X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=lzma%2Flzma%2Flzma_decoder.c;fp=lzma%2Flzma%2Flzma_decoder.c;h=b8f931705bf9b7214046cdcb2058533fb25851ba;hb=32b8a6b26ed8843828e03e505d2256960bda0980;hp=0000000000000000000000000000000000000000;hpb=d48fc23a4bcf8ca3c406d6e8c8a6f8c6b0fa2f1e;p=zpackage diff --git a/lzma/lzma/lzma_decoder.c b/lzma/lzma/lzma_decoder.c new file mode 100644 index 0000000..b8f9317 --- /dev/null +++ b/lzma/lzma/lzma_decoder.c @@ -0,0 +1,1061 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lzma_decoder.c +/// \brief LZMA decoder +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "lz_decoder.h" +#include "lzma_common.h" +#include "lzma_decoder.h" +#include "range_decoder.h" + + +#ifdef HAVE_SMALL + +// Macros for (somewhat) size-optimized code. +#define seq_4(seq) seq + +#define seq_6(seq) seq + +#define seq_8(seq) seq + +#define seq_len(seq) \ + seq ## _CHOICE, \ + seq ## _CHOICE2, \ + seq ## _BITTREE + +#define len_decode(target, ld, pos_state, seq) \ +do { \ +case seq ## _CHOICE: \ + rc_if_0(ld.choice, seq ## _CHOICE) { \ + rc_update_0(ld.choice); \ + probs = ld.low[pos_state];\ + limit = LEN_LOW_SYMBOLS; \ + target = MATCH_LEN_MIN; \ + } else { \ + rc_update_1(ld.choice); \ +case seq ## _CHOICE2: \ + rc_if_0(ld.choice2, seq ## _CHOICE2) { \ + rc_update_0(ld.choice2); \ + probs = ld.mid[pos_state]; \ + limit = LEN_MID_SYMBOLS; \ + target = MATCH_LEN_MIN + LEN_LOW_SYMBOLS; \ + } else { \ + rc_update_1(ld.choice2); \ + probs = ld.high; \ + limit = LEN_HIGH_SYMBOLS; \ + target = MATCH_LEN_MIN + LEN_LOW_SYMBOLS \ + + LEN_MID_SYMBOLS; \ + } \ + } \ + symbol = 1; \ +case seq ## _BITTREE: \ + do { \ + rc_bit(probs[symbol], , , seq ## _BITTREE); \ + } while (symbol < limit); \ + target += symbol - limit; \ +} while (0) + +#else // HAVE_SMALL + +// Unrolled versions +#define seq_4(seq) \ + seq ## 0, \ + seq ## 1, \ + seq ## 2, \ + seq ## 3 + +#define seq_6(seq) \ + seq ## 0, \ + seq ## 1, \ + seq ## 2, \ + seq ## 3, \ + seq ## 4, \ + seq ## 5 + +#define seq_8(seq) \ + seq ## 0, \ + seq ## 1, \ + seq ## 2, \ + seq ## 3, \ + seq ## 4, \ + seq ## 5, \ + seq ## 6, \ + seq ## 7 + +#define seq_len(seq) \ + seq ## _CHOICE, \ + seq ## _LOW0, \ + seq ## _LOW1, \ + seq ## _LOW2, \ + seq ## _CHOICE2, \ + seq ## _MID0, \ + seq ## _MID1, \ + seq ## _MID2, \ + seq ## _HIGH0, \ + seq ## _HIGH1, \ + seq ## _HIGH2, \ + seq ## _HIGH3, \ + seq ## _HIGH4, \ + seq ## _HIGH5, \ + seq ## _HIGH6, \ + seq ## _HIGH7 + +#define len_decode(target, ld, pos_state, seq) \ +do { \ + symbol = 1; \ +case seq ## _CHOICE: \ + rc_if_0(ld.choice, seq ## _CHOICE) { \ + rc_update_0(ld.choice); \ + rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW0); \ + rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW1); \ + rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW2); \ + target = symbol - LEN_LOW_SYMBOLS + MATCH_LEN_MIN; \ + } else { \ + rc_update_1(ld.choice); \ +case seq ## _CHOICE2: \ + rc_if_0(ld.choice2, seq ## _CHOICE2) { \ + rc_update_0(ld.choice2); \ + rc_bit_case(ld.mid[pos_state][symbol], , , \ + seq ## _MID0); \ + rc_bit_case(ld.mid[pos_state][symbol], , , \ + seq ## _MID1); \ + rc_bit_case(ld.mid[pos_state][symbol], , , \ + seq ## _MID2); \ + target = symbol - LEN_MID_SYMBOLS \ + + MATCH_LEN_MIN + LEN_LOW_SYMBOLS; \ + } else { \ + rc_update_1(ld.choice2); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH0); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH1); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH2); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH3); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH4); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH5); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH6); \ + rc_bit_case(ld.high[symbol], , , seq ## _HIGH7); \ + target = symbol - LEN_HIGH_SYMBOLS \ + + MATCH_LEN_MIN \ + + LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS; \ + } \ + } \ +} while (0) + +#endif // HAVE_SMALL + + +/// Length decoder probabilities; see comments in lzma_common.h. +typedef struct { + probability choice; + probability choice2; + probability low[POS_STATES_MAX][LEN_LOW_SYMBOLS]; + probability mid[POS_STATES_MAX][LEN_MID_SYMBOLS]; + probability high[LEN_HIGH_SYMBOLS]; +} lzma_length_decoder; + + +struct lzma_coder_s { + /////////////////// + // Probabilities // + /////////////////// + + /// Literals; see comments in lzma_common.h. + probability literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE]; + + /// If 1, it's a match. Otherwise it's a single 8-bit literal. + probability is_match[STATES][POS_STATES_MAX]; + + /// If 1, it's a repeated match. The distance is one of rep0 .. rep3. + probability is_rep[STATES]; + + /// If 0, distance of a repeated match is rep0. + /// Otherwise check is_rep1. + probability is_rep0[STATES]; + + /// If 0, distance of a repeated match is rep1. + /// Otherwise check is_rep2. + probability is_rep1[STATES]; + + /// If 0, distance of a repeated match is rep2. Otherwise it is rep3. + probability is_rep2[STATES]; + + /// If 1, the repeated match has length of one byte. Otherwise + /// the length is decoded from rep_len_decoder. + probability is_rep0_long[STATES][POS_STATES_MAX]; + + /// Probability tree for the highest two bits of the match distance. + /// There is a separate probability tree for match lengths of + /// 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273]. + probability dist_slot[DIST_STATES][DIST_SLOTS]; + + /// Probability trees for additional bits for match distance when the + /// distance is in the range [4, 127]. + probability pos_special[FULL_DISTANCES - DIST_MODEL_END]; + + /// Probability tree for the lowest four bits of a match distance + /// that is equal to or greater than 128. + probability pos_align[ALIGN_SIZE]; + + /// Length of a normal match + lzma_length_decoder match_len_decoder; + + /// Length of a repeated match + lzma_length_decoder rep_len_decoder; + + /////////////////// + // Decoder state // + /////////////////// + + // Range coder + lzma_range_decoder rc; + + // Types of the most recently seen LZMA symbols + lzma_lzma_state state; + + uint32_t rep0; ///< Distance of the latest match + uint32_t rep1; ///< Distance of second latest match + uint32_t rep2; ///< Distance of third latest match + uint32_t rep3; ///< Distance of fourth latest match + + uint32_t pos_mask; // (1U << pb) - 1 + uint32_t literal_context_bits; + uint32_t literal_pos_mask; + + /// Uncompressed size as bytes, or LZMA_VLI_UNKNOWN if end of + /// payload marker is expected. + lzma_vli uncompressed_size; + + //////////////////////////////// + // State of incomplete symbol // + //////////////////////////////// + + /// Position where to continue the decoder loop + enum { + SEQ_NORMALIZE, + SEQ_IS_MATCH, + seq_8(SEQ_LITERAL), + seq_8(SEQ_LITERAL_MATCHED), + SEQ_LITERAL_WRITE, + SEQ_IS_REP, + seq_len(SEQ_MATCH_LEN), + seq_6(SEQ_DIST_SLOT), + SEQ_DIST_MODEL, + SEQ_DIRECT, + seq_4(SEQ_ALIGN), + SEQ_EOPM, + SEQ_IS_REP0, + SEQ_SHORTREP, + SEQ_IS_REP0_LONG, + SEQ_IS_REP1, + SEQ_IS_REP2, + seq_len(SEQ_REP_LEN), + SEQ_COPY, + } sequence; + + /// Base of the current probability tree + probability *probs; + + /// Symbol being decoded. This is also used as an index variable in + /// bittree decoders: probs[symbol] + uint32_t symbol; + + /// Used as a loop termination condition on bittree decoders and + /// direct bits decoder. + uint32_t limit; + + /// Matched literal decoder: 0x100 or 0 to help avoiding branches. + /// Bittree reverse decoders: Offset of the next bit: 1 << offset + uint32_t offset; + + /// If decoding a literal: match byte. + /// If decoding a match: length of the match. + uint32_t len; +}; + + +static lzma_ret +lzma_decode(lzma_coder *restrict coder, lzma_dict *restrict dictptr, + const uint8_t *restrict in, + size_t *restrict in_pos, size_t in_size) +{ + //////////////////// + // Initialization // + //////////////////// + + { + const lzma_ret ret = rc_read_init( + &coder->rc, in, in_pos, in_size); + if (ret != LZMA_STREAM_END) + return ret; + } + + /////////////// + // Variables // + /////////////// + + // Making local copies of often-used variables improves both + // speed and readability. + + lzma_dict dict = *dictptr; + + const size_t dict_start = dict.pos; + + // Range decoder + rc_to_local(coder->rc, *in_pos); + + // State + uint32_t state = coder->state; + uint32_t rep0 = coder->rep0; + uint32_t rep1 = coder->rep1; + uint32_t rep2 = coder->rep2; + uint32_t rep3 = coder->rep3; + + const uint32_t pos_mask = coder->pos_mask; + + // These variables are actually needed only if we last time ran + // out of input in the middle of the decoder loop. + probability *probs = coder->probs; + uint32_t symbol = coder->symbol; + uint32_t limit = coder->limit; + uint32_t offset = coder->offset; + uint32_t len = coder->len; + + const uint32_t literal_pos_mask = coder->literal_pos_mask; + const uint32_t literal_context_bits = coder->literal_context_bits; + + // Temporary variables + uint32_t pos_state = dict.pos & pos_mask; + + lzma_ret ret = LZMA_OK; + + // If uncompressed size is known, there must be no end of payload + // marker. + const bool no_eopm = coder->uncompressed_size + != LZMA_VLI_UNKNOWN; + if (no_eopm && coder->uncompressed_size < dict.limit - dict.pos) + dict.limit = dict.pos + (size_t)(coder->uncompressed_size); + + // The main decoder loop. The "switch" is used to restart the decoder at + // correct location. Once restarted, the "switch" is no longer used. + switch (coder->sequence) + while (true) { + // Calculate new pos_state. This is skipped on the first loop + // since we already calculated it when setting up the local + // variables. + pos_state = dict.pos & pos_mask; + + case SEQ_NORMALIZE: + case SEQ_IS_MATCH: + if (unlikely(no_eopm && dict.pos == dict.limit)) + break; + + rc_if_0(coder->is_match[state][pos_state], SEQ_IS_MATCH) { + rc_update_0(coder->is_match[state][pos_state]); + + // It's a literal i.e. a single 8-bit byte. + + probs = literal_subcoder(coder->literal, + literal_context_bits, literal_pos_mask, + dict.pos, dict_get(&dict, 0)); + symbol = 1; + + if (is_literal_state(state)) { + // Decode literal without match byte. +#ifdef HAVE_SMALL + case SEQ_LITERAL: + do { + rc_bit(probs[symbol], , , SEQ_LITERAL); + } while (symbol < (1 << 8)); +#else + rc_bit_case(probs[symbol], , , SEQ_LITERAL0); + rc_bit_case(probs[symbol], , , SEQ_LITERAL1); + rc_bit_case(probs[symbol], , , SEQ_LITERAL2); + rc_bit_case(probs[symbol], , , SEQ_LITERAL3); + rc_bit_case(probs[symbol], , , SEQ_LITERAL4); + rc_bit_case(probs[symbol], , , SEQ_LITERAL5); + rc_bit_case(probs[symbol], , , SEQ_LITERAL6); + rc_bit_case(probs[symbol], , , SEQ_LITERAL7); +#endif + } else { + // Decode literal with match byte. + // + // We store the byte we compare against + // ("match byte") to "len" to minimize the + // number of variables we need to store + // between decoder calls. + len = dict_get(&dict, rep0) << 1; + + // The usage of "offset" allows omitting some + // branches, which should give tiny speed + // improvement on some CPUs. "offset" gets + // set to zero if match_bit didn't match. + offset = 0x100; + +#ifdef HAVE_SMALL + case SEQ_LITERAL_MATCHED: + do { + const uint32_t match_bit + = len & offset; + const uint32_t subcoder_index + = offset + match_bit + + symbol; + + rc_bit(probs[subcoder_index], + offset &= ~match_bit, + offset &= match_bit, + SEQ_LITERAL_MATCHED); + + // It seems to be faster to do this + // here instead of putting it to the + // beginning of the loop and then + // putting the "case" in the middle + // of the loop. + len <<= 1; + + } while (symbol < (1 << 8)); +#else + // Unroll the loop. + uint32_t match_bit; + uint32_t subcoder_index; + +# define d(seq) \ + case seq: \ + match_bit = len & offset; \ + subcoder_index = offset + match_bit + symbol; \ + rc_bit(probs[subcoder_index], \ + offset &= ~match_bit, \ + offset &= match_bit, \ + seq) + + d(SEQ_LITERAL_MATCHED0); + len <<= 1; + d(SEQ_LITERAL_MATCHED1); + len <<= 1; + d(SEQ_LITERAL_MATCHED2); + len <<= 1; + d(SEQ_LITERAL_MATCHED3); + len <<= 1; + d(SEQ_LITERAL_MATCHED4); + len <<= 1; + d(SEQ_LITERAL_MATCHED5); + len <<= 1; + d(SEQ_LITERAL_MATCHED6); + len <<= 1; + d(SEQ_LITERAL_MATCHED7); +# undef d +#endif + } + + //update_literal(state); + // Use a lookup table to update to literal state, + // since compared to other state updates, this would + // need two branches. + static const lzma_lzma_state next_state[] = { + STATE_LIT_LIT, + STATE_LIT_LIT, + STATE_LIT_LIT, + STATE_LIT_LIT, + STATE_MATCH_LIT_LIT, + STATE_REP_LIT_LIT, + STATE_SHORTREP_LIT_LIT, + STATE_MATCH_LIT, + STATE_REP_LIT, + STATE_SHORTREP_LIT, + STATE_MATCH_LIT, + STATE_REP_LIT + }; + state = next_state[state]; + + case SEQ_LITERAL_WRITE: + if (unlikely(dict_put(&dict, symbol))) { + coder->sequence = SEQ_LITERAL_WRITE; + goto out; + } + + continue; + } + + // Instead of a new byte we are going to get a byte range + // (distance and length) which will be repeated from our + // output history. + + rc_update_1(coder->is_match[state][pos_state]); + + case SEQ_IS_REP: + rc_if_0(coder->is_rep[state], SEQ_IS_REP) { + // Not a repeated match + rc_update_0(coder->is_rep[state]); + update_match(state); + + // The latest three match distances are kept in + // memory in case there are repeated matches. + rep3 = rep2; + rep2 = rep1; + rep1 = rep0; + + // Decode the length of the match. + len_decode(len, coder->match_len_decoder, + pos_state, SEQ_MATCH_LEN); + + // Prepare to decode the highest two bits of the + // match distance. + probs = coder->dist_slot[get_dist_state(len)]; + symbol = 1; + +#ifdef HAVE_SMALL + case SEQ_DIST_SLOT: + do { + rc_bit(probs[symbol], , , SEQ_DIST_SLOT); + } while (symbol < DIST_SLOTS); +#else + rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT0); + rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT1); + rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT2); + rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT3); + rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT4); + rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT5); +#endif + // Get rid of the highest bit that was needed for + // indexing of the probability array. + symbol -= DIST_SLOTS; + assert(symbol <= 63); + + if (symbol < DIST_MODEL_START) { + // Match distances [0, 3] have only two bits. + rep0 = symbol; + } else { + // Decode the lowest [1, 29] bits of + // the match distance. + limit = (symbol >> 1) - 1; + assert(limit >= 1 && limit <= 30); + rep0 = 2 + (symbol & 1); + + if (symbol < DIST_MODEL_END) { + // Prepare to decode the low bits for + // a distance of [4, 127]. + assert(limit <= 5); + rep0 <<= limit; + assert(rep0 <= 96); + // -1 is fine, because we start + // decoding at probs[1], not probs[0]. + // NOTE: This violates the C standard, + // since we are doing pointer + // arithmetic past the beginning of + // the array. + assert((int32_t)(rep0 - symbol - 1) + >= -1); + assert((int32_t)(rep0 - symbol - 1) + <= 82); + probs = coder->pos_special + rep0 + - symbol - 1; + symbol = 1; + offset = 0; + case SEQ_DIST_MODEL: +#ifdef HAVE_SMALL + do { + rc_bit(probs[symbol], , + rep0 += 1 << offset, + SEQ_DIST_MODEL); + } while (++offset < limit); +#else + switch (limit) { + case 5: + assert(offset == 0); + rc_bit(probs[symbol], , + rep0 += 1, + SEQ_DIST_MODEL); + ++offset; + --limit; + case 4: + rc_bit(probs[symbol], , + rep0 += 1 << offset, + SEQ_DIST_MODEL); + ++offset; + --limit; + case 3: + rc_bit(probs[symbol], , + rep0 += 1 << offset, + SEQ_DIST_MODEL); + ++offset; + --limit; + case 2: + rc_bit(probs[symbol], , + rep0 += 1 << offset, + SEQ_DIST_MODEL); + ++offset; + --limit; + case 1: + // We need "symbol" only for + // indexing the probability + // array, thus we can use + // rc_bit_last() here to omit + // the unneeded updating of + // "symbol". + rc_bit_last(probs[symbol], , + rep0 += 1 << offset, + SEQ_DIST_MODEL); + } +#endif + } else { + // The distance is >= 128. Decode the + // lower bits without probabilities + // except the lowest four bits. + assert(symbol >= 14); + assert(limit >= 6); + limit -= ALIGN_BITS; + assert(limit >= 2); + case SEQ_DIRECT: + // Not worth manual unrolling + do { + rc_direct(rep0, SEQ_DIRECT); + } while (--limit > 0); + + // Decode the lowest four bits using + // probabilities. + rep0 <<= ALIGN_BITS; + symbol = 1; +#ifdef HAVE_SMALL + offset = 0; + case SEQ_ALIGN: + do { + rc_bit(coder->pos_align[ + symbol], , + rep0 += 1 << offset, + SEQ_ALIGN); + } while (++offset < ALIGN_BITS); +#else + case SEQ_ALIGN0: + rc_bit(coder->pos_align[symbol], , + rep0 += 1, SEQ_ALIGN0); + case SEQ_ALIGN1: + rc_bit(coder->pos_align[symbol], , + rep0 += 2, SEQ_ALIGN1); + case SEQ_ALIGN2: + rc_bit(coder->pos_align[symbol], , + rep0 += 4, SEQ_ALIGN2); + case SEQ_ALIGN3: + // Like in SEQ_DIST_MODEL, we don't + // need "symbol" for anything else + // than indexing the probability array. + rc_bit_last(coder->pos_align[symbol], , + rep0 += 8, SEQ_ALIGN3); +#endif + + if (rep0 == UINT32_MAX) { + // End of payload marker was + // found. It must not be + // present if uncompressed + // size is known. + if (coder->uncompressed_size + != LZMA_VLI_UNKNOWN) { + ret = LZMA_DATA_ERROR; + goto out; + } + + case SEQ_EOPM: + // LZMA1 stream with + // end-of-payload marker. + rc_normalize(SEQ_EOPM); + ret = LZMA_STREAM_END; + goto out; + } + } + } + + // Validate the distance we just decoded. + if (unlikely(!dict_is_distance_valid(&dict, rep0))) { + ret = LZMA_DATA_ERROR; + goto out; + } + + } else { + rc_update_1(coder->is_rep[state]); + + // Repeated match + // + // The match distance is a value that we have had + // earlier. The latest four match distances are + // available as rep0, rep1, rep2 and rep3. We will + // now decode which of them is the new distance. + // + // There cannot be a match if we haven't produced + // any output, so check that first. + if (unlikely(!dict_is_distance_valid(&dict, 0))) { + ret = LZMA_DATA_ERROR; + goto out; + } + + case SEQ_IS_REP0: + rc_if_0(coder->is_rep0[state], SEQ_IS_REP0) { + rc_update_0(coder->is_rep0[state]); + // The distance is rep0. + + case SEQ_IS_REP0_LONG: + rc_if_0(coder->is_rep0_long[state][pos_state], + SEQ_IS_REP0_LONG) { + rc_update_0(coder->is_rep0_long[ + state][pos_state]); + + update_short_rep(state); + + case SEQ_SHORTREP: + if (unlikely(dict_put(&dict, dict_get( + &dict, rep0)))) { + coder->sequence = SEQ_SHORTREP; + goto out; + } + + continue; + } + + // Repeating more than one byte at + // distance of rep0. + rc_update_1(coder->is_rep0_long[ + state][pos_state]); + + } else { + rc_update_1(coder->is_rep0[state]); + + case SEQ_IS_REP1: + // The distance is rep1, rep2 or rep3. Once + // we find out which one of these three, it + // is stored to rep0 and rep1, rep2 and rep3 + // are updated accordingly. + rc_if_0(coder->is_rep1[state], SEQ_IS_REP1) { + rc_update_0(coder->is_rep1[state]); + + const uint32_t distance = rep1; + rep1 = rep0; + rep0 = distance; + + } else { + rc_update_1(coder->is_rep1[state]); + case SEQ_IS_REP2: + rc_if_0(coder->is_rep2[state], + SEQ_IS_REP2) { + rc_update_0(coder->is_rep2[ + state]); + + const uint32_t distance = rep2; + rep2 = rep1; + rep1 = rep0; + rep0 = distance; + + } else { + rc_update_1(coder->is_rep2[ + state]); + + const uint32_t distance = rep3; + rep3 = rep2; + rep2 = rep1; + rep1 = rep0; + rep0 = distance; + } + } + } + + update_long_rep(state); + + // Decode the length of the repeated match. + len_decode(len, coder->rep_len_decoder, + pos_state, SEQ_REP_LEN); + } + + ///////////////////////////////// + // Repeat from history buffer. // + ///////////////////////////////// + + // The length is always between these limits. There is no way + // to trigger the algorithm to set len outside this range. + assert(len >= MATCH_LEN_MIN); + assert(len <= MATCH_LEN_MAX); + + case SEQ_COPY: + // Repeat len bytes from distance of rep0. + if (unlikely(dict_repeat(&dict, rep0, &len))) { + coder->sequence = SEQ_COPY; + goto out; + } + } + + rc_normalize(SEQ_NORMALIZE); + coder->sequence = SEQ_IS_MATCH; + +out: + // Save state + + // NOTE: Must not copy dict.limit. + dictptr->pos = dict.pos; + dictptr->full = dict.full; + + rc_from_local(coder->rc, *in_pos); + + coder->state = state; + coder->rep0 = rep0; + coder->rep1 = rep1; + coder->rep2 = rep2; + coder->rep3 = rep3; + + coder->probs = probs; + coder->symbol = symbol; + coder->limit = limit; + coder->offset = offset; + coder->len = len; + + // Update the remaining amount of uncompressed data if uncompressed + // size was known. + if (coder->uncompressed_size != LZMA_VLI_UNKNOWN) { + coder->uncompressed_size -= dict.pos - dict_start; + + // Since there cannot be end of payload marker if the + // uncompressed size was known, we check here if we + // finished decoding. + if (coder->uncompressed_size == 0 && ret == LZMA_OK + && coder->sequence != SEQ_NORMALIZE) + ret = coder->sequence == SEQ_IS_MATCH + ? LZMA_STREAM_END : LZMA_DATA_ERROR; + } + + // We can do an additional check in the range decoder to catch some + // corrupted files. + if (ret == LZMA_STREAM_END) { + if (!rc_is_finished(coder->rc)) + ret = LZMA_DATA_ERROR; + + // Reset the range decoder so that it is ready to reinitialize + // for a new LZMA2 chunk. + rc_reset(coder->rc); + } + + return ret; +} + + + +static void +lzma_decoder_uncompressed(lzma_coder *coder, lzma_vli uncompressed_size) +{ + coder->uncompressed_size = uncompressed_size; +} + +/* +extern void +lzma_lzma_decoder_uncompressed(void *coder_ptr, lzma_vli uncompressed_size) +{ + // This is hack. + (*(lzma_coder **)(coder))->uncompressed_size = uncompressed_size; +} +*/ + +static void +lzma_decoder_reset(lzma_coder *coder, const void *opt) +{ + const lzma_options_lzma *options = opt; + + // NOTE: We assume that lc/lp/pb are valid since they were + // successfully decoded with lzma_lzma_decode_properties(). + + // Calculate pos_mask. We don't need pos_bits as is for anything. + coder->pos_mask = (1U << options->pb) - 1; + + // Initialize the literal decoder. + literal_init(coder->literal, options->lc, options->lp); + + coder->literal_context_bits = options->lc; + coder->literal_pos_mask = (1U << options->lp) - 1; + + // State + coder->state = STATE_LIT_LIT; + coder->rep0 = 0; + coder->rep1 = 0; + coder->rep2 = 0; + coder->rep3 = 0; + coder->pos_mask = (1U << options->pb) - 1; + + // Range decoder + rc_reset(coder->rc); + + // Bit and bittree decoders + for (uint32_t i = 0; i < STATES; ++i) { + for (uint32_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 (uint32_t i = 0; i < DIST_STATES; ++i) + bittree_reset(coder->dist_slot[i], DIST_SLOT_BITS); + + for (uint32_t i = 0; i < FULL_DISTANCES - DIST_MODEL_END; ++i) + bit_reset(coder->pos_special[i]); + + bittree_reset(coder->pos_align, ALIGN_BITS); + + // Len decoders (also bit/bittree) + const uint32_t num_pos_states = 1U << options->pb; + bit_reset(coder->match_len_decoder.choice); + bit_reset(coder->match_len_decoder.choice2); + bit_reset(coder->rep_len_decoder.choice); + bit_reset(coder->rep_len_decoder.choice2); + + for (uint32_t pos_state = 0; pos_state < num_pos_states; ++pos_state) { + bittree_reset(coder->match_len_decoder.low[pos_state], + LEN_LOW_BITS); + bittree_reset(coder->match_len_decoder.mid[pos_state], + LEN_MID_BITS); + + bittree_reset(coder->rep_len_decoder.low[pos_state], + LEN_LOW_BITS); + bittree_reset(coder->rep_len_decoder.mid[pos_state], + LEN_MID_BITS); + } + + bittree_reset(coder->match_len_decoder.high, LEN_HIGH_BITS); + bittree_reset(coder->rep_len_decoder.high, LEN_HIGH_BITS); + + coder->sequence = SEQ_IS_MATCH; + coder->probs = NULL; + coder->symbol = 0; + coder->limit = 0; + coder->offset = 0; + coder->len = 0; + + return; +} + + +extern lzma_ret +lzma_lzma_decoder_create(lzma_lz_decoder *lz, const lzma_allocator *allocator, + const void *opt, lzma_lz_options *lz_options) +{ + if (lz->coder == NULL) { + lz->coder = lzma_alloc(sizeof(lzma_coder), allocator); + if (lz->coder == NULL) + return LZMA_MEM_ERROR; + + lz->code = &lzma_decode; + lz->reset = &lzma_decoder_reset; + lz->set_uncompressed = &lzma_decoder_uncompressed; + } + + // All dictionary sizes are OK here. LZ decoder will take care of + // the special cases. + const lzma_options_lzma *options = opt; + lz_options->dict_size = options->dict_size; + lz_options->preset_dict = options->preset_dict; + lz_options->preset_dict_size = options->preset_dict_size; + + return LZMA_OK; +} + + +/// Allocate and initialize LZMA decoder. This is used only via LZ +/// initialization (lzma_lzma_decoder_init() passes function pointer to +/// the LZ initialization). +static lzma_ret +lzma_decoder_init(lzma_lz_decoder *lz, const lzma_allocator *allocator, + const void *options, lzma_lz_options *lz_options) +{ + if (!is_lclppb_valid(options)) + return LZMA_PROG_ERROR; + + return_if_error(lzma_lzma_decoder_create( + lz, allocator, options, lz_options)); + + lzma_decoder_reset(lz->coder, options); + lzma_decoder_uncompressed(lz->coder, LZMA_VLI_UNKNOWN); + + return LZMA_OK; +} + + +extern lzma_ret +lzma_lzma_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, + const lzma_filter_info *filters) +{ + // LZMA can only be the last filter in the chain. This is enforced + // by the raw_decoder initialization. + assert(filters[1].init == NULL); + + return lzma_lz_decoder_init(next, allocator, filters, + &lzma_decoder_init); +} + + +extern bool +lzma_lzma_lclppb_decode(lzma_options_lzma *options, uint8_t byte) +{ + if (byte > (4 * 5 + 4) * 9 + 8) + return true; + + // See the file format specification to understand this. + options->pb = byte / (9 * 5); + byte -= options->pb * 9 * 5; + options->lp = byte / 9; + options->lc = byte - options->lp * 9; + + return options->lc + options->lp > LZMA_LCLP_MAX; +} + + +extern uint64_t +lzma_lzma_decoder_memusage_nocheck(const void *options) +{ + const lzma_options_lzma *const opt = options; + return sizeof(lzma_coder) + lzma_lz_decoder_memusage(opt->dict_size); +} + + +extern uint64_t +lzma_lzma_decoder_memusage(const void *options) +{ + if (!is_lclppb_valid(options)) + return UINT64_MAX; + + return lzma_lzma_decoder_memusage_nocheck(options); +} + + +extern lzma_ret +lzma_lzma_props_decode(void **options, const lzma_allocator *allocator, + const uint8_t *props, size_t props_size) +{ + if (props_size != 5) + return LZMA_OPTIONS_ERROR; + + lzma_options_lzma *opt + = lzma_alloc(sizeof(lzma_options_lzma), allocator); + if (opt == NULL) + return LZMA_MEM_ERROR; + + if (lzma_lzma_lclppb_decode(opt, props[0])) + goto error; + + // All dictionary sizes are accepted, including zero. LZ decoder + // will automatically use a dictionary at least a few KiB even if + // a smaller dictionary is requested. + opt->dict_size = unaligned_read32le(props + 1); + + opt->preset_dict = NULL; + opt->preset_dict_size = 0; + + *options = opt; + + return LZMA_OK; + +error: + lzma_free(opt, allocator); + return LZMA_OPTIONS_ERROR; +}