Campbell Barton
e12c08e8d1
Apply clang format as proposed in T53211. For details on usage and instructions for migrating branches without conflicts, see: https://wiki.blender.org/wiki/Tools/ClangFormat
141 lines
3.1 KiB
C
141 lines
3.1 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* Copyright (C) 2018 Blender Foundation.
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*/
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/** \file
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* \ingroup bli
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*
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* Functions to compute Murmur3 hash key.
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*
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* This Code is based on alShaders/Cryptomatte/MurmurHash3.h:
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*
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* MurmurHash3 was written by Austin Appleby, and is placed in the public
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* domain. The author hereby disclaims copyright to this source code.
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*/
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#include "BLI_compiler_compat.h"
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#include "BLI_compiler_attrs.h"
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#include "BLI_hash_mm3.h" /* own include */
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#if defined(_MSC_VER)
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# include <stdlib.h>
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# define ROTL32(x, y) _rotl(x, y)
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# define BIG_CONSTANT(x) (x)
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/* Other compilers */
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#else /* defined(_MSC_VER) */
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static inline uint32_t rotl32(uint32_t x, int8_t r)
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{
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return (x << r) | (x >> (32 - r));
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}
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# define ROTL32(x, y) rotl32(x, y)
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# define BIG_CONSTANT(x) (x##LLU)
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#endif /* !defined(_MSC_VER) */
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/* Block read - if your platform needs to do endian-swapping or can only
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* handle aligned reads, do the conversion here
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*/
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BLI_INLINE uint32_t getblock32(const uint32_t *p, int i)
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{
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return p[i];
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}
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BLI_INLINE uint64_t getblock64(const uint64_t *p, int i)
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{
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return p[i];
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}
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/* Finalization mix - force all bits of a hash block to avalanche */
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BLI_INLINE uint32_t fmix32(uint32_t h)
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{
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h ^= h >> 16;
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h *= 0x85ebca6b;
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h ^= h >> 13;
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h *= 0xc2b2ae35;
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h ^= h >> 16;
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return h;
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}
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BLI_INLINE uint64_t fmix64(uint64_t k)
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{
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k ^= k >> 33;
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k *= BIG_CONSTANT(0xff51afd7ed558ccd);
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k ^= k >> 33;
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k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
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k ^= k >> 33;
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return k;
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}
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uint32_t BLI_hash_mm3(const unsigned char *in, size_t len, uint32_t seed)
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{
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const uint8_t *data = (const uint8_t *)in;
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const int nblocks = len / 4;
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uint32_t h1 = seed;
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const uint32_t c1 = 0xcc9e2d51;
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const uint32_t c2 = 0x1b873593;
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/* body */
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const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
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for (int i = -nblocks; i; i++) {
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uint32_t k1 = getblock32(blocks, i);
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k1 *= c1;
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k1 = ROTL32(k1, 15);
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k1 *= c2;
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h1 ^= k1;
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h1 = ROTL32(h1, 13);
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h1 = h1 * 5 + 0xe6546b64;
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}
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/* tail */
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const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
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uint32_t k1 = 0;
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switch (len & 3) {
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case 3:
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k1 ^= tail[2] << 16;
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ATTR_FALLTHROUGH;
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case 2:
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k1 ^= tail[1] << 8;
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ATTR_FALLTHROUGH;
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case 1:
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k1 ^= tail[0];
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k1 *= c1;
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k1 = ROTL32(k1, 15);
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k1 *= c2;
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h1 ^= k1;
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}
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/* finalization */
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h1 ^= len;
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h1 = fmix32(h1);
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return h1;
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}
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