#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"
* as the window. */
u32 *prev_tab;
+ /* Suffix array match-finder. */
+ struct lz_sarray lz_sarray;
+
/* 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. */
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_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;
+
-static struct lzms_match
-lzms_get_best_match(struct lzms_compressor *ctx)
+ /* 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)
{
- struct lzms_match match;
+ while (n--)
+ lz_sarray_skip_position(&ctx->lz_sarray);
+}
- /* TODO */
+static struct raw_match
+lzms_get_near_optimal_match(struct lzms_compressor *ctx)
+{
+ struct raw_match matches[10];
+ u32 num_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 };
- match.length = 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);
+#endif
- return match;
+ lzms_lz_skip_bytes(ctx, matches[0].len - 1);
+ return matches[0];
}
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);
/* 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 == 0) {
/* 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);
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;
+
+
ctx->max_block_size = max_block_size;
*ctx_ret = ctx;
git://wimlib.net / wimlib / blobdiff