Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/lzma/lzma_encoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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 pos_slot = get_pos_slot(distance);
+        const uint32_t len_to_pos_state = get_len_to_pos_state(len);
+        rc_bittree(&coder->rc, coder->pos_slot[len_to_pos_state],
+                        POS_SLOT_BITS, pos_slot);
+
+        if (pos_slot >= START_POS_MODEL_INDEX) {
+                const uint32_t footer_bits = (pos_slot >> 1) - 1;
+                const uint32_t base = (2 | (pos_slot & 1)) << footer_bits;
+                const uint32_t pos_reduced = distance - base;
+
+                if (pos_slot < END_POS_MODEL_INDEX) {
+                        // Careful here: base - pos_slot - 1 can be -1, but
+                        // rc_bittree_reverse starts at probs[1], not probs[0].
+                        rc_bittree_reverse(&coder->rc,
+                                coder->pos_special + base - pos_slot - 1,
+                                footer_bits, pos_reduced);
+                } else {
+                        rc_direct(&coder->rc, pos_reduced >> ALIGN_BITS,
+                                        footer_bits - ALIGN_BITS);
+                        rc_bittree_reverse(
+                                        &coder->rc, coder->pos_align,
+                                        ALIGN_BITS, pos_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 < REP_DISTANCES) {
+                        // 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 - REP_DISTANCES, 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.
+                // TODO
+                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, REP_DISTANCES): repeated match
+                //   - [REP_DISTANCES, UINT32_MAX):
+                //     match at (pos - REP_DISTANCES)
+                //   - 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 (size_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 < REP_DISTANCES; ++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 - END_POS_MODEL_INDEX; ++i)
+                bit_reset(coder->pos_special[i]);
+
+        // Bit tree encoders
+        for (size_t i = 0; i < LEN_TO_POS_STATES; ++i)
+                bittree_reset(coder->pos_slot[i], POS_SLOT_BITS);
+
+        bittree_reset(coder->pos_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, 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, 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, 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;
+}