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Diffstat (limited to 'Build/source/extra/xz/src/liblzma/lz/lz_encoder_mf.c')
-rw-r--r-- | Build/source/extra/xz/src/liblzma/lz/lz_encoder_mf.c | 753 |
1 files changed, 0 insertions, 753 deletions
diff --git a/Build/source/extra/xz/src/liblzma/lz/lz_encoder_mf.c b/Build/source/extra/xz/src/liblzma/lz/lz_encoder_mf.c deleted file mode 100644 index f82a1c1d295..00000000000 --- a/Build/source/extra/xz/src/liblzma/lz/lz_encoder_mf.c +++ /dev/null @@ -1,753 +0,0 @@ -/////////////////////////////////////////////////////////////////////////////// -// -/// \file lz_encoder_mf.c -/// \brief Match finders -/// -// Authors: Igor Pavlov -// Lasse Collin -// -// This file has been put into the public domain. -// You can do whatever you want with this file. -// -/////////////////////////////////////////////////////////////////////////////// - -#include "lz_encoder.h" -#include "lz_encoder_hash.h" - - -/// \brief Find matches starting from the current byte -/// -/// \return The length of the longest match found -extern uint32_t -lzma_mf_find(lzma_mf *mf, uint32_t *count_ptr, lzma_match *matches) -{ - // Call the match finder. It returns the number of length-distance - // pairs found. - // FIXME: Minimum count is zero, what _exactly_ is the maximum? - const uint32_t count = mf->find(mf, matches); - - // Length of the longest match; assume that no matches were found - // and thus the maximum length is zero. - uint32_t len_best = 0; - - if (count > 0) { -#ifndef NDEBUG - // Validate the matches. - for (uint32_t i = 0; i < count; ++i) { - assert(matches[i].len <= mf->nice_len); - assert(matches[i].dist < mf->read_pos); - assert(memcmp(mf_ptr(mf) - 1, - mf_ptr(mf) - matches[i].dist - 2, - matches[i].len) == 0); - } -#endif - - // The last used element in the array contains - // the longest match. - len_best = matches[count - 1].len; - - // If a match of maximum search length was found, try to - // extend the match to maximum possible length. - if (len_best == mf->nice_len) { - // The limit for the match length is either the - // maximum match length supported by the LZ-based - // encoder or the number of bytes left in the - // dictionary, whichever is smaller. - uint32_t limit = mf_avail(mf) + 1; - if (limit > mf->match_len_max) - limit = mf->match_len_max; - - // Pointer to the byte we just ran through - // the match finder. - const uint8_t *p1 = mf_ptr(mf) - 1; - - // Pointer to the beginning of the match. We need -1 - // here because the match distances are zero based. - const uint8_t *p2 = p1 - matches[count - 1].dist - 1; - - while (len_best < limit - && p1[len_best] == p2[len_best]) - ++len_best; - } - } - - *count_ptr = count; - - // Finally update the read position to indicate that match finder was - // run for this dictionary offset. - ++mf->read_ahead; - - return len_best; -} - - -/// Hash value to indicate unused element in the hash. Since we start the -/// positions from dict_size + 1, zero is always too far to qualify -/// as usable match position. -#define EMPTY_HASH_VALUE 0 - - -/// Normalization must be done when lzma_mf.offset + lzma_mf.read_pos -/// reaches MUST_NORMALIZE_POS. -#define MUST_NORMALIZE_POS UINT32_MAX - - -/// \brief Normalizes hash values -/// -/// The hash arrays store positions of match candidates. The positions are -/// relative to an arbitrary offset that is not the same as the absolute -/// offset in the input stream. The relative position of the current byte -/// is lzma_mf.offset + lzma_mf.read_pos. The distances of the matches are -/// the differences of the current read position and the position found from -/// the hash. -/// -/// To prevent integer overflows of the offsets stored in the hash arrays, -/// we need to "normalize" the stored values now and then. During the -/// normalization, we drop values that indicate distance greater than the -/// dictionary size, thus making space for new values. -static void -normalize(lzma_mf *mf) -{ - assert(mf->read_pos + mf->offset == MUST_NORMALIZE_POS); - - // In future we may not want to touch the lowest bits, because there - // may be match finders that use larger resolution than one byte. - const uint32_t subvalue - = (MUST_NORMALIZE_POS - mf->cyclic_size); - // & (~(UINT32_C(1) << 10) - 1); - - const uint32_t count = mf->hash_size_sum + mf->sons_count; - uint32_t *hash = mf->hash; - - for (uint32_t i = 0; i < count; ++i) { - // If the distance is greater than the dictionary size, - // we can simply mark the hash element as empty. - // - // NOTE: Only the first mf->hash_size_sum elements are - // initialized for sure. There may be uninitialized elements - // in mf->son. Since we go through both mf->hash and - // mf->son here in normalization, Valgrind may complain - // that the "if" below depends on uninitialized value. In - // this case it is safe to ignore the warning. See also the - // comments in lz_encoder_init() in lz_encoder.c. - if (hash[i] <= subvalue) - hash[i] = EMPTY_HASH_VALUE; - else - hash[i] -= subvalue; - } - - // Update offset to match the new locations. - mf->offset -= subvalue; - - return; -} - - -/// Mark the current byte as processed from point of view of the match finder. -static void -move_pos(lzma_mf *mf) -{ - if (++mf->cyclic_pos == mf->cyclic_size) - mf->cyclic_pos = 0; - - ++mf->read_pos; - assert(mf->read_pos <= mf->write_pos); - - if (unlikely(mf->read_pos + mf->offset == UINT32_MAX)) - normalize(mf); -} - - -/// When flushing, we cannot run the match finder unless there is nice_len -/// bytes available in the dictionary. Instead, we skip running the match -/// finder (indicating that no match was found), and count how many bytes we -/// have ignored this way. -/// -/// When new data is given after the flushing was completed, the match finder -/// is restarted by rewinding mf->read_pos backwards by mf->pending. Then -/// the missed bytes are added to the hash using the match finder's skip -/// function (with small amount of input, it may start using mf->pending -/// again if flushing). -/// -/// Due to this rewinding, we don't touch cyclic_pos or test for -/// normalization. It will be done when the match finder's skip function -/// catches up after a flush. -static void -move_pending(lzma_mf *mf) -{ - ++mf->read_pos; - assert(mf->read_pos <= mf->write_pos); - ++mf->pending; -} - - -/// Calculate len_limit and determine if there is enough input to run -/// the actual match finder code. Sets up "cur" and "pos". This macro -/// is used by all find functions and binary tree skip functions. Hash -/// chain skip function doesn't need len_limit so a simpler code is used -/// in them. -#define header(is_bt, len_min, ret_op) \ - uint32_t len_limit = mf_avail(mf); \ - if (mf->nice_len <= len_limit) { \ - len_limit = mf->nice_len; \ - } else if (len_limit < (len_min) \ - || (is_bt && mf->action == LZMA_SYNC_FLUSH)) { \ - assert(mf->action != LZMA_RUN); \ - move_pending(mf); \ - ret_op; \ - } \ - const uint8_t *cur = mf_ptr(mf); \ - const uint32_t pos = mf->read_pos + mf->offset - - -/// Header for find functions. "return 0" indicates that zero matches -/// were found. -#define header_find(is_bt, len_min) \ - header(is_bt, len_min, return 0); \ - uint32_t matches_count = 0 - - -/// Header for a loop in a skip function. "continue" tells to skip the rest -/// of the code in the loop. -#define header_skip(is_bt, len_min) \ - header(is_bt, len_min, continue) - - -/// Calls hc_find_func() or bt_find_func() and calculates the total number -/// of matches found. Updates the dictionary position and returns the number -/// of matches found. -#define call_find(func, len_best) \ -do { \ - matches_count = func(len_limit, pos, cur, cur_match, mf->depth, \ - mf->son, mf->cyclic_pos, mf->cyclic_size, \ - matches + matches_count, len_best) \ - - matches; \ - move_pos(mf); \ - return matches_count; \ -} while (0) - - -//////////////// -// Hash Chain // -//////////////// - -#if defined(HAVE_MF_HC3) || defined(HAVE_MF_HC4) -/// -/// -/// \param len_limit Don't look for matches longer than len_limit. -/// \param pos lzma_mf.read_pos + lzma_mf.offset -/// \param cur Pointer to current byte (mf_ptr(mf)) -/// \param cur_match Start position of the current match candidate -/// \param depth Maximum length of the hash chain -/// \param son lzma_mf.son (contains the hash chain) -/// \param cyclic_pos -/// \param cyclic_size -/// \param matches Array to hold the matches. -/// \param len_best The length of the longest match found so far. -static lzma_match * -hc_find_func( - const uint32_t len_limit, - const uint32_t pos, - const uint8_t *const cur, - uint32_t cur_match, - uint32_t depth, - uint32_t *const son, - const uint32_t cyclic_pos, - const uint32_t cyclic_size, - lzma_match *matches, - uint32_t len_best) -{ - son[cyclic_pos] = cur_match; - - while (true) { - const uint32_t delta = pos - cur_match; - if (depth-- == 0 || delta >= cyclic_size) - return matches; - - const uint8_t *const pb = cur - delta; - cur_match = son[cyclic_pos - delta - + (delta > cyclic_pos ? cyclic_size : 0)]; - - if (pb[len_best] == cur[len_best] && pb[0] == cur[0]) { - uint32_t len = 0; - while (++len != len_limit) - if (pb[len] != cur[len]) - break; - - if (len_best < len) { - len_best = len; - matches->len = len; - matches->dist = delta - 1; - ++matches; - - if (len == len_limit) - return matches; - } - } - } -} - - -#define hc_find(len_best) \ - call_find(hc_find_func, len_best) - - -#define hc_skip() \ -do { \ - mf->son[mf->cyclic_pos] = cur_match; \ - move_pos(mf); \ -} while (0) - -#endif - - -#ifdef HAVE_MF_HC3 -extern uint32_t -lzma_mf_hc3_find(lzma_mf *mf, lzma_match *matches) -{ - header_find(false, 3); - - hash_3_calc(); - - const uint32_t delta2 = pos - mf->hash[hash_2_value]; - const uint32_t cur_match = mf->hash[FIX_3_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; - - uint32_t len_best = 2; - - if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { - for ( ; len_best != len_limit; ++len_best) - if (*(cur + len_best - delta2) != cur[len_best]) - break; - - matches[0].len = len_best; - matches[0].dist = delta2 - 1; - matches_count = 1; - - if (len_best == len_limit) { - hc_skip(); - return 1; // matches_count - } - } - - hc_find(len_best); -} - - -extern void -lzma_mf_hc3_skip(lzma_mf *mf, uint32_t amount) -{ - do { - if (mf_avail(mf) < 3) { - move_pending(mf); - continue; - } - - const uint8_t *cur = mf_ptr(mf); - const uint32_t pos = mf->read_pos + mf->offset; - - hash_3_calc(); - - const uint32_t cur_match - = mf->hash[FIX_3_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; - - hc_skip(); - - } while (--amount != 0); -} -#endif - - -#ifdef HAVE_MF_HC4 -extern uint32_t -lzma_mf_hc4_find(lzma_mf *mf, lzma_match *matches) -{ - header_find(false, 4); - - hash_4_calc(); - - uint32_t delta2 = pos - mf->hash[hash_2_value]; - const uint32_t delta3 - = pos - mf->hash[FIX_3_HASH_SIZE + hash_3_value]; - const uint32_t cur_match = mf->hash[FIX_4_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value ] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; - mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; - - uint32_t len_best = 1; - - if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { - len_best = 2; - matches[0].len = 2; - matches[0].dist = delta2 - 1; - matches_count = 1; - } - - if (delta2 != delta3 && delta3 < mf->cyclic_size - && *(cur - delta3) == *cur) { - len_best = 3; - matches[matches_count++].dist = delta3 - 1; - delta2 = delta3; - } - - if (matches_count != 0) { - for ( ; len_best != len_limit; ++len_best) - if (*(cur + len_best - delta2) != cur[len_best]) - break; - - matches[matches_count - 1].len = len_best; - - if (len_best == len_limit) { - hc_skip(); - return matches_count; - } - } - - if (len_best < 3) - len_best = 3; - - hc_find(len_best); -} - - -extern void -lzma_mf_hc4_skip(lzma_mf *mf, uint32_t amount) -{ - do { - if (mf_avail(mf) < 4) { - move_pending(mf); - continue; - } - - const uint8_t *cur = mf_ptr(mf); - const uint32_t pos = mf->read_pos + mf->offset; - - hash_4_calc(); - - const uint32_t cur_match - = mf->hash[FIX_4_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; - mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; - - hc_skip(); - - } while (--amount != 0); -} -#endif - - -///////////////// -// Binary Tree // -///////////////// - -#if defined(HAVE_MF_BT2) || defined(HAVE_MF_BT3) || defined(HAVE_MF_BT4) -static lzma_match * -bt_find_func( - const uint32_t len_limit, - const uint32_t pos, - const uint8_t *const cur, - uint32_t cur_match, - uint32_t depth, - uint32_t *const son, - const uint32_t cyclic_pos, - const uint32_t cyclic_size, - lzma_match *matches, - uint32_t len_best) -{ - uint32_t *ptr0 = son + (cyclic_pos << 1) + 1; - uint32_t *ptr1 = son + (cyclic_pos << 1); - - uint32_t len0 = 0; - uint32_t len1 = 0; - - while (true) { - const uint32_t delta = pos - cur_match; - if (depth-- == 0 || delta >= cyclic_size) { - *ptr0 = EMPTY_HASH_VALUE; - *ptr1 = EMPTY_HASH_VALUE; - return matches; - } - - uint32_t *const pair = son + ((cyclic_pos - delta - + (delta > cyclic_pos ? cyclic_size : 0)) - << 1); - - const uint8_t *const pb = cur - delta; - uint32_t len = my_min(len0, len1); - - if (pb[len] == cur[len]) { - while (++len != len_limit) - if (pb[len] != cur[len]) - break; - - if (len_best < len) { - len_best = len; - matches->len = len; - matches->dist = delta - 1; - ++matches; - - if (len == len_limit) { - *ptr1 = pair[0]; - *ptr0 = pair[1]; - return matches; - } - } - } - - 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; - } - } -} - - -static void -bt_skip_func( - const uint32_t len_limit, - const uint32_t pos, - const uint8_t *const cur, - uint32_t cur_match, - uint32_t depth, - uint32_t *const son, - const uint32_t cyclic_pos, - const uint32_t cyclic_size) -{ - uint32_t *ptr0 = son + (cyclic_pos << 1) + 1; - uint32_t *ptr1 = son + (cyclic_pos << 1); - - uint32_t len0 = 0; - uint32_t len1 = 0; - - while (true) { - const uint32_t delta = pos - cur_match; - if (depth-- == 0 || delta >= cyclic_size) { - *ptr0 = EMPTY_HASH_VALUE; - *ptr1 = EMPTY_HASH_VALUE; - return; - } - - uint32_t *pair = son + ((cyclic_pos - delta - + (delta > cyclic_pos ? cyclic_size : 0)) - << 1); - const uint8_t *pb = cur - delta; - uint32_t len = my_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]; - return; - } - } - - 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; - } - } -} - - -#define bt_find(len_best) \ - call_find(bt_find_func, len_best) - -#define bt_skip() \ -do { \ - bt_skip_func(len_limit, pos, cur, cur_match, mf->depth, \ - mf->son, mf->cyclic_pos, \ - mf->cyclic_size); \ - move_pos(mf); \ -} while (0) - -#endif - - -#ifdef HAVE_MF_BT2 -extern uint32_t -lzma_mf_bt2_find(lzma_mf *mf, lzma_match *matches) -{ - header_find(true, 2); - - hash_2_calc(); - - const uint32_t cur_match = mf->hash[hash_value]; - mf->hash[hash_value] = pos; - - bt_find(1); -} - - -extern void -lzma_mf_bt2_skip(lzma_mf *mf, uint32_t amount) -{ - do { - header_skip(true, 2); - - hash_2_calc(); - - const uint32_t cur_match = mf->hash[hash_value]; - mf->hash[hash_value] = pos; - - bt_skip(); - - } while (--amount != 0); -} -#endif - - -#ifdef HAVE_MF_BT3 -extern uint32_t -lzma_mf_bt3_find(lzma_mf *mf, lzma_match *matches) -{ - header_find(true, 3); - - hash_3_calc(); - - const uint32_t delta2 = pos - mf->hash[hash_2_value]; - const uint32_t cur_match = mf->hash[FIX_3_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; - - uint32_t len_best = 2; - - if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { - for ( ; len_best != len_limit; ++len_best) - if (*(cur + len_best - delta2) != cur[len_best]) - break; - - matches[0].len = len_best; - matches[0].dist = delta2 - 1; - matches_count = 1; - - if (len_best == len_limit) { - bt_skip(); - return 1; // matches_count - } - } - - bt_find(len_best); -} - - -extern void -lzma_mf_bt3_skip(lzma_mf *mf, uint32_t amount) -{ - do { - header_skip(true, 3); - - hash_3_calc(); - - const uint32_t cur_match - = mf->hash[FIX_3_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_value] = pos; - - bt_skip(); - - } while (--amount != 0); -} -#endif - - -#ifdef HAVE_MF_BT4 -extern uint32_t -lzma_mf_bt4_find(lzma_mf *mf, lzma_match *matches) -{ - header_find(true, 4); - - hash_4_calc(); - - uint32_t delta2 = pos - mf->hash[hash_2_value]; - const uint32_t delta3 - = pos - mf->hash[FIX_3_HASH_SIZE + hash_3_value]; - const uint32_t cur_match = mf->hash[FIX_4_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; - mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; - - uint32_t len_best = 1; - - if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) { - len_best = 2; - matches[0].len = 2; - matches[0].dist = delta2 - 1; - matches_count = 1; - } - - if (delta2 != delta3 && delta3 < mf->cyclic_size - && *(cur - delta3) == *cur) { - len_best = 3; - matches[matches_count++].dist = delta3 - 1; - delta2 = delta3; - } - - if (matches_count != 0) { - for ( ; len_best != len_limit; ++len_best) - if (*(cur + len_best - delta2) != cur[len_best]) - break; - - matches[matches_count - 1].len = len_best; - - if (len_best == len_limit) { - bt_skip(); - return matches_count; - } - } - - if (len_best < 3) - len_best = 3; - - bt_find(len_best); -} - - -extern void -lzma_mf_bt4_skip(lzma_mf *mf, uint32_t amount) -{ - do { - header_skip(true, 4); - - hash_4_calc(); - - const uint32_t cur_match - = mf->hash[FIX_4_HASH_SIZE + hash_value]; - - mf->hash[hash_2_value] = pos; - mf->hash[FIX_3_HASH_SIZE + hash_3_value] = pos; - mf->hash[FIX_4_HASH_SIZE + hash_value] = pos; - - bt_skip(); - - } while (--amount != 0); -} -#endif |