/* Copyright 2013 Google Inc. All Rights Reserved.

   Distributed under MIT license.

   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT

*/

/* Function to find backward reference copies. */

#include "backward_references.h"

#include <brotli/types.h>

#include "../common/constants.h"

#include "../common/dictionary.h"

#include "../common/platform.h"

#include "command.h"

#include "compound_dictionary.h"

#include "dictionary_hash.h"

#include "encoder_dict.h"

#include "memory.h"

#include "quality.h"

#if defined(__cplusplus) || defined(c_plusplus)

extern "C" {

#endif

static BROTLI_INLINE size_t ComputeDistanceCode(size_t distance,

                                                size_t max_distance,

                                                const int* dist_cache) {

  if (distance <= max_distance) {

    size_t distance_plus_3 = distance + 3;

    size_t offset0 = distance_plus_3 - (size_t)dist_cache[0];

    size_t offset1 = distance_plus_3 - (size_t)dist_cache[1];

    if (distance == (size_t)dist_cache[0]) {

      return 0;

    } else if (distance == (size_t)dist_cache[1]) {

      return 1;

    } else if (offset0 < 7) {

      return (0x9750468 >> (4 * offset0)) & 0xF;

    } else if (offset1 < 7) {

      return (0xFDB1ACE >> (4 * offset1)) & 0xF;

    } else if (distance == (size_t)dist_cache[2]) {

      return 2;

    } else if (distance == (size_t)dist_cache[3]) {

      return 3;

    }

  }

  return distance + BROTLI_NUM_DISTANCE_SHORT_CODES - 1;

}

#define EXPAND_CAT(a, b) CAT(a, b)

#define CAT(a, b) a ## b

#define FN(X) EXPAND_CAT(X, HASHER())

#define EXPORT_FN(X) EXPAND_CAT(X, EXPAND_CAT(PREFIX(), HASHER()))

#define PREFIX() N

#define ENABLE_COMPOUND_DICTIONARY 0

#define HASHER() H2

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H3

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H4

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H5

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H6

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H40

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H41

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H42

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H54

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H35

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H55

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H65

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#undef ENABLE_COMPOUND_DICTIONARY

#undef PREFIX

#define PREFIX() D

#define ENABLE_COMPOUND_DICTIONARY 1

#define HASHER() H5

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H6

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H40

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H41

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H42

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H55

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#define HASHER() H65

/* NOLINTNEXTLINE(build/include) */

#include "backward_references_inc.h"

#undef HASHER

#undef ENABLE_COMPOUND_DICTIONARY

#undef PREFIX

#undef EXPORT_FN

#undef FN

#undef CAT

#undef EXPAND_CAT

void BrotliCreateBackwardReferences(size_t num_bytes,

    size_t position, const uint8_t* ringbuffer, size_t ringbuffer_mask,

    ContextLut literal_context_lut, const BrotliEncoderParams* params,

    Hasher* hasher, int* dist_cache, size_t* last_insert_len,

    Command* commands, size_t* num_commands, size_t* num_literals) {

  if (params->dictionary.compound.num_chunks != 0) {

    switch (params->hasher.type) {

#define CASE_(N)                                                    \

      case N:                                                       \

        CreateBackwardReferencesDH ## N(num_bytes,                  \

            position, ringbuffer, ringbuffer_mask,                  \

            literal_context_lut, params, hasher, dist_cache,        \

            last_insert_len, commands, num_commands, num_literals); \

        return;

      CASE_(5)

      CASE_(6)

      CASE_(40)

      CASE_(41)

      CASE_(42)

      CASE_(55)

      CASE_(65)

#undef CASE_

      default:

        BROTLI_DCHECK(false);

        break;

    }

  }

  switch (params->hasher.type) {

#define CASE_(N)                                                  \

    case N:                                                       \

      CreateBackwardReferencesNH ## N(num_bytes,                  \

          position, ringbuffer, ringbuffer_mask,                  \

          literal_context_lut, params, hasher, dist_cache,        \

          last_insert_len, commands, num_commands, num_literals); \

      return;

    FOR_GENERIC_HASHERS(CASE_)

#undef CASE_

    default:

      BROTLI_DCHECK(false);

      break;

  }

}

#if defined(__cplusplus) || defined(c_plusplus)

}  /* extern "C" */

#endif