summaryrefslogtreecommitdiff
path: root/deps/node/deps/brotli/c/enc/hash_longest_match_quickly_inc.h
diff options
context:
space:
mode:
Diffstat (limited to 'deps/node/deps/brotli/c/enc/hash_longest_match_quickly_inc.h')
-rw-r--r--deps/node/deps/brotli/c/enc/hash_longest_match_quickly_inc.h235
1 files changed, 0 insertions, 235 deletions
diff --git a/deps/node/deps/brotli/c/enc/hash_longest_match_quickly_inc.h b/deps/node/deps/brotli/c/enc/hash_longest_match_quickly_inc.h
deleted file mode 100644
index a7b9639f..00000000
--- a/deps/node/deps/brotli/c/enc/hash_longest_match_quickly_inc.h
+++ /dev/null
@@ -1,235 +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, BUCKET_SWEEP, HASH_LEN,
- USE_DICTIONARY
- */
-
-#define HashLongestMatchQuickly HASHER()
-
-#define BUCKET_SIZE (1 << BUCKET_BITS)
-
-#define HASH_MAP_SIZE (4 << BUCKET_BITS)
-
-static BROTLI_INLINE size_t FN(HashTypeLength)(void) { return 8; }
-static BROTLI_INLINE size_t FN(StoreLookahead)(void) { return 8; }
-
-/* 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) {
- const uint64_t h = ((BROTLI_UNALIGNED_LOAD64LE(data) << (64 - 8 * HASH_LEN)) *
- kHashMul64);
- /* The higher bits contain more mixture from the multiplication,
- so we take our results from there. */
- return (uint32_t)(h >> (64 - BUCKET_BITS));
-}
-
-/* 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). Starting from the
- given index, BUCKET_SWEEP buckets are used to store values of a key. */
-typedef struct HashLongestMatchQuickly {
- uint32_t buckets_[BUCKET_SIZE + BUCKET_SWEEP];
-} HashLongestMatchQuickly;
-
-static BROTLI_INLINE HashLongestMatchQuickly* FN(Self)(HasherHandle handle) {
- return (HashLongestMatchQuickly*)&(GetHasherCommon(handle)[1]);
-}
-
-static void FN(Initialize)(
- HasherHandle handle, const BrotliEncoderParams* params) {
- BROTLI_UNUSED(handle);
- BROTLI_UNUSED(params);
-}
-
-static void FN(Prepare)(HasherHandle handle, BROTLI_BOOL one_shot,
- size_t input_size, const uint8_t* data) {
- HashLongestMatchQuickly* self = FN(Self)(handle);
- /* Partial preparation is 100 times slower (per socket). */
- size_t partial_prepare_threshold = HASH_MAP_SIZE >> 7;
- if (one_shot && input_size <= partial_prepare_threshold) {
- size_t i;
- for (i = 0; i < input_size; ++i) {
- const uint32_t key = FN(HashBytes)(&data[i]);
- memset(&self->buckets_[key], 0, BUCKET_SWEEP * sizeof(self->buckets_[0]));
- }
- } else {
- /* It is not strictly necessary to fill this buffer here, but
- not filling will make the results of the compression stochastic
- (but correct). This is because random data would cause the
- system to find accidentally good backward references here and there. */
- memset(&self->buckets_[0], 0, sizeof(self->buckets_));
- }
-}
-
-static BROTLI_INLINE size_t FN(HashMemAllocInBytes)(
- const BrotliEncoderParams* params, BROTLI_BOOL one_shot,
- size_t input_size) {
- BROTLI_UNUSED(params);
- BROTLI_UNUSED(one_shot);
- BROTLI_UNUSED(input_size);
- return sizeof(HashLongestMatchQuickly);
-}
-
-/* Look at 5 bytes at &data[ix & mask].
- Compute a hash from these, and store the value somewhere within
- [ix .. ix+3]. */
-static BROTLI_INLINE void FN(Store)(HasherHandle handle,
- const uint8_t* data, const size_t mask, const size_t ix) {
- const uint32_t key = FN(HashBytes)(&data[ix & mask]);
- /* Wiggle the value with the bucket sweep range. */
- const uint32_t off = (ix >> 3) % BUCKET_SWEEP;
- FN(Self)(handle)->buckets_[key + off] = (uint32_t)ix;
-}
-
-static BROTLI_INLINE void FN(StoreRange)(HasherHandle handle,
- 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)(handle, data, mask, i);
- }
-}
-
-static BROTLI_INLINE void FN(StitchToPreviousBlock)(
- HasherHandle handle, 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)(handle, ringbuffer, ringbuffer_mask, position - 3);
- FN(Store)(handle, ringbuffer, ringbuffer_mask, position - 2);
- FN(Store)(handle, ringbuffer, ringbuffer_mask, position - 1);
- }
-}
-
-static BROTLI_INLINE void FN(PrepareDistanceCache)(
- HasherHandle handle, int* BROTLI_RESTRICT distance_cache) {
- BROTLI_UNUSED(handle);
- BROTLI_UNUSED(distance_cache);
-}
-
-/* Find a longest backward match of &data[cur_ix & ring_buffer_mask]
- 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|.
- |out|->score is updated only if a better match is found. */
-static BROTLI_INLINE void FN(FindLongestMatch)(
- HasherHandle handle, const BrotliEncoderDictionary* dictionary,
- 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,
- const size_t gap, const size_t max_distance,
- HasherSearchResult* BROTLI_RESTRICT out) {
- HashLongestMatchQuickly* self = FN(Self)(handle);
- const size_t best_len_in = out->len;
- const size_t cur_ix_masked = cur_ix & ring_buffer_mask;
- const uint32_t key = FN(HashBytes)(&data[cur_ix_masked]);
- int compare_char = data[cur_ix_masked + best_len_in];
- score_t min_score = out->score;
- score_t best_score = out->score;
- size_t best_len = best_len_in;
- size_t cached_backward = (size_t)distance_cache[0];
- size_t prev_ix = cur_ix - cached_backward;
- out->len_code_delta = 0;
- if (prev_ix < cur_ix) {
- prev_ix &= (uint32_t)ring_buffer_mask;
- if (compare_char == data[prev_ix + best_len]) {
- size_t len = FindMatchLengthWithLimit(&data[prev_ix],
- &data[cur_ix_masked],
- max_length);
- if (len >= 4) {
- const score_t score = BackwardReferenceScoreUsingLastDistance(len);
- if (best_score < score) {
- best_score = score;
- best_len = len;
- out->len = len;
- out->distance = cached_backward;
- out->score = best_score;
- compare_char = data[cur_ix_masked + best_len];
- if (BUCKET_SWEEP == 1) {
- self->buckets_[key] = (uint32_t)cur_ix;
- return;
- }
- }
- }
- }
- }
- if (BUCKET_SWEEP == 1) {
- size_t backward;
- size_t len;
- /* Only one to look for, don't bother to prepare for a loop. */
- prev_ix = self->buckets_[key];
- self->buckets_[key] = (uint32_t)cur_ix;
- backward = cur_ix - prev_ix;
- prev_ix &= (uint32_t)ring_buffer_mask;
- if (compare_char != data[prev_ix + best_len_in]) {
- return;
- }
- if (BROTLI_PREDICT_FALSE(backward == 0 || backward > max_backward)) {
- return;
- }
- len = FindMatchLengthWithLimit(&data[prev_ix],
- &data[cur_ix_masked],
- max_length);
- if (len >= 4) {
- const score_t score = BackwardReferenceScore(len, backward);
- if (best_score < score) {
- out->len = len;
- out->distance = backward;
- out->score = score;
- return;
- }
- }
- } else {
- uint32_t* bucket = self->buckets_ + key;
- int i;
- prev_ix = *bucket++;
- for (i = 0; i < BUCKET_SWEEP; ++i, prev_ix = *bucket++) {
- const size_t backward = cur_ix - prev_ix;
- size_t len;
- prev_ix &= (uint32_t)ring_buffer_mask;
- if (compare_char != data[prev_ix + best_len]) {
- continue;
- }
- if (BROTLI_PREDICT_FALSE(backward == 0 || backward > max_backward)) {
- continue;
- }
- len = FindMatchLengthWithLimit(&data[prev_ix],
- &data[cur_ix_masked],
- max_length);
- if (len >= 4) {
- const 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 = score;
- compare_char = data[cur_ix_masked + best_len];
- }
- }
- }
- }
- if (USE_DICTIONARY && min_score == out->score) {
- SearchInStaticDictionary(dictionary,
- handle, &data[cur_ix_masked], max_length, max_backward + gap,
- max_distance, out, BROTLI_TRUE);
- }
- self->buckets_[key + ((cur_ix >> 3) % BUCKET_SWEEP)] = (uint32_t)cur_ix;
-}
-
-#undef HASH_MAP_SIZE
-#undef BUCKET_SIZE
-
-#undef HashLongestMatchQuickly
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-26 01:16:50 +0000