///////////////////////////////////////////////////////////////////////////////
//
/// \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"
// The macros unroll loops with switch statements.
// Silence warnings about missing fall-through comments.
#if TUKLIB_GNUC_REQ(7, 0)
# pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
#endif
#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;
typedef struct {
///////////////////
// 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;
} lzma_lzma1_decoder;
static lzma_ret
lzma_decode(void *coder_ptr, lzma_dict *restrict dictptr,
const uint8_t *restrict in,
size_t *restrict in_pos, size_t in_size)
{
lzma_lzma1_decoder *restrict coder = coder_ptr;
////////////////////
// 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(void *coder_ptr, lzma_vli uncompressed_size)
{
lzma_lzma1_decoder *coder = coder_ptr;
coder->uncompressed_size = uncompressed_size;
}
static void
lzma_decoder_reset(void *coder_ptr, const void *opt)
{
lzma_lzma1_decoder *coder = coder_ptr;
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_lzma1_decoder), 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_lzma1_decoder)
+ 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;
}