hash_longest_match_inc.h | Explore in Territory

/* 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 …

static BROTLI_INLINE size_t FN(HashTypeLength)(void) { … }
static BROTLI_INLINE size_t FN(StoreLookahead)(void) { … }

/* 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) { … }

H5;

static void FN(Initialize)(
    HasherCommon* common, HashLongestMatch* BROTLI_RESTRICT self,
    const BrotliEncoderParams* params) { … }

static void FN(Prepare)(
    HashLongestMatch* BROTLI_RESTRICT self, BROTLI_BOOL one_shot,
    size_t input_size, const uint8_t* BROTLI_RESTRICT data) { … }

static BROTLI_INLINE void FN(HashMemAllocInBytes)(
    const BrotliEncoderParams* params, BROTLI_BOOL one_shot,
    size_t input_size, size_t* alloc_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) { … }

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) { … }

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) { … }

static BROTLI_INLINE void FN(PrepareDistanceCache)(
    HashLongestMatch* BROTLI_RESTRICT self,
    int* BROTLI_RESTRICT distance_cache) { … }

/* 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) { … }

#undef HashLongestMatch
chromium/third_party/brotli/enc/hash_longest_match_inc.h
