hash_forgetful_chain_inc.h | Explore in Territory

/* NOLINT(build/header_guard) */
/* Copyright 2016 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, BUCKET_BITS, NUM_BANKS, BANK_BITS,
                        NUM_LAST_DISTANCES_TO_CHECK */

/* A (forgetful) hash table to the data seen by the compressor, to
   help create backward references to previous data.

   Hashes are stored in chains which are bucketed to groups. Group of chains
   share a storage "bank". When more than "bank size" chain nodes are added,
   oldest nodes are replaced; this way several chains may share a tail. */

#define HashForgetfulChain …

#define BANK_SIZE …

/* Number of hash buckets. */
#define BUCKET_SIZE …

#define CAPPED_CHAINS …

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 BROTLI_INLINE size_t FN(HashBytes)(const uint8_t* BROTLI_RESTRICT data) { … }

SlotH40;

BankH40;

H40;

static uint32_t* FN(Addr)(void* extra) { … }

static uint16_t* FN(Head)(void* extra) { … }

static uint8_t* FN(TinyHash)(void* extra) { … }

static FN(Bank)* FN(Banks)(void* extra) { … }

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

static void FN(Prepare)(
    HashForgetfulChain* 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 prepend
   node to corresponding chain; also update tiny_hash for current position. */
static BROTLI_INLINE void FN(Store)(HashForgetfulChain* BROTLI_RESTRICT self,
    const uint8_t* BROTLI_RESTRICT data, const size_t mask, const size_t ix) { … }

static BROTLI_INLINE void FN(StoreRange)(
    HashForgetfulChain* 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)(
    HashForgetfulChain* BROTLI_RESTRICT self,
    size_t num_bytes, size_t position, const uint8_t* ringbuffer,
    size_t ring_buffer_mask) { … }

static BROTLI_INLINE void FN(PrepareDistanceCache)(
    HashForgetfulChain* 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)(
    HashForgetfulChain* 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 BANK_SIZE
#undef BUCKET_SIZE
#undef CAPPED_CHAINS

#undef HashForgetfulChain
chromium/third_party/brotli/enc/hash_forgetful_chain_inc.h
