diff options
Diffstat (limited to 'BaseTools/Source/C/BrotliCompress/enc/hash_longest_match_inc.h')
| -rw-r--r-- | BaseTools/Source/C/BrotliCompress/enc/hash_longest_match_inc.h | 241 |
1 files changed, 0 insertions, 241 deletions
diff --git a/BaseTools/Source/C/BrotliCompress/enc/hash_longest_match_inc.h b/BaseTools/Source/C/BrotliCompress/enc/hash_longest_match_inc.h deleted file mode 100644 index 4791b6f81b..0000000000 --- a/BaseTools/Source/C/BrotliCompress/enc/hash_longest_match_inc.h +++ /dev/null @@ -1,241 +0,0 @@ -/* NOLINT(build/header_guard) */
-/* Copyright 2010 Google Inc. All Rights Reserved.
-
- Distributed under MIT license.
- See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
-*/
-
-/* template parameters: FN, BUCKET_BITS, BLOCK_BITS,
- NUM_LAST_DISTANCES_TO_CHECK */
-
-/* A (forgetful) hash table to the data seen by the compressor, to
- help create backward references to previous data.
-
- This is a hash map of fixed size (BUCKET_SIZE) to a ring buffer of
- fixed size (BLOCK_SIZE). The ring buffer contains the last BLOCK_SIZE
- index positions of the given hash key in the compressed data. */
-
-#define HashLongestMatch HASHER()
-
-/* Number of hash buckets. */
-#define BUCKET_SIZE (1 << BUCKET_BITS)
-
-/* Only BLOCK_SIZE newest backward references are kept,
- and the older are forgotten. */
-#define BLOCK_SIZE (1u << BLOCK_BITS)
-
-/* Mask for accessing entries in a block (in a ringbuffer manner). */
-#define BLOCK_MASK ((1 << BLOCK_BITS) - 1)
-
-#define HASH_MAP_SIZE (2 << BUCKET_BITS)
-
-static BROTLI_INLINE size_t FN(HashTypeLength)(void) { return 4; }
-static BROTLI_INLINE size_t FN(StoreLookahead)(void) { return 4; }
-
-/* HashBytes is the function that chooses the bucket to place
- the address in. The HashLongestMatch and HashLongestMatchQuickly
- classes have separate, different implementations of hashing. */
-static uint32_t FN(HashBytes)(const uint8_t *data) {
- uint32_t h = BROTLI_UNALIGNED_LOAD32(data) * kHashMul32;
- /* The higher bits contain more mixture from the multiplication,
- so we take our results from there. */
- return h >> (32 - BUCKET_BITS);
-}
-
-typedef struct HashLongestMatch {
- /* Number of entries in a particular bucket. */
- uint16_t num_[BUCKET_SIZE];
-
- /* Buckets containing BLOCK_SIZE of backward references. */
- uint32_t buckets_[BLOCK_SIZE << BUCKET_BITS];
-
- /* True if num_ array needs to be initialized. */
- BROTLI_BOOL is_dirty_;
-
- DictionarySearchStatictics dict_search_stats_;
-} HashLongestMatch;
-
-static void FN(Reset)(HashLongestMatch* self) {
- self->is_dirty_ = BROTLI_TRUE;
- DictionarySearchStaticticsReset(&self->dict_search_stats_);
-}
-
-static void FN(InitEmpty)(HashLongestMatch* self) {
- if (self->is_dirty_) {
- memset(self->num_, 0, sizeof(self->num_));
- self->is_dirty_ = BROTLI_FALSE;
- }
-}
-
-static void FN(InitForData)(HashLongestMatch* self, const uint8_t* data,
- size_t num) {
- size_t i;
- for (i = 0; i < num; ++i) {
- const uint32_t key = FN(HashBytes)(&data[i]);
- self->num_[key] = 0;
- }
- if (num != 0) {
- self->is_dirty_ = BROTLI_FALSE;
- }
-}
-
-static void FN(Init)(
- MemoryManager* m, HashLongestMatch* self, const uint8_t* data,
- const BrotliEncoderParams* params, size_t position, size_t bytes,
- BROTLI_BOOL is_last) {
- /* Choose which init method is faster.
- Init() is about 100 times faster than InitForData(). */
- const size_t kMaxBytesForPartialHashInit = HASH_MAP_SIZE >> 7;
- BROTLI_UNUSED(m);
- BROTLI_UNUSED(params);
- if (position == 0 && is_last && bytes <= kMaxBytesForPartialHashInit) {
- FN(InitForData)(self, data, bytes);
- } else {
- FN(InitEmpty)(self);
- }
-}
-
-/* Look at 4 bytes at &data[ix & mask].
- Compute a hash from these, and store the value of ix at that position. */
-static BROTLI_INLINE void FN(Store)(HashLongestMatch* self, const uint8_t *data,
- const size_t mask, const size_t ix) {
- const uint32_t key = FN(HashBytes)(&data[ix & mask]);
- const size_t minor_ix = self->num_[key] & BLOCK_MASK;
- self->buckets_[minor_ix + (key << BLOCK_BITS)] = (uint32_t)ix;
- ++self->num_[key];
-}
-
-static BROTLI_INLINE void FN(StoreRange)(HashLongestMatch* self,
- const uint8_t *data, const size_t mask, const size_t ix_start,
- const size_t ix_end) {
- size_t i;
- for (i = ix_start; i < ix_end; ++i) {
- FN(Store)(self, data, mask, i);
- }
-}
-
-static BROTLI_INLINE void FN(StitchToPreviousBlock)(HashLongestMatch* self,
- size_t num_bytes, size_t position, const uint8_t* ringbuffer,
- size_t ringbuffer_mask) {
- if (num_bytes >= FN(HashTypeLength)() - 1 && position >= 3) {
- /* Prepare the hashes for three last bytes of the last write.
- These could not be calculated before, since they require knowledge
- of both the previous and the current block. */
- FN(Store)(self, ringbuffer, ringbuffer_mask, position - 3);
- FN(Store)(self, ringbuffer, ringbuffer_mask, position - 2);
- FN(Store)(self, ringbuffer, ringbuffer_mask, position - 1);
- }
-}
-
-/* Find a longest backward match of &data[cur_ix] up to the length of
- max_length and stores the position cur_ix in the hash table.
-
- Does not look for matches longer than max_length.
- Does not look for matches further away than max_backward.
- Writes the best match into |out|.
- Returns true when match is found, otherwise false. */
-static BROTLI_INLINE BROTLI_BOOL FN(FindLongestMatch)(HashLongestMatch* self,
- const uint8_t* BROTLI_RESTRICT data, const size_t ring_buffer_mask,
- const int* BROTLI_RESTRICT distance_cache, const size_t cur_ix,
- const size_t max_length, const size_t max_backward,
- HasherSearchResult* BROTLI_RESTRICT out) {
- const size_t cur_ix_masked = cur_ix & ring_buffer_mask;
- BROTLI_BOOL is_match_found = BROTLI_FALSE;
- /* Don't accept a short copy from far away. */
- score_t best_score = out->score;
- size_t best_len = out->len;
- size_t i;
- out->len = 0;
- out->len_x_code = 0;
- /* Try last distance first. */
- for (i = 0; i < NUM_LAST_DISTANCES_TO_CHECK; ++i) {
- const size_t idx = kDistanceCacheIndex[i];
- const size_t backward =
- (size_t)(distance_cache[idx] + kDistanceCacheOffset[i]);
- size_t prev_ix = (size_t)(cur_ix - backward);
- if (prev_ix >= cur_ix) {
- continue;
- }
- if (PREDICT_FALSE(backward > max_backward)) {
- continue;
- }
- prev_ix &= ring_buffer_mask;
-
- if (cur_ix_masked + best_len > ring_buffer_mask ||
- prev_ix + best_len > ring_buffer_mask ||
- data[cur_ix_masked + best_len] != data[prev_ix + best_len]) {
- continue;
- }
- {
- const size_t len = FindMatchLengthWithLimit(&data[prev_ix],
- &data[cur_ix_masked],
- max_length);
- if (len >= 3 || (len == 2 && i < 2)) {
- /* Comparing for >= 2 does not change the semantics, but just saves for
- a few unnecessary binary logarithms in backward reference score,
- since we are not interested in such short matches. */
- score_t score = BackwardReferenceScoreUsingLastDistance(len, i);
- if (best_score < score) {
- best_score = score;
- best_len = len;
- out->len = best_len;
- out->distance = backward;
- out->score = best_score;
- is_match_found = BROTLI_TRUE;
- }
- }
- }
- }
- {
- const uint32_t key = FN(HashBytes)(&data[cur_ix_masked]);
- uint32_t* BROTLI_RESTRICT bucket = &self->buckets_[key << BLOCK_BITS];
- const size_t down =
- (self->num_[key] > BLOCK_SIZE) ? (self->num_[key] - BLOCK_SIZE) : 0u;
- for (i = self->num_[key]; i > down;) {
- size_t prev_ix = bucket[--i & BLOCK_MASK];
- const size_t backward = cur_ix - prev_ix;
- if (PREDICT_FALSE(backward > max_backward)) {
- break;
- }
- prev_ix &= ring_buffer_mask;
- if (cur_ix_masked + best_len > ring_buffer_mask ||
- prev_ix + best_len > ring_buffer_mask ||
- data[cur_ix_masked + best_len] != data[prev_ix + best_len]) {
- continue;
- }
- {
- const size_t len = FindMatchLengthWithLimit(&data[prev_ix],
- &data[cur_ix_masked],
- max_length);
- if (len >= 4) {
- /* Comparing for >= 3 does not change the semantics, but just saves
- for a few unnecessary binary logarithms in backward reference
- score, since we are not interested in such short matches. */
- score_t score = BackwardReferenceScore(len, backward);
- if (best_score < score) {
- best_score = score;
- best_len = len;
- out->len = best_len;
- out->distance = backward;
- out->score = best_score;
- is_match_found = BROTLI_TRUE;
- }
- }
- }
- }
- bucket[self->num_[key] & BLOCK_MASK] = (uint32_t)cur_ix;
- ++self->num_[key];
- }
- if (!is_match_found) {
- is_match_found = SearchInStaticDictionary(&self->dict_search_stats_,
- &data[cur_ix_masked], max_length, max_backward, out, BROTLI_FALSE);
- }
- return is_match_found;
-}
-
-#undef HASH_MAP_SIZE
-#undef BLOCK_MASK
-#undef BLOCK_SIZE
-#undef BUCKET_SIZE
-
-#undef HashLongestMatch
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