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Diffstat (limited to 'deps/node/deps/brotli/c/enc/hash_longest_match64_inc.h')
| -rw-r--r-- | deps/node/deps/brotli/c/enc/hash_longest_match64_inc.h | 267 |
1 files changed, 0 insertions, 267 deletions
diff --git a/deps/node/deps/brotli/c/enc/hash_longest_match64_inc.h b/deps/node/deps/brotli/c/enc/hash_longest_match64_inc.h deleted file mode 100644 index cb953a64..00000000 --- a/deps/node/deps/brotli/c/enc/hash_longest_match64_inc.h +++ /dev/null @@ -1,267 +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 */ - -/* 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() - -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. */ -static BROTLI_INLINE uint32_t FN(HashBytes)(const uint8_t* data, - const uint64_t mask, - const int shift) { - const uint64_t h = (BROTLI_UNALIGNED_LOAD64LE(data) & mask) * kHashMul64Long; - /* The higher bits contain more mixture from the multiplication, - so we take our results from there. */ - return (uint32_t)(h >> shift); -} - -typedef struct HashLongestMatch { - /* Number of hash buckets. */ - size_t bucket_size_; - /* Only block_size_ newest backward references are kept, - and the older are forgotten. */ - size_t block_size_; - /* Left-shift for computing hash bucket index from hash value. */ - int hash_shift_; - /* Mask for selecting the next 4-8 bytes of input */ - uint64_t hash_mask_; - /* Mask for accessing entries in a block (in a ring-buffer manner). */ - uint32_t block_mask_; - - /* --- Dynamic size members --- */ - - /* Number of entries in a particular bucket. */ - /* uint16_t num[bucket_size]; */ - - /* Buckets containing block_size_ of backward references. */ - /* uint32_t* buckets[bucket_size * block_size]; */ -} HashLongestMatch; - -static BROTLI_INLINE HashLongestMatch* FN(Self)(HasherHandle handle) { - return (HashLongestMatch*)&(GetHasherCommon(handle)[1]); -} - -static BROTLI_INLINE uint16_t* FN(Num)(HashLongestMatch* self) { - return (uint16_t*)(&self[1]); -} - -static BROTLI_INLINE uint32_t* FN(Buckets)(HashLongestMatch* self) { - return (uint32_t*)(&FN(Num)(self)[self->bucket_size_]); -} - -static void FN(Initialize)( - HasherHandle handle, const BrotliEncoderParams* params) { - HasherCommon* common = GetHasherCommon(handle); - HashLongestMatch* self = FN(Self)(handle); - BROTLI_UNUSED(params); - self->hash_shift_ = 64 - common->params.bucket_bits; - self->hash_mask_ = (~((uint64_t)0U)) >> (64 - 8 * common->params.hash_len); - self->bucket_size_ = (size_t)1 << common->params.bucket_bits; - self->block_size_ = (size_t)1 << common->params.block_bits; - self->block_mask_ = (uint32_t)(self->block_size_ - 1); -} - -static void FN(Prepare)(HasherHandle handle, BROTLI_BOOL one_shot, - size_t input_size, const uint8_t* data) { - HashLongestMatch* self = FN(Self)(handle); - uint16_t* num = FN(Num)(self); - /* Partial preparation is 100 times slower (per socket). */ - size_t partial_prepare_threshold = self->bucket_size_ >> 6; - 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], self->hash_mask_, - self->hash_shift_); - num[key] = 0; - } - } else { - memset(num, 0, self->bucket_size_ * sizeof(num[0])); - } -} - -static BROTLI_INLINE size_t FN(HashMemAllocInBytes)( - const BrotliEncoderParams* params, BROTLI_BOOL one_shot, - size_t input_size) { - size_t bucket_size = (size_t)1 << params->hasher.bucket_bits; - size_t block_size = (size_t)1 << params->hasher.block_bits; - BROTLI_UNUSED(one_shot); - BROTLI_UNUSED(input_size); - return sizeof(HashLongestMatch) + bucket_size * (2 + 4 * block_size); -} - -/* 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)(HasherHandle handle, const uint8_t* data, - const size_t mask, const size_t ix) { - HashLongestMatch* self = FN(Self)(handle); - uint16_t* num = FN(Num)(self); - const uint32_t key = FN(HashBytes)(&data[ix & mask], self->hash_mask_, - self->hash_shift_); - const size_t minor_ix = num[key] & self->block_mask_; - const size_t offset = - minor_ix + (key << GetHasherCommon(handle)->params.block_bits); - FN(Buckets)(self)[offset] = (uint32_t)ix; - ++num[key]; -} - -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) { - PrepareDistanceCache(distance_cache, - GetHasherCommon(handle)->params.num_last_distances_to_check); -} - -/* 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. - - REQUIRES: FN(PrepareDistanceCache) must be invoked for current distance cache - values; if this method is invoked repeatedly with the same distance - cache values, it is enough to invoke FN(PrepareDistanceCache) once. - - 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) { - HasherCommon* common = GetHasherCommon(handle); - HashLongestMatch* self = FN(Self)(handle); - uint16_t* num = FN(Num)(self); - uint32_t* buckets = FN(Buckets)(self); - const size_t cur_ix_masked = cur_ix & ring_buffer_mask; - /* Don't accept a short copy from far away. */ - score_t min_score = out->score; - score_t best_score = out->score; - size_t best_len = out->len; - size_t i; - out->len = 0; - out->len_code_delta = 0; - /* Try last distance first. */ - for (i = 0; i < (size_t)common->params.num_last_distances_to_check; ++i) { - const size_t backward = (size_t)distance_cache[i]; - size_t prev_ix = (size_t)(cur_ix - backward); - if (prev_ix >= cur_ix) { - continue; - } - if (BROTLI_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); - if (best_score < score) { - if (i != 0) score -= BackwardReferencePenaltyUsingLastDistance(i); - if (best_score < score) { - best_score = score; - best_len = len; - out->len = best_len; - out->distance = backward; - out->score = best_score; - } - } - } - } - } - { - const uint32_t key = FN(HashBytes)( - &data[cur_ix_masked], self->hash_mask_, self->hash_shift_); - uint32_t* BROTLI_RESTRICT bucket = - &buckets[key << common->params.block_bits]; - const size_t down = - (num[key] > self->block_size_) ? - (num[key] - self->block_size_) : 0u; - for (i = num[key]; i > down;) { - size_t prev_ix = bucket[--i & self->block_mask_]; - const size_t backward = cur_ix - prev_ix; - if (BROTLI_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; - } - } - } - } - bucket[num[key] & self->block_mask_] = (uint32_t)cur_ix; - ++num[key]; - } - if (min_score == out->score) { - SearchInStaticDictionary(dictionary, - handle, &data[cur_ix_masked], max_length, max_backward + gap, - max_distance, out, BROTLI_FALSE); - } -} - -#undef HashLongestMatch |