diff options
Diffstat (limited to 'src/liblzma/lzma/lzma_encoder_getoptimumfast.c')
| -rw-r--r-- | src/liblzma/lzma/lzma_encoder_getoptimumfast.c | 201 |
1 files changed, 0 insertions, 201 deletions
diff --git a/src/liblzma/lzma/lzma_encoder_getoptimumfast.c b/src/liblzma/lzma/lzma_encoder_getoptimumfast.c deleted file mode 100644 index fa06be21..00000000 --- a/src/liblzma/lzma/lzma_encoder_getoptimumfast.c +++ /dev/null @@ -1,201 +0,0 @@ -/////////////////////////////////////////////////////////////////////////////// -// -/// \file lzma_encoder_getoptimumfast.c -// -// 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. -// -/////////////////////////////////////////////////////////////////////////////// - -// NOTE: If you want to keep the line length in 80 characters, set -// tab width to 4 or less in your editor when editing this file. - - -#include "lzma_encoder_private.h" - - -#define change_pair(small_dist, big_dist) \ - (((big_dist) >> 7) > (small_dist)) - - -extern void -lzma_get_optimum_fast(lzma_coder *restrict coder, - uint32_t *restrict back_res, uint32_t *restrict len_res) -{ - // Local copies - const uint32_t fast_bytes = coder->fast_bytes; - - uint32_t len_main; - uint32_t num_distance_pairs; - if (!coder->longest_match_was_found) { - lzma_read_match_distances(coder, &len_main, &num_distance_pairs); - } else { - len_main = coder->longest_match_length; - num_distance_pairs = coder->num_distance_pairs; - coder->longest_match_was_found = false; - } - - const uint8_t *buf = coder->lz.buffer + coder->lz.read_pos - 1; - uint32_t num_available_bytes - = coder->lz.write_pos - coder->lz.read_pos + 1; - - if (num_available_bytes < 2) { - // There's not enough input left to encode a match. - *back_res = UINT32_MAX; - *len_res = 1; - return; - } - - if (num_available_bytes > MATCH_MAX_LEN) - num_available_bytes = MATCH_MAX_LEN; - - - // Look for repetitive matches; scan the previous four match distances - uint32_t rep_lens[REP_DISTANCES]; - uint32_t rep_max_index = 0; - - for (uint32_t i = 0; i < REP_DISTANCES; ++i) { - const uint32_t back_offset = coder->reps[i] + 1; - - // If the first two bytes (2 == MATCH_MIN_LEN) do not match, - // this rep_distance[i] is not useful. This is indicated - // using zero as the length of the repetitive match. - if (buf[0] != *(buf - back_offset) - || buf[1] != *(buf + 1 - back_offset)) { - rep_lens[i] = 0; - continue; - } - - // The first two bytes matched. - // Calculate the length of the match. - uint32_t len; - for (len = 2; len < num_available_bytes - && buf[len] == *(buf + len - back_offset); - ++len) ; - - // If we have found a repetitive match that is at least - // as long as fast_bytes, return it immediatelly. - if (len >= fast_bytes) { - *back_res = i; - *len_res = len; - move_pos(len - 1); - return; - } - - rep_lens[i] = len; - - // After this loop, rep_lens[rep_max_index] is the biggest - // value of all values in rep_lens[]. - if (len > rep_lens[rep_max_index]) - rep_max_index = i; - } - - - if (len_main >= fast_bytes) { - *back_res = coder->match_distances[num_distance_pairs] - + REP_DISTANCES; - *len_res = len_main; - move_pos(len_main - 1); - return; - } - - uint32_t back_main = 0; - if (len_main >= 2) { - back_main = coder->match_distances[num_distance_pairs]; - - while (num_distance_pairs > 2 && len_main == - coder->match_distances[num_distance_pairs - 3] + 1) { - if (!change_pair(coder->match_distances[ - num_distance_pairs - 2], back_main)) - break; - - num_distance_pairs -= 2; - len_main = coder->match_distances[num_distance_pairs - 1]; - back_main = coder->match_distances[num_distance_pairs]; - } - - if (len_main == 2 && back_main >= 0x80) - len_main = 1; - } - - if (rep_lens[rep_max_index] >= 2) { - if (rep_lens[rep_max_index] + 1 >= len_main - || (rep_lens[rep_max_index] + 2 >= len_main - && (back_main > (1 << 9))) - || (rep_lens[rep_max_index] + 3 >= len_main - && (back_main > (1 << 15)))) { - *back_res = rep_max_index; - *len_res = rep_lens[rep_max_index]; - move_pos(*len_res - 1); - return; - } - } - - if (len_main >= 2 && num_available_bytes > 2) { - lzma_read_match_distances(coder, &coder->longest_match_length, - &coder->num_distance_pairs); - - if (coder->longest_match_length >= 2) { - const uint32_t new_distance = coder->match_distances[ - coder->num_distance_pairs]; - - if ((coder->longest_match_length >= len_main - && new_distance < back_main) - || (coder->longest_match_length == len_main + 1 - && !change_pair(back_main, new_distance)) - || (coder->longest_match_length > len_main + 1) - || (coder->longest_match_length + 1 >= len_main - && len_main >= 3 - && change_pair(new_distance, back_main))) { - coder->longest_match_was_found = true; - *back_res = UINT32_MAX; - *len_res = 1; - return; - } - } - - ++buf; - --num_available_bytes; - - for (uint32_t i = 0; i < REP_DISTANCES; ++i) { - const uint32_t back_offset = coder->reps[i] + 1; - - if (buf[1] != *(buf + 1 - back_offset) - || buf[2] != *(buf + 2 - back_offset)) { - rep_lens[i] = 0; - continue; - } - - uint32_t len; - for (len = 2; len < num_available_bytes - && buf[len] == *(buf + len - back_offset); - ++len) ; - - if (len + 1 >= len_main) { - coder->longest_match_was_found = true; - *back_res = UINT32_MAX; - *len_res = 1; - return; - } - } - - *back_res = back_main + REP_DISTANCES; - *len_res = len_main; - move_pos(len_main - 2); - return; - } - - *back_res = UINT32_MAX; - *len_res = 1; - return; -} |