/*
xxHash - Fast Hash algorithm
Copyright (C) 2012-2013, Yann Collet.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

You can contact the author at :
- xxHash source repository : http://code.google.com/p/xxhash/
*/



//**************************************
// Tuning parameters
//**************************************
// XXH_ACCEPT_NULL_INPUT_POINTER :
// If the input pointer is a null pointer, xxHash default behavior is to crash, since it is a bad input.
// If 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 to your application, you may uncomment the #define below
// It will improve speed for Big-endian CPU.
// This option has no impact on Little_Endian CPU.
//#define XXH_FORCE_NATIVE_FORMAT 1



//**************************************
// Includes
//**************************************
#include <stdlib.h>    // for malloc(), free()
#include <string.h>    // for memcpy()
#include "xxhash.h"



//**************************************
// CPU Feature Detection
//**************************************
// Little Endian or Big Endian ?
// You can overwrite the #define below if you know your architecture endianess
#if defined(XXH_FORCE_NATIVE_FORMAT) && (XXH_FORCE_NATIVE_FORMAT==1)
// Force native format. The result will be endian dependant.
#  define XXH_BIG_ENDIAN 0
#elif defined (__GLIBC__)
#  include <endian.h>
#  if (__BYTE_ORDER == __BIG_ENDIAN)
#     define XXH_BIG_ENDIAN 1
#  endif
#elif (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(__LITTLE_ENDIAN__) || defined(__LITTLE_ENDIAN) || defined(_LITTLE_ENDIAN))
#  define XXH_BIG_ENDIAN 1
#elif defined(__sparc) || defined(__sparc__) \
    || defined(__ppc__) || defined(_POWER) || defined(__powerpc__) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) \
    || defined(__hpux)  || defined(__hppa) \
    || defined(_MIPSEB) || defined(__s390__)
#  define XXH_BIG_ENDIAN 1
#endif

#if !defined(XXH_BIG_ENDIAN)
// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.
#  define XXH_BIG_ENDIAN 0
#endif


//**************************************
// 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


//**************************************
// Compiler-specific Options & Functions
//**************************************
#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)

// Note : under GCC, it may sometimes be faster to enable the (2nd) macro definition, instead of using win32 intrinsic
#if defined(_WIN32)
#  define XXH_rotl32(x,r) _rotl(x,r)
#else
#  define XXH_rotl32(x,r) ((x << r) | (x >> (32 - r)))
#endif

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


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


//**************************************
// Macros
//**************************************
#define XXH_LE32(p)  (XXH_BIG_ENDIAN ? XXH_swap32(*(U32*)(p)) : *(U32*)(p))



//****************************
// Simple Hash Functions
//****************************

U32 XXH32(const void* input, int len, U32 seed)
{
#if 0
    // Simple version, good for code maintenance, but unfortunately slow for small inputs
    void* state = XXH32_init(seed);
    XXH32_update(state, input, len);
    return XXH32_digest(state);
#else

    const BYTE* p = (const BYTE*)input;
    const BYTE* const bEnd = p + len;
    U32 h32;

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (p==NULL) { len=0; p=(const BYTE*)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_LE32(p) * PRIME32_2; v1 = XXH_rotl32(v1, 13); v1 *= PRIME32_1; p+=4;
            v2 += XXH_LE32(p) * PRIME32_2; v2 = XXH_rotl32(v2, 13); v2 *= PRIME32_1; p+=4;
            v3 += XXH_LE32(p) * PRIME32_2; v3 = XXH_rotl32(v3, 13); v3 *= PRIME32_1; p+=4;
            v4 += XXH_LE32(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<=bEnd-4)
    {
        h32 += XXH_LE32(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;

#endif
}


//****************************
// Advanced Hash Functions
//****************************

struct XXH_state32_t
{
    U32 seed;
    U32 v1;
    U32 v2;
    U32 v3;
    U32 v4;
    U64 total_len;
    char memory[16];
    int memsize;
};


int XXH32_sizeofState() { return sizeof(struct XXH_state32_t); }


XXH_errorcode XXH32_resetState(void* state_in, unsigned int seed)
{ 
    struct XXH_state32_t * state = (struct XXH_state32_t *) state_in;
    state->seed = seed;
    state->v1 = seed + PRIME32_1 + PRIME32_2;
    state->v2 = seed + PRIME32_2;
    state->v3 = seed + 0;
    state->v4 = seed - PRIME32_1;
    state->total_len = 0;
    state->memsize = 0;
    return OK;
}


void* XXH32_init (U32 seed)
{
    struct XXH_state32_t * state = (struct XXH_state32_t *) malloc (sizeof(struct XXH_state32_t));
    XXH32_resetState(state, seed);
    return (void*)state;
}


XXH_errorcode XXH32_update (void* state_in, const void* input, int len)
{
    struct XXH_state32_t * state = (struct XXH_state32_t *) state_in;
    const BYTE* p = (const BYTE*)input;
    const BYTE* const bEnd = p + len;

#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
    if (input==NULL) return XXH_ERROR;
#endif

    state->total_len += len;

    if (state->memsize + len < 16)   // fill in tmp buffer
    {
        memcpy(state->memory + state->memsize, input, len);
        state->memsize +=  len;
        return OK;
    }

    if (state->memsize)   // some data left from previous update
    {
        memcpy(state->memory + state->memsize, input, 16-state->memsize);
        {
            const U32* p32 = (const U32*)state->memory;
            state->v1 += XXH_LE32(p32) * PRIME32_2; state->v1 = XXH_rotl32(state->v1, 13); state->v1 *= PRIME32_1; p32++;
            state->v2 += XXH_LE32(p32) * PRIME32_2; state->v2 = XXH_rotl32(state->v2, 13); state->v2 *= PRIME32_1; p32++; 
            state->v3 += XXH_LE32(p32) * PRIME32_2; state->v3 = XXH_rotl32(state->v3, 13); state->v3 *= PRIME32_1; p32++;
            state->v4 += XXH_LE32(p32) * PRIME32_2; state->v4 = XXH_rotl32(state->v4, 13); state->v4 *= PRIME32_1; p32++;
        }
        p += 16-state->memsize;
        state->memsize = 0;
    }

    if (p <= bEnd-16)
    {
        const BYTE* const limit = bEnd - 16;
        U32 v1 = state->v1;
        U32 v2 = state->v2;
        U32 v3 = state->v3;
        U32 v4 = state->v4;

        do
        {
            v1 += XXH_LE32(p) * PRIME32_2; v1 = XXH_rotl32(v1, 13); v1 *= PRIME32_1; p+=4;
            v2 += XXH_LE32(p) * PRIME32_2; v2 = XXH_rotl32(v2, 13); v2 *= PRIME32_1; p+=4;
            v3 += XXH_LE32(p) * PRIME32_2; v3 = XXH_rotl32(v3, 13); v3 *= PRIME32_1; p+=4;
            v4 += XXH_LE32(p) * PRIME32_2; v4 = XXH_rotl32(v4, 13); v4 *= PRIME32_1; p+=4;
        } while (p<=limit);

        state->v1 = v1;
        state->v2 = v2;
        state->v3 = v3;
        state->v4 = v4;
    }

    if (p < bEnd)
    {
        memcpy(state->memory, p, bEnd-p);
        state->memsize = (int)(bEnd-p);
    }

    return OK;
}


U32 XXH32_intermediateDigest (void* state_in)
{
    struct XXH_state32_t * state = (struct XXH_state32_t *) state_in;
    BYTE * p   = (BYTE*)state->memory;
    BYTE* bEnd = (BYTE*)state->memory + state->memsize;
    U32 h32;


    if (state->total_len >= 16)
    {
        h32 = XXH_rotl32(state->v1, 1) + XXH_rotl32(state->v2, 7) + XXH_rotl32(state->v3, 12) + XXH_rotl32(state->v4, 18);
    }
    else
    {
        h32  = state->seed + PRIME32_5;
    }

    h32 += (U32) state->total_len;

    while (p<=bEnd-4)
    {
        h32 += XXH_LE32(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;
}


U32 XXH32_digest (void* state_in)
{
    U32 h32 = XXH32_intermediateDigest(state_in);

    free(state_in);

    return h32;
}
