aboutsummaryrefslogtreecommitdiff
path: root/c/enc/hash_longest_match64_simd_inc.h
diff options
context:
space:
mode:
Diffstat (limited to 'c/enc/hash_longest_match64_simd_inc.h')
-rw-r--r--c/enc/hash_longest_match64_simd_inc.h300
1 files changed, 0 insertions, 300 deletions
diff --git a/c/enc/hash_longest_match64_simd_inc.h b/c/enc/hash_longest_match64_simd_inc.h
deleted file mode 100644
index cd4e7b1..0000000
--- a/c/enc/hash_longest_match64_simd_inc.h
+++ /dev/null
@@ -1,300 +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 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 size_t FN(HashBytes)(const uint8_t* BROTLI_RESTRICT data,
- uint64_t hash_mul) {
- const uint64_t h = BROTLI_UNALIGNED_LOAD64LE(data) * hash_mul;
- /* The higher bits contain more mixture from the multiplication,
- so we take our results from there. */
- return (size_t)(h >> (64 - 15 - TAG_HASH_BITS));
-}
-
-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_;
- /* Hash multiplier tuned to match length. */
- uint64_t hash_mul_;
- /* 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_mul_ = kHashMul64 << (64 - 5 * 8);
- BROTLI_DCHECK(common->params.bucket_bits == 15);
- self->bucket_size_ = (size_t)1 << common->params.bucket_bits;
- self->block_bits_ = common->params.block_bits;
- self->block_size_ = (size_t)1 << common->params.block_bits;
- self->block_mask_ = (uint32_t)(self->block_size_ - 1);
- self->num_last_distances_to_check_ =
- common->params.num_last_distances_to_check;
- self->num_ = (uint16_t*)common->extra[0];
- self->tags_ = (uint8_t*)common->extra[1];
- self->buckets_ = (uint32_t*)common->extra[2];
-}
-
-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 size_t hash = FN(HashBytes)(&data[i], self->hash_mul_);
- const size_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_mul_);
- 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 size_t hash = FN(HashBytes)(&data[cur_ix_masked], self->hash_mul_);
- const size_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 uint32_t first4 = BrotliUnalignedRead32(data + cur_ix_masked);
- const size_t max_length_m4 = max_length - 4;
- 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];
- uint32_t current4;
- 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;
- }
- current4 = BrotliUnalignedRead32(data + prev_ix);
- if (first4 != current4) continue;
- {
- const size_t len = FindMatchLengthWithLimit(&data[prev_ix + 4],
- &data[cur_ix_masked + 4],
- max_length_m4) + 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 = 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
generated by cgit v1.1 at 2024-06-28 13:01:01 +0000