*/
/*
- * Copyright (C) 2013 Eric Biggers
+ * Copyright (C) 2013, 2014 Eric Biggers
*
* This file is part of wimlib, a library for working with WIM files.
*
/* This a compressor for the LZMS compression format. More details about this
* format can be found in lzms-decompress.c.
*
+ * Also see lzx-compress.c for general information about match-finding and
+ * match-choosing that also applies to this LZMS compressor.
+ *
* NOTE: this compressor currently does not code any delta matches.
*/
#include "wimlib/compress_common.h"
#include "wimlib/endianness.h"
#include "wimlib/error.h"
-#include "wimlib/lz_sarray.h"
+#include "wimlib/lz.h"
+#include "wimlib/lz_bt.h"
#include "wimlib/lzms.h"
#include "wimlib/util.h"
#include <limits.h>
#include <pthread.h>
-struct lzms_compressor;
-struct lzms_adaptive_state {
- struct lzms_lz_lru_queues lru;
- u8 main_state;
- u8 match_state;
- u8 lz_match_state;
- u8 lz_repeat_match_state[LZMS_NUM_RECENT_OFFSETS - 1];
-};
-#define LZ_ADAPTIVE_STATE struct lzms_adaptive_state
-#define LZ_COMPRESSOR struct lzms_compressor
-#include "wimlib/lz_optimal.h"
-
/* Stucture used for writing raw bits to the end of the LZMS-compressed data as
* a series of 16-bit little endian coding units. */
struct lzms_output_bitstream {
/* State of the LZMS compressor. */
struct lzms_compressor {
+ struct wimlib_lzms_compressor_params params;
+
/* Pointer to a buffer holding the preprocessed data to compress. */
u8 *window;
/* Size of the data in @buffer. */
u32 window_size;
- /* Suffix array match-finder. */
- struct lz_sarray lz_sarray;
+ /* Binary tree match-finder. */
+ struct lz_bt mf;
/* Temporary space to store found matches. */
struct raw_match *matches;
- /* Match-chooser. */
- struct lz_match_chooser mc;
+ /* Match-chooser data. */
+ struct lzms_mc_pos_data *optimum;
+ unsigned optimum_cur_idx;
+ unsigned optimum_end_idx;
/* Maximum block size this compressor instantiation allows. This is the
* allocated size of @window. */
s32 last_target_usages[65536];
};
+struct lzms_mc_pos_data {
+ u32 cost;
+#define MC_INFINITE_COST ((u32)~0UL)
+ union {
+ struct {
+ u32 link;
+ u32 match_offset;
+ } prev;
+ struct {
+ u32 link;
+ u32 match_offset;
+ } next;
+ };
+ struct lzms_adaptive_state {
+ struct lzms_lz_lru_queues lru;
+ u8 main_state;
+ u8 match_state;
+ u8 lz_match_state;
+ u8 lz_repeat_match_state[LZMS_NUM_RECENT_OFFSETS - 1];
+ } state;
+};
+
/* Initialize the output bitstream @os to write forwards to the specified
* compressed data buffer @out that is @out_limit 16-bit integers long. */
static void
lzms_end_encode_item(ctx, length);
}
-/* Fast heuristic cost evaluation to use in the inner loop of the match-finder.
- * Unlike lzms_get_lz_match_cost(), which does a true cost evaluation, this
- * simply prioritize matches based on their offset. */
-static input_idx_t
-lzms_lz_match_cost_fast(input_idx_t length, input_idx_t offset, const void *_lru)
-{
- const struct lzms_lz_lru_queues *lru = _lru;
-
- for (input_idx_t i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++)
- if (offset == lru->recent_offsets[i])
- return i;
-
- return offset;
-}
-
#define LZMS_COST_SHIFT 5
/*#define LZMS_RC_COSTS_USE_FLOATING_POINT*/
}
static u32
-lzms_get_matches(struct lzms_compressor *ctx,
- const struct lzms_adaptive_state *state,
- struct raw_match **matches_ret)
+lzms_get_matches(struct lzms_compressor *ctx, struct raw_match **matches_ret)
{
*matches_ret = ctx->matches;
- return lz_sarray_get_matches(&ctx->lz_sarray,
- ctx->matches,
- lzms_lz_match_cost_fast,
- &state->lru);
+ return lz_bt_get_matches(&ctx->mf, ctx->matches);
}
static void
-lzms_skip_bytes(struct lzms_compressor *ctx, input_idx_t n)
+lzms_skip_bytes(struct lzms_compressor *ctx, u32 n)
{
- while (n--)
- lz_sarray_skip_position(&ctx->lz_sarray);
+ lz_bt_skip_positions(&ctx->mf, n);
}
static u32
-lzms_get_prev_literal_cost(struct lzms_compressor *ctx,
- struct lzms_adaptive_state *state)
+lzms_get_literal_cost(struct lzms_compressor *ctx,
+ struct lzms_adaptive_state *state, u8 literal)
{
- u8 literal = ctx->window[lz_sarray_get_pos(&ctx->lz_sarray) - 1];
u32 cost = 0;
state->lru.upcoming_offset = 0;
static u32
lzms_get_lz_match_cost(struct lzms_compressor *ctx,
struct lzms_adaptive_state *state,
- input_idx_t length, input_idx_t offset)
+ u32 length, u32 offset)
{
u32 cost = 0;
int recent_offset_idx;
return cost;
}
+static struct raw_match
+lzms_match_chooser_reverse_list(struct lzms_compressor *ctx, unsigned cur_pos)
+{
+ unsigned prev_link, saved_prev_link;
+ unsigned prev_match_offset, saved_prev_match_offset;
+
+ ctx->optimum_end_idx = cur_pos;
+
+ saved_prev_link = ctx->optimum[cur_pos].prev.link;
+ saved_prev_match_offset = ctx->optimum[cur_pos].prev.match_offset;
+
+ do {
+ prev_link = saved_prev_link;
+ prev_match_offset = saved_prev_match_offset;
+
+ saved_prev_link = ctx->optimum[prev_link].prev.link;
+ saved_prev_match_offset = ctx->optimum[prev_link].prev.match_offset;
+
+ ctx->optimum[prev_link].next.link = cur_pos;
+ ctx->optimum[prev_link].next.match_offset = prev_match_offset;
+
+ cur_pos = prev_link;
+ } while (cur_pos != 0);
+
+ ctx->optimum_cur_idx = ctx->optimum[0].next.link;
+
+ return (struct raw_match)
+ { .len = ctx->optimum_cur_idx,
+ .offset = ctx->optimum[0].next.match_offset,
+ };
+}
+
+/* This is similar to lzx_get_near_optimal_match() in lzx-compress.c.
+ * Read that one if you want to understand it. */
static struct raw_match
lzms_get_near_optimal_match(struct lzms_compressor *ctx)
{
+ u32 num_matches;
+ struct raw_match *matches;
+ struct raw_match match;
+ u32 longest_len;
+ u32 longest_rep_len;
+ u32 longest_rep_offset;
+ struct raw_match *matchptr;
+ unsigned cur_pos;
+ unsigned end_pos;
struct lzms_adaptive_state initial_state;
+ if (ctx->optimum_cur_idx != ctx->optimum_end_idx) {
+ match.len = ctx->optimum[ctx->optimum_cur_idx].next.link -
+ ctx->optimum_cur_idx;
+ match.offset = ctx->optimum[ctx->optimum_cur_idx].next.match_offset;
+
+ ctx->optimum_cur_idx = ctx->optimum[ctx->optimum_cur_idx].next.link;
+ return match;
+ }
+
+ ctx->optimum_cur_idx = 0;
+ ctx->optimum_end_idx = 0;
+
+ longest_rep_len = ctx->params.min_match_length - 1;
+ if (lz_bt_get_position(&ctx->mf) >= 1) {
+ u32 limit = min(ctx->params.max_match_length,
+ lz_bt_get_remaining_size(&ctx->mf));
+ for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
+ u32 offset = ctx->lru.lz.recent_offsets[i];
+ const u8 *strptr = lz_bt_get_window_ptr(&ctx->mf);
+ const u8 *matchptr = strptr - offset;
+ u32 len = 0;
+ while (len < limit && strptr[len] == matchptr[len])
+ len++;
+ if (len > longest_rep_len) {
+ longest_rep_len = len;
+ longest_rep_offset = offset;
+ }
+ }
+ }
+
+ if (longest_rep_len >= ctx->params.nice_match_length) {
+ lzms_skip_bytes(ctx, longest_rep_len);
+ return (struct raw_match) {
+ .len = longest_rep_len,
+ .offset = longest_rep_offset,
+ };
+ }
+
+ num_matches = lzms_get_matches(ctx, &matches);
+
+ if (num_matches) {
+ longest_len = matches[num_matches - 1].len;
+ if (longest_len >= ctx->params.nice_match_length) {
+ lzms_skip_bytes(ctx, longest_len - 1);
+ return matches[num_matches - 1];
+ }
+ } else {
+ longest_len = 1;
+ }
+
initial_state.lru = ctx->lru.lz;
initial_state.main_state = ctx->main_range_encoder.state;
initial_state.match_state = ctx->match_range_encoder.state;
initial_state.lz_match_state = ctx->lz_match_range_encoder.state;
for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS - 1; i++)
- initial_state.lz_repeat_match_state[i] =
- ctx->lz_repeat_match_range_encoders[i].state;
- return lz_get_near_optimal_match(&ctx->mc,
- lzms_get_matches,
- lzms_skip_bytes,
- lzms_get_prev_literal_cost,
- lzms_get_lz_match_cost,
- ctx,
- &initial_state);
+ initial_state.lz_repeat_match_state[i] = ctx->lz_repeat_match_range_encoders[i].state;
+
+ ctx->optimum[1].state = initial_state;
+ ctx->optimum[1].cost = lzms_get_literal_cost(ctx,
+ &ctx->optimum[1].state,
+ *(lz_bt_get_window_ptr(&ctx->mf) - 1));
+ ctx->optimum[1].prev.link = 0;
+
+ matchptr = matches;
+ for (u32 len = 2; len <= longest_len; len++) {
+ u32 offset = matchptr->offset;
+
+ ctx->optimum[len].state = initial_state;
+ ctx->optimum[len].prev.link = 0;
+ ctx->optimum[len].prev.match_offset = offset;
+ ctx->optimum[len].cost = lzms_get_lz_match_cost(ctx,
+ &ctx->optimum[len].state,
+ len, offset);
+ if (len == matchptr->len)
+ matchptr++;
+ }
+ end_pos = longest_len;
+
+ if (longest_rep_len >= ctx->params.min_match_length) {
+ struct lzms_adaptive_state state;
+ u32 cost;
+
+ while (end_pos < longest_rep_len)
+ ctx->optimum[++end_pos].cost = MC_INFINITE_COST;
+
+ state = initial_state;
+ cost = lzms_get_lz_match_cost(ctx,
+ &state,
+ longest_rep_len,
+ longest_rep_offset);
+ if (cost <= ctx->optimum[longest_rep_len].cost) {
+ ctx->optimum[longest_rep_len].state = state;
+ ctx->optimum[longest_rep_len].prev.link = 0;
+ ctx->optimum[longest_rep_len].prev.match_offset = longest_rep_offset;
+ ctx->optimum[longest_rep_len].cost = cost;
+ }
+ }
+
+ cur_pos = 0;
+ for (;;) {
+ u32 cost;
+ struct lzms_adaptive_state state;
+
+ cur_pos++;
+
+ if (cur_pos == end_pos || cur_pos == ctx->params.optim_array_length)
+ return lzms_match_chooser_reverse_list(ctx, cur_pos);
+
+ longest_rep_len = ctx->params.min_match_length - 1;
+ u32 limit = min(ctx->params.max_match_length,
+ lz_bt_get_remaining_size(&ctx->mf));
+ for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
+ u32 offset = ctx->optimum[cur_pos].state.lru.recent_offsets[i];
+ const u8 *strptr = lz_bt_get_window_ptr(&ctx->mf);
+ const u8 *matchptr = strptr - offset;
+ u32 len = 0;
+ while (len < limit && strptr[len] == matchptr[len])
+ len++;
+ if (len > longest_rep_len) {
+ longest_rep_len = len;
+ longest_rep_offset = offset;
+ }
+ }
+
+ if (longest_rep_len >= ctx->params.nice_match_length) {
+ match = lzms_match_chooser_reverse_list(ctx, cur_pos);
+
+ ctx->optimum[cur_pos].next.match_offset = longest_rep_offset;
+ ctx->optimum[cur_pos].next.link = cur_pos + longest_rep_len;
+ ctx->optimum_end_idx = cur_pos + longest_rep_len;
+
+ lzms_skip_bytes(ctx, longest_rep_len);
+
+ return match;
+ }
+
+ num_matches = lzms_get_matches(ctx, &matches);
+
+ if (num_matches) {
+ longest_len = matches[num_matches - 1].len;
+ if (longest_len >= ctx->params.nice_match_length) {
+ match = lzms_match_chooser_reverse_list(ctx, cur_pos);
+
+ ctx->optimum[cur_pos].next.match_offset =
+ matches[num_matches - 1].offset;
+ ctx->optimum[cur_pos].next.link = cur_pos + longest_len;
+ ctx->optimum_end_idx = cur_pos + longest_len;
+
+ lzms_skip_bytes(ctx, longest_len - 1);
+
+ return match;
+ }
+ } else {
+ longest_len = 1;
+ }
+
+ while (end_pos < cur_pos + longest_len)
+ ctx->optimum[++end_pos].cost = MC_INFINITE_COST;
+
+ state = ctx->optimum[cur_pos].state;
+ cost = ctx->optimum[cur_pos].cost +
+ lzms_get_literal_cost(ctx,
+ &state,
+ *(lz_bt_get_window_ptr(&ctx->mf) - 1));
+ if (cost < ctx->optimum[cur_pos + 1].cost) {
+ ctx->optimum[cur_pos + 1].state = state;
+ ctx->optimum[cur_pos + 1].cost = cost;
+ ctx->optimum[cur_pos + 1].prev.link = cur_pos;
+ }
+
+ matchptr = matches;
+ for (u32 len = 2; len <= longest_len; len++) {
+ u32 offset;
+
+ offset = matchptr->offset;
+ state = ctx->optimum[cur_pos].state;
+
+ cost = ctx->optimum[cur_pos].cost +
+ lzms_get_lz_match_cost(ctx, &state, len, offset);
+ if (cost < ctx->optimum[cur_pos + len].cost) {
+ ctx->optimum[cur_pos + len].state = state;
+ ctx->optimum[cur_pos + len].prev.link = cur_pos;
+ ctx->optimum[cur_pos + len].prev.match_offset = offset;
+ ctx->optimum[cur_pos + len].cost = cost;
+ }
+ if (len == matchptr->len)
+ matchptr++;
+ }
+
+ if (longest_rep_len >= ctx->params.min_match_length) {
+
+ while (end_pos < cur_pos + longest_rep_len)
+ ctx->optimum[++end_pos].cost = MC_INFINITE_COST;
+
+ state = ctx->optimum[cur_pos].state;
+
+ cost = ctx->optimum[cur_pos].cost +
+ lzms_get_lz_match_cost(ctx,
+ &state,
+ longest_rep_len,
+ longest_rep_offset);
+ if (cost <= ctx->optimum[cur_pos + longest_rep_len].cost) {
+ ctx->optimum[cur_pos + longest_rep_len].state =
+ state;
+ ctx->optimum[cur_pos + longest_rep_len].prev.link =
+ cur_pos;
+ ctx->optimum[cur_pos + longest_rep_len].prev.match_offset =
+ longest_rep_offset;
+ ctx->optimum[cur_pos + longest_rep_len].cost =
+ cost;
+ }
+ }
+ }
}
/*
*
* Notes:
*
- * - This uses near-optimal LZ parsing backed by a suffix-array match-finder.
- * More details can be found in the corresponding files (lz_optimal.h,
- * lz_sarray.{h,c}).
+ * - This uses near-optimal LZ parsing backed by a binary tree match-finder.
*
- * - This does not output any delta matches. It would take a specialized
- * algorithm to find them, then more code in lz_optimal.h and here to handle
- * evaluating and outputting them.
+ * - This does not output any delta matches.
*
* - The costs of literals and matches are estimated using the range encoder
* states and the semi-adaptive Huffman codes. Except for range encoding
{
struct raw_match match;
- /* Load window into suffix array match-finder. */
- lz_sarray_load_window(&ctx->lz_sarray, ctx->window, ctx->window_size);
+ /* Load window into the binary tree match-finder. */
+ lz_bt_load_window(&ctx->mf, ctx->window, ctx->window_size);
/* Reset the match-chooser. */
- lz_match_chooser_begin(&ctx->mc);
+ ctx->optimum_cur_idx = 0;
+ ctx->optimum_end_idx = 0;
while (ctx->cur_window_pos != ctx->window_size) {
match = lzms_get_near_optimal_match(ctx);
if (ctx) {
FREE(ctx->window);
FREE(ctx->matches);
- lz_sarray_destroy(&ctx->lz_sarray);
- lz_match_chooser_destroy(&ctx->mc);
+ lz_bt_destroy(&ctx->mf);
+ FREE(ctx->optimum);
FREE(ctx);
}
}
.max_match_length = UINT32_MAX,
.nice_match_length = 32,
.max_search_depth = 50,
- .max_matches_per_pos = 3,
.optim_array_length = 1024,
};
ctx->matches = MALLOC(min(params->max_match_length -
params->min_match_length + 1,
- params->max_matches_per_pos) *
+ params->max_search_depth + 2) *
sizeof(ctx->matches[0]));
if (ctx->matches == NULL)
goto oom;
- if (!lz_sarray_init(&ctx->lz_sarray, max_block_size,
- params->min_match_length,
- min(params->max_match_length, LZ_SARRAY_LEN_MAX),
- params->max_search_depth,
- params->max_matches_per_pos))
+ if (!lz_bt_init(&ctx->mf,
+ max_block_size,
+ params->min_match_length,
+ params->max_match_length,
+ params->nice_match_length,
+ params->max_search_depth))
goto oom;
- if (!lz_match_chooser_init(&ctx->mc,
- params->optim_array_length,
- params->nice_match_length,
- params->max_match_length))
+ ctx->optimum = MALLOC((params->optim_array_length +
+ min(params->nice_match_length,
+ params->max_match_length)) *
+ sizeof(ctx->optimum[0]));
+ if (!ctx->optimum)
goto oom;
/* Initialize position and length slot data if not done already. */
lzms_init_rc_costs();
ctx->max_block_size = max_block_size;
+ memcpy(&ctx->params, params, sizeof(*params));
*ctx_ret = ctx;
return 0;
size += max_block_size;
size += sizeof(struct lzms_compressor);
- size += lz_sarray_get_needed_memory(max_block_size);
- size += lz_match_chooser_get_needed_memory(params->optim_array_length,
- params->nice_match_length,
- params->max_match_length);
- size += min(params->max_match_length -
- params->min_match_length + 1,
- params->max_matches_per_pos) *
+ size += lz_bt_get_needed_memory(max_block_size);
+ size += (params->optim_array_length +
+ min(params->nice_match_length,
+ params->max_match_length)) *
+ sizeof(((struct lzms_compressor *)0)->optimum[0]);
+ size += min(params->max_match_length - params->min_match_length + 1,
+ params->max_search_depth + 2) *
sizeof(((struct lzms_compressor*)0)->matches[0]);
return size;
}
git://wimlib.net / wimlib / blobdiff