diff options
author | Lasse Collin <lasse.collin@tukaani.org> | 2007-12-09 00:42:33 +0200 |
---|---|---|
committer | Lasse Collin <lasse.collin@tukaani.org> | 2007-12-09 00:42:33 +0200 |
commit | 5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch) | |
tree | 1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/liblzma/lz/match_c.h | |
download | xz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz |
Imported to git.
Diffstat (limited to 'src/liblzma/lz/match_c.h')
-rw-r--r-- | src/liblzma/lz/match_c.h | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/src/liblzma/lz/match_c.h b/src/liblzma/lz/match_c.h new file mode 100644 index 00000000..68766385 --- /dev/null +++ b/src/liblzma/lz/match_c.h @@ -0,0 +1,401 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file match_c.h +/// \brief Template for different match finders +/// +/// This file is included by hc3.c, hc4, bt2.c, bt3.c and bt4.c. Each file +/// sets slighly different #defines, resulting the different match finders. +// +// Copyright (C) 1999-2006 Igor Pavlov +// Copyright (C) 2007 Lasse Collin +// +// This library is free software; you can redistribute it and/or +// modify it under the terms of the GNU Lesser General Public +// License as published by the Free Software Foundation; either +// version 2.1 of the License, or (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Lesser General Public License for more details. +// +/////////////////////////////////////////////////////////////////////////////// + +////////////// +// Includes // +////////////// + +#include "check.h" + + +/////////////// +// Constants // +/////////////// + +#define START_MAX_LEN 1 + +#ifdef HASH_ARRAY_2 +# define NUM_HASH_DIRECT_BYTES 0 +# define HASH_2_SIZE (1 << 10) +# ifdef HASH_ARRAY_3 +# define NUM_HASH_BYTES 4 +# define HASH_3_SIZE (1 << 16) +# define HASH_3_OFFSET HASH_2_SIZE +# define FIX_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE) +# else +# define NUM_HASH_BYTES 3 +# define FIX_HASH_SIZE HASH_2_SIZE +# endif +# define HASH_SIZE 0 +# define MIN_MATCH_CHECK NUM_HASH_BYTES +#else +# define NUM_HASH_DIRECT_BYTES 2 +# define NUM_HASH_BYTES 2 +# define HASH_SIZE (1 << (8 * NUM_HASH_BYTES)) +# define MIN_MATCH_CHECK (NUM_HASH_BYTES + 1) +# define FIX_HASH_SIZE 0 +#endif + + +//////////// +// Macros // +//////////// + +#ifdef HASH_ARRAY_2 +# ifdef HASH_ARRAY_3 +# define HASH_CALC() \ + do { \ + const uint32_t temp = lzma_crc32_table[0][ \ + cur[0]] ^ cur[1]; \ + hash_2_value = temp & (HASH_2_SIZE - 1); \ + hash_3_value = (temp ^ ((uint32_t)(cur[2]) << 8)) \ + & (HASH_3_SIZE - 1); \ + hash_value = (temp ^ ((uint32_t)(cur[2]) << 8) \ + ^ (lzma_crc32_table[0][cur[3]] << 5)) \ + & lz->hash_mask; \ + } while (0) +# else +# define HASH_CALC() \ + do { \ + const uint32_t temp = lzma_crc32_table[0][ \ + cur[0]] ^ cur[1]; \ + hash_2_value = temp & (HASH_2_SIZE - 1); \ + hash_value = (temp ^ ((uint32_t)(cur[2]) << 8)) \ + & lz->hash_mask; \ + } while (0) +# endif +#else +# define HASH_CALC() hash_value = cur[0] ^ ((uint32_t)(cur[1]) << 8) +#endif + + +// Moves the current read position forward by one byte. In LZMA SDK, +// CLZInWindow::MovePos() can read more input data if needed, because of +// the callback style API. In liblzma we must have ensured earlier, that +// there is enough data available in lz->buffer. +#define move_pos() \ +do { \ + if (++lz->cyclic_buffer_pos == lz->cyclic_buffer_size) \ + lz->cyclic_buffer_pos = 0; \ + ++lz->read_pos; \ + assert(lz->read_pos <= lz->write_pos); \ + if (lz->read_pos == MAX_VAL_FOR_NORMALIZE) \ + lzma_lz_encoder_normalize(lz); \ +} while (0) + + +////////////////////// +// Global constants // +////////////////////// + +LZMA_HASH_SIZE(LZMA_MATCH_FINDER_NAME_UPPER) = HASH_SIZE; +LZMA_FIX_HASH_SIZE(LZMA_MATCH_FINDER_NAME_UPPER) = FIX_HASH_SIZE; + + +/////////////////// +// API functions // +/////////////////// + +LZMA_GET_MATCHES(LZMA_MATCH_FINDER_NAME_LOWER) +{ + uint32_t len_limit; + if (lz->read_pos + lz->match_max_len <= lz->write_pos) { + len_limit = lz->match_max_len; + } else { + assert(lz->stream_end_was_reached); + len_limit = lz->write_pos - lz->read_pos; + if (len_limit < MIN_MATCH_CHECK) { + distances[0] = 0; + move_pos(); + return; + } + } + + int32_t offset = 1; + const uint32_t match_min_pos + = lz->read_pos + lz->offset > lz->cyclic_buffer_size + ? lz->read_pos + lz->offset - lz->cyclic_buffer_size + : 0; + const uint8_t *cur = lz->buffer + lz->read_pos; + uint32_t max_len = START_MAX_LEN; // to avoid items for len < hash_size + +#ifdef HASH_ARRAY_2 + uint32_t hash_2_value; +# ifdef HASH_ARRAY_3 + uint32_t hash_3_value; +# endif +#endif + uint32_t hash_value; + HASH_CALC(); + + uint32_t cur_match = lz->hash[FIX_HASH_SIZE + hash_value]; +#ifdef HASH_ARRAY_2 + uint32_t cur_match2 = lz->hash[hash_2_value]; +# ifdef HASH_ARRAY_3 + uint32_t cur_match3 = lz->hash[HASH_3_OFFSET + hash_3_value]; +# endif + lz->hash[hash_2_value] = lz->read_pos + lz->offset; + + if (cur_match2 > match_min_pos) { + if (lz->buffer[cur_match2 - lz->offset] == cur[0]) { + max_len = 2; + distances[offset++] = 2; + distances[offset++] = lz->read_pos + lz->offset + - cur_match2 - 1; + } + } + +# ifdef HASH_ARRAY_3 + lz->hash[HASH_3_OFFSET + hash_3_value] = lz->read_pos + lz->offset; + if (cur_match3 > match_min_pos) { + if (lz->buffer[cur_match3 - lz->offset] == cur[0]) { + if (cur_match3 == cur_match2) + offset -= 2; + + max_len = 3; + distances[offset++] = 3; + distances[offset++] = lz->read_pos + lz->offset + - cur_match3 - 1; + cur_match2 = cur_match3; + } + } +# endif + + if (offset != 1 && cur_match2 == cur_match) { + offset -= 2; + max_len = START_MAX_LEN; + } +#endif + + lz->hash[FIX_HASH_SIZE + hash_value] = lz->read_pos + lz->offset; + +#ifdef IS_HASH_CHAIN + lz->son[lz->cyclic_buffer_pos] = cur_match; +#else + uint32_t *ptr0 = lz->son + (lz->cyclic_buffer_pos << 1) + 1; + uint32_t *ptr1 = lz->son + (lz->cyclic_buffer_pos << 1); + + uint32_t len0 = NUM_HASH_DIRECT_BYTES; + uint32_t len1 = NUM_HASH_DIRECT_BYTES; +#endif + +#if NUM_HASH_DIRECT_BYTES != 0 + if (cur_match > match_min_pos) { + if (lz->buffer[cur_match + NUM_HASH_DIRECT_BYTES - lz->offset] + != cur[NUM_HASH_DIRECT_BYTES]) { + max_len = NUM_HASH_DIRECT_BYTES; + distances[offset++] = NUM_HASH_DIRECT_BYTES; + distances[offset++] = lz->read_pos + lz->offset + - cur_match - 1; + } + } +#endif + + uint32_t count = lz->cut_value; + + while (true) { + if (cur_match <= match_min_pos || count-- == 0) { +#ifndef IS_HASH_CHAIN + *ptr0 = EMPTY_HASH_VALUE; + *ptr1 = EMPTY_HASH_VALUE; +#endif + break; + } + + const uint32_t delta = lz->read_pos + lz->offset - cur_match; + const uint32_t cyclic_pos = delta <= lz->cyclic_buffer_pos + ? lz->cyclic_buffer_pos - delta + : lz->cyclic_buffer_pos - delta + + lz->cyclic_buffer_size; + uint32_t *pair = lz->son + +#ifdef IS_HASH_CHAIN + cyclic_pos; +#else + (cyclic_pos << 1); +#endif + + const uint8_t *pb = lz->buffer + cur_match - lz->offset; + uint32_t len = +#ifdef IS_HASH_CHAIN + NUM_HASH_DIRECT_BYTES; + if (pb[max_len] == cur[max_len]) +#else + MIN(len0, len1); +#endif + + if (pb[len] == cur[len]) { + while (++len != len_limit) + if (pb[len] != cur[len]) + break; + + if (max_len < len) { + max_len = len; + distances[offset++] = len; + distances[offset++] = delta - 1; + if (len == len_limit) { +#ifndef IS_HASH_CHAIN + *ptr1 = pair[0]; + *ptr0 = pair[1]; +#endif + break; + } + } + } + +#ifdef IS_HASH_CHAIN + cur_match = *pair; +#else + if (pb[len] < cur[len]) { + *ptr1 = cur_match; + ptr1 = pair + 1; + cur_match = *ptr1; + len1 = len; + } else { + *ptr0 = cur_match; + ptr0 = pair; + cur_match = *ptr0; + len0 = len; + } +#endif + } + + distances[0] = offset - 1; + + move_pos(); + + return; +} + + +LZMA_SKIP(LZMA_MATCH_FINDER_NAME_LOWER) +{ + do { +#ifdef IS_HASH_CHAIN + if (lz->write_pos - lz->read_pos < NUM_HASH_BYTES) { + move_pos(); + continue; + } +#else + uint32_t len_limit; + if (lz->read_pos + lz->match_max_len <= lz->write_pos) { + len_limit = lz->match_max_len; + } else { + assert(lz->stream_end_was_reached == true); + len_limit = lz->write_pos - lz->read_pos; + if (len_limit < MIN_MATCH_CHECK) { + move_pos(); + continue; + } + } + const uint32_t match_min_pos + = lz->read_pos + lz->offset > lz->cyclic_buffer_size + ? lz->read_pos + lz->offset - lz->cyclic_buffer_size + : 0; +#endif + + const uint8_t *cur = lz->buffer + lz->read_pos; + +#ifdef HASH_ARRAY_2 + uint32_t hash_2_value; +# ifdef HASH_ARRAY_3 + uint32_t hash_3_value; + uint32_t hash_value; + HASH_CALC(); + lz->hash[HASH_3_OFFSET + hash_3_value] + = lz->read_pos + lz->offset; +# else + uint32_t hash_value; + HASH_CALC(); +# endif + lz->hash[hash_2_value] = lz->read_pos + lz->offset; +#else + uint32_t hash_value; + HASH_CALC(); +#endif + + uint32_t cur_match = lz->hash[FIX_HASH_SIZE + hash_value]; + lz->hash[FIX_HASH_SIZE + hash_value] + = lz->read_pos + lz->offset; + +#ifdef IS_HASH_CHAIN + lz->son[lz->cyclic_buffer_pos] = cur_match; +#else + uint32_t *ptr0 = lz->son + (lz->cyclic_buffer_pos << 1) + 1; + uint32_t *ptr1 = lz->son + (lz->cyclic_buffer_pos << 1); + + uint32_t len0 = NUM_HASH_DIRECT_BYTES; + uint32_t len1 = NUM_HASH_DIRECT_BYTES; + uint32_t count = lz->cut_value; + + while (true) { + if (cur_match <= match_min_pos || count-- == 0) { + *ptr0 = EMPTY_HASH_VALUE; + *ptr1 = EMPTY_HASH_VALUE; + break; + } + + const uint32_t delta = lz->read_pos + + lz->offset - cur_match; + const uint32_t cyclic_pos + = delta <= lz->cyclic_buffer_pos + ? lz->cyclic_buffer_pos - delta + : lz->cyclic_buffer_pos - delta + + lz->cyclic_buffer_size; + uint32_t *pair = lz->son + (cyclic_pos << 1); + + const uint8_t *pb = lz->buffer + cur_match + - lz->offset; + uint32_t len = MIN(len0, len1); + + if (pb[len] == cur[len]) { + while (++len != len_limit) + if (pb[len] != cur[len]) + break; + + if (len == len_limit) { + *ptr1 = pair[0]; + *ptr0 = pair[1]; + break; + } + } + + if (pb[len] < cur[len]) { + *ptr1 = cur_match; + ptr1 = pair + 1; + cur_match = *ptr1; + len1 = len; + } else { + *ptr0 = cur_match; + ptr0 = pair; + cur_match = *ptr0; + len0 = len; + } + } +#endif + + move_pos(); + + } while (--num != 0); + + return; +} |