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// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-only
/*
* The xxhash is copied from the linux kernel at:
* https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/lib/xxhash.c
*
* The original copyright is:
*
* 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 program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation. This program is dual-licensed; you may select
* either version 2 of the GNU General Public License ("GPL") or BSD license
* ("BSD").
*
* You can contact the author at:
* - xxHash homepage: https://cyan4973.github.io/xxHash/
* - xxHash source repository: https://github.com/Cyan4973/xxHash
*/
#include "erofs/defs.h"
#include "liberofs_xxhash.h"
/*-*************************************
* Macros
**************************************/
#define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r)))
#define xxh_rotl64(x, r) ((x << r) | (x >> (64 - r)))
/*-*************************************
* Constants
**************************************/
static const uint32_t PRIME32_1 = 2654435761U;
static const uint32_t PRIME32_2 = 2246822519U;
static const uint32_t PRIME32_3 = 3266489917U;
static const uint32_t PRIME32_4 = 668265263U;
static const uint32_t PRIME32_5 = 374761393U;
static const uint64_t PRIME64_1 = 11400714785074694791ULL;
static const uint64_t PRIME64_2 = 14029467366897019727ULL;
static const uint64_t PRIME64_3 = 1609587929392839161ULL;
static const uint64_t PRIME64_4 = 9650029242287828579ULL;
static const uint64_t PRIME64_5 = 2870177450012600261ULL;
/*-***************************
* Simple Hash Functions
****************************/
static uint32_t xxh32_round(uint32_t seed, const uint32_t input)
{
seed += input * PRIME32_2;
seed = xxh_rotl32(seed, 13);
seed *= PRIME32_1;
return seed;
}
uint32_t xxh32(const void *input, const size_t len, const uint32_t seed)
{
const uint8_t *p = (const uint8_t *)input;
const uint8_t *b_end = p + len;
uint32_t h32;
if (len >= 16) {
const uint8_t *const limit = b_end - 16;
uint32_t v1 = seed + PRIME32_1 + PRIME32_2;
uint32_t v2 = seed + PRIME32_2;
uint32_t v3 = seed + 0;
uint32_t v4 = seed - PRIME32_1;
do {
v1 = xxh32_round(v1, get_unaligned_le32(p));
p += 4;
v2 = xxh32_round(v2, get_unaligned_le32(p));
p += 4;
v3 = xxh32_round(v3, get_unaligned_le32(p));
p += 4;
v4 = xxh32_round(v4, get_unaligned_le32(p));
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 += (uint32_t)len;
while (p + 4 <= b_end) {
h32 += get_unaligned_le32(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;
}
static uint64_t xxh64_round(uint64_t acc, const uint64_t input)
{
acc += input * PRIME64_2;
acc = xxh_rotl64(acc, 31);
acc *= PRIME64_1;
return acc;
}
static uint64_t xxh64_merge_round(uint64_t acc, uint64_t val)
{
val = xxh64_round(0, val);
acc ^= val;
acc = acc * PRIME64_1 + PRIME64_4;
return acc;
}
uint64_t xxh64(const void *input, const size_t len, const uint64_t seed)
{
const uint8_t *p = (const uint8_t *)input;
const uint8_t *const b_end = p + len;
uint64_t h64;
if (len >= 32) {
const uint8_t *const limit = b_end - 32;
uint64_t v1 = seed + PRIME64_1 + PRIME64_2;
uint64_t v2 = seed + PRIME64_2;
uint64_t v3 = seed + 0;
uint64_t v4 = seed - PRIME64_1;
do {
v1 = xxh64_round(v1, get_unaligned_le64(p));
p += 8;
v2 = xxh64_round(v2, get_unaligned_le64(p));
p += 8;
v3 = xxh64_round(v3, get_unaligned_le64(p));
p += 8;
v4 = xxh64_round(v4, get_unaligned_le64(p));
p += 8;
} while (p <= limit);
h64 = xxh_rotl64(v1, 1) + xxh_rotl64(v2, 7) +
xxh_rotl64(v3, 12) + xxh_rotl64(v4, 18);
h64 = xxh64_merge_round(h64, v1);
h64 = xxh64_merge_round(h64, v2);
h64 = xxh64_merge_round(h64, v3);
h64 = xxh64_merge_round(h64, v4);
} else {
h64 = seed + PRIME64_5;
}
h64 += (uint64_t)len;
while (p + 8 <= b_end) {
const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));
h64 ^= k1;
h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
p += 8;
}
if (p + 4 <= b_end) {
h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
p += 4;
}
while (p < b_end) {
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;
}
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