cloudflared-mirror/vendor/github.com/cloudflare/brotli-go/backward_references.c

131 lines
3.9 KiB
C

/* 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 "./enc/backward_references.h"
#include "./common/constants.h"
#include "./common/dictionary.h"
#include <brotli/types.h>
#include "./enc/command.h"
#include "./enc/dictionary_hash.h"
#include "./enc/memory.h"
#include "./enc/port.h"
#include "./enc/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 HASHER() H2
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H3
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H4
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H5
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H6
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H40
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H41
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H42
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#define HASHER() H54
/* NOLINTNEXTLINE(build/include) */
#include "./enc/backward_references_inc.h"
#undef HASHER
#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: \
CreateBackwardReferencesH ## N(dictionary, \
kStaticDictionaryHash, num_bytes, position, ringbuffer, \
ringbuffer_mask, params, hasher, dist_cache, \
last_insert_len, commands, num_commands, num_literals); \
break;
FOR_GENERIC_HASHERS(CASE_)
#undef CASE_
default:
break;
}
}
#if defined(__cplusplus) || defined(c_plusplus)
} /* extern "C" */
#endif