X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=lzma%2Flzma%2Flzma_encoder.c;fp=lzma%2Flzma%2Flzma_encoder.c;h=4c5f99c3823db92fc37e2cddbf7e9befbdaee6f4;hb=32b8a6b26ed8843828e03e505d2256960bda0980;hp=0000000000000000000000000000000000000000;hpb=d48fc23a4bcf8ca3c406d6e8c8a6f8c6b0fa2f1e;p=zpackage diff --git a/lzma/lzma/lzma_encoder.c b/lzma/lzma/lzma_encoder.c new file mode 100644 index 0000000..4c5f99c --- /dev/null +++ b/lzma/lzma/lzma_encoder.c @@ -0,0 +1,676 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lzma_encoder.c +/// \brief LZMA encoder +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "lzma2_encoder.h" +#include "lzma_encoder_private.h" +#include "fastpos.h" + + +///////////// +// Literal // +///////////// + +static inline void +literal_matched(lzma_range_encoder *rc, probability *subcoder, + uint32_t match_byte, uint32_t symbol) +{ + uint32_t offset = 0x100; + symbol += UINT32_C(1) << 8; + + do { + match_byte <<= 1; + const uint32_t match_bit = match_byte & offset; + const uint32_t subcoder_index + = offset + match_bit + (symbol >> 8); + const uint32_t bit = (symbol >> 7) & 1; + rc_bit(rc, &subcoder[subcoder_index], bit); + + symbol <<= 1; + offset &= ~(match_byte ^ symbol); + + } while (symbol < (UINT32_C(1) << 16)); +} + + +static inline void +literal(lzma_coder *coder, lzma_mf *mf, uint32_t position) +{ + // Locate the literal byte to be encoded and the subcoder. + const uint8_t cur_byte = mf->buffer[ + mf->read_pos - mf->read_ahead]; + probability *subcoder = literal_subcoder(coder->literal, + coder->literal_context_bits, coder->literal_pos_mask, + position, mf->buffer[mf->read_pos - mf->read_ahead - 1]); + + if (is_literal_state(coder->state)) { + // Previous LZMA-symbol was a literal. Encode a normal + // literal without a match byte. + rc_bittree(&coder->rc, subcoder, 8, cur_byte); + } else { + // Previous LZMA-symbol was a match. Use the last byte of + // the match as a "match byte". That is, compare the bits + // of the current literal and the match byte. + const uint8_t match_byte = mf->buffer[ + mf->read_pos - coder->reps[0] - 1 + - mf->read_ahead]; + literal_matched(&coder->rc, subcoder, match_byte, cur_byte); + } + + update_literal(coder->state); +} + + +////////////////// +// Match length // +////////////////// + +static void +length_update_prices(lzma_length_encoder *lc, const uint32_t pos_state) +{ + const uint32_t table_size = lc->table_size; + lc->counters[pos_state] = table_size; + + const uint32_t a0 = rc_bit_0_price(lc->choice); + const uint32_t a1 = rc_bit_1_price(lc->choice); + const uint32_t b0 = a1 + rc_bit_0_price(lc->choice2); + const uint32_t b1 = a1 + rc_bit_1_price(lc->choice2); + uint32_t *const prices = lc->prices[pos_state]; + + uint32_t i; + for (i = 0; i < table_size && i < LEN_LOW_SYMBOLS; ++i) + prices[i] = a0 + rc_bittree_price(lc->low[pos_state], + LEN_LOW_BITS, i); + + for (; i < table_size && i < LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS; ++i) + prices[i] = b0 + rc_bittree_price(lc->mid[pos_state], + LEN_MID_BITS, i - LEN_LOW_SYMBOLS); + + for (; i < table_size; ++i) + prices[i] = b1 + rc_bittree_price(lc->high, LEN_HIGH_BITS, + i - LEN_LOW_SYMBOLS - LEN_MID_SYMBOLS); + + return; +} + + +static inline void +length(lzma_range_encoder *rc, lzma_length_encoder *lc, + const uint32_t pos_state, uint32_t len, const bool fast_mode) +{ + assert(len <= MATCH_LEN_MAX); + len -= MATCH_LEN_MIN; + + if (len < LEN_LOW_SYMBOLS) { + rc_bit(rc, &lc->choice, 0); + rc_bittree(rc, lc->low[pos_state], LEN_LOW_BITS, len); + } else { + rc_bit(rc, &lc->choice, 1); + len -= LEN_LOW_SYMBOLS; + + if (len < LEN_MID_SYMBOLS) { + rc_bit(rc, &lc->choice2, 0); + rc_bittree(rc, lc->mid[pos_state], LEN_MID_BITS, len); + } else { + rc_bit(rc, &lc->choice2, 1); + len -= LEN_MID_SYMBOLS; + rc_bittree(rc, lc->high, LEN_HIGH_BITS, len); + } + } + + // Only getoptimum uses the prices so don't update the table when + // in fast mode. + if (!fast_mode) + if (--lc->counters[pos_state] == 0) + length_update_prices(lc, pos_state); +} + + +/////////// +// Match // +/////////// + +static inline void +match(lzma_coder *coder, const uint32_t pos_state, + const uint32_t distance, const uint32_t len) +{ + update_match(coder->state); + + length(&coder->rc, &coder->match_len_encoder, pos_state, len, + coder->fast_mode); + + const uint32_t dist_slot = get_dist_slot(distance); + const uint32_t dist_state = get_dist_state(len); + rc_bittree(&coder->rc, coder->dist_slot[dist_state], + DIST_SLOT_BITS, dist_slot); + + if (dist_slot >= DIST_MODEL_START) { + const uint32_t footer_bits = (dist_slot >> 1) - 1; + const uint32_t base = (2 | (dist_slot & 1)) << footer_bits; + const uint32_t dist_reduced = distance - base; + + if (dist_slot < DIST_MODEL_END) { + // Careful here: base - dist_slot - 1 can be -1, but + // rc_bittree_reverse starts at probs[1], not probs[0]. + rc_bittree_reverse(&coder->rc, + coder->dist_special + base - dist_slot - 1, + footer_bits, dist_reduced); + } else { + rc_direct(&coder->rc, dist_reduced >> ALIGN_BITS, + footer_bits - ALIGN_BITS); + rc_bittree_reverse( + &coder->rc, coder->dist_align, + ALIGN_BITS, dist_reduced & ALIGN_MASK); + ++coder->align_price_count; + } + } + + coder->reps[3] = coder->reps[2]; + coder->reps[2] = coder->reps[1]; + coder->reps[1] = coder->reps[0]; + coder->reps[0] = distance; + ++coder->match_price_count; +} + + +//////////////////// +// Repeated match // +//////////////////// + +static inline void +rep_match(lzma_coder *coder, const uint32_t pos_state, + const uint32_t rep, const uint32_t len) +{ + if (rep == 0) { + rc_bit(&coder->rc, &coder->is_rep0[coder->state], 0); + rc_bit(&coder->rc, + &coder->is_rep0_long[coder->state][pos_state], + len != 1); + } else { + const uint32_t distance = coder->reps[rep]; + rc_bit(&coder->rc, &coder->is_rep0[coder->state], 1); + + if (rep == 1) { + rc_bit(&coder->rc, &coder->is_rep1[coder->state], 0); + } else { + rc_bit(&coder->rc, &coder->is_rep1[coder->state], 1); + rc_bit(&coder->rc, &coder->is_rep2[coder->state], + rep - 2); + + if (rep == 3) + coder->reps[3] = coder->reps[2]; + + coder->reps[2] = coder->reps[1]; + } + + coder->reps[1] = coder->reps[0]; + coder->reps[0] = distance; + } + + if (len == 1) { + update_short_rep(coder->state); + } else { + length(&coder->rc, &coder->rep_len_encoder, pos_state, len, + coder->fast_mode); + update_long_rep(coder->state); + } +} + + +////////// +// Main // +////////// + +static void +encode_symbol(lzma_coder *coder, lzma_mf *mf, + uint32_t back, uint32_t len, uint32_t position) +{ + const uint32_t pos_state = position & coder->pos_mask; + + if (back == UINT32_MAX) { + // Literal i.e. eight-bit byte + assert(len == 1); + rc_bit(&coder->rc, + &coder->is_match[coder->state][pos_state], 0); + literal(coder, mf, position); + } else { + // Some type of match + rc_bit(&coder->rc, + &coder->is_match[coder->state][pos_state], 1); + + if (back < REPS) { + // It's a repeated match i.e. the same distance + // has been used earlier. + rc_bit(&coder->rc, &coder->is_rep[coder->state], 1); + rep_match(coder, pos_state, back, len); + } else { + // Normal match + rc_bit(&coder->rc, &coder->is_rep[coder->state], 0); + match(coder, pos_state, back - REPS, len); + } + } + + assert(mf->read_ahead >= len); + mf->read_ahead -= len; +} + + +static bool +encode_init(lzma_coder *coder, lzma_mf *mf) +{ + assert(mf_position(mf) == 0); + + if (mf->read_pos == mf->read_limit) { + if (mf->action == LZMA_RUN) + return false; // We cannot do anything. + + // We are finishing (we cannot get here when flushing). + assert(mf->write_pos == mf->read_pos); + assert(mf->action == LZMA_FINISH); + } else { + // Do the actual initialization. The first LZMA symbol must + // always be a literal. + mf_skip(mf, 1); + mf->read_ahead = 0; + rc_bit(&coder->rc, &coder->is_match[0][0], 0); + rc_bittree(&coder->rc, coder->literal[0], 8, mf->buffer[0]); + } + + // Initialization is done (except if empty file). + coder->is_initialized = true; + + return true; +} + + +static void +encode_eopm(lzma_coder *coder, uint32_t position) +{ + const uint32_t pos_state = position & coder->pos_mask; + rc_bit(&coder->rc, &coder->is_match[coder->state][pos_state], 1); + rc_bit(&coder->rc, &coder->is_rep[coder->state], 0); + match(coder, pos_state, UINT32_MAX, MATCH_LEN_MIN); +} + + +/// Number of bytes that a single encoding loop in lzma_lzma_encode() can +/// consume from the dictionary. This limit comes from lzma_lzma_optimum() +/// and may need to be updated if that function is significantly modified. +#define LOOP_INPUT_MAX (OPTS + 1) + + +extern lzma_ret +lzma_lzma_encode(lzma_coder *restrict coder, lzma_mf *restrict mf, + uint8_t *restrict out, size_t *restrict out_pos, + size_t out_size, uint32_t limit) +{ + // Initialize the stream if no data has been encoded yet. + if (!coder->is_initialized && !encode_init(coder, mf)) + return LZMA_OK; + + // Get the lowest bits of the uncompressed offset from the LZ layer. + uint32_t position = mf_position(mf); + + while (true) { + // Encode pending bits, if any. Calling this before encoding + // the next symbol is needed only with plain LZMA, since + // LZMA2 always provides big enough buffer to flush + // everything out from the range encoder. For the same reason, + // rc_encode() never returns true when this function is used + // as part of LZMA2 encoder. + if (rc_encode(&coder->rc, out, out_pos, out_size)) { + assert(limit == UINT32_MAX); + return LZMA_OK; + } + + // With LZMA2 we need to take care that compressed size of + // a chunk doesn't get too big. + // FIXME? Check if this could be improved. + if (limit != UINT32_MAX + && (mf->read_pos - mf->read_ahead >= limit + || *out_pos + rc_pending(&coder->rc) + >= LZMA2_CHUNK_MAX + - LOOP_INPUT_MAX)) + break; + + // Check that there is some input to process. + if (mf->read_pos >= mf->read_limit) { + if (mf->action == LZMA_RUN) + return LZMA_OK; + + if (mf->read_ahead == 0) + break; + } + + // Get optimal match (repeat position and length). + // Value ranges for pos: + // - [0, REPS): repeated match + // - [REPS, UINT32_MAX): + // match at (pos - REPS) + // - UINT32_MAX: not a match but a literal + // Value ranges for len: + // - [MATCH_LEN_MIN, MATCH_LEN_MAX] + uint32_t len; + uint32_t back; + + if (coder->fast_mode) + lzma_lzma_optimum_fast(coder, mf, &back, &len); + else + lzma_lzma_optimum_normal( + coder, mf, &back, &len, position); + + encode_symbol(coder, mf, back, len, position); + + position += len; + } + + if (!coder->is_flushed) { + coder->is_flushed = true; + + // We don't support encoding plain LZMA streams without EOPM, + // and LZMA2 doesn't use EOPM at LZMA level. + if (limit == UINT32_MAX) + encode_eopm(coder, position); + + // Flush the remaining bytes from the range encoder. + rc_flush(&coder->rc); + + // Copy the remaining bytes to the output buffer. If there + // isn't enough output space, we will copy out the remaining + // bytes on the next call to this function by using + // the rc_encode() call in the encoding loop above. + if (rc_encode(&coder->rc, out, out_pos, out_size)) { + assert(limit == UINT32_MAX); + return LZMA_OK; + } + } + + // Make it ready for the next LZMA2 chunk. + coder->is_flushed = false; + + return LZMA_STREAM_END; +} + + +static lzma_ret +lzma_encode(lzma_coder *restrict coder, lzma_mf *restrict mf, + uint8_t *restrict out, size_t *restrict out_pos, + size_t out_size) +{ + // Plain LZMA has no support for sync-flushing. + if (unlikely(mf->action == LZMA_SYNC_FLUSH)) + return LZMA_OPTIONS_ERROR; + + return lzma_lzma_encode(coder, mf, out, out_pos, out_size, UINT32_MAX); +} + + +//////////////////// +// Initialization // +//////////////////// + +static bool +is_options_valid(const lzma_options_lzma *options) +{ + // Validate some of the options. LZ encoder validates nice_len too + // but we need a valid value here earlier. + return is_lclppb_valid(options) + && options->nice_len >= MATCH_LEN_MIN + && options->nice_len <= MATCH_LEN_MAX + && (options->mode == LZMA_MODE_FAST + || options->mode == LZMA_MODE_NORMAL); +} + + +static void +set_lz_options(lzma_lz_options *lz_options, const lzma_options_lzma *options) +{ + // LZ encoder initialization does the validation for these so we + // don't need to validate here. + lz_options->before_size = OPTS; + lz_options->dict_size = options->dict_size; + lz_options->after_size = LOOP_INPUT_MAX; + lz_options->match_len_max = MATCH_LEN_MAX; + lz_options->nice_len = options->nice_len; + lz_options->match_finder = options->mf; + lz_options->depth = options->depth; + lz_options->preset_dict = options->preset_dict; + lz_options->preset_dict_size = options->preset_dict_size; + return; +} + + +static void +length_encoder_reset(lzma_length_encoder *lencoder, + const uint32_t num_pos_states, const bool fast_mode) +{ + bit_reset(lencoder->choice); + bit_reset(lencoder->choice2); + + for (size_t pos_state = 0; pos_state < num_pos_states; ++pos_state) { + bittree_reset(lencoder->low[pos_state], LEN_LOW_BITS); + bittree_reset(lencoder->mid[pos_state], LEN_MID_BITS); + } + + bittree_reset(lencoder->high, LEN_HIGH_BITS); + + if (!fast_mode) + for (uint32_t pos_state = 0; pos_state < num_pos_states; + ++pos_state) + length_update_prices(lencoder, pos_state); + + return; +} + + +extern lzma_ret +lzma_lzma_encoder_reset(lzma_coder *coder, const lzma_options_lzma *options) +{ + if (!is_options_valid(options)) + return LZMA_OPTIONS_ERROR; + + coder->pos_mask = (1U << options->pb) - 1; + coder->literal_context_bits = options->lc; + coder->literal_pos_mask = (1U << options->lp) - 1; + + // Range coder + rc_reset(&coder->rc); + + // State + coder->state = STATE_LIT_LIT; + for (size_t i = 0; i < REPS; ++i) + coder->reps[i] = 0; + + literal_init(coder->literal, options->lc, options->lp); + + // Bit encoders + for (size_t i = 0; i < STATES; ++i) { + for (size_t j = 0; j <= coder->pos_mask; ++j) { + bit_reset(coder->is_match[i][j]); + bit_reset(coder->is_rep0_long[i][j]); + } + + bit_reset(coder->is_rep[i]); + bit_reset(coder->is_rep0[i]); + bit_reset(coder->is_rep1[i]); + bit_reset(coder->is_rep2[i]); + } + + for (size_t i = 0; i < FULL_DISTANCES - DIST_MODEL_END; ++i) + bit_reset(coder->dist_special[i]); + + // Bit tree encoders + for (size_t i = 0; i < DIST_STATES; ++i) + bittree_reset(coder->dist_slot[i], DIST_SLOT_BITS); + + bittree_reset(coder->dist_align, ALIGN_BITS); + + // Length encoders + length_encoder_reset(&coder->match_len_encoder, + 1U << options->pb, coder->fast_mode); + + length_encoder_reset(&coder->rep_len_encoder, + 1U << options->pb, coder->fast_mode); + + // Price counts are incremented every time appropriate probabilities + // are changed. price counts are set to zero when the price tables + // are updated, which is done when the appropriate price counts have + // big enough value, and lzma_mf.read_ahead == 0 which happens at + // least every OPTS (a few thousand) possible price count increments. + // + // By resetting price counts to UINT32_MAX / 2, we make sure that the + // price tables will be initialized before they will be used (since + // the value is definitely big enough), and that it is OK to increment + // price counts without risk of integer overflow (since UINT32_MAX / 2 + // is small enough). The current code doesn't increment price counts + // before initializing price tables, but it maybe done in future if + // we add support for saving the state between LZMA2 chunks. + coder->match_price_count = UINT32_MAX / 2; + coder->align_price_count = UINT32_MAX / 2; + + coder->opts_end_index = 0; + coder->opts_current_index = 0; + + return LZMA_OK; +} + + +extern lzma_ret +lzma_lzma_encoder_create(lzma_coder **coder_ptr, + const lzma_allocator *allocator, + const lzma_options_lzma *options, lzma_lz_options *lz_options) +{ + // Allocate lzma_coder if it wasn't already allocated. + if (*coder_ptr == NULL) { + *coder_ptr = lzma_alloc(sizeof(lzma_coder), allocator); + if (*coder_ptr == NULL) + return LZMA_MEM_ERROR; + } + + lzma_coder *coder = *coder_ptr; + + // Set compression mode. We haven't validates the options yet, + // but it's OK here, since nothing bad happens with invalid + // options in the code below, and they will get rejected by + // lzma_lzma_encoder_reset() call at the end of this function. + switch (options->mode) { + case LZMA_MODE_FAST: + coder->fast_mode = true; + break; + + case LZMA_MODE_NORMAL: { + coder->fast_mode = false; + + // Set dist_table_size. + // Round the dictionary size up to next 2^n. + uint32_t log_size = 0; + while ((UINT32_C(1) << log_size) < options->dict_size) + ++log_size; + + coder->dist_table_size = log_size * 2; + + // Length encoders' price table size + coder->match_len_encoder.table_size + = options->nice_len + 1 - MATCH_LEN_MIN; + coder->rep_len_encoder.table_size + = options->nice_len + 1 - MATCH_LEN_MIN; + break; + } + + default: + return LZMA_OPTIONS_ERROR; + } + + // We don't need to write the first byte as literal if there is + // a non-empty preset dictionary. encode_init() wouldn't even work + // if there is a non-empty preset dictionary, because encode_init() + // assumes that position is zero and previous byte is also zero. + coder->is_initialized = options->preset_dict != NULL + && options->preset_dict_size > 0; + coder->is_flushed = false; + + set_lz_options(lz_options, options); + + return lzma_lzma_encoder_reset(coder, options); +} + + +static lzma_ret +lzma_encoder_init(lzma_lz_encoder *lz, const lzma_allocator *allocator, + const void *options, lzma_lz_options *lz_options) +{ + lz->code = &lzma_encode; + return lzma_lzma_encoder_create( + &lz->coder, allocator, options, lz_options); +} + + +extern lzma_ret +lzma_lzma_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator, + const lzma_filter_info *filters) +{ + return lzma_lz_encoder_init( + next, allocator, filters, &lzma_encoder_init); +} + + +extern uint64_t +lzma_lzma_encoder_memusage(const void *options) +{ + if (!is_options_valid(options)) + return UINT64_MAX; + + lzma_lz_options lz_options; + set_lz_options(&lz_options, options); + + const uint64_t lz_memusage = lzma_lz_encoder_memusage(&lz_options); + if (lz_memusage == UINT64_MAX) + return UINT64_MAX; + + return (uint64_t)(sizeof(lzma_coder)) + lz_memusage; +} + + +extern bool +lzma_lzma_lclppb_encode(const lzma_options_lzma *options, uint8_t *byte) +{ + if (!is_lclppb_valid(options)) + return true; + + *byte = (options->pb * 5 + options->lp) * 9 + options->lc; + assert(*byte <= (4 * 5 + 4) * 9 + 8); + + return false; +} + + +#ifdef HAVE_ENCODER_LZMA1 +extern lzma_ret +lzma_lzma_props_encode(const void *options, uint8_t *out) +{ + const lzma_options_lzma *const opt = options; + + if (lzma_lzma_lclppb_encode(opt, out)) + return LZMA_PROG_ERROR; + + unaligned_write32le(out + 1, opt->dict_size); + + return LZMA_OK; +} +#endif + + +extern LZMA_API(lzma_bool) +lzma_mode_is_supported(lzma_mode mode) +{ + return mode == LZMA_MODE_FAST || mode == LZMA_MODE_NORMAL; +}