mirror of https://git.tukaani.org/xz.git
105 lines
3.6 KiB
C
105 lines
3.6 KiB
C
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file lz_encoder_hash.h
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/// \brief Hash macros for match finders
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//
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// Copyright (C) 1999-2008 Igor Pavlov
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library 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 GNU
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// Lesser General Public License for more details.
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//
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///////////////////////////////////////////////////////////////////////////////
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#ifndef LZMA_LZ_ENCODER_HASH_H
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#define LZMA_LZ_ENCODER_HASH_H
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#define HASH_2_SIZE (UINT32_C(1) << 10)
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#define HASH_3_SIZE (UINT32_C(1) << 16)
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#define HASH_4_SIZE (UINT32_C(1) << 20)
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#define HASH_2_MASK (HASH_2_SIZE - 1)
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#define HASH_3_MASK (HASH_3_SIZE - 1)
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#define HASH_4_MASK (HASH_4_SIZE - 1)
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#define FIX_3_HASH_SIZE (HASH_2_SIZE)
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#define FIX_4_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE)
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#define FIX_5_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE + HASH_4_SIZE)
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// TODO Benchmark, and probably doesn't need to be endian dependent.
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#if !defined(WORDS_BIGENDIAN) && defined(HAVE_FAST_UNALIGNED_ACCESS)
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# define hash_2_calc() \
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const uint32_t hash_value = *(const uint16_t *)(cur);
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#else
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# define hash_2_calc() \
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const uint32_t hash_value \
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= (uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8)
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#endif
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#define hash_3_calc() \
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const uint32_t temp = lzma_crc32_table[0][cur[0]] ^ cur[1]; \
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const uint32_t hash_2_value = temp & HASH_2_MASK; \
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const uint32_t hash_value \
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= (temp ^ ((uint32_t)(cur[2]) << 8)) & mf->hash_mask
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#define hash_4_calc() \
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const uint32_t temp = lzma_crc32_table[0][cur[0]] ^ cur[1]; \
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const uint32_t hash_2_value = temp & HASH_2_MASK; \
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const uint32_t hash_3_value \
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= (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \
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const uint32_t hash_value = (temp ^ ((uint32_t)(cur[2]) << 8) \
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^ (lzma_crc32_table[0][cur[3]] << 5)) & mf->hash_mask
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// The following are not currently used.
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#define hash_5_calc() \
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const uint32_t temp = lzma_crc32_table[0][cur[0]] ^ cur[1]; \
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const uint32_t hash_2_value = temp & HASH_2_MASK; \
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const uint32_t hash_3_value \
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= (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \
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uint32_t hash_4_value = (temp ^ ((uint32_t)(cur[2]) << 8) ^ \
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^ lzma_crc32_table[0][cur[3]] << 5); \
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const uint32_t hash_value \
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= (hash_4_value ^ (lzma_crc32_table[0][cur[4]] << 3)) \
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& mf->hash_mask; \
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hash_4_value &= HASH_4_MASK
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/*
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#define hash_zip_calc() \
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const uint32_t hash_value \
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= (((uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8)) \
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^ lzma_crc32_table[0][cur[2]]) & 0xFFFF
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*/
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#define hash_zip_calc() \
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const uint32_t hash_value \
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= (((uint32_t)(cur[2]) | ((uint32_t)(cur[0]) << 8)) \
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^ lzma_crc32_table[0][cur[1]]) & 0xFFFF
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#define mt_hash_2_calc() \
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const uint32_t hash_2_value \
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= (lzma_crc32_table[0][cur[0]] ^ cur[1]) & HASH_2_MASK
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#define mt_hash_3_calc() \
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const uint32_t temp = lzma_crc32_table[0][cur[0]] ^ cur[1]; \
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const uint32_t hash_2_value = temp & HASH_2_MASK; \
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const uint32_t hash_3_value \
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= (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK
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#define mt_hash_4_calc() \
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const uint32_t temp = lzma_crc32_table[0][cur[0]] ^ cur[1]; \
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const uint32_t hash_2_value = temp & HASH_2_MASK; \
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const uint32_t hash_3_value \
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= (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \
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const uint32_t hash_4_value = (temp ^ ((uint32_t)(cur[2]) << 8) ^ \
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(lzma_crc32_table[0][cur[3]] << 5)) & HASH_4_MASK
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#endif
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