791 lines
30 KiB
C
791 lines
30 KiB
C
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/* Copyright 2013 Google Inc. All Rights Reserved.
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Distributed under MIT license.
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See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
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*/
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/* Function to find backward reference copies. */
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#include "./enc/backward_references_hq.h"
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#include <string.h> /* memcpy, memset */
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#include "./common/constants.h"
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#include <brotli/types.h>
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#include "./enc/command.h"
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#include "./enc/fast_log.h"
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#include "./enc/find_match_length.h"
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#include "./enc/literal_cost.h"
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#include "./enc/memory.h"
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#include "./enc/port.h"
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#include "./enc/prefix.h"
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#include "./enc/quality.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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static const float kInfinity = 1.7e38f; /* ~= 2 ^ 127 */
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static const uint32_t kDistanceCacheIndex[] = {
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0, 1, 2, 3, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,
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};
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static const int kDistanceCacheOffset[] = {
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0, 0, 0, 0, -1, 1, -2, 2, -3, 3, -1, 1, -2, 2, -3, 3
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};
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void BrotliInitZopfliNodes(ZopfliNode* array, size_t length) {
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ZopfliNode stub;
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size_t i;
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stub.length = 1;
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stub.distance = 0;
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stub.insert_length = 0;
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stub.u.cost = kInfinity;
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for (i = 0; i < length; ++i) array[i] = stub;
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}
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static BROTLI_INLINE uint32_t ZopfliNodeCopyLength(const ZopfliNode* self) {
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return self->length & 0xffffff;
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}
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static BROTLI_INLINE uint32_t ZopfliNodeLengthCode(const ZopfliNode* self) {
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const uint32_t modifier = self->length >> 24;
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return ZopfliNodeCopyLength(self) + 9u - modifier;
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}
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static BROTLI_INLINE uint32_t ZopfliNodeCopyDistance(const ZopfliNode* self) {
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return self->distance & 0x1ffffff;
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}
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static BROTLI_INLINE uint32_t ZopfliNodeDistanceCode(const ZopfliNode* self) {
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const uint32_t short_code = self->distance >> 25;
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return short_code == 0 ?
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ZopfliNodeCopyDistance(self) + BROTLI_NUM_DISTANCE_SHORT_CODES - 1 :
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short_code - 1;
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}
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static BROTLI_INLINE uint32_t ZopfliNodeCommandLength(const ZopfliNode* self) {
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return ZopfliNodeCopyLength(self) + self->insert_length;
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}
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/* Histogram based cost model for zopflification. */
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typedef struct ZopfliCostModel {
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/* The insert and copy length symbols. */
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float cost_cmd_[BROTLI_NUM_COMMAND_SYMBOLS];
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float cost_dist_[BROTLI_NUM_DISTANCE_SYMBOLS];
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/* Cumulative costs of literals per position in the stream. */
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float* literal_costs_;
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float min_cost_cmd_;
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size_t num_bytes_;
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} ZopfliCostModel;
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static void InitZopfliCostModel(
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MemoryManager* m, ZopfliCostModel* self, size_t num_bytes) {
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self->num_bytes_ = num_bytes;
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self->literal_costs_ = BROTLI_ALLOC(m, float, num_bytes + 2);
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if (BROTLI_IS_OOM(m)) return;
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}
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static void CleanupZopfliCostModel(MemoryManager* m, ZopfliCostModel* self) {
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BROTLI_FREE(m, self->literal_costs_);
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}
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static void SetCost(const uint32_t* histogram, size_t histogram_size,
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float* cost) {
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size_t sum = 0;
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float log2sum;
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size_t i;
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for (i = 0; i < histogram_size; i++) {
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sum += histogram[i];
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}
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log2sum = (float)FastLog2(sum);
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for (i = 0; i < histogram_size; i++) {
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if (histogram[i] == 0) {
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cost[i] = log2sum + 2;
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continue;
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}
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/* Shannon bits for this symbol. */
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cost[i] = log2sum - (float)FastLog2(histogram[i]);
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/* Cannot be coded with less than 1 bit */
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if (cost[i] < 1) cost[i] = 1;
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}
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}
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static void ZopfliCostModelSetFromCommands(ZopfliCostModel* self,
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size_t position,
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const uint8_t* ringbuffer,
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size_t ringbuffer_mask,
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const Command* commands,
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size_t num_commands,
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size_t last_insert_len) {
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uint32_t histogram_literal[BROTLI_NUM_LITERAL_SYMBOLS];
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uint32_t histogram_cmd[BROTLI_NUM_COMMAND_SYMBOLS];
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uint32_t histogram_dist[BROTLI_NUM_DISTANCE_SYMBOLS];
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float cost_literal[BROTLI_NUM_LITERAL_SYMBOLS];
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size_t pos = position - last_insert_len;
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float min_cost_cmd = kInfinity;
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size_t i;
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float* cost_cmd = self->cost_cmd_;
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memset(histogram_literal, 0, sizeof(histogram_literal));
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memset(histogram_cmd, 0, sizeof(histogram_cmd));
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memset(histogram_dist, 0, sizeof(histogram_dist));
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for (i = 0; i < num_commands; i++) {
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size_t inslength = commands[i].insert_len_;
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size_t copylength = CommandCopyLen(&commands[i]);
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size_t distcode = commands[i].dist_prefix_;
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size_t cmdcode = commands[i].cmd_prefix_;
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size_t j;
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histogram_cmd[cmdcode]++;
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if (cmdcode >= 128) histogram_dist[distcode]++;
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for (j = 0; j < inslength; j++) {
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histogram_literal[ringbuffer[(pos + j) & ringbuffer_mask]]++;
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}
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pos += inslength + copylength;
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}
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SetCost(histogram_literal, BROTLI_NUM_LITERAL_SYMBOLS, cost_literal);
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SetCost(histogram_cmd, BROTLI_NUM_COMMAND_SYMBOLS, cost_cmd);
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SetCost(histogram_dist, BROTLI_NUM_DISTANCE_SYMBOLS, self->cost_dist_);
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for (i = 0; i < BROTLI_NUM_COMMAND_SYMBOLS; ++i) {
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min_cost_cmd = BROTLI_MIN(float, min_cost_cmd, cost_cmd[i]);
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}
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self->min_cost_cmd_ = min_cost_cmd;
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{
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float* literal_costs = self->literal_costs_;
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size_t num_bytes = self->num_bytes_;
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literal_costs[0] = 0.0;
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for (i = 0; i < num_bytes; ++i) {
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literal_costs[i + 1] = literal_costs[i] +
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cost_literal[ringbuffer[(position + i) & ringbuffer_mask]];
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}
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}
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}
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static void ZopfliCostModelSetFromLiteralCosts(ZopfliCostModel* self,
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size_t position,
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const uint8_t* ringbuffer,
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size_t ringbuffer_mask) {
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float* literal_costs = self->literal_costs_;
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float* cost_dist = self->cost_dist_;
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float* cost_cmd = self->cost_cmd_;
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size_t num_bytes = self->num_bytes_;
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size_t i;
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BrotliEstimateBitCostsForLiterals(position, num_bytes, ringbuffer_mask,
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ringbuffer, &literal_costs[1]);
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literal_costs[0] = 0.0;
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for (i = 0; i < num_bytes; ++i) {
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literal_costs[i + 1] += literal_costs[i];
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}
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for (i = 0; i < BROTLI_NUM_COMMAND_SYMBOLS; ++i) {
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cost_cmd[i] = (float)FastLog2(11 + (uint32_t)i);
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}
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for (i = 0; i < BROTLI_NUM_DISTANCE_SYMBOLS; ++i) {
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cost_dist[i] = (float)FastLog2(20 + (uint32_t)i);
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}
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self->min_cost_cmd_ = (float)FastLog2(11);
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}
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static BROTLI_INLINE float ZopfliCostModelGetCommandCost(
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const ZopfliCostModel* self, uint16_t cmdcode) {
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return self->cost_cmd_[cmdcode];
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}
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static BROTLI_INLINE float ZopfliCostModelGetDistanceCost(
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const ZopfliCostModel* self, size_t distcode) {
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return self->cost_dist_[distcode];
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}
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static BROTLI_INLINE float ZopfliCostModelGetLiteralCosts(
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const ZopfliCostModel* self, size_t from, size_t to) {
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return self->literal_costs_[to] - self->literal_costs_[from];
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}
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static BROTLI_INLINE float ZopfliCostModelGetMinCostCmd(
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const ZopfliCostModel* self) {
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return self->min_cost_cmd_;
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}
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/* REQUIRES: len >= 2, start_pos <= pos */
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/* REQUIRES: cost < kInfinity, nodes[start_pos].cost < kInfinity */
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/* Maintains the "ZopfliNode array invariant". */
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static BROTLI_INLINE void UpdateZopfliNode(ZopfliNode* nodes, size_t pos,
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size_t start_pos, size_t len, size_t len_code, size_t dist,
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size_t short_code, float cost) {
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ZopfliNode* next = &nodes[pos + len];
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next->length = (uint32_t)(len | ((len + 9u - len_code) << 24));
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next->distance = (uint32_t)(dist | (short_code << 25));
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next->insert_length = (uint32_t)(pos - start_pos);
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next->u.cost = cost;
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}
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typedef struct PosData {
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size_t pos;
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int distance_cache[4];
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float costdiff;
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float cost;
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} PosData;
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/* Maintains the smallest 8 cost difference together with their positions */
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typedef struct StartPosQueue {
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PosData q_[8];
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size_t idx_;
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} StartPosQueue;
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static BROTLI_INLINE void InitStartPosQueue(StartPosQueue* self) {
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self->idx_ = 0;
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}
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static size_t StartPosQueueSize(const StartPosQueue* self) {
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return BROTLI_MIN(size_t, self->idx_, 8);
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}
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static void StartPosQueuePush(StartPosQueue* self, const PosData* posdata) {
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size_t offset = ~(self->idx_++) & 7;
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size_t len = StartPosQueueSize(self);
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size_t i;
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PosData* q = self->q_;
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q[offset] = *posdata;
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/* Restore the sorted order. In the list of |len| items at most |len - 1|
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adjacent element comparisons / swaps are required. */
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for (i = 1; i < len; ++i) {
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if (q[offset & 7].costdiff > q[(offset + 1) & 7].costdiff) {
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BROTLI_SWAP(PosData, q, offset & 7, (offset + 1) & 7);
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}
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++offset;
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}
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}
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static const PosData* StartPosQueueAt(const StartPosQueue* self, size_t k) {
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return &self->q_[(k - self->idx_) & 7];
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}
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/* Returns the minimum possible copy length that can improve the cost of any */
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/* future position. */
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static size_t ComputeMinimumCopyLength(const float start_cost,
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const ZopfliNode* nodes,
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const size_t num_bytes,
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const size_t pos) {
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/* Compute the minimum possible cost of reaching any future position. */
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float min_cost = start_cost;
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size_t len = 2;
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size_t next_len_bucket = 4;
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size_t next_len_offset = 10;
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while (pos + len <= num_bytes && nodes[pos + len].u.cost <= min_cost) {
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/* We already reached (pos + len) with no more cost than the minimum
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possible cost of reaching anything from this pos, so there is no point in
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looking for lengths <= len. */
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++len;
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if (len == next_len_offset) {
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/* We reached the next copy length code bucket, so we add one more
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extra bit to the minimum cost. */
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min_cost += 1.0f;
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next_len_offset += next_len_bucket;
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next_len_bucket *= 2;
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}
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}
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return len;
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}
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/* REQUIRES: nodes[pos].cost < kInfinity
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REQUIRES: nodes[0..pos] satisfies that "ZopfliNode array invariant". */
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static uint32_t ComputeDistanceShortcut(const size_t block_start,
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const size_t pos,
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const size_t max_backward,
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const ZopfliNode* nodes) {
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const size_t clen = ZopfliNodeCopyLength(&nodes[pos]);
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const size_t ilen = nodes[pos].insert_length;
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const size_t dist = ZopfliNodeCopyDistance(&nodes[pos]);
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/* Since |block_start + pos| is the end position of the command, the copy part
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starts from |block_start + pos - clen|. Distances that are greater than
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this or greater than |max_backward| are static dictionary references, and
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do not update the last distances. Also distance code 0 (last distance)
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does not update the last distances. */
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if (pos == 0) {
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return 0;
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} else if (dist + clen <= block_start + pos &&
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dist <= max_backward &&
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ZopfliNodeDistanceCode(&nodes[pos]) > 0) {
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return (uint32_t)pos;
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} else {
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return nodes[pos - clen - ilen].u.shortcut;
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}
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}
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/* Fills in dist_cache[0..3] with the last four distances (as defined by
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Section 4. of the Spec) that would be used at (block_start + pos) if we
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used the shortest path of commands from block_start, computed from
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nodes[0..pos]. The last four distances at block_start are in
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starting_dist_cache[0..3].
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REQUIRES: nodes[pos].cost < kInfinity
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REQUIRES: nodes[0..pos] satisfies that "ZopfliNode array invariant". */
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static void ComputeDistanceCache(const size_t pos,
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const int* starting_dist_cache,
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const ZopfliNode* nodes,
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int* dist_cache) {
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int idx = 0;
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size_t p = nodes[pos].u.shortcut;
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while (idx < 4 && p > 0) {
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const size_t ilen = nodes[p].insert_length;
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const size_t clen = ZopfliNodeCopyLength(&nodes[p]);
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const size_t dist = ZopfliNodeCopyDistance(&nodes[p]);
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dist_cache[idx++] = (int)dist;
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/* Because of prerequisite, p >= clen + ilen >= 2. */
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|
p = nodes[p - clen - ilen].u.shortcut;
|
||
|
|
}
|
||
|
|
for (; idx < 4; ++idx) {
|
||
|
|
dist_cache[idx] = *starting_dist_cache++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Maintains "ZopfliNode array invariant" and pushes node to the queue, if it
|
||
|
|
is eligible. */
|
||
|
|
static void EvaluateNode(
|
||
|
|
const size_t block_start, const size_t pos, const size_t max_backward_limit,
|
||
|
|
const int* starting_dist_cache, const ZopfliCostModel* model,
|
||
|
|
StartPosQueue* queue, ZopfliNode* nodes) {
|
||
|
|
/* Save cost, because ComputeDistanceCache invalidates it. */
|
||
|
|
float node_cost = nodes[pos].u.cost;
|
||
|
|
nodes[pos].u.shortcut = ComputeDistanceShortcut(
|
||
|
|
block_start, pos, max_backward_limit, nodes);
|
||
|
|
if (node_cost <= ZopfliCostModelGetLiteralCosts(model, 0, pos)) {
|
||
|
|
PosData posdata;
|
||
|
|
posdata.pos = pos;
|
||
|
|
posdata.cost = node_cost;
|
||
|
|
posdata.costdiff = node_cost -
|
||
|
|
ZopfliCostModelGetLiteralCosts(model, 0, pos);
|
||
|
|
ComputeDistanceCache(
|
||
|
|
pos, starting_dist_cache, nodes, posdata.distance_cache);
|
||
|
|
StartPosQueuePush(queue, &posdata);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Returns longest copy length. */
|
||
|
|
static size_t UpdateNodes(
|
||
|
|
const size_t num_bytes, const size_t block_start, const size_t pos,
|
||
|
|
const uint8_t* ringbuffer, const size_t ringbuffer_mask,
|
||
|
|
const BrotliEncoderParams* params, const size_t max_backward_limit,
|
||
|
|
const int* starting_dist_cache, const size_t num_matches,
|
||
|
|
const BackwardMatch* matches, const ZopfliCostModel* model,
|
||
|
|
StartPosQueue* queue, ZopfliNode* nodes) {
|
||
|
|
const size_t cur_ix = block_start + pos;
|
||
|
|
const size_t cur_ix_masked = cur_ix & ringbuffer_mask;
|
||
|
|
const size_t max_distance = BROTLI_MIN(size_t, cur_ix, max_backward_limit);
|
||
|
|
const size_t max_len = num_bytes - pos;
|
||
|
|
const size_t max_zopfli_len = MaxZopfliLen(params);
|
||
|
|
const size_t max_iters = MaxZopfliCandidates(params);
|
||
|
|
size_t min_len;
|
||
|
|
size_t result = 0;
|
||
|
|
size_t k;
|
||
|
|
|
||
|
|
EvaluateNode(block_start, pos, max_backward_limit, starting_dist_cache, model,
|
||
|
|
queue, nodes);
|
||
|
|
|
||
|
|
{
|
||
|
|
const PosData* posdata = StartPosQueueAt(queue, 0);
|
||
|
|
float min_cost = (posdata->cost + ZopfliCostModelGetMinCostCmd(model) +
|
||
|
|
ZopfliCostModelGetLiteralCosts(model, posdata->pos, pos));
|
||
|
|
min_len = ComputeMinimumCopyLength(min_cost, nodes, num_bytes, pos);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Go over the command starting positions in order of increasing cost
|
||
|
|
difference. */
|
||
|
|
for (k = 0; k < max_iters && k < StartPosQueueSize(queue); ++k) {
|
||
|
|
const PosData* posdata = StartPosQueueAt(queue, k);
|
||
|
|
const size_t start = posdata->pos;
|
||
|
|
const uint16_t inscode = GetInsertLengthCode(pos - start);
|
||
|
|
const float start_costdiff = posdata->costdiff;
|
||
|
|
const float base_cost = start_costdiff + (float)GetInsertExtra(inscode) +
|
||
|
|
ZopfliCostModelGetLiteralCosts(model, 0, pos);
|
||
|
|
|
||
|
|
/* Look for last distance matches using the distance cache from this
|
||
|
|
starting position. */
|
||
|
|
size_t best_len = min_len - 1;
|
||
|
|
size_t j = 0;
|
||
|
|
for (; j < BROTLI_NUM_DISTANCE_SHORT_CODES && best_len < max_len; ++j) {
|
||
|
|
const size_t idx = kDistanceCacheIndex[j];
|
||
|
|
const size_t backward =
|
||
|
|
(size_t)(posdata->distance_cache[idx] + kDistanceCacheOffset[j]);
|
||
|
|
size_t prev_ix = cur_ix - backward;
|
||
|
|
if (prev_ix >= cur_ix) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
if (BROTLI_PREDICT_FALSE(backward > max_distance)) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
prev_ix &= ringbuffer_mask;
|
||
|
|
|
||
|
|
if (cur_ix_masked + best_len > ringbuffer_mask ||
|
||
|
|
prev_ix + best_len > ringbuffer_mask ||
|
||
|
|
ringbuffer[cur_ix_masked + best_len] !=
|
||
|
|
ringbuffer[prev_ix + best_len]) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
{
|
||
|
|
const size_t len =
|
||
|
|
FindMatchLengthWithLimit(&ringbuffer[prev_ix],
|
||
|
|
&ringbuffer[cur_ix_masked],
|
||
|
|
max_len);
|
||
|
|
const float dist_cost = base_cost +
|
||
|
|
ZopfliCostModelGetDistanceCost(model, j);
|
||
|
|
size_t l;
|
||
|
|
for (l = best_len + 1; l <= len; ++l) {
|
||
|
|
const uint16_t copycode = GetCopyLengthCode(l);
|
||
|
|
const uint16_t cmdcode =
|
||
|
|
CombineLengthCodes(inscode, copycode, j == 0);
|
||
|
|
const float cost = (cmdcode < 128 ? base_cost : dist_cost) +
|
||
|
|
(float)GetCopyExtra(copycode) +
|
||
|
|
ZopfliCostModelGetCommandCost(model, cmdcode);
|
||
|
|
if (cost < nodes[pos + l].u.cost) {
|
||
|
|
UpdateZopfliNode(nodes, pos, start, l, l, backward, j + 1, cost);
|
||
|
|
result = BROTLI_MAX(size_t, result, l);
|
||
|
|
}
|
||
|
|
best_len = l;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* At higher iterations look only for new last distance matches, since
|
||
|
|
looking only for new command start positions with the same distances
|
||
|
|
does not help much. */
|
||
|
|
if (k >= 2) continue;
|
||
|
|
|
||
|
|
{
|
||
|
|
/* Loop through all possible copy lengths at this position. */
|
||
|
|
size_t len = min_len;
|
||
|
|
for (j = 0; j < num_matches; ++j) {
|
||
|
|
BackwardMatch match = matches[j];
|
||
|
|
size_t dist = match.distance;
|
||
|
|
BROTLI_BOOL is_dictionary_match = TO_BROTLI_BOOL(dist > max_distance);
|
||
|
|
/* We already tried all possible last distance matches, so we can use
|
||
|
|
normal distance code here. */
|
||
|
|
size_t dist_code = dist + BROTLI_NUM_DISTANCE_SHORT_CODES - 1;
|
||
|
|
uint16_t dist_symbol;
|
||
|
|
uint32_t distextra;
|
||
|
|
uint32_t distnumextra;
|
||
|
|
float dist_cost;
|
||
|
|
size_t max_match_len;
|
||
|
|
PrefixEncodeCopyDistance(dist_code, 0, 0, &dist_symbol, &distextra);
|
||
|
|
distnumextra = distextra >> 24;
|
||
|
|
dist_cost = base_cost + (float)distnumextra +
|
||
|
|
ZopfliCostModelGetDistanceCost(model, dist_symbol);
|
||
|
|
|
||
|
|
/* Try all copy lengths up until the maximum copy length corresponding
|
||
|
|
to this distance. If the distance refers to the static dictionary, or
|
||
|
|
the maximum length is long enough, try only one maximum length. */
|
||
|
|
max_match_len = BackwardMatchLength(&match);
|
||
|
|
if (len < max_match_len &&
|
||
|
|
(is_dictionary_match || max_match_len > max_zopfli_len)) {
|
||
|
|
len = max_match_len;
|
||
|
|
}
|
||
|
|
for (; len <= max_match_len; ++len) {
|
||
|
|
const size_t len_code =
|
||
|
|
is_dictionary_match ? BackwardMatchLengthCode(&match) : len;
|
||
|
|
const uint16_t copycode = GetCopyLengthCode(len_code);
|
||
|
|
const uint16_t cmdcode = CombineLengthCodes(inscode, copycode, 0);
|
||
|
|
const float cost = dist_cost + (float)GetCopyExtra(copycode) +
|
||
|
|
ZopfliCostModelGetCommandCost(model, cmdcode);
|
||
|
|
if (cost < nodes[pos + len].u.cost) {
|
||
|
|
UpdateZopfliNode(nodes, pos, start, len, len_code, dist, 0, cost);
|
||
|
|
result = BROTLI_MAX(size_t, result, len);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
static size_t ComputeShortestPathFromNodes(size_t num_bytes,
|
||
|
|
ZopfliNode* nodes) {
|
||
|
|
size_t index = num_bytes;
|
||
|
|
size_t num_commands = 0;
|
||
|
|
while (nodes[index].insert_length == 0 && nodes[index].length == 1) --index;
|
||
|
|
nodes[index].u.next = BROTLI_UINT32_MAX;
|
||
|
|
while (index != 0) {
|
||
|
|
size_t len = ZopfliNodeCommandLength(&nodes[index]);
|
||
|
|
index -= len;
|
||
|
|
nodes[index].u.next = (uint32_t)len;
|
||
|
|
num_commands++;
|
||
|
|
}
|
||
|
|
return num_commands;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* REQUIRES: nodes != NULL and len(nodes) >= num_bytes + 1 */
|
||
|
|
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) {
|
||
|
|
size_t pos = 0;
|
||
|
|
uint32_t offset = nodes[0].u.next;
|
||
|
|
size_t i;
|
||
|
|
for (i = 0; offset != BROTLI_UINT32_MAX; i++) {
|
||
|
|
const ZopfliNode* next = &nodes[pos + offset];
|
||
|
|
size_t copy_length = ZopfliNodeCopyLength(next);
|
||
|
|
size_t insert_length = next->insert_length;
|
||
|
|
pos += insert_length;
|
||
|
|
offset = next->u.next;
|
||
|
|
if (i == 0) {
|
||
|
|
insert_length += *last_insert_len;
|
||
|
|
*last_insert_len = 0;
|
||
|
|
}
|
||
|
|
{
|
||
|
|
size_t distance = ZopfliNodeCopyDistance(next);
|
||
|
|
size_t len_code = ZopfliNodeLengthCode(next);
|
||
|
|
size_t max_distance =
|
||
|
|
BROTLI_MIN(size_t, block_start + pos, max_backward_limit);
|
||
|
|
BROTLI_BOOL is_dictionary = TO_BROTLI_BOOL(distance > max_distance);
|
||
|
|
size_t dist_code = ZopfliNodeDistanceCode(next);
|
||
|
|
|
||
|
|
InitCommand(&commands[i], insert_length,
|
||
|
|
copy_length, (int)len_code - (int)copy_length, dist_code);
|
||
|
|
|
||
|
|
if (!is_dictionary && dist_code > 0) {
|
||
|
|
dist_cache[3] = dist_cache[2];
|
||
|
|
dist_cache[2] = dist_cache[1];
|
||
|
|
dist_cache[1] = dist_cache[0];
|
||
|
|
dist_cache[0] = (int)distance;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
*num_literals += insert_length;
|
||
|
|
pos += copy_length;
|
||
|
|
}
|
||
|
|
*last_insert_len += num_bytes - pos;
|
||
|
|
}
|
||
|
|
|
||
|
|
static size_t ZopfliIterate(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,
|
||
|
|
const ZopfliCostModel* model,
|
||
|
|
const uint32_t* num_matches,
|
||
|
|
const BackwardMatch* matches,
|
||
|
|
ZopfliNode* nodes) {
|
||
|
|
const size_t max_zopfli_len = MaxZopfliLen(params);
|
||
|
|
StartPosQueue queue;
|
||
|
|
size_t cur_match_pos = 0;
|
||
|
|
size_t i;
|
||
|
|
nodes[0].length = 0;
|
||
|
|
nodes[0].u.cost = 0;
|
||
|
|
InitStartPosQueue(&queue);
|
||
|
|
for (i = 0; i + 3 < num_bytes; i++) {
|
||
|
|
size_t skip = UpdateNodes(num_bytes, position, i, ringbuffer,
|
||
|
|
ringbuffer_mask, params, max_backward_limit, dist_cache,
|
||
|
|
num_matches[i], &matches[cur_match_pos], model, &queue, nodes);
|
||
|
|
if (skip < BROTLI_LONG_COPY_QUICK_STEP) skip = 0;
|
||
|
|
cur_match_pos += num_matches[i];
|
||
|
|
if (num_matches[i] == 1 &&
|
||
|
|
BackwardMatchLength(&matches[cur_match_pos - 1]) > max_zopfli_len) {
|
||
|
|
skip = BROTLI_MAX(size_t,
|
||
|
|
BackwardMatchLength(&matches[cur_match_pos - 1]), skip);
|
||
|
|
}
|
||
|
|
if (skip > 1) {
|
||
|
|
skip--;
|
||
|
|
while (skip) {
|
||
|
|
i++;
|
||
|
|
if (i + 3 >= num_bytes) break;
|
||
|
|
EvaluateNode(
|
||
|
|
position, i, max_backward_limit, dist_cache, model, &queue, nodes);
|
||
|
|
cur_match_pos += num_matches[i];
|
||
|
|
skip--;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return ComputeShortestPathFromNodes(num_bytes, nodes);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* REQUIRES: nodes != NULL and len(nodes) >= num_bytes + 1 */
|
||
|
|
size_t BrotliZopfliComputeShortestPath(MemoryManager* m,
|
||
|
|
const BrotliDictionary* dictionary,
|
||
|
|
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,
|
||
|
|
HasherHandle hasher,
|
||
|
|
ZopfliNode* nodes) {
|
||
|
|
const size_t max_zopfli_len = MaxZopfliLen(params);
|
||
|
|
ZopfliCostModel model;
|
||
|
|
StartPosQueue queue;
|
||
|
|
BackwardMatch matches[MAX_NUM_MATCHES_H10];
|
||
|
|
const size_t store_end = num_bytes >= StoreLookaheadH10() ?
|
||
|
|
position + num_bytes - StoreLookaheadH10() + 1 : position;
|
||
|
|
size_t i;
|
||
|
|
nodes[0].length = 0;
|
||
|
|
nodes[0].u.cost = 0;
|
||
|
|
InitZopfliCostModel(m, &model, num_bytes);
|
||
|
|
if (BROTLI_IS_OOM(m)) return 0;
|
||
|
|
ZopfliCostModelSetFromLiteralCosts(
|
||
|
|
&model, position, ringbuffer, ringbuffer_mask);
|
||
|
|
InitStartPosQueue(&queue);
|
||
|
|
for (i = 0; i + HashTypeLengthH10() - 1 < num_bytes; i++) {
|
||
|
|
const size_t pos = position + i;
|
||
|
|
const size_t max_distance = BROTLI_MIN(size_t, pos, max_backward_limit);
|
||
|
|
size_t num_matches = FindAllMatchesH10(hasher, dictionary, ringbuffer,
|
||
|
|
ringbuffer_mask, pos, num_bytes - i, max_distance, params, matches);
|
||
|
|
size_t skip;
|
||
|
|
if (num_matches > 0 &&
|
||
|
|
BackwardMatchLength(&matches[num_matches - 1]) > max_zopfli_len) {
|
||
|
|
matches[0] = matches[num_matches - 1];
|
||
|
|
num_matches = 1;
|
||
|
|
}
|
||
|
|
skip = UpdateNodes(num_bytes, position, i, ringbuffer, ringbuffer_mask,
|
||
|
|
params, max_backward_limit, dist_cache, num_matches, matches, &model,
|
||
|
|
&queue, nodes);
|
||
|
|
if (skip < BROTLI_LONG_COPY_QUICK_STEP) skip = 0;
|
||
|
|
if (num_matches == 1 && BackwardMatchLength(&matches[0]) > max_zopfli_len) {
|
||
|
|
skip = BROTLI_MAX(size_t, BackwardMatchLength(&matches[0]), skip);
|
||
|
|
}
|
||
|
|
if (skip > 1) {
|
||
|
|
/* Add the tail of the copy to the hasher. */
|
||
|
|
StoreRangeH10(hasher, ringbuffer, ringbuffer_mask, pos + 1, BROTLI_MIN(
|
||
|
|
size_t, pos + skip, store_end));
|
||
|
|
skip--;
|
||
|
|
while (skip) {
|
||
|
|
i++;
|
||
|
|
if (i + HashTypeLengthH10() - 1 >= num_bytes) break;
|
||
|
|
EvaluateNode(
|
||
|
|
position, i, max_backward_limit, dist_cache, &model, &queue, nodes);
|
||
|
|
skip--;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
CleanupZopfliCostModel(m, &model);
|
||
|
|
return ComputeShortestPathFromNodes(num_bytes, nodes);
|
||
|
|
}
|
||
|
|
|
||
|
|
void BrotliCreateZopfliBackwardReferences(
|
||
|
|
MemoryManager* m, 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) {
|
||
|
|
const size_t max_backward_limit = BROTLI_MAX_BACKWARD_LIMIT(params->lgwin);
|
||
|
|
ZopfliNode* nodes;
|
||
|
|
nodes = BROTLI_ALLOC(m, ZopfliNode, num_bytes + 1);
|
||
|
|
if (BROTLI_IS_OOM(m)) return;
|
||
|
|
BrotliInitZopfliNodes(nodes, num_bytes + 1);
|
||
|
|
*num_commands += BrotliZopfliComputeShortestPath(m, dictionary, num_bytes,
|
||
|
|
position, ringbuffer, ringbuffer_mask, params, max_backward_limit,
|
||
|
|
dist_cache, hasher, nodes);
|
||
|
|
if (BROTLI_IS_OOM(m)) return;
|
||
|
|
BrotliZopfliCreateCommands(num_bytes, position, max_backward_limit, nodes,
|
||
|
|
dist_cache, last_insert_len, commands, num_literals);
|
||
|
|
BROTLI_FREE(m, nodes);
|
||
|
|
}
|
||
|
|
|
||
|
|
void BrotliCreateHqZopfliBackwardReferences(
|
||
|
|
MemoryManager* m, 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) {
|
||
|
|
const size_t max_backward_limit = BROTLI_MAX_BACKWARD_LIMIT(params->lgwin);
|
||
|
|
uint32_t* num_matches = BROTLI_ALLOC(m, uint32_t, num_bytes);
|
||
|
|
size_t matches_size = 4 * num_bytes;
|
||
|
|
const size_t store_end = num_bytes >= StoreLookaheadH10() ?
|
||
|
|
position + num_bytes - StoreLookaheadH10() + 1 : position;
|
||
|
|
size_t cur_match_pos = 0;
|
||
|
|
size_t i;
|
||
|
|
size_t orig_num_literals;
|
||
|
|
size_t orig_last_insert_len;
|
||
|
|
int orig_dist_cache[4];
|
||
|
|
size_t orig_num_commands;
|
||
|
|
ZopfliCostModel model;
|
||
|
|
ZopfliNode* nodes;
|
||
|
|
BackwardMatch* matches = BROTLI_ALLOC(m, BackwardMatch, matches_size);
|
||
|
|
if (BROTLI_IS_OOM(m)) return;
|
||
|
|
for (i = 0; i + HashTypeLengthH10() - 1 < num_bytes; ++i) {
|
||
|
|
const size_t pos = position + i;
|
||
|
|
size_t max_distance = BROTLI_MIN(size_t, pos, max_backward_limit);
|
||
|
|
size_t max_length = num_bytes - i;
|
||
|
|
size_t num_found_matches;
|
||
|
|
size_t cur_match_end;
|
||
|
|
size_t j;
|
||
|
|
/* Ensure that we have enough free slots. */
|
||
|
|
BROTLI_ENSURE_CAPACITY(m, BackwardMatch, matches, matches_size,
|
||
|
|
cur_match_pos + MAX_NUM_MATCHES_H10);
|
||
|
|
if (BROTLI_IS_OOM(m)) return;
|
||
|
|
num_found_matches = FindAllMatchesH10(hasher, dictionary, ringbuffer,
|
||
|
|
ringbuffer_mask, pos, max_length, max_distance, params,
|
||
|
|
&matches[cur_match_pos]);
|
||
|
|
cur_match_end = cur_match_pos + num_found_matches;
|
||
|
|
for (j = cur_match_pos; j + 1 < cur_match_end; ++j) {
|
||
|
|
assert(BackwardMatchLength(&matches[j]) <
|
||
|
|
BackwardMatchLength(&matches[j + 1]));
|
||
|
|
assert(matches[j].distance > max_distance ||
|
||
|
|
matches[j].distance <= matches[j + 1].distance);
|
||
|
|
}
|
||
|
|
num_matches[i] = (uint32_t)num_found_matches;
|
||
|
|
if (num_found_matches > 0) {
|
||
|
|
const size_t match_len = BackwardMatchLength(&matches[cur_match_end - 1]);
|
||
|
|
if (match_len > MAX_ZOPFLI_LEN_QUALITY_11) {
|
||
|
|
const size_t skip = match_len - 1;
|
||
|
|
matches[cur_match_pos++] = matches[cur_match_end - 1];
|
||
|
|
num_matches[i] = 1;
|
||
|
|
/* Add the tail of the copy to the hasher. */
|
||
|
|
StoreRangeH10(hasher, ringbuffer, ringbuffer_mask, pos + 1,
|
||
|
|
BROTLI_MIN(size_t, pos + match_len, store_end));
|
||
|
|
memset(&num_matches[i + 1], 0, skip * sizeof(num_matches[0]));
|
||
|
|
i += skip;
|
||
|
|
} else {
|
||
|
|
cur_match_pos = cur_match_end;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
orig_num_literals = *num_literals;
|
||
|
|
orig_last_insert_len = *last_insert_len;
|
||
|
|
memcpy(orig_dist_cache, dist_cache, 4 * sizeof(dist_cache[0]));
|
||
|
|
orig_num_commands = *num_commands;
|
||
|
|
nodes = BROTLI_ALLOC(m, ZopfliNode, num_bytes + 1);
|
||
|
|
if (BROTLI_IS_OOM(m)) return;
|
||
|
|
InitZopfliCostModel(m, &model, num_bytes);
|
||
|
|
if (BROTLI_IS_OOM(m)) return;
|
||
|
|
for (i = 0; i < 2; i++) {
|
||
|
|
BrotliInitZopfliNodes(nodes, num_bytes + 1);
|
||
|
|
if (i == 0) {
|
||
|
|
ZopfliCostModelSetFromLiteralCosts(
|
||
|
|
&model, position, ringbuffer, ringbuffer_mask);
|
||
|
|
} else {
|
||
|
|
ZopfliCostModelSetFromCommands(&model, position, ringbuffer,
|
||
|
|
ringbuffer_mask, commands, *num_commands - orig_num_commands,
|
||
|
|
orig_last_insert_len);
|
||
|
|
}
|
||
|
|
*num_commands = orig_num_commands;
|
||
|
|
*num_literals = orig_num_literals;
|
||
|
|
*last_insert_len = orig_last_insert_len;
|
||
|
|
memcpy(dist_cache, orig_dist_cache, 4 * sizeof(dist_cache[0]));
|
||
|
|
*num_commands += ZopfliIterate(num_bytes, position, ringbuffer,
|
||
|
|
ringbuffer_mask, params, max_backward_limit, dist_cache,
|
||
|
|
&model, num_matches, matches, nodes);
|
||
|
|
BrotliZopfliCreateCommands(num_bytes, position, max_backward_limit,
|
||
|
|
nodes, dist_cache, last_insert_len, commands, num_literals);
|
||
|
|
}
|
||
|
|
CleanupZopfliCostModel(m, &model);
|
||
|
|
BROTLI_FREE(m, nodes);
|
||
|
|
BROTLI_FREE(m, matches);
|
||
|
|
BROTLI_FREE(m, num_matches);
|
||
|
|
}
|
||
|
|
|
||
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
||
|
|
} /* extern "C" */
|
||
|
|
#endif
|