diff options
Diffstat (limited to 'c/enc/hash_longest_match_simd_inc.h')
-rw-r--r-- | c/enc/hash_longest_match_simd_inc.h | 274 |
1 files changed, 0 insertions, 274 deletions
diff --git a/c/enc/hash_longest_match_simd_inc.h b/c/enc/hash_longest_match_simd_inc.h deleted file mode 100644 index 2bf9b6c..0000000 --- a/c/enc/hash_longest_match_simd_inc.h +++ /dev/null @@ -1,274 +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() -#define TAG_HASH_BITS 8 -#define TAG_HASH_MASK ((1 << TAG_HASH_BITS) - 1) -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. */ -static uint32_t FN(HashBytes)( - const uint8_t* BROTLI_RESTRICT data, const int shift) { - uint32_t h = BROTLI_UNALIGNED_LOAD32LE(data) * kHashMul32; - /* 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 accessing entries in a block (in a ring-buffer manner). */ - uint32_t block_mask_; - int block_bits_; - int num_last_distances_to_check_; - /* Shortcuts. */ - HasherCommon* common_; - /* --- Dynamic size members --- */ - /* Number of entries in a particular bucket. */ - uint16_t* num_; /* uint16_t[bucket_size]; */ - uint8_t* tags_; - /* Buckets containing block_size_ of backward references. */ - uint32_t* buckets_; /* uint32_t[bucket_size * block_size]; */ -} HashLongestMatch; -static void FN(Initialize)( - HasherCommon* common, HashLongestMatch* BROTLI_RESTRICT self, - const BrotliEncoderParams* params) { - self->common_ = common; - BROTLI_UNUSED(params); - self->hash_shift_ = 32 - common->params.bucket_bits - TAG_HASH_BITS; - 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); - self->num_ = (uint16_t*)common->extra[0]; - self->tags_ = (uint8_t*)common->extra[1]; - self->buckets_ = (uint32_t*)common->extra[2]; - self->block_bits_ = common->params.block_bits; - self->num_last_distances_to_check_ = - common->params.num_last_distances_to_check; -} -static void FN(Prepare)( - HashLongestMatch* BROTLI_RESTRICT self, BROTLI_BOOL one_shot, - size_t input_size, const uint8_t* BROTLI_RESTRICT data) { - uint16_t* BROTLI_RESTRICT num = self->num_; - /* 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 hash = FN(HashBytes)(&data[i], self->hash_shift_); - const uint32_t key = hash >> TAG_HASH_BITS; - num[key] = 65535; - } - } else { - /* Set all the bytes of num to 255, which makes each uint16_t 65535. */ - memset(num, 255, self->bucket_size_ * sizeof(num[0])); - } -} -static BROTLI_INLINE void FN(HashMemAllocInBytes)( - const BrotliEncoderParams* params, BROTLI_BOOL one_shot, - size_t input_size, size_t* alloc_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); - alloc_size[0] = sizeof(uint16_t) * bucket_size; - alloc_size[1] = sizeof(uint8_t) * bucket_size * block_size; - alloc_size[2] = sizeof(uint32_t) * bucket_size * 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)( - HashLongestMatch* BROTLI_RESTRICT self, const uint8_t* BROTLI_RESTRICT data, - const size_t mask, const size_t ix) { - uint16_t* BROTLI_RESTRICT num = self->num_; - uint8_t* BROTLI_RESTRICT tags = self->tags_; - uint32_t* BROTLI_RESTRICT buckets = self->buckets_; - const size_t hash = FN(HashBytes)(&data[ix & mask], self->hash_shift_); - const size_t key = hash >> TAG_HASH_BITS; - const uint8_t tag = hash & TAG_HASH_MASK; - const size_t minor_ix = num[key] & self->block_mask_; - const size_t offset = minor_ix + (key << self->block_bits_); - --num[key]; - buckets[offset] = (uint32_t)ix; - tags[offset] = tag; -} -static BROTLI_INLINE void FN(StoreRange)(HashLongestMatch* BROTLI_RESTRICT self, - const uint8_t* BROTLI_RESTRICT 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* BROTLI_RESTRICT 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); - } -} -static BROTLI_INLINE void FN(PrepareDistanceCache)( - HashLongestMatch* BROTLI_RESTRICT self, - int* BROTLI_RESTRICT distance_cache) { - PrepareDistanceCache(distance_cache, self->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)( - HashLongestMatch* BROTLI_RESTRICT self, - 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 dictionary_distance, const size_t max_distance, - HasherSearchResult* BROTLI_RESTRICT out) { - uint16_t* BROTLI_RESTRICT num = self->num_; - uint32_t* BROTLI_RESTRICT buckets = self->buckets_; - uint8_t* BROTLI_RESTRICT tags = self->tags_; - 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; - /* Precalculate the hash key and prefetch the bucket. */ - const uint32_t hash = - FN(HashBytes)(&data[cur_ix_masked], self->hash_shift_); - const uint32_t key = hash >> TAG_HASH_BITS; - uint32_t* BROTLI_RESTRICT bucket = &buckets[key << self->block_bits_]; - uint8_t* BROTLI_RESTRICT tag_bucket = &tags[key << self->block_bits_]; - PREFETCH_L1(bucket); - PREFETCH_L1(tag_bucket); - if (self->block_bits_ > 4) PREFETCH_L1(bucket + 16); - out->len = 0; - out->len_code_delta = 0; - - BROTLI_DCHECK(cur_ix_masked + max_length <= ring_buffer_mask); - - /* Try last distance first. */ - for (i = 0; i < (size_t)self->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; - } - } - } - } - } - /* we require matches of len >4, so increase best_len to 3, so we can compare - * 4 bytes all the time. */ - if (best_len < 3) { - best_len = 3; - } - { - const uint8_t tag = hash & TAG_HASH_MASK; - const size_t head = (num[key] + 1) & self->block_mask_; - uint64_t matches = - GetMatchingTagMask(self->block_size_ / 16, tag, tag_bucket, head); - /* Mask off any matches from uninitialized tags. */ - uint16_t n = 65535 - num[key]; - uint64_t block_has_unused_slots = self->block_size_ > n; - uint64_t mask = (block_has_unused_slots << (n & (64 - 1))) - 1; - matches &= mask; - for (; matches > 0; matches &= (matches - 1)) { - const size_t rb_index = - (head + (size_t)BROTLI_TZCNT64(matches)) & self->block_mask_; - size_t prev_ix = bucket[rb_index]; - 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 || - /* compare 4 bytes ending at best_len + 1 */ - BrotliUnalignedRead32(&data[cur_ix_masked + best_len - 3]) != - BrotliUnalignedRead32(&data[prev_ix + best_len - 3])) { - 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; - tag_bucket[num[key] & self->block_mask_] = tag; - --num[key]; - } - if (min_score == out->score) { - SearchInStaticDictionary(dictionary, - self->common_, &data[cur_ix_masked], max_length, dictionary_distance, - max_distance, out, BROTLI_FALSE); - } -} -#undef HashLongestMatch |