chromium/third_party/brotli/enc/hash_rolling_inc.h

/* NOLINT(build/header_guard) */
/* Copyright 2018 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, JUMP, NUMBUCKETS, MASK, CHUNKLEN */
/* NUMBUCKETS / (MASK + 1) = probability of storing and using hash code. */
/* JUMP = skip bytes for speedup */

/* Rolling hash for long distance long string matches. Stores one position
   per bucket, bucket key is computed over a long region. */

#define HashRolling …

static const uint32_t FN(kRollingHashMul32) = …;
static const uint32_t FN(kInvalidPos) = …;

/* This hasher uses a longer forward length, but returning a higher value here
   will hurt compression by the main hasher when combined with a composite
   hasher. The hasher tests for forward itself instead. */
static BROTLI_INLINE size_t FN(HashTypeLength)(void) { … }
static BROTLI_INLINE size_t FN(StoreLookahead)(void) { … }

/* Computes a code from a single byte. A lookup table of 256 values could be
   used, but simply adding 1 works about as good. */
static uint32_t FN(HashByte)(uint8_t byte) { … }

static uint32_t FN(HashRollingFunctionInitial)(uint32_t state, uint8_t add,
                                               uint32_t factor) { … }

static uint32_t FN(HashRollingFunction)(uint32_t state, uint8_t add,
                                        uint8_t rem, uint32_t factor,
                                        uint32_t factor_remove) { … }

HROLLING_FAST;

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

static void FN(Prepare)(HashRolling* 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) { … }

static BROTLI_INLINE void FN(Store)(HashRolling* BROTLI_RESTRICT self,
    const uint8_t* BROTLI_RESTRICT data, const size_t mask, const size_t ix) { … }

static BROTLI_INLINE void FN(StoreRange)(HashRolling* 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)(
    HashRolling* 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)(
    HashRolling* BROTLI_RESTRICT self,
    int* BROTLI_RESTRICT distance_cache) { … }

static BROTLI_INLINE void FN(FindLongestMatch)(
    HashRolling* 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 HashRolling