/* 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 "../common/constants.h"

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

#include <brotli/types.h>

#include "./command.h"

#include "./dictionary_hash.h"

#include "./memory.h"

#include "./port.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 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

#undef PREFIX

#undef EXPORT_FN

#undef FN

#undef CAT

#undef EXPAND_CAT

void BrotliCreateBackwardReferences(const BrotliDictionary* dictionary,

                                    size_t num_bytes,

                                    size_t position,

                                    const uint8_t* ringbuffer,

                                    size_t ringbuffer_mask,

                                    const BrotliEncoderParams* params,

                                    HasherHandle hasher,

                                    int* dist_cache,

                                    size_t* last_insert_len,

                                    Command* commands,

                                    size_t* num_commands,

                                    size_t* num_literals) {

  switch (params->hasher.type) {

#define CASE_(N)                                                  \

    case N:                                                       \

      CreateBackwardReferencesNH ## N(dictionary,                 \

          kStaticDictionaryHash, num_bytes, position, ringbuffer, \

          ringbuffer_mask, params, hasher, dist_cache,            \

          last_insert_len, commands, num_commands, num_literals); \

      return;

    FOR_GENERIC_HASHERS(CASE_)

#undef CASE_

    default:

      break;

  }

}

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

}  /* extern "C" */

#endif