#include "wimlib/endianness.h"
#include "wimlib/error.h"
#include "wimlib/lz_hash.h"
+#include "wimlib/lz_sarray.h"
#include "wimlib/lzms.h"
#include "wimlib/util.h"
#include <string.h>
#include <limits.h>
+#define LZMS_OPTIM_ARRAY_SIZE 1024
+
+struct lzms_compressor;
+struct lzms_cost_state {
+ struct lzms_lz_lru_queues lru;
+ u8 main_state;
+ u8 match_state;
+ u8 lz_match_state;
+};
+#define LZ_FORMAT_STATE struct lzms_cost_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 {
* as the window. */
u32 *prev_tab;
+ /* Suffix array match-finder. */
+ struct lz_sarray lz_sarray;
+
+ struct raw_match matches[64];
+
+ /* Match-chooser. */
+ struct lz_match_chooser mc;
+
/* Maximum block size this compressor instantiation allows. This is the
* allocated size of @window. */
u32 max_block_size;
struct lzms_huffman_encoder delta_power_encoder;
struct lzms_huffman_encoder delta_offset_encoder;
- /* LRU (least-recently-used) queue of LZ match offsets. */
- u64 recent_lz_offsets[LZMS_NUM_RECENT_OFFSETS + 1];
-
- /* LRU (least-recently-used) queue of delta match powers. */
- u32 recent_delta_powers[LZMS_NUM_RECENT_OFFSETS + 1];
-
- /* LRU (least-recently-used) queue of delta match offsets. */
- u32 recent_delta_offsets[LZMS_NUM_RECENT_OFFSETS + 1];
-
- /* These variables are used to delay updates to the LRU queues by one
- * decoded item. */
- u32 prev_lz_offset;
- u32 prev_delta_power;
- u32 prev_delta_offset;
- u32 upcoming_lz_offset;
- u32 upcoming_delta_power;
- u32 upcoming_delta_offset;
+ /* LRU (least-recently-used) queues for match information. */
+ struct lzms_lru_queues lru;
/* Used for preprocessing. */
s32 last_target_usages[65536];
};
-struct lzms_match {
- u32 length;
- u32 offset;
-};
-
/* 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
static void
lzms_begin_encode_item(struct lzms_compressor *ctx)
{
- ctx->upcoming_delta_offset = 0;
- ctx->upcoming_lz_offset = 0;
- ctx->upcoming_delta_power = 0;
+ ctx->lru.lz.upcoming_offset = 0;
+ ctx->lru.delta.upcoming_offset = 0;
+ ctx->lru.delta.upcoming_power = 0;
}
static void
{
LZMS_ASSERT(ctx->window_size - ctx->cur_window_pos >= length);
ctx->cur_window_pos += length;
-
- /* Update LRU queues */
- if (ctx->prev_lz_offset != 0) {
- for (int i = LZMS_NUM_RECENT_OFFSETS - 1; i >= 0; i--)
- ctx->recent_lz_offsets[i + 1] = ctx->recent_lz_offsets[i];
- ctx->recent_lz_offsets[0] = ctx->prev_lz_offset;
- }
-
- if (ctx->prev_delta_offset != 0) {
- for (int i = LZMS_NUM_RECENT_OFFSETS - 1; i >= 0; i--) {
- ctx->recent_delta_powers[i + 1] = ctx->recent_delta_powers[i];
- ctx->recent_delta_offsets[i + 1] = ctx->recent_delta_offsets[i];
- }
- ctx->recent_delta_powers[0] = ctx->prev_delta_power;
- ctx->recent_delta_offsets[0] = ctx->prev_delta_offset;
- }
-
- ctx->prev_lz_offset = ctx->upcoming_lz_offset;
- ctx->prev_delta_offset = ctx->upcoming_delta_offset;
- ctx->prev_delta_power = ctx->upcoming_delta_power;
+ lzms_update_lru_queues(&ctx->lru);
}
/* Encode a literal byte. */
{
int recent_offset_idx;
+ LZMS_ASSERT(!memcmp(&ctx->window[ctx->cur_window_pos],
+ &ctx->window[ctx->cur_window_pos - offset],
+ length));
+
lzms_begin_encode_item(ctx);
LZMS_DEBUG("Position %u: Encoding LZ match {length=%u, offset=%u}",
for (recent_offset_idx = 0;
recent_offset_idx < LZMS_NUM_RECENT_OFFSETS;
recent_offset_idx++)
- if (offset == ctx->recent_lz_offsets[recent_offset_idx])
+ if (offset == ctx->lru.lz.recent_offsets[recent_offset_idx])
break;
if (recent_offset_idx == LZMS_NUM_RECENT_OFFSETS) {
/* Initial update of the LZ match offset LRU queue. */
for (; i < LZMS_NUM_RECENT_OFFSETS; i++)
- ctx->recent_lz_offsets[i] = ctx->recent_lz_offsets[i + 1];
+ ctx->lru.lz.recent_offsets[i] = ctx->lru.lz.recent_offsets[i + 1];
}
/* Encode the match length. */
/* Save the match offset for later insertion at the front of the LZ
* match offset LRU queue. */
- ctx->upcoming_lz_offset = offset;
+ ctx->lru.lz.upcoming_offset = offset;
lzms_end_encode_item(ctx, length);
}
}
-#if 0
+/* Fast heuristic cost evaluation to use in the inner loop of the match-finder.
+ * Unlike lzms_get_match_cost(), which does a true cost evaluation, this simply
+ * prioritize matches based on their offset. */
+static input_idx_t
+lzms_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;
-static struct lzms_match
-lzms_get_best_match(struct lzms_compressor *ctx)
+ return offset;
+}
+
+static u32
+lzms_rc_bit_cost(const struct lzms_range_encoder *enc, u8 *cur_state, int bit)
{
- struct lzms_match match;
+ u32 prob;
+ u32 cost;
- /* TODO */
+ prob = enc->prob_entries[*cur_state & enc->mask].num_recent_zero_bits;
+ if (prob == 0)
+ prob = 1;
+ else if (prob == LZMS_PROBABILITY_MAX)
+ prob = LZMS_PROBABILITY_MAX - 1;
+
+ if (bit == 0)
+ prob = LZMS_PROBABILITY_MAX - prob;
+
+ cost = prob * 2; /* TODO */
+
+ *cur_state = (*cur_state << 1) | bit;
+
+ return cost;
+}
+
+#define LZMS_COST_SCALE 64
+
+static u32
+lzms_huffman_symbol_cost(const struct lzms_huffman_encoder *enc, u32 sym)
+{
+ return enc->lens[sym] * LZMS_COST_SCALE;
+}
+
+static u32
+lzms_value_cost(const struct lzms_huffman_encoder *enc, u32 value)
+{
+ u32 slot;
+ u32 num_extra_bits;
+ u32 cost = 0;
+
+ slot = lzms_get_slot(value, enc->slot_base_tab, enc->num_syms);
+
+ cost += lzms_huffman_symbol_cost(enc, slot);
- match.length = 0;
+ num_extra_bits = bsr32(enc->slot_base_tab[slot + 1] -
+ enc->slot_base_tab[slot]);
- return match;
+ cost += num_extra_bits * LZMS_COST_SCALE;
+
+ return cost;
+}
+
+static u32
+lzms_get_matches(struct lzms_compressor *ctx,
+ const struct lzms_cost_state *cost_state,
+ struct raw_match **matches_ret)
+{
+ u32 num_matches;
+ struct raw_match *matches = ctx->matches;
+
+ num_matches = lz_sarray_get_matches(&ctx->lz_sarray,
+ matches,
+ lzms_match_cost_fast,
+ &cost_state->lru);
+
+#ifdef ENABLE_LZMS_DEBUG
+ u32 curpos = lz_sarray_get_pos(&ctx->lz_sarray) - 1;
+ LZMS_ASSERT(curpos >= 0);
+ for (u32 i = 0; i < num_matches; i++) {
+ LZMS_ASSERT(matches[i].len <= ctx->window_size - curpos);
+ LZMS_ASSERT(matches[i].offset > 0);
+ LZMS_ASSERT(matches[i].offset <= curpos);
+ LZMS_ASSERT(!memcmp(&ctx->window[curpos],
+ &ctx->window[curpos - matches[i].offset],
+ matches[i].len));
+ if (i > 0)
+ LZMS_ASSERT(matches[i - 1].len > matches[i].len);
+
+ }
+#endif
+
+ *matches_ret = matches;
+ return num_matches;
+}
+
+static void
+lzms_skip_bytes(struct lzms_compressor *ctx, input_idx_t n)
+{
+ while (n--)
+ lz_sarray_skip_position(&ctx->lz_sarray);
+}
+
+static u32
+lzms_get_prev_literal_cost(struct lzms_compressor *ctx,
+ struct lzms_cost_state *cost_state)
+{
+ u8 literal = ctx->window[lz_sarray_get_pos(&ctx->lz_sarray) - 1];
+ u32 cost = 0;
+
+ cost_state->lru.upcoming_offset = 0;
+ lzms_update_lz_lru_queues(&cost_state->lru);
+
+ cost += lzms_rc_bit_cost(&ctx->main_range_encoder,
+ &cost_state->main_state, 0);
+ cost += lzms_huffman_symbol_cost(&ctx->literal_encoder, literal);
+
+ return cost;
+}
+
+static u32
+lzms_get_match_cost(struct lzms_compressor *ctx,
+ struct lzms_cost_state *cost_state,
+ input_idx_t length, input_idx_t offset)
+{
+ u32 cost = 0;
+ int recent_offset_idx;
+
+ cost += lzms_rc_bit_cost(&ctx->main_range_encoder,
+ &cost_state->main_state, 1);
+ cost += lzms_rc_bit_cost(&ctx->match_range_encoder,
+ &cost_state->match_state, 0);
+
+ for (recent_offset_idx = 0;
+ recent_offset_idx < LZMS_NUM_RECENT_OFFSETS;
+ recent_offset_idx++)
+ if (offset == cost_state->lru.recent_offsets[recent_offset_idx])
+ break;
+
+ if (recent_offset_idx == LZMS_NUM_RECENT_OFFSETS) {
+ /* Explicit offset. */
+ cost += lzms_rc_bit_cost(&ctx->lz_match_range_encoder,
+ &cost_state->lz_match_state, 0);
+
+ cost += lzms_value_cost(&ctx->lz_offset_encoder, offset);
+ } else {
+ int i;
+
+ /* Repeat offset. */
+ cost += lzms_rc_bit_cost(&ctx->lz_match_range_encoder,
+ &cost_state->lz_match_state, 1);
+
+ for (i = 0; i < recent_offset_idx; i++)
+ cost++; /* TODO */
+
+ if (i < LZMS_NUM_RECENT_OFFSETS - 1)
+ cost++; /* TODO */
+
+ /* Initial update of the LZ match offset LRU queue. */
+ for (; i < LZMS_NUM_RECENT_OFFSETS; i++)
+ cost_state->lru.recent_offsets[i] = cost_state->lru.recent_offsets[i + 1];
+ }
+
+ cost += lzms_value_cost(&ctx->length_encoder, length);
+
+ cost_state->lru.upcoming_offset = offset;
+ lzms_update_lz_lru_queues(&cost_state->lru);
+
+ return cost;
+}
+
+static struct raw_match
+lzms_get_near_optimal_match(struct lzms_compressor *ctx)
+{
+ struct lzms_cost_state initial_state = {
+ .lru = ctx->lru.lz,
+ .main_state = ctx->main_range_encoder.state,
+ .match_state = ctx->match_range_encoder.state,
+ .lz_match_state = ctx->lz_match_range_encoder.state,
+ };
+ return lz_get_near_optimal_match(&ctx->mc,
+ lzms_get_matches,
+ lzms_skip_bytes,
+ lzms_get_prev_literal_cost,
+ lzms_get_match_cost,
+ ctx,
+ &initial_state);
}
static void
lzms_slow_encode(struct lzms_compressor *ctx)
{
- struct lzms_match match;
+ struct raw_match match;
+
+ /* Load window into suffix array match-finder. */
+ lz_sarray_load_window(&ctx->lz_sarray, ctx->window, ctx->window_size);
+
+ /* Reset the match-chooser. */
+ lz_match_chooser_begin(&ctx->mc);
/* TODO */
while (ctx->cur_window_pos != ctx->window_size) {
- match = lzms_get_best_match(ctx);
- if (match.length == 0) {
+
+ match = lzms_get_near_optimal_match(ctx);
+ if (match.len <= 1) {
/* Literal */
lzms_encode_literal(ctx, ctx->window[ctx->cur_window_pos]);
} else {
/* LZ match */
- lzms_encode_lz_match(ctx, match.length, match.offset);
+ lzms_encode_lz_match(ctx, match.len, match.offset);
}
}
}
-#endif
static void
lzms_init_range_encoder(struct lzms_range_encoder *enc,
lzms_init_range_encoder(&ctx->delta_repeat_match_range_encoders[i],
&ctx->rc, LZMS_NUM_DELTA_REPEAT_MATCH_STATES);
- /* Initialize the LRU queue for recent match offsets. */
- for (size_t i = 0; i < LZMS_NUM_RECENT_OFFSETS + 1; i++)
- ctx->recent_lz_offsets[i] = i + 1;
-
- for (size_t i = 0; i < LZMS_NUM_RECENT_OFFSETS + 1; i++) {
- ctx->recent_delta_powers[i] = 0;
- ctx->recent_delta_offsets[i] = i + 1;
- }
- ctx->prev_lz_offset = 0;
- ctx->prev_delta_offset = 0;
- ctx->prev_delta_power = 0;
- ctx->upcoming_lz_offset = 0;
- ctx->upcoming_delta_offset = 0;
- ctx->upcoming_delta_power = 0;
+ /* Initialize LRU match information. */
+ lzms_init_lru_queues(&ctx->lru);
}
/* Flush the output streams, prepare the final compressed data, and return its
/* Determine and output a literal/match sequence that decompresses to
* the preprocessed data. */
- lzms_fast_encode(ctx);
+ if (1)
+ lzms_slow_encode(ctx);
+ else
+ lzms_fast_encode(ctx);
/* Get and return the compressed data size. */
compressed_size = lzms_finalize(ctx, compressed_data,
if (ctx) {
FREE(ctx->window);
FREE(ctx->prev_tab);
+ lz_sarray_destroy(&ctx->lz_sarray);
+ lz_match_chooser_destroy(&ctx->mc);
FREE(ctx);
}
}
if (ctx->prev_tab == NULL)
goto oom;
+ if (!lz_sarray_init(&ctx->lz_sarray,
+ max_block_size,
+ 2,
+ max_block_size,
+ 100,
+ 10))
+ goto oom;
+
+ if (!lz_match_chooser_init(&ctx->mc,
+ LZMS_OPTIM_ARRAY_SIZE,
+ 32,
+ max_block_size))
+ goto oom;
+
ctx->max_block_size = max_block_size;
*ctx_ret = ctx;
git://wimlib.net / wimlib / blobdiff