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/*
* xxHash - Extremely Fast Hash algorithm
* Copyright (C) 2012-2016, 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.
* ----------------------------------------------------------------------------
* This code has been lifted from Linux (the OS kernel) and adapted for use in
* libsquashfs. For the original, unmodified and complete source, see below.
*
* You can contact the author at:
* - xxHash homepage: http://cyan4973.github.io/xxHash/
* - xxHash source repository: https://github.com/Cyan4973/xxHash
*/
#include "config.h"
#include "util/util.h"
#include <string.h>
#define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r)))
static const sqfs_u32 PRIME32_1 = 2654435761U;
static const sqfs_u32 PRIME32_2 = 2246822519U;
static const sqfs_u32 PRIME32_3 = 3266489917U;
static const sqfs_u32 PRIME32_4 = 668265263U;
static const sqfs_u32 PRIME32_5 = 374761393U;
static sqfs_u32 xxh32_round(sqfs_u32 seed, sqfs_u32 input)
{
seed += input * PRIME32_2;
seed = xxh_rotl32(seed, 13);
seed *= PRIME32_1;
return seed;
}
static sqfs_u32 XXH_readLE32(const sqfs_u8 *ptr)
{
sqfs_u32 value;
memcpy(&value, ptr, sizeof(value));
return le32toh(value);
}
sqfs_u32 xxh32(const void *input, const size_t len)
{
const sqfs_u8 *p = (const sqfs_u8 *)input;
const sqfs_u8 *b_end = p + len;
sqfs_u32 h32;
if (len >= 16) {
const sqfs_u8 *const limit = b_end - 16;
sqfs_u32 v1 = PRIME32_1 + PRIME32_2;
sqfs_u32 v2 = PRIME32_2;
sqfs_u32 v3 = 0;
sqfs_u32 v4 = PRIME32_1;
do {
v1 = xxh32_round(v1, XXH_readLE32(p ));
v2 = xxh32_round(v2, XXH_readLE32(p + 4));
v3 = xxh32_round(v3, XXH_readLE32(p + 8));
v4 = xxh32_round(v4, XXH_readLE32(p + 12));
p += 16;
} while (p <= limit);
h32 = xxh_rotl32(v1, 1) + xxh_rotl32(v2, 7) +
xxh_rotl32(v3, 12) + xxh_rotl32(v4, 18);
} else {
h32 = PRIME32_5;
}
h32 += (sqfs_u32)len;
while (p + 4 <= b_end) {
h32 += XXH_readLE32(p) * PRIME32_3;
h32 = xxh_rotl32(h32, 17) * PRIME32_4;
p += 4;
}
while (p < b_end) {
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;
}
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