mirror of https://github.com/acidanthera/audk.git
100 lines
4.1 KiB
C
100 lines
4.1 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. */
|
||
|
|
|
||
|
|
#ifndef BROTLI_ENC_BACKWARD_REFERENCES_H_
|
||
|
|
#define BROTLI_ENC_BACKWARD_REFERENCES_H_
|
||
|
|
|
||
|
|
#include "../common/types.h"
|
||
|
|
#include "./command.h"
|
||
|
|
#include "./hash.h"
|
||
|
|
#include "./memory.h"
|
||
|
|
#include "./port.h"
|
||
|
|
#include "./quality.h"
|
||
|
|
|
||
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
||
|
|
extern "C" {
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* "commands" points to the next output command to write to, "*num_commands" is
|
||
|
|
initially the total amount of commands output by previous
|
||
|
|
CreateBackwardReferences calls, and must be incremented by the amount written
|
||
|
|
by this call. */
|
||
|
|
BROTLI_INTERNAL void BrotliCreateBackwardReferences(
|
||
|
|
MemoryManager* m, size_t num_bytes, size_t position, BROTLI_BOOL is_last,
|
||
|
|
const uint8_t* ringbuffer, size_t ringbuffer_mask,
|
||
|
|
const BrotliEncoderParams* params, Hashers* hashers, int* dist_cache,
|
||
|
|
size_t* last_insert_len, Command* commands, size_t* num_commands,
|
||
|
|
size_t* num_literals);
|
||
|
|
|
||
|
|
typedef struct ZopfliNode {
|
||
|
|
/* best length to get up to this byte (not including this byte itself)
|
||
|
|
highest 8 bit is used to reconstruct the length code */
|
||
|
|
uint32_t length;
|
||
|
|
/* distance associated with the length
|
||
|
|
highest 7 bit contains distance short code + 1 (or zero if no short code)
|
||
|
|
*/
|
||
|
|
uint32_t distance;
|
||
|
|
/* number of literal inserts before this copy */
|
||
|
|
uint32_t insert_length;
|
||
|
|
|
||
|
|
/* This union holds information used by dynamic-programming. During forward
|
||
|
|
pass |cost| it used to store the goal function. When node is processed its
|
||
|
|
|cost| is invalidated in favor of |shortcut|. On path backtracing pass
|
||
|
|
|next| is assigned the offset to next node on the path. */
|
||
|
|
union {
|
||
|
|
/* Smallest cost to get to this byte from the beginning, as found so far. */
|
||
|
|
float cost;
|
||
|
|
/* Offset to the next node on the path. Equals to command_length() of the
|
||
|
|
next node on the path. For last node equals to BROTLI_UINT32_MAX */
|
||
|
|
uint32_t next;
|
||
|
|
/* Node position that provides next distance for distance cache. */
|
||
|
|
uint32_t shortcut;
|
||
|
|
} u;
|
||
|
|
} ZopfliNode;
|
||
|
|
|
||
|
|
BROTLI_INTERNAL void BrotliInitZopfliNodes(ZopfliNode* array, size_t length);
|
||
|
|
|
||
|
|
/* Computes the shortest path of commands from position to at most
|
||
|
|
position + num_bytes.
|
||
|
|
|
||
|
|
On return, path->size() is the number of commands found and path[i] is the
|
||
|
|
length of the ith command (copy length plus insert length).
|
||
|
|
Note that the sum of the lengths of all commands can be less than num_bytes.
|
||
|
|
|
||
|
|
On return, the nodes[0..num_bytes] array will have the following
|
||
|
|
"ZopfliNode array invariant":
|
||
|
|
For each i in [1..num_bytes], if nodes[i].cost < kInfinity, then
|
||
|
|
(1) nodes[i].copy_length() >= 2
|
||
|
|
(2) nodes[i].command_length() <= i and
|
||
|
|
(3) nodes[i - nodes[i].command_length()].cost < kInfinity */
|
||
|
|
BROTLI_INTERNAL size_t BrotliZopfliComputeShortestPath(
|
||
|
|
MemoryManager* m, size_t num_bytes, size_t position,
|
||
|
|
const uint8_t* ringbuffer, size_t ringbuffer_mask,
|
||
|
|
const BrotliEncoderParams* params, const size_t max_backward_limit,
|
||
|
|
const int* dist_cache, H10* hasher, ZopfliNode* nodes);
|
||
|
|
|
||
|
|
BROTLI_INTERNAL void BrotliZopfliCreateCommands(const size_t num_bytes,
|
||
|
|
const size_t block_start,
|
||
|
|
const size_t max_backward_limit,
|
||
|
|
const ZopfliNode* nodes,
|
||
|
|
int* dist_cache,
|
||
|
|
size_t* last_insert_len,
|
||
|
|
Command* commands,
|
||
|
|
size_t* num_literals);
|
||
|
|
|
||
|
|
/* Maximum distance, see section 9.1. of the spec. */
|
||
|
|
static BROTLI_INLINE size_t MaxBackwardLimit(int lgwin) {
|
||
|
|
return (1u << lgwin) - 16;
|
||
|
|
}
|
||
|
|
|
||
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
||
|
|
} /* extern "C" */
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif /* BROTLI_ENC_BACKWARD_REFERENCES_H_ */
|