/* This a compressor for the LZMS compression format. More details about this
* format can be found in lzms-decompress.c.
*
- * This is currently an unsophisticated implementation that is fast but does not
- * attain the best compression ratios allowed by the format.
+ * NOTE: this compressor currently does not code any delta matches.
*/
#ifdef HAVE_CONFIG_H
#endif
#include "wimlib.h"
-#include "wimlib/assert.h"
#include "wimlib/compiler.h"
#include "wimlib/compressor_ops.h"
#include "wimlib/compress_common.h"
#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 <limits.h>
#include <pthread.h>
-#define LZMS_OPTIM_ARRAY_SIZE 1024
-
struct lzms_compressor;
struct lzms_adaptive_state {
struct lzms_lz_lru_queues lru;
struct lzms_probability_entry prob_entries[LZMS_MAX_NUM_STATES];
};
-/* Structure used for Huffman encoding, optionally encoding larger "values" as a
- * Huffman symbol specifying a slot and a slot-dependent number of extra bits.
- * */
+/* Structure used for Huffman encoding. */
struct lzms_huffman_encoder {
/* Bitstream to write Huffman-encoded symbols and verbatim bits to.
*/
struct lzms_output_bitstream *os;
- /* Pointer to the slot base table to use. */
- const u32 *slot_base_tab;
-
/* Number of symbols that have been written using this code far. Reset
* to 0 whenever the code is rebuilt. */
u32 num_syms_written;
/* Size of the data in @buffer. */
u32 window_size;
-#if 0
- /* Temporary array used by lz_analyze_block(); must be at least as long
- * as the window. */
- u32 *prev_tab;
-#endif
-
/* Suffix array match-finder. */
struct lz_sarray lz_sarray;
- struct raw_match matches[64];
+ /* Temporary space to store found matches. */
+ struct raw_match *matches;
/* Match-chooser. */
struct lz_match_chooser mc;
}
}
-/* Encode a number as a Huffman symbol specifying a slot, plus a number of
- * slot-dependent extra bits. */
static void
-lzms_encode_value(struct lzms_huffman_encoder *enc, u32 value)
+lzms_encode_length(struct lzms_huffman_encoder *enc, u32 length)
{
unsigned slot;
unsigned num_extra_bits;
u32 extra_bits;
- LZMS_ASSERT(enc->slot_base_tab != NULL);
+ slot = lzms_get_length_slot(length);
- slot = lzms_get_slot(value, enc->slot_base_tab, enc->num_syms);
+ num_extra_bits = lzms_extra_length_bits[slot];
- /* Get the number of extra bits needed to represent the range of values
- * that share the slot. */
- num_extra_bits = bsr32(enc->slot_base_tab[slot + 1] -
- enc->slot_base_tab[slot]);
+ extra_bits = length - lzms_length_slot_base[slot];
- /* Calculate the extra bits as the offset from the slot base. */
- extra_bits = value - enc->slot_base_tab[slot];
+ lzms_huffman_encode_symbol(enc, slot);
+ lzms_output_bitstream_put_bits(enc->os, extra_bits, num_extra_bits);
+}
+
+static void
+lzms_encode_offset(struct lzms_huffman_encoder *enc, u32 offset)
+{
+ unsigned slot;
+ unsigned num_extra_bits;
+ u32 extra_bits;
+
+ slot = lzms_get_position_slot(offset);
+
+ num_extra_bits = lzms_extra_position_bits[slot];
+
+ extra_bits = offset - lzms_position_slot_base[slot];
- /* Output the slot (Huffman-encoded), then the extra bits (verbatim).
- */
lzms_huffman_encode_symbol(enc, slot);
lzms_output_bitstream_put_bits(enc->os, extra_bits, num_extra_bits);
}
lzms_range_encode_bit(&ctx->lz_match_range_encoder, 0);
/* Encode the match offset. */
- lzms_encode_value(&ctx->lz_offset_encoder, offset);
+ lzms_encode_offset(&ctx->lz_offset_encoder, offset);
} else {
int i;
}
/* Encode the match length. */
- lzms_encode_value(&ctx->length_encoder, length);
+ lzms_encode_length(&ctx->length_encoder, length);
/* Save the match offset for later insertion at the front of the LZ
* match offset LRU queue. */
lzms_end_encode_item(ctx, length);
}
-#if 0
-static void
-lzms_record_literal(u8 literal, void *_ctx)
-{
- struct lzms_compressor *ctx = _ctx;
-
- lzms_encode_literal(ctx, literal);
-}
-
-static void
-lzms_record_match(unsigned length, unsigned offset, void *_ctx)
-{
- struct lzms_compressor *ctx = _ctx;
-
- lzms_encode_lz_match(ctx, length, offset);
-}
-
-static void
-lzms_fast_encode(struct lzms_compressor *ctx)
-{
- static const struct lz_params lzms_lz_params = {
- .min_match = 3,
- .max_match = UINT_MAX,
- .max_offset = UINT_MAX,
- .nice_match = 64,
- .good_match = 32,
- .max_chain_len = 64,
- .max_lazy_match = 258,
- .too_far = 4096,
- };
-
- lz_analyze_block(ctx->window,
- ctx->window_size,
- lzms_record_match,
- lzms_record_literal,
- ctx,
- &lzms_lz_params,
- ctx->prev_tab);
-
-}
-#endif
-
/* 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. */
/*#define LZMS_RC_COSTS_USE_FLOATING_POINT*/
static u32
-lzms_rc_costs[LZMS_PROBABILITY_MAX];
+lzms_rc_costs[LZMS_PROBABILITY_MAX + 1];
#ifdef LZMS_RC_COSTS_USE_FLOATING_POINT
# include <math.h>
* really interpreted as 1 / 64 and 64 / 64 is really interpreted as
* 63 / 64.
*/
- for (u32 i = 0; i < LZMS_PROBABILITY_MAX; i++) {
+ for (u32 i = 0; i <= LZMS_PROBABILITY_MAX; i++) {
u32 prob = i;
if (prob == 0)
static bool done = false;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
- if (!done) {
+ if (unlikely(!done)) {
pthread_mutex_lock(&mutex);
if (!done) {
lzms_do_init_rc_costs();
*cur_state = (*cur_state << 1) | bit;
- if (prob_zero == 0)
- prob_zero = 1;
- else if (prob_zero == LZMS_PROBABILITY_MAX)
- prob_zero = LZMS_PROBABILITY_MAX - 1;
-
if (bit == 0)
prob_correct = prob_zero;
else
return enc->lens[sym] << LZMS_COST_SHIFT;
}
-/* Compute the cost to encode a number with lzms_encode_value(). */
static u32
-lzms_value_cost(const struct lzms_huffman_encoder *enc, u32 value)
+lzms_offset_cost(const struct lzms_huffman_encoder *enc, u32 offset)
+{
+ u32 slot;
+ u32 num_extra_bits;
+ u32 cost = 0;
+
+ slot = lzms_get_position_slot(offset);
+
+ cost += lzms_huffman_symbol_cost(enc, slot);
+
+ num_extra_bits = lzms_extra_position_bits[slot];
+
+ cost += num_extra_bits << LZMS_COST_SHIFT;
+
+ return cost;
+}
+
+static u32
+lzms_length_cost(const struct lzms_huffman_encoder *enc, u32 length)
{
u32 slot;
u32 num_extra_bits;
u32 cost = 0;
- slot = lzms_get_slot(value, enc->slot_base_tab, enc->num_syms);
+ slot = lzms_get_length_slot(length);
cost += lzms_huffman_symbol_cost(enc, slot);
- num_extra_bits = bsr32(enc->slot_base_tab[slot + 1] -
- enc->slot_base_tab[slot]);
+ num_extra_bits = lzms_extra_length_bits[slot];
cost += num_extra_bits << LZMS_COST_SHIFT;
const struct lzms_adaptive_state *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_lz_match_cost_fast,
- &state->lru);
-#if 0
- fprintf(stderr, "Pos %u: %u matches\n",
- lz_sarray_get_pos(&ctx->lz_sarray) - 1, num_matches);
- for (u32 i = 0; i < num_matches; i++)
- fprintf(stderr, "\tLen %u Offset %u\n", matches[i].len, matches[i].offset);
-#endif
-
-#ifdef ENABLE_LZMS_DEBUG
- LZMS_ASSERT(lz_sarray_get_pos(&ctx->lz_sarray) > 0);
- u32 curpos = lz_sarray_get_pos(&ctx->lz_sarray) - 1;
- 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 < num_matches - 1)
- LZMS_ASSERT(matches[i].len > matches[i + 1].len);
-
- }
-#endif
- *matches_ret = matches;
- return num_matches;
+ *matches_ret = ctx->matches;
+ return lz_sarray_get_matches(&ctx->lz_sarray,
+ ctx->matches,
+ lzms_lz_match_cost_fast,
+ &state->lru);
}
static void
cost += lzms_rc_bit_cost(&ctx->lz_match_range_encoder,
&state->lz_match_state, 0);
- cost += lzms_value_cost(&ctx->lz_offset_encoder, offset);
+ cost += lzms_offset_cost(&ctx->lz_offset_encoder, offset);
} else {
int i;
state->lru.recent_offsets[i] = state->lru.recent_offsets[i + 1];
}
- cost += lzms_value_cost(&ctx->length_encoder, length);
+ cost += lzms_length_cost(&ctx->length_encoder, length);
state->lru.upcoming_offset = offset;
lzms_update_lz_lru_queues(&state->lru);
* - The costs of literals and matches are estimated using the range encoder
* states and the semi-adaptive Huffman codes. Except for range encoding
* states, costs are assumed to be constant throughout a single run of the
- * parsing algorithm, which can parse up to LZMS_OPTIM_ARRAY_SIZE bytes of
- * data. This introduces a source of inaccuracy because the probabilities and
- * Huffman codes can change over this part of the data.
+ * parsing algorithm, which can parse up to @optim_array_length (from the
+ * `struct wimlib_lzms_compressor_params') bytes of data. This introduces a
+ * source of inaccuracy because the probabilities and Huffman codes can change
+ * over this part of the data.
*/
static void
-lzms_normal_encode(struct lzms_compressor *ctx)
+lzms_encode(struct lzms_compressor *ctx)
{
struct raw_match match;
static void
lzms_init_huffman_encoder(struct lzms_huffman_encoder *enc,
struct lzms_output_bitstream *os,
- const u32 *slot_base_tab,
unsigned num_syms,
unsigned rebuild_freq)
{
enc->os = os;
- enc->slot_base_tab = slot_base_tab;
enc->num_syms_written = 0;
enc->rebuild_freq = rebuild_freq;
enc->num_syms = num_syms;
/* Copy the uncompressed data into the @ctx->window buffer. */
memcpy(ctx->window, udata, ulen);
- memset(&ctx->window[ulen], 0, 8);
ctx->cur_window_pos = 0;
ctx->window_size = ulen;
/* Initialize Huffman encoders for each alphabet used in the compressed
* representation. */
lzms_init_huffman_encoder(&ctx->literal_encoder, &ctx->os,
- NULL, LZMS_NUM_LITERAL_SYMS,
+ LZMS_NUM_LITERAL_SYMS,
LZMS_LITERAL_CODE_REBUILD_FREQ);
lzms_init_huffman_encoder(&ctx->lz_offset_encoder, &ctx->os,
- lzms_position_slot_base, num_position_slots,
+ num_position_slots,
LZMS_LZ_OFFSET_CODE_REBUILD_FREQ);
lzms_init_huffman_encoder(&ctx->length_encoder, &ctx->os,
- lzms_length_slot_base, LZMS_NUM_LEN_SYMS,
+ LZMS_NUM_LEN_SYMS,
LZMS_LENGTH_CODE_REBUILD_FREQ);
lzms_init_huffman_encoder(&ctx->delta_offset_encoder, &ctx->os,
- lzms_position_slot_base, num_position_slots,
+ num_position_slots,
LZMS_DELTA_OFFSET_CODE_REBUILD_FREQ);
lzms_init_huffman_encoder(&ctx->delta_power_encoder, &ctx->os,
- NULL, LZMS_NUM_DELTA_POWER_SYMS,
+ LZMS_NUM_DELTA_POWER_SYMS,
LZMS_DELTA_POWER_CODE_REBUILD_FREQ);
/* Initialize range encoders, all of which wrap around the same
&ctx->rc, LZMS_NUM_DELTA_REPEAT_MATCH_STATES);
/* Initialize LRU match information. */
- lzms_init_lru_queues(&ctx->lru);
+ lzms_init_lru_queues(&ctx->lru);
}
/* Flush the output streams, prepare the final compressed data, and return its
/* Compute and encode a literal/match sequence that decompresses to the
* preprocessed data. */
- lzms_normal_encode(ctx);
-#if 0
- lzms_fast_encode(ctx);
-#endif
+ lzms_encode(ctx);
/* Get and return the compressed data size. */
compressed_size = lzms_finalize(ctx, compressed_data,
if (ctx) {
FREE(ctx->window);
-#if 0
- FREE(ctx->prev_tab);
-#endif
+ FREE(ctx->matches);
lz_sarray_destroy(&ctx->lz_sarray);
lz_match_chooser_destroy(&ctx->mc);
FREE(ctx);
}
}
-static const struct wimlib_lzms_compressor_params default_params = {
- .hdr = sizeof(struct wimlib_lzms_compressor_params),
+static const struct wimlib_lzms_compressor_params lzms_default = {
+ .hdr = {
+ .size = sizeof(struct wimlib_lzms_compressor_params),
+ },
.min_match_length = 2,
.max_match_length = UINT32_MAX,
.nice_match_length = 32,
.optim_array_length = 1024,
};
+static const struct wimlib_lzms_compressor_params *
+lzms_get_params(const struct wimlib_compressor_params_header *_params)
+{
+ const struct wimlib_lzms_compressor_params *params =
+ (const struct wimlib_lzms_compressor_params*)_params;
+
+ if (params == NULL)
+ params = &lzms_default;
+
+ return params;
+}
+
static int
lzms_create_compressor(size_t max_block_size,
const struct wimlib_compressor_params_header *_params,
void **ctx_ret)
{
struct lzms_compressor *ctx;
- const struct wimlib_lzms_compressor_params *params;
+ const struct wimlib_lzms_compressor_params *params = lzms_get_params(_params);
if (max_block_size == 0 || max_block_size >= INT32_MAX) {
LZMS_DEBUG("Invalid max_block_size (%u)", max_block_size);
return WIMLIB_ERR_INVALID_PARAM;
}
- if (_params)
- params = (const struct wimlib_lzms_compressor_params*)_params;
- else
- params = &default_params;
-
- if (params->max_match_length < params->min_match_length ||
- params->min_match_length < 2 ||
- params->optim_array_length == 0 ||
- min(params->max_match_length, params->nice_match_length) > 65536) {
- LZMS_DEBUG("Invalid compression parameter!");
- return WIMLIB_ERR_INVALID_PARAM;
- }
-
ctx = CALLOC(1, sizeof(struct lzms_compressor));
if (ctx == NULL)
goto oom;
- ctx->window = MALLOC(max_block_size + 8);
+ ctx->window = MALLOC(max_block_size);
if (ctx->window == NULL)
goto oom;
-#if 0
- ctx->prev_tab = MALLOC(max_block_size * sizeof(ctx->prev_tab[0]));
- if (ctx->prev_tab == NULL)
+ ctx->matches = MALLOC(min(params->max_match_length -
+ params->min_match_length + 1,
+ params->max_matches_per_pos) *
+ sizeof(ctx->matches[0]));
+ if (ctx->matches == NULL)
goto oom;
-#endif
if (!lz_sarray_init(&ctx->lz_sarray, max_block_size,
params->min_match_length,
params->max_match_length))
goto oom;
- /* Initialize position and length slot bases if not done already. */
- lzms_init_slot_bases();
+ /* Initialize position and length slot data if not done already. */
+ lzms_init_slots();
/* Initialize range encoding cost table if not done already. */
lzms_init_rc_costs();
return WIMLIB_ERR_NOMEM;
}
+static u64
+lzms_get_needed_memory(size_t max_block_size,
+ const struct wimlib_compressor_params_header *_params)
+{
+ const struct wimlib_lzms_compressor_params *params = lzms_get_params(_params);
+
+ u64 size = 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) *
+ sizeof(((struct lzms_compressor*)0)->matches[0]);
+ return size;
+}
+
+static bool
+lzms_params_valid(const struct wimlib_compressor_params_header *_params)
+{
+ const struct wimlib_lzms_compressor_params *params =
+ (const struct wimlib_lzms_compressor_params*)_params;
+
+ if (params->hdr.size != sizeof(*params) ||
+ params->max_match_length < params->min_match_length ||
+ params->min_match_length < 2 ||
+ params->optim_array_length == 0 ||
+ min(params->max_match_length, params->nice_match_length) > 65536)
+ return false;
+
+ return true;
+}
+
const struct compressor_ops lzms_compressor_ops = {
+ .params_valid = lzms_params_valid,
+ .get_needed_memory = lzms_get_needed_memory,
.create_compressor = lzms_create_compressor,
.compress = lzms_compress,
.free_compressor = lzms_free_compressor,
git://wimlib.net / wimlib / blobdiff