*/
/*
- * 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.
*
- * This is currently an unsophisticated implementation that is fast but does not
- * attain the best compression ratios allowed by the format.
+ * 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.
*/
#ifdef HAVE_CONFIG_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/lz_mf.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;
- 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 {
* lzms_range_encoder_raw. */
struct lzms_range_encoder_raw *rc;
- /* Bits recently encoded by this range encoder. This are used as in
+ /* Bits recently encoded by this range encoder. This is used as an
* index into @prob_entries. */
u32 state;
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;
u8 lens[LZMS_MAX_NUM_SYMS];
/* The codeword of each symbol in the Huffman code. */
- u16 codewords[LZMS_MAX_NUM_SYMS];
+ u32 codewords[LZMS_MAX_NUM_SYMS];
+};
+
+struct lzms_compressor_params {
+ u32 min_match_length;
+ u32 nice_match_length;
+ u32 max_search_depth;
+ u32 optim_array_length;
};
/* State of the LZMS compressor. */
/* 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;
+ /* Lempel-Ziv match-finder. */
+ struct lz_mf *mf;
- struct raw_match matches[64];
+ /* Temporary space to store found matches. */
+ struct lz_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. */
u32 max_block_size;
+ /* Compression parameters. */
+ struct lzms_compressor_params params;
+
/* Raw range encoder which outputs to the beginning of the compressed
* data buffer, proceeding forwards. */
struct lzms_range_encoder_raw rc;
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
}
}
-/* 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);
+
+ num_extra_bits = lzms_extra_length_bits[slot];
+
+ extra_bits = length - lzms_length_slot_base[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_slot(value, enc->slot_base_tab, enc->num_syms);
+ slot = lzms_get_position_slot(offset);
- /* 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]);
+ num_extra_bits = lzms_extra_position_bits[slot];
- /* Calculate the extra bits as the offset from the slot base. */
- extra_bits = value - enc->slot_base_tab[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);
}
/* Main bit: 1 = a match, not a literal. */
lzms_range_encode_bit(&ctx->main_range_encoder, 1);
- /* Match bit: 0 = a LZ match, not a delta match. */
+ /* Match bit: 0 = an LZ match, not a delta match. */
lzms_range_encode_bit(&ctx->match_range_encoder, 0);
/* Determine if the offset can be represented as a recent offset. */
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. */
-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_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 void
lzms_init_rc_costs(void)
{
- static bool done = false;
- static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-
- if (!done) {
- pthread_mutex_lock(&mutex);
- if (!done) {
- lzms_do_init_rc_costs();
- done = true;
- }
- pthread_mutex_unlock(&mutex);
- }
+ static pthread_once_t once = PTHREAD_ONCE_INIT;
+
+ pthread_once(&once, 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_slot(value, enc->slot_base_tab, enc->num_syms);
+ slot = lzms_get_position_slot(offset);
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_position_bits[slot];
cost += num_extra_bits << LZMS_COST_SHIFT;
}
static u32
-lzms_get_matches(struct lzms_compressor *ctx,
- const struct lzms_adaptive_state *state,
- struct raw_match **matches_ret)
+lzms_get_length_cost(const struct lzms_huffman_encoder *enc, u32 length)
{
- 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
+ u32 slot;
+ u32 num_extra_bits;
+ u32 cost = 0;
-#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);
+ slot = lzms_get_length_slot(length);
- }
-#endif
- *matches_ret = matches;
- return num_matches;
+ cost += lzms_huffman_symbol_cost(enc, slot);
+
+ num_extra_bits = lzms_extra_length_bits[slot];
+
+ cost += num_extra_bits << LZMS_COST_SHIFT;
+
+ return cost;
+}
+
+static u32
+lzms_get_matches(struct lzms_compressor *ctx, struct lz_match **matches_ret)
+{
+ *matches_ret = ctx->matches;
+ return lz_mf_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_mf_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)
+lzms_get_lz_match_cost_nolen(struct lzms_compressor *ctx,
+ struct lzms_adaptive_state *state, u32 offset)
{
u32 cost = 0;
int recent_offset_idx;
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);
state->lru.upcoming_offset = offset;
lzms_update_lz_lru_queues(&state->lru);
return cost;
}
-static struct raw_match
+static u32
+lzms_get_lz_match_cost(struct lzms_compressor *ctx,
+ struct lzms_adaptive_state *state,
+ u32 length, u32 offset)
+{
+ return lzms_get_lz_match_cost_nolen(ctx, state, offset) +
+ lzms_get_length_cost(&ctx->length_encoder, length);
+}
+
+static struct lz_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 lz_match)
+ { .len = ctx->optimum_cur_idx,
+ .offset = ctx->optimum[0].next.match_offset,
+ };
+}
+
+/* This is similar to lzx_choose_near_optimal_match() in lzx-compress.c.
+ * Read that one if you want to understand it. */
+static struct lz_match
lzms_get_near_optimal_match(struct lzms_compressor *ctx)
{
+ u32 num_matches;
+ struct lz_match *matches;
+ struct lz_match match;
+ u32 longest_len;
+ u32 longest_rep_len;
+ u32 longest_rep_offset;
+ 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_mf_get_position(ctx->mf) >= LZMS_MAX_INIT_RECENT_OFFSET) {
+ u32 limit = lz_mf_get_bytes_remaining(ctx->mf);
+ for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
+ u32 offset = ctx->lru.lz.recent_offsets[i];
+ const u8 *strptr = lz_mf_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 lz_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_mf_get_window_ptr(ctx->mf) - 1));
+ ctx->optimum[1].prev.link = 0;
+
+ for (u32 i = 0, len = 2; i < num_matches; i++) {
+ u32 offset = matches[i].offset;
+ struct lzms_adaptive_state state;
+ u32 position_cost;
+
+ state = initial_state;
+ position_cost = 0;
+ position_cost += lzms_get_lz_match_cost_nolen(ctx, &state, offset);
+
+ do {
+ u32 cost;
+
+ cost = position_cost;
+ cost += lzms_get_length_cost(&ctx->length_encoder, len);
+
+ ctx->optimum[len].state = state;
+ ctx->optimum[len].prev.link = 0;
+ ctx->optimum[len].prev.match_offset = offset;
+ ctx->optimum[len].cost = cost;
+ } while (++len <= matches[i].len);
+ }
+ 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;
+ if (lz_mf_get_position(ctx->mf) >= LZMS_MAX_INIT_RECENT_OFFSET) {
+ u32 limit = lz_mf_get_bytes_remaining(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_mf_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_mf_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;
+ }
+
+ for (u32 i = 0, len = 2; i < num_matches; i++) {
+ u32 offset = matches[i].offset;
+ struct lzms_adaptive_state state;
+ u32 position_cost;
+
+ state = ctx->optimum[cur_pos].state;
+ position_cost = ctx->optimum[cur_pos].cost;
+ position_cost += lzms_get_lz_match_cost_nolen(ctx, &state, offset);
+
+ do {
+ u32 cost;
+
+ cost = position_cost;
+ cost += lzms_get_length_cost(&ctx->length_encoder, len);
+
+ 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;
+ }
+ } while (++len <= matches[i].len);
+ }
+
+ 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 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
* 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
+ * parsing algorithm, which can parse up to @optim_array_length 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;
+ struct lz_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 match-finder. */
+ lz_mf_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);
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
return compressed_size;
}
+
+static void
+lzms_build_params(unsigned int compression_level,
+ struct lzms_compressor_params *lzms_params)
+{
+ lzms_params->min_match_length = (compression_level >= 50) ? 2 : 3;
+ lzms_params->nice_match_length = ((u64)compression_level * 32) / 50;
+ lzms_params->max_search_depth = ((u64)compression_level * 50) / 50;
+ lzms_params->optim_array_length = 224 + compression_level * 16;
+}
+
+static void
+lzms_build_mf_params(const struct lzms_compressor_params *lzms_params,
+ u32 max_window_size, struct lz_mf_params *mf_params)
+{
+ memset(mf_params, 0, sizeof(*mf_params));
+
+ mf_params->algorithm = LZ_MF_DEFAULT;
+ mf_params->max_window_size = max_window_size;
+ mf_params->min_match_len = lzms_params->min_match_length;
+ mf_params->max_search_depth = lzms_params->max_search_depth;
+ mf_params->nice_match_len = lzms_params->nice_match_length;
+}
+
+static void
+lzms_free_compressor(void *_ctx);
+
+static u64
+lzms_get_needed_memory(size_t max_block_size, unsigned int compression_level)
+{
+ struct lzms_compressor_params params;
+
+ lzms_build_params(compression_level, ¶ms);
+
+ u64 size = 0;
+
+ size += sizeof(struct lzms_compressor);
+ size += max_block_size;
+ size += lz_mf_get_needed_memory(LZ_MF_DEFAULT, max_block_size);
+ size += params.max_search_depth * sizeof(struct lz_match);
+ size += (params.optim_array_length + params.nice_match_length) *
+ sizeof(struct lzms_mc_pos_data);
+
+ return size;
+}
+
+static int
+lzms_create_compressor(size_t max_block_size, unsigned int compression_level,
+ void **ctx_ret)
+{
+ struct lzms_compressor *ctx;
+ struct lzms_compressor_params params;
+ struct lz_mf_params mf_params;
+
+ if (max_block_size >= INT32_MAX)
+ return WIMLIB_ERR_INVALID_PARAM;
+
+ lzms_build_params(compression_level, ¶ms);
+ lzms_build_mf_params(¶ms, max_block_size, &mf_params);
+ if (!lz_mf_params_valid(&mf_params))
+ return WIMLIB_ERR_INVALID_PARAM;
+
+ ctx = CALLOC(1, sizeof(struct lzms_compressor));
+ if (!ctx)
+ goto oom;
+
+ ctx->params = params;
+ ctx->max_block_size = max_block_size;
+
+ ctx->window = MALLOC(max_block_size);
+ if (!ctx->window)
+ goto oom;
+
+ ctx->mf = lz_mf_alloc(&mf_params);
+ if (!ctx->mf)
+ goto oom;
+
+ ctx->matches = MALLOC(params.max_search_depth * sizeof(struct lz_match));
+ if (!ctx->matches)
+ goto oom;
+
+ ctx->optimum = MALLOC((params.optim_array_length +
+ params.nice_match_length) *
+ sizeof(struct lzms_mc_pos_data));
+ if (!ctx->optimum)
+ goto oom;
+
+ /* 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();
+
+ *ctx_ret = ctx;
+ return 0;
+
+oom:
+ lzms_free_compressor(ctx);
+ return WIMLIB_ERR_NOMEM;
+}
+
static size_t
lzms_compress(const void *uncompressed_data, size_t uncompressed_size,
void *compressed_data, size_t compressed_size_avail, void *_ctx)
LZMS_DEBUG("uncompressed_size=%zu, compressed_size_avail=%zu",
uncompressed_size, compressed_size_avail);
- /* Make sure the uncompressed size is compatible with this compressor.
- */
- if (uncompressed_size > ctx->max_block_size) {
- LZMS_DEBUG("Can't compress %zu bytes: LZMS context "
- "only supports %u bytes",
- uncompressed_size, ctx->max_block_size);
- return 0;
- }
-
/* Don't bother compressing extremely small inputs. */
if (uncompressed_size < 4) {
LZMS_DEBUG("Input too small to bother compressing.");
/* 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,
LZMS_DEBUG("Compressed %zu => %zu bytes",
uncompressed_size, compressed_size);
-#if defined(ENABLE_VERIFY_COMPRESSION) || defined(ENABLE_LZMS_DEBUG)
- /* Verify that we really get the same thing back when decompressing. */
- {
- struct wimlib_decompressor *decompressor;
-
- LZMS_DEBUG("Verifying LZMS compression.");
-
- if (0 == wimlib_create_decompressor(WIMLIB_COMPRESSION_TYPE_LZMS,
- ctx->max_block_size,
- NULL,
- &decompressor))
- {
- int ret;
- ret = wimlib_decompress(compressed_data,
- compressed_size,
- ctx->window,
- uncompressed_size,
- decompressor);
- wimlib_free_decompressor(decompressor);
-
- if (ret) {
- ERROR("Failed to decompress data we "
- "compressed using LZMS algorithm");
- wimlib_assert(0);
- return 0;
- }
- if (memcmp(uncompressed_data, ctx->window,
- uncompressed_size))
- {
- ERROR("Data we compressed using LZMS algorithm "
- "didn't decompress to original");
- wimlib_assert(0);
- return 0;
- }
- } else {
- WARNING("Failed to create decompressor for "
- "data verification!");
- }
- }
-#endif /* ENABLE_LZMS_DEBUG || ENABLE_VERIFY_COMPRESSION */
-
return compressed_size;
}
if (ctx) {
FREE(ctx->window);
-#if 0
- FREE(ctx->prev_tab);
-#endif
- lz_sarray_destroy(&ctx->lz_sarray);
- lz_match_chooser_destroy(&ctx->mc);
+ lz_mf_free(ctx->mf);
+ FREE(ctx->matches);
+ FREE(ctx->optimum);
FREE(ctx);
}
}
-static const struct wimlib_lzms_compressor_params default_params = {
- .hdr = sizeof(struct wimlib_lzms_compressor_params),
- .min_match_length = 2,
- .max_match_length = UINT32_MAX,
- .nice_match_length = 32,
- .max_search_depth = 50,
- .max_matches_per_pos = 3,
- .optim_array_length = 1024,
-};
-
-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;
-
- 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);
- 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)
- goto oom;
-#endif
-
- if (!lz_sarray_init(&ctx->lz_sarray, max_block_size,
- params->min_match_length,
- params->max_match_length,
- params->max_search_depth,
- params->max_matches_per_pos))
- goto oom;
-
- if (!lz_match_chooser_init(&ctx->mc,
- params->optim_array_length,
- params->nice_match_length,
- params->max_match_length))
- goto oom;
-
- /* Initialize position and length slot bases if not done already. */
- lzms_init_slot_bases();
-
- /* Initialize range encoding cost table if not done already. */
- lzms_init_rc_costs();
-
- ctx->max_block_size = max_block_size;
-
- *ctx_ret = ctx;
- return 0;
-
-oom:
- lzms_free_compressor(ctx);
- return WIMLIB_ERR_NOMEM;
-}
-
const struct compressor_ops lzms_compressor_ops = {
+ .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