summaryrefslogtreecommitdiffstats
path: root/modules/brotli/enc/backward_references.c
blob: cd023d9b41ce2400854e51fda2a823d8e50a3b1f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
/* 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 "../common/platform.h"
#include <brotli/types.h>
#include "./command.h"
#include "./dictionary_hash.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 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 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, 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(                            \
          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