
    const BYTE *bEnd = p + len;
    U64 h64;
#define XXH_get64bits(p) XXH_readLE64_align(p, endian, align)

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (p == NULL) {
        len = 0;
        bEnd = p = (const BYTE *)(size_t)32;
    }
#endif

    if (len >= 32) {
        const BYTE *const limit = bEnd - 32;
        U64 v1 = seed + PRIME64_1 + PRIME64_2;
        U64 v2 = seed + PRIME64_2;
        U64 v3 = seed + 0;
        U64 v4 = seed - PRIME64_1;

        do {
            v1 += XXH_get64bits(p) * PRIME64_2;
            p += 8;
            v1 = XXH_rotl64(v1, 31);
            v1 *= PRIME64_1;
            v2 += XXH_get64bits(p) * PRIME64_2;
            p += 8;
            v2 = XXH_rotl64(v2, 31);
            v2 *= PRIME64_1;
            v3 += XXH_get64bits(p) * PRIME64_2;
            p += 8;
            v3 = XXH_rotl64(v3, 31);
            v3 *= PRIME64_1;
            v4 += XXH_get64bits(p) * PRIME64_2;
            p += 8;
            v4 = XXH_rotl64(v4, 31);
            v4 *= PRIME64_1;
        }
        while (p <= limit);

        h64 =
            XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3,
                                       12) +
            XXH_rotl64(v4, 18);

        v1 *= PRIME64_2;
        v1 = XXH_rotl64(v1, 31);
        v1 *= PRIME64_1;
        h64 ^= v1;
        h64 = h64 * PRIME64_1 + PRIME64_4;

        v2 *= PRIME64_2;
        v2 = XXH_rotl64(v2, 31);
        v2 *= PRIME64_1;
        h64 ^= v2;
        h64 = h64 * PRIME64_1 + PRIME64_4;

        v3 *= PRIME64_2;
        v3 = XXH_rotl64(v3, 31);
        v3 *= PRIME64_1;
        h64 ^= v3;
        h64 = h64 * PRIME64_1 + PRIME64_4;

        v4 *= PRIME64_2;
        v4 = XXH_rotl64(v4, 31);
        v4 *= PRIME64_1;
        h64 ^= v4;
        h64 = h64 * PRIME64_1 + PRIME64_4;
    } else {
        h64 = seed + PRIME64_5;
    }

    h64 += (U64) len;

    while (p + 8 <= bEnd) {
        U64 k1 = XXH_get64bits(p);
        k1 *= PRIME64_2;
        k1 = XXH_rotl64(k1, 31);
        k1 *= PRIME64_1;
        h64 ^= k1;
        h64 = XXH_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
        p += 8;
    }

    if (p + 4 <= bEnd) {
        h64 ^= (U64) (XXH_get32bits(p)) * PRIME64_1;
        h64 = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
        p += 4;
    }

    while (p < bEnd) {
        h64 ^= (*p) * PRIME64_5;
        h64 = XXH_rotl64(h64, 11) * PRIME64_1;
        p++;
    }

    h64 ^= h64 >> 33;
    h64 *= PRIME64_2;
    h64 ^= h64 >> 29;
    h64 *= PRIME64_3;
    h64 ^= h64 >> 32;

    return h64;
}

unsigned long long XXH64(const void *input, size_t len, unsigned long long seed)
{
#if 0
    // Simple version, good for code maintenance, but unfortunately slow for small inputs
    XXH64_state_t state;
    XXH64_reset(&state, seed);
    XXH64_update(&state, input, len);
    return XXH64_digest(&state);
#else
    XXH_endianess endian_detected = (XXH_endianess) XXH_CPU_LITTLE_ENDIAN;

#if !defined(XXH_USE_UNALIGNED_ACCESS)
    if ((((size_t)input) & 7) == 0) // Input is aligned, let's leverage the speed advantage
    {
        if ((endian_detected == XXH_littleEndian)
            || XXH_FORCE_NATIVE_FORMAT)
            return XXH64_endian_align(input, len, seed,
                          XXH_littleEndian,
                          XXH_aligned);
        else
            return XXH64_endian_align(input, len, seed,
                          XXH_bigEndian, XXH_aligned);
    }
#endif

    if ((endian_detected == XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
        return XXH64_endian_align(input, len, seed, XXH_littleEndian,
                      XXH_unaligned);
    else
        return XXH64_endian_align(input, len, seed, XXH_bigEndian,
                      XXH_unaligned);
#endif
}

#endif              /* EXTRA_CHECKS */