snapraid/tommyds/tommyhash.c
2020-09-11 13:42:22 +02:00

242 lines
6.7 KiB
C

/*
* Copyright (c) 2010, Andrea Mazzoleni. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*/
#include "tommyhash.h"
/******************************************************************************/
/* hash */
tommy_inline tommy_uint32_t tommy_le_uint32_read(const void* ptr)
{
/* allow unaligned read on Intel x86 and x86_64 platforms */
#if defined(__i386__) || defined(_M_IX86) || defined(_X86_) || defined(__x86_64__) || defined(_M_X64)
/* defines from http://predef.sourceforge.net/ */
return *(const tommy_uint32_t*)ptr;
#else
const unsigned char* ptr8 = tommy_cast(const unsigned char*, ptr);
return ptr8[0] + ((tommy_uint32_t)ptr8[1] << 8) + ((tommy_uint32_t)ptr8[2] << 16) + ((tommy_uint32_t)ptr8[3] << 24);
#endif
}
#define tommy_rot(x, k) \
(((x) << (k)) | ((x) >> (32 - (k))))
#define tommy_mix(a, b, c) \
do { \
a -= c; a ^= tommy_rot(c, 4); c += b; \
b -= a; b ^= tommy_rot(a, 6); a += c; \
c -= b; c ^= tommy_rot(b, 8); b += a; \
a -= c; a ^= tommy_rot(c, 16); c += b; \
b -= a; b ^= tommy_rot(a, 19); a += c; \
c -= b; c ^= tommy_rot(b, 4); b += a; \
} while (0)
#define tommy_final(a, b, c) \
do { \
c ^= b; c -= tommy_rot(b, 14); \
a ^= c; a -= tommy_rot(c, 11); \
b ^= a; b -= tommy_rot(a, 25); \
c ^= b; c -= tommy_rot(b, 16); \
a ^= c; a -= tommy_rot(c, 4); \
b ^= a; b -= tommy_rot(a, 14); \
c ^= b; c -= tommy_rot(b, 24); \
} while (0)
tommy_uint32_t tommy_hash_u32(tommy_uint32_t init_val, const void* void_key, tommy_size_t key_len)
{
const unsigned char* key = tommy_cast(const unsigned char*, void_key);
tommy_uint32_t a, b, c;
a = b = c = 0xdeadbeef + ((tommy_uint32_t)key_len) + init_val;
while (key_len > 12) {
a += tommy_le_uint32_read(key + 0);
b += tommy_le_uint32_read(key + 4);
c += tommy_le_uint32_read(key + 8);
tommy_mix(a, b, c);
key_len -= 12;
key += 12;
}
switch (key_len) {
case 0 :
return c; /* used only when called with a zero length */
case 12 :
c += tommy_le_uint32_read(key + 8);
b += tommy_le_uint32_read(key + 4);
a += tommy_le_uint32_read(key + 0);
break;
case 11 : c += ((tommy_uint32_t)key[10]) << 16; /* fallthrough */
case 10 : c += ((tommy_uint32_t)key[9]) << 8; /* fallthrough */
case 9 : c += key[8]; /* fallthrough */
case 8 :
b += tommy_le_uint32_read(key + 4);
a += tommy_le_uint32_read(key + 0);
break;
case 7 : b += ((tommy_uint32_t)key[6]) << 16; /* fallthrough */
case 6 : b += ((tommy_uint32_t)key[5]) << 8; /* fallthrough */
case 5 : b += key[4]; /* fallthrough */
case 4 :
a += tommy_le_uint32_read(key + 0);
break;
case 3 : a += ((tommy_uint32_t)key[2]) << 16; /* fallthrough */
case 2 : a += ((tommy_uint32_t)key[1]) << 8; /* fallthrough */
case 1 : a += key[0]; /* fallthrough */
}
tommy_final(a, b, c);
return c;
}
tommy_uint64_t tommy_hash_u64(tommy_uint64_t init_val, const void* void_key, tommy_size_t key_len)
{
const unsigned char* key = tommy_cast(const unsigned char*, void_key);
tommy_uint32_t a, b, c;
a = b = c = 0xdeadbeef + ((tommy_uint32_t)key_len) + (init_val & 0xffffffff);
c += init_val >> 32;
while (key_len > 12) {
a += tommy_le_uint32_read(key + 0);
b += tommy_le_uint32_read(key + 4);
c += tommy_le_uint32_read(key + 8);
tommy_mix(a, b, c);
key_len -= 12;
key += 12;
}
switch (key_len) {
case 0 :
return c + ((tommy_uint64_t)b << 32); /* used only when called with a zero length */
case 12 :
c += tommy_le_uint32_read(key + 8);
b += tommy_le_uint32_read(key + 4);
a += tommy_le_uint32_read(key + 0);
break;
case 11 : c += ((tommy_uint32_t)key[10]) << 16; /* fallthrough */
case 10 : c += ((tommy_uint32_t)key[9]) << 8; /* fallthrough */
case 9 : c += key[8]; /* fallthrough */
case 8 :
b += tommy_le_uint32_read(key + 4);
a += tommy_le_uint32_read(key + 0);
break;
case 7 : b += ((tommy_uint32_t)key[6]) << 16; /* fallthrough */
case 6 : b += ((tommy_uint32_t)key[5]) << 8; /* fallthrough */
case 5 : b += key[4]; /* fallthrough */
case 4 :
a += tommy_le_uint32_read(key + 0);
break;
case 3 : a += ((tommy_uint32_t)key[2]) << 16; /* fallthrough */
case 2 : a += ((tommy_uint32_t)key[1]) << 8; /* fallthrough */
case 1 : a += key[0]; /* fallthrough */
}
tommy_final(a, b, c);
return c + ((tommy_uint64_t)b << 32);
}
tommy_uint32_t tommy_strhash_u32(tommy_uint64_t init_val, const void* void_key)
{
const unsigned char* key = tommy_cast(const unsigned char*, void_key);
tommy_uint32_t a, b, c;
tommy_uint32_t m[3] = { 0xff, 0xff00, 0xff0000 };
a = b = c = 0xdeadbeef + init_val;
/* this is different than original lookup3 and the result won't match */
while (1) {
tommy_uint32_t v = tommy_le_uint32_read(key);
if (tommy_haszero_u32(v)) {
if (v & m[0]) {
a += v & m[0];
if (v & m[1]) {
a += v & m[1];
if (v & m[2])
a += v & m[2];
}
}
break;
}
a += v;
v = tommy_le_uint32_read(key + 4);
if (tommy_haszero_u32(v)) {
if (v & m[0]) {
b += v & m[0];
if (v & m[1]) {
b += v & m[1];
if (v & m[2])
b += v & m[2];
}
}
break;
}
b += v;
v = tommy_le_uint32_read(key + 8);
if (tommy_haszero_u32(v)) {
if (v & m[0]) {
c += v & m[0];
if (v & m[1]) {
c += v & m[1];
if (v & m[2])
c += v & m[2];
}
}
break;
}
c += v;
tommy_mix(a, b, c);
key += 12;
}
/* for lengths that are multipliers of 12 we already have called mix */
/* this is different than the original lookup3 and the result won't match */
tommy_final(a, b, c);
return c;
}