#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 {
/* 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;
{
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}",
}
/* Fast heuristic cost evaluation to use in the inner loop of the match-finder.
- * Unlike lzms_match_cost() which does a true cost evaluation, this simply
+ * 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;
-
- /* It seems well worth it to take the time to give priority to recently
- * used offsets. */
for (input_idx_t i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++)
if (offset == lru->recent_offsets[i])
return i;
return offset;
}
-static void
-lzms_lz_skip_bytes(struct lzms_compressor *ctx, u32 n)
+static u32
+lzms_rc_bit_cost(const struct lzms_range_encoder *enc, u8 *cur_state, int bit)
{
- while (n--)
- lz_sarray_skip_position(&ctx->lz_sarray);
+ u32 prob;
+ u32 cost;
+
+ 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;
}
-static struct raw_match
-lzms_get_near_optimal_match(struct lzms_compressor *ctx)
+#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);
+
+ num_extra_bits = bsr32(enc->slot_base_tab[slot + 1] -
+ enc->slot_base_tab[slot]);
+
+ 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)
{
- struct raw_match matches[10];
u32 num_matches;
+ struct raw_match *matches = ctx->matches;
num_matches = lz_sarray_get_matches(&ctx->lz_sarray,
matches,
lzms_match_cost_fast,
- &ctx->lru.lz);
- if (num_matches == 0)
- return (struct raw_match) { .len = 0 };
-
-#if 0
- fprintf(stderr, "Pos %u/%u: %u matches\n",
- lz_sarray_get_pos(&ctx->lz_sarray) - 1,
- ctx->window_size, num_matches);
- for (u32 i = 0; i < num_matches; i++)
- fprintf(stderr, "\tLen %u Offset %u\n", matches[i].len, matches[i].offset);
+ &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
- lzms_lz_skip_bytes(ctx, matches[0].len - 1);
- return matches[0];
+ *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
/* 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_near_optimal_match(ctx);
- if (match.len == 0) {
+ if (match.len <= 1) {
/* Literal */
lzms_encode_literal(ctx, ctx->window[ctx->cur_window_pos]);
} else {
FREE(ctx->window);
FREE(ctx->prev_tab);
lz_sarray_destroy(&ctx->lz_sarray);
+ lz_match_chooser_destroy(&ctx->mc);
FREE(ctx);
}
}
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;
git://wimlib.net / wimlib / blobdiff