159 lines
3.7 KiB
C
Executable file
159 lines
3.7 KiB
C
Executable file
/*
|
|
* Copyright (C) 2013 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
#include <stdint.h>
|
|
#include "mem.h"
|
|
#include "intreadwrite.h"
|
|
#include "murmur3.h"
|
|
|
|
typedef struct AVMurMur3 {
|
|
uint64_t h1, h2;
|
|
uint8_t state[16];
|
|
int state_pos;
|
|
uint64_t len;
|
|
} AVMurMur3;
|
|
|
|
AVMurMur3 *av_murmur3_alloc(void)
|
|
{
|
|
return av_mallocz(sizeof(AVMurMur3));
|
|
}
|
|
|
|
void av_murmur3_init_seeded(AVMurMur3 *c, uint64_t seed)
|
|
{
|
|
memset(c, 0, sizeof(*c));
|
|
c->h1 = c->h2 = seed;
|
|
}
|
|
|
|
void av_murmur3_init(AVMurMur3 *c)
|
|
{
|
|
// arbitrary random number as seed
|
|
av_murmur3_init_seeded(c, 0x725acc55daddca55);
|
|
}
|
|
|
|
static const uint64_t c1 = UINT64_C(0x87c37b91114253d5);
|
|
static const uint64_t c2 = UINT64_C(0x4cf5ad432745937f);
|
|
|
|
#define ROT(a, b) (((a) << (b)) | ((a) >> (64 - (b))))
|
|
|
|
static uint64_t inline get_k1(const uint8_t *src)
|
|
{
|
|
uint64_t k = AV_RL64(src);
|
|
k *= c1;
|
|
k = ROT(k, 31);
|
|
k *= c2;
|
|
return k;
|
|
}
|
|
|
|
static inline uint64_t get_k2(const uint8_t *src)
|
|
{
|
|
uint64_t k = AV_RL64(src + 8);
|
|
k *= c2;
|
|
k = ROT(k, 33);
|
|
k *= c1;
|
|
return k;
|
|
}
|
|
|
|
static inline uint64_t update_h1(uint64_t k, uint64_t h1, uint64_t h2)
|
|
{
|
|
k ^= h1;
|
|
k = ROT(k, 27);
|
|
k += h2;
|
|
k *= 5;
|
|
k += 0x52dce729;
|
|
return k;
|
|
}
|
|
|
|
static inline uint64_t update_h2(uint64_t k, uint64_t h1, uint64_t h2)
|
|
{
|
|
k ^= h2;
|
|
k = ROT(k, 31);
|
|
k += h1;
|
|
k *= 5;
|
|
k += 0x38495ab5;
|
|
return k;
|
|
}
|
|
|
|
#if FF_API_CRYPTO_SIZE_T
|
|
void av_murmur3_update(AVMurMur3 *c, const uint8_t *src, int len)
|
|
#else
|
|
void av_murmur3_update(AVMurMur3 *c, const uint8_t *src, size_t len)
|
|
#endif
|
|
{
|
|
const uint8_t *end;
|
|
uint64_t h1 = c->h1, h2 = c->h2;
|
|
uint64_t k1, k2;
|
|
if (len <= 0) return;
|
|
c->len += len;
|
|
if (c->state_pos > 0) {
|
|
while (c->state_pos < 16) {
|
|
c->state[c->state_pos++] = *src++;
|
|
if (--len <= 0) return;
|
|
}
|
|
c->state_pos = 0;
|
|
k1 = get_k1(c->state);
|
|
k2 = get_k2(c->state);
|
|
h1 = update_h1(k1, h1, h2);
|
|
h2 = update_h2(k2, h1, h2);
|
|
}
|
|
|
|
end = src + (len & ~15);
|
|
while (src < end) {
|
|
// These could be done sequentially instead
|
|
// of interleaved, but like this is over 10% faster
|
|
k1 = get_k1(src);
|
|
k2 = get_k2(src);
|
|
h1 = update_h1(k1, h1, h2);
|
|
h2 = update_h2(k2, h1, h2);
|
|
src += 16;
|
|
}
|
|
c->h1 = h1;
|
|
c->h2 = h2;
|
|
|
|
len &= 15;
|
|
if (len > 0) {
|
|
memcpy(c->state, src, len);
|
|
c->state_pos = len;
|
|
}
|
|
}
|
|
|
|
static inline uint64_t fmix(uint64_t k)
|
|
{
|
|
k ^= k >> 33;
|
|
k *= UINT64_C(0xff51afd7ed558ccd);
|
|
k ^= k >> 33;
|
|
k *= UINT64_C(0xc4ceb9fe1a85ec53);
|
|
k ^= k >> 33;
|
|
return k;
|
|
}
|
|
|
|
void av_murmur3_final(AVMurMur3 *c, uint8_t dst[16])
|
|
{
|
|
uint64_t h1 = c->h1, h2 = c->h2;
|
|
memset(c->state + c->state_pos, 0, sizeof(c->state) - c->state_pos);
|
|
h1 ^= get_k1(c->state) ^ c->len;
|
|
h2 ^= get_k2(c->state) ^ c->len;
|
|
h1 += h2;
|
|
h2 += h1;
|
|
h1 = fmix(h1);
|
|
h2 = fmix(h2);
|
|
h1 += h2;
|
|
h2 += h1;
|
|
AV_WL64(dst, h1);
|
|
AV_WL64(dst + 8, h2);
|
|
}
|