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Use a hash table header and SIMD to speed up hash table operations (similar to [Swiss Tables](https://abseil.io/about/design/swisstables)).

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PiperOrigin-RevId: 632238409
This commit is contained in:
Brotli 2024-05-09 12:41:57 -07:00 committed by Copybara-Service
parent bb809ac908
commit 04388304a6
7 changed files with 7 additions and 729 deletions
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29
c/common/platform.h
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@ -282,11 +282,6 @@ static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
memcpy(&t, p, sizeof t);
return t;
}
static BROTLI_INLINE size_t BrotliUnalignedReadSizeT(const void* p) {
size_t t;
memcpy(&t, p, sizeof t);
return t;
}
static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
memcpy(p, &v, sizeof v);
}
@ -494,23 +489,6 @@ BROTLI_COMMON_API void* BrotliDefaultAllocFunc(void* opaque, size_t size);
/* Default brotli_free_func */
BROTLI_COMMON_API void BrotliDefaultFreeFunc(void* opaque, void* address);
/* Circular logical rotates. */
static BROTLI_INLINE uint16_t BrotliRotateRight16(uint16_t const value,
size_t count) {
count &= 0x0F; /* for fickle pattern recognition */
return (value >> count) | (uint16_t)(value << ((0U - count) & 0x0F));
}
static BROTLI_INLINE uint32_t BrotliRotateRight32(uint32_t const value,
size_t count) {
count &= 0x1F; /* for fickle pattern recognition */
return (value >> count) | (uint32_t)(value << ((0U - count) & 0x1F));
}
static BROTLI_INLINE uint64_t BrotliRotateRight64(uint64_t const value,
size_t count) {
count &= 0x3F; /* for fickle pattern recognition */
return (value >> count) | (uint64_t)(value << ((0U - count) & 0x3F));
}
BROTLI_UNUSED_FUNCTION void BrotliSuppressUnusedFunctions(void) {
BROTLI_UNUSED(&BrotliSuppressUnusedFunctions);
BROTLI_UNUSED(&BrotliUnalignedRead16);
@ -556,13 +534,6 @@ BROTLI_UNUSED_FUNCTION void BrotliSuppressUnusedFunctions(void) {
# define PREFETCH_L1(ptr) do { (void)(ptr); } while (0) /* disabled */
# define PREFETCH_L2(ptr) do { (void)(ptr); } while (0) /* disabled */
#endif
/* The SIMD matchers are only faster at certain quality levels. */
#if defined(_M_X64) && defined(BROTLI_TZCNT64)
#define BROTLI_MAX_SIMD_QUALITY 7
#elif defined(BROTLI_TZCNT64)
#define BROTLI_MAX_SIMD_QUALITY 6
#endif
}
#endif /* BROTLI_COMMON_PLATFORM_H_ */

26
c/enc/backward_references.c
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@ -116,18 +116,6 @@ static BROTLI_INLINE size_t ComputeDistanceCode(size_t distance,
#include "backward_references_inc.h"
#undef HASHER
#if defined(BROTLI_MAX_SIMD_QUALITY)
#define HASHER() H58
/* NOLINTNEXTLINE(build/include) */
#include "backward_references_inc.h"
#undef HASHER
#define HASHER() H68
/* NOLINTNEXTLINE(build/include) */
#include "backward_references_inc.h"
#undef HASHER
#endif
#undef ENABLE_COMPOUND_DICTIONARY
#undef PREFIX
#define PREFIX() D
@ -161,16 +149,6 @@ static BROTLI_INLINE size_t ComputeDistanceCode(size_t distance,
/* NOLINTNEXTLINE(build/include) */
#include "backward_references_inc.h"
#undef HASHER
#if defined(BROTLI_MAX_SIMD_QUALITY)
#define HASHER() H58
/* NOLINTNEXTLINE(build/include) */
#include "backward_references_inc.h"
#undef HASHER
#define HASHER() H68
/* NOLINTNEXTLINE(build/include) */
#include "backward_references_inc.h"
#undef HASHER
#endif
#undef ENABLE_COMPOUND_DICTIONARY
#undef PREFIX
@ -196,10 +174,6 @@ void BrotliCreateBackwardReferences(size_t num_bytes,
return;
CASE_(5)
CASE_(6)
#if defined(BROTLI_MAX_SIMD_QUALITY)
CASE_(58)
CASE_(68)
#endif
CASE_(40)
CASE_(41)
CASE_(42)

19
c/enc/hash.h
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@ -22,7 +22,6 @@
#include "encoder_dict.h"
#include "fast_log.h"
#include "find_match_length.h"
#include "matching_tag_mask.h"
#include "memory.h"
#include "quality.h"
#include "static_dict.h"
@ -298,16 +297,6 @@ static BROTLI_INLINE size_t BackwardMatchLengthCode(const BackwardMatch* self) {
#include "hash_longest_match64_inc.h" /* NOLINT(build/include) */
#undef HASHER
#if defined(BROTLI_MAX_SIMD_QUALITY)
#define HASHER() H58
#include "hash_longest_match_simd_inc.h" /* NOLINT(build/include) */
#undef HASHER
#define HASHER() H68
#include "hash_longest_match64_simd_inc.h" /* NOLINT(build/include) */
#undef HASHER
#endif
#define BUCKET_BITS 15
#define NUM_LAST_DISTANCES_TO_CHECK 4
@ -399,13 +388,7 @@ static BROTLI_INLINE size_t BackwardMatchLengthCode(const BackwardMatch* self) {
#undef CAT
#undef EXPAND_CAT
#if defined(BROTLI_MAX_SIMD_QUALITY)
#define FOR_SIMPLE_HASHERS(H) \
H(2) H(3) H(4) H(5) H(6) H(40) H(41) H(42) H(54) H(58) H(68)
#else
#define FOR_SIMPLE_HASHERS(H) \
H(2) H(3) H(4) H(5) H(6) H(40) H(41) H(42) H(54)
#endif
#define FOR_SIMPLE_HASHERS(H) H(2) H(3) H(4) H(5) H(6) H(40) H(41) H(42) H(54)
#define FOR_COMPOSITE_HASHERS(H) H(35) H(55) H(65)
#define FOR_GENERIC_HASHERS(H) FOR_SIMPLE_HASHERS(H) FOR_COMPOSITE_HASHERS(H)
#define FOR_ALL_HASHERS(H) FOR_GENERIC_HASHERS(H) H(10)

300
c/enc/hash_longest_match64_simd_inc.h
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@ -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

274
c/enc/hash_longest_match_simd_inc.h
View File

@ -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

68
c/enc/matching_tag_mask.h
View File

@ -1,68 +0,0 @@
#ifndef THIRD_PARTY_BROTLI_ENC_MATCHING_TAG_MASK_H_
#define THIRD_PARTY_BROTLI_ENC_MATCHING_TAG_MASK_H_
#include "../common/platform.h"
#if defined(__SSE2__) || defined(_M_AMD64) || (defined (_M_IX86) && defined(_M_IX86_FP) && (_M_IX86_FP >= 2))
#define SUPPORTS_SSE_2
#endif
#if defined(SUPPORTS_SSE_2)
#include <immintrin.h>
#endif
static BROTLI_INLINE uint64_t GetMatchingTagMask(
size_t chunk_count, const uint8_t tag,
const uint8_t* BROTLI_RESTRICT tag_bucket, const size_t head) {
uint64_t matches = 0;
#if defined(SUPPORTS_SSE_2)
const __m128i comparison_mask = _mm_set1_epi8((char)tag);
size_t i;
for (i = 0; i < chunk_count && i < 4; i++) {
const __m128i chunk =
_mm_loadu_si128((const __m128i*)(const void*)(tag_bucket + 16 * i));
const __m128i equal_mask = _mm_cmpeq_epi8(chunk, comparison_mask);
matches |= (uint64_t)_mm_movemask_epi8(equal_mask) << 16 * i;
}
#else
const int chunk_size = sizeof(size_t);
const size_t shift_amount = ((chunk_size * 8) - chunk_size);
const size_t xFF = ~((size_t)0);
const size_t x01 = xFF / 0xFF;
const size_t x80 = x01 << 7;
const size_t splat_char = tag * x01;
int i = ((int)chunk_count * 16) - chunk_size;
BROTLI_DCHECK((sizeof(size_t) == 4) || (sizeof(size_t) == 8));
#if BROTLI_LITTLE_ENDIAN
const size_t extractMagic = (xFF / 0x7F) >> chunk_size;
do {
size_t chunk = BrotliUnalignedReadSizeT(&tag_bucket[i]);
chunk ^= splat_char;
chunk = (((chunk | x80) - x01) | chunk) & x80;
matches <<= chunk_size;
matches |= (chunk * extractMagic) >> shift_amount;
i -= chunk_size;
} while (i >= 0);
#else
const size_t msb = xFF ^ (xFF >> 1);
const size_t extractMagic = (msb / 0x1FF) | msb;
do {
size_t chunk = BrotliUnalignedReadSizeT(&tag_bucket[i]);
chunk ^= splat_char;
chunk = (((chunk | x80) - x01) | chunk) & x80;
matches <<= chunk_size;
matches |= ((chunk >> 7) * extractMagic) >> shift_amount;
i -= chunk_size;
} while (i >= 0);
#endif
matches = ~matches;
#endif
if (chunk_count == 1) return BrotliRotateRight16((uint16_t)matches, head);
if (chunk_count == 2) return BrotliRotateRight32((uint32_t)matches, head);
return BrotliRotateRight64(matches, head);
}
#undef SUPPORTS_SSE_2
#endif // THIRD_PARTY_BROTLI_ENC_MATCHING_TAG_MASK_H_

20
c/enc/quality.h
View File

@ -128,16 +128,16 @@ static BROTLI_INLINE size_t LiteralSpreeLengthForSparseSearch(
- q04: h04 (longest_match_quickly), b17, l5
- q04: h54 (longest_match_quickly), b20, l7 | for large files
- q05: h58 (longest_match_simd ), b14, l4
- q05: h68 (longest_match64_simd ), b15, l5 | for large files
- q05: h05 (longest_match ), b14, l4
- q05: h06 (longest_match64 ), b15, l5 | for large files
- q05: h40 (forgetful_chain ), b15, l4 | for small window
- q06: h58 (longest_match_simd ), b14, l4
- q06: h68 (longest_match64_simd ), b15, l5 | for large files
- q06: h05 (longest_match ), b14, l4
- q06: h06 (longest_match64 ), b15, l5 | for large files
- q06: h40 (forgetful_chain ), b15, l4 | for small window
- q07: h58 (longest_match_simd ), b15, l4
- q07: h68 (longest_match64_simd ), b15, l5 | for large files
- q07: h05 (longest_match ), b15, l4
- q07: h06 (longest_match64 ), b15, l5 | for large files
- q07: h41 (forgetful_chain ), b15, l4 | for small window
- q08: h05 (longest_match ), b15, l4
@ -165,11 +165,7 @@ static BROTLI_INLINE void ChooseHasher(const BrotliEncoderParams* params,
} else if (params->lgwin <= 16) {
hparams->type = params->quality < 7 ? 40 : params->quality < 9 ? 41 : 42;
} else if (params->size_hint >= (1 << 20) && params->lgwin >= 19) {
#if defined(BROTLI_MAX_SIMD_QUALITY)
hparams->type = params->quality <= BROTLI_MAX_SIMD_QUALITY ? 68 : 6;
#else
hparams->type = 6;
#endif
hparams->block_bits = params->quality - 1;
hparams->bucket_bits = 15;
hparams->num_last_distances_to_check =
@ -177,11 +173,7 @@ static BROTLI_INLINE void ChooseHasher(const BrotliEncoderParams* params,
} else {
/* TODO(eustas): often previous setting (H6) is faster and denser; consider
adding an option to use it. */
#if defined(BROTLI_MAX_SIMD_QUALITY)
hparams->type = params->quality <= BROTLI_MAX_SIMD_QUALITY ? 58 : 5;
#else
hparams->type = 5;
#endif
hparams->block_bits = params->quality - 1;
hparams->bucket_bits = params->quality < 7 ? 14 : 15;
hparams->num_last_distances_to_check =