aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/lzma/lzma_decoder.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/liblzma/lzma/lzma_decoder.c')
-rw-r--r--src/liblzma/lzma/lzma_decoder.c844
1 files changed, 844 insertions, 0 deletions
diff --git a/src/liblzma/lzma/lzma_decoder.c b/src/liblzma/lzma/lzma_decoder.c
new file mode 100644
index 00000000..6e2c166d
--- /dev/null
+++ b/src/liblzma/lzma/lzma_decoder.c
@@ -0,0 +1,844 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file lzma_decoder.c
+/// \brief LZMA decoder
+//
+// Copyright (C) 1999-2006 Igor Pavlov
+// Copyright (C) 2007 Lasse Collin
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// Lesser General Public License for more details.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "lzma_common.h"
+#include "lzma_decoder.h"
+#include "lz_decoder.h"
+#include "range_decoder.h"
+
+
+/// REQUIRED_IN_BUFFER_SIZE is the number of required input bytes
+/// for the worst case: longest match with longest distance.
+/// LZMA_IN_BUFFER_SIZE must be larger than REQUIRED_IN_BUFFER_SIZE.
+/// 23 bits = 2 (match select) + 10 (len) + 6 (distance) + 4 (align)
+/// + 1 (rc_normalize)
+///
+/// \todo Is this correct for sure?
+///
+#define REQUIRED_IN_BUFFER_SIZE \
+ ((23 * (BIT_MODEL_TOTAL_BITS - MOVE_BITS + 1) + 26 + 9) / 8)
+
+
+// Length decoders are easiest to have as macros, because they use range
+// decoder macros, which use local variables rc_range and rc_code.
+
+#define length_decode(target, len_decoder, pos_state) \
+do { \
+ if_bit_0(len_decoder.choice) { \
+ update_bit_0(len_decoder.choice); \
+ target = MATCH_MIN_LEN; \
+ bittree_decode(target, \
+ len_decoder.low[pos_state], LEN_LOW_BITS); \
+ } else { \
+ update_bit_1(len_decoder.choice); \
+ if_bit_0(len_decoder.choice2) { \
+ update_bit_0(len_decoder.choice2); \
+ target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS; \
+ bittree_decode(target, len_decoder.mid[pos_state], \
+ LEN_MID_BITS); \
+ } else { \
+ update_bit_1(len_decoder.choice2); \
+ target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS \
+ + LEN_MID_SYMBOLS; \
+ bittree_decode(target, len_decoder.high, \
+ LEN_HIGH_BITS); \
+ } \
+ } \
+} while (0)
+
+
+#define length_decode_dummy(target, len_decoder, pos_state) \
+do { \
+ if_bit_0(len_decoder.choice) { \
+ update_bit_0_dummy(); \
+ target = MATCH_MIN_LEN; \
+ bittree_decode_dummy(target, \
+ len_decoder.low[pos_state], LEN_LOW_BITS); \
+ } else { \
+ update_bit_1_dummy(); \
+ if_bit_0(len_decoder.choice2) { \
+ update_bit_0_dummy(); \
+ target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS; \
+ bittree_decode_dummy(target, \
+ len_decoder.mid[pos_state], \
+ LEN_MID_BITS); \
+ } else { \
+ update_bit_1_dummy(); \
+ target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS \
+ + LEN_MID_SYMBOLS; \
+ bittree_decode_dummy(target, len_decoder.high, \
+ LEN_HIGH_BITS); \
+ } \
+ } \
+} while (0)
+
+
+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 {
+ /// Data of the next coder, if any.
+ lzma_next_coder next;
+
+ /// Sliding output window a.k.a. dictionary a.k.a. history buffer.
+ lzma_lz_decoder lz;
+
+ // Range coder
+ lzma_range_decoder rc;
+
+ // State
+ uint32_t 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_bits;
+ uint32_t pos_mask;
+ uint32_t now_pos; // Lowest 32-bits are enough here.
+
+ lzma_literal_coder *literal_coder;
+
+ /// 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_match_len_decoder.
+ probability is_rep0_long[STATES][POS_STATES_MAX];
+
+ probability pos_slot_decoder[LEN_TO_POS_STATES][1 << POS_SLOT_BITS];
+ probability pos_decoders[FULL_DISTANCES - END_POS_MODEL_INDEX];
+ probability pos_align_decoder[1 << ALIGN_BITS];
+
+ /// Length of a match
+ lzma_length_decoder len_decoder;
+
+ /// Length of a repeated match.
+ lzma_length_decoder rep_match_len_decoder;
+
+ /// The first five bytes of LZMA compressed data are treated
+ /// specially. Once they are read, this stays at zero.
+ size_t init_bytes_left;
+};
+
+
+/// \brief Check if the next iteration of the decoder loop can be run.
+///
+/// \note There must always be REQUIRED_IN_BUFFER_SIZE bytes
+/// readable space!
+///
+static bool lzma_attribute((pure))
+decode_dummy(const lzma_coder *restrict coder,
+ const uint8_t *restrict in, size_t in_pos_local,
+ const size_t in_size, uint32_t rc_range, uint32_t rc_code,
+ uint32_t state, uint32_t rep0, const uint32_t now_pos)
+{
+ uint32_t rc_bound;
+
+ do {
+ const uint32_t pos_state = now_pos & coder->pos_mask;
+
+ if_bit_0(coder->is_match[state][pos_state]) {
+ // It's a literal i.e. a single 8-bit byte.
+
+ update_bit_0_dummy();
+
+ const probability *subcoder = literal_get_subcoder(
+ coder->literal_coder,
+ now_pos, lz_get_byte(coder->lz, 0));
+ uint32_t symbol = 1;
+
+ if (!is_char_state(state)) {
+ // Decode literal with match byte.
+
+ assert(rep0 != UINT32_MAX);
+ uint32_t match_byte
+ = lz_get_byte(coder->lz, rep0);
+
+ do {
+ match_byte <<= 1;
+ const uint32_t match_bit
+ = match_byte & 0x100;
+ const uint32_t subcoder_index = 0x100
+ + match_bit + symbol;
+
+ if_bit_0(subcoder[subcoder_index]) {
+ update_bit_0_dummy();
+ symbol <<= 1;
+ if (match_bit != 0)
+ break;
+ } else {
+ update_bit_1_dummy();
+ symbol = (symbol << 1) | 1;
+ if (match_bit == 0)
+ break;
+ }
+ } while (symbol < 0x100);
+ }
+
+ // Decode literal without match byte. This is also
+ // the tail of the with-match-byte function.
+ while (symbol < 0x100) {
+ if_bit_0(subcoder[symbol]) {
+ update_bit_0_dummy();
+ symbol <<= 1;
+ } else {
+ update_bit_1_dummy();
+ symbol = (symbol << 1) | 1;
+ }
+ }
+
+ break;
+ }
+
+ update_bit_1_dummy();
+ uint32_t len;
+
+ if_bit_0(coder->is_rep[state]) {
+ update_bit_0_dummy();
+ length_decode_dummy(len, coder->len_decoder, pos_state);
+ update_match(state);
+
+ const uint32_t len_to_pos_state
+ = get_len_to_pos_state(len);
+ uint32_t pos_slot = 0;
+ bittree_decode_dummy(pos_slot, coder->pos_slot_decoder[
+ len_to_pos_state], POS_SLOT_BITS);
+ assert(pos_slot <= 63);
+
+ if (pos_slot >= START_POS_MODEL_INDEX) {
+ uint32_t direct_bits = (pos_slot >> 1) - 1;
+ assert(direct_bits >= 1 && direct_bits <= 31);
+ rep0 = 2 | (pos_slot & 1);
+
+ if (pos_slot < END_POS_MODEL_INDEX) {
+ assert(direct_bits <= 5);
+ rep0 <<= direct_bits;
+ assert(rep0 <= 96);
+ // -1 is fine, because
+ // bittree_reverse_decode()
+ // starts from table index [1]
+ // (not [0]).
+ assert((int32_t)(rep0 - pos_slot - 1)
+ >= -1);
+ assert((int32_t)(rep0 - pos_slot - 1)
+ <= 82);
+ // We add the result to rep0, so rep0
+ // must not be part of second argument
+ // of the macro.
+ const int32_t offset
+ = rep0 - pos_slot - 1;
+ bittree_reverse_decode_dummy(
+ coder->pos_decoders + offset,
+ direct_bits);
+ } else {
+ // Decode direct bits
+ assert(pos_slot >= 14);
+ assert(direct_bits >= 6);
+ direct_bits -= ALIGN_BITS;
+ assert(direct_bits >= 2);
+ do {
+ rc_normalize();
+ rc_range >>= 1;
+ const uint32_t t
+ = (rc_code - rc_range)
+ >> 31;
+ rc_code -= rc_range & (t - 1);
+ } while (--direct_bits > 0);
+ rep0 <<= ALIGN_BITS;
+
+ bittree_reverse_decode_dummy(
+ coder->pos_align_decoder,
+ ALIGN_BITS);
+ }
+ }
+
+ } else {
+ update_bit_1_dummy();
+
+ if_bit_0(coder->is_rep0[state]) {
+ update_bit_0_dummy();
+
+ if_bit_0(coder->is_rep0_long[state][
+ pos_state]) {
+ update_bit_0_dummy();
+ break;
+ } else {
+ update_bit_1_dummy();
+ }
+
+ } else {
+ update_bit_1_dummy();
+
+ if_bit_0(coder->is_rep1[state]) {
+ update_bit_0_dummy();
+ } else {
+ update_bit_1_dummy();
+
+ if_bit_0(coder->is_rep2[state]) {
+ update_bit_0_dummy();
+ } else {
+ update_bit_1_dummy();
+ }
+ }
+ }
+
+ length_decode_dummy(len, coder->rep_match_len_decoder,
+ pos_state);
+ }
+ } while (0);
+
+ rc_normalize();
+
+ // Validate the buffer position.
+ if (in_pos_local > in_size)
+ return false;
+
+ return true;
+}
+
+
+static bool
+decode_real(lzma_coder *restrict coder, const uint8_t *restrict in,
+ size_t *restrict in_pos, size_t in_size, bool has_safe_buffer)
+{
+ ////////////////////
+ // Initialization //
+ ////////////////////
+
+ while (coder->init_bytes_left > 0) {
+ if (*in_pos == in_size)
+ return false;
+
+ coder->rc.code = (coder->rc.code << 8) | in[*in_pos];
+ ++*in_pos;
+ --coder->init_bytes_left;
+ }
+
+
+ ///////////////
+ // Variables //
+ ///////////////
+
+ // Making local copies of often-used variables improves both
+ // speed and readability.
+
+ // Range decoder
+ rc_to_local(coder->rc);
+
+ // 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;
+
+ // Misc
+ uint32_t now_pos = coder->now_pos;
+
+ // Variables derived from decoder settings
+ const uint32_t pos_mask = coder->pos_mask;
+
+ size_t in_pos_local = *in_pos; // Local copy
+ size_t in_limit;
+ if (in_size <= REQUIRED_IN_BUFFER_SIZE)
+ in_limit = 0;
+ else
+ in_limit = in_size - REQUIRED_IN_BUFFER_SIZE;
+
+
+ while (coder->lz.pos < coder->lz.limit && (in_pos_local < in_limit
+ || (has_safe_buffer && decode_dummy(
+ coder, in, in_pos_local, in_size,
+ rc_range, rc_code, state, rep0, now_pos)))) {
+
+ /////////////////////
+ // Actual decoding //
+ /////////////////////
+
+ const uint32_t pos_state = now_pos & pos_mask;
+
+ if_bit_0(coder->is_match[state][pos_state]) {
+ update_bit_0(coder->is_match[state][pos_state]);
+
+ // It's a literal i.e. a single 8-bit byte.
+
+ probability *subcoder = literal_get_subcoder(
+ coder->literal_coder,
+ now_pos, lz_get_byte(coder->lz, 0));
+ uint32_t symbol = 1;
+
+ if (!is_char_state(state)) {
+ // Decode literal with match byte.
+
+ assert(rep0 != UINT32_MAX);
+ uint32_t match_byte
+ = lz_get_byte(coder->lz, rep0);
+
+ do {
+ match_byte <<= 1;
+ const uint32_t match_bit
+ = match_byte & 0x100;
+ const uint32_t subcoder_index = 0x100
+ + match_bit + symbol;
+
+ if_bit_0(subcoder[subcoder_index]) {
+ update_bit_0(subcoder[
+ subcoder_index]);
+ symbol <<= 1;
+ if (match_bit != 0)
+ break;
+ } else {
+ update_bit_1(subcoder[
+ subcoder_index]);
+ symbol = (symbol << 1) | 1;
+ if (match_bit == 0)
+ break;
+ }
+ } while (symbol < 0x100);
+ }
+
+ // Decode literal without match byte. This is also
+ // the tail of the with-match-byte function.
+ while (symbol < 0x100) {
+ if_bit_0(subcoder[symbol]) {
+ update_bit_0(subcoder[symbol]);
+ symbol <<= 1;
+ } else {
+ update_bit_1(subcoder[symbol]);
+ symbol = (symbol << 1) | 1;
+ }
+ }
+
+ // Put the decoded byte to the dictionary, update the
+ // decoder state, and start a new decoding loop.
+ coder->lz.dict[coder->lz.pos++] = (uint8_t)(symbol);
+ ++now_pos;
+ update_char(state);
+ 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.
+
+ update_bit_1(coder->is_match[state][pos_state]);
+ uint32_t len;
+
+ if_bit_0(coder->is_rep[state]) {
+ update_bit_0(coder->is_rep[state]);
+
+ // Not a repeated match
+ //
+ // We will decode a new distance and store
+ // the value to rep0.
+
+ // 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.
+ length_decode(len, coder->len_decoder, pos_state);
+
+ update_match(state);
+
+ const uint32_t len_to_pos_state
+ = get_len_to_pos_state(len);
+ uint32_t pos_slot = 0;
+ bittree_decode(pos_slot, coder->pos_slot_decoder[
+ len_to_pos_state], POS_SLOT_BITS);
+ assert(pos_slot <= 63);
+
+ if (pos_slot >= START_POS_MODEL_INDEX) {
+ uint32_t direct_bits = (pos_slot >> 1) - 1;
+ assert(direct_bits >= 1 && direct_bits <= 30);
+ rep0 = 2 | (pos_slot & 1);
+
+ if (pos_slot < END_POS_MODEL_INDEX) {
+ assert(direct_bits <= 5);
+ rep0 <<= direct_bits;
+ assert(rep0 <= 96);
+ // -1 is fine, because
+ // bittree_reverse_decode()
+ // starts from table index [1]
+ // (not [0]).
+ assert((int32_t)(rep0 - pos_slot - 1)
+ >= -1);
+ assert((int32_t)(rep0 - pos_slot - 1)
+ <= 82);
+ // We add the result to rep0, so rep0
+ // must not be part of second argument
+ // of the macro.
+ const int32_t offset
+ = rep0 - pos_slot - 1;
+ bittree_reverse_decode(rep0,
+ coder->pos_decoders + offset,
+ direct_bits);
+ } else {
+ // Decode direct bits
+ assert(pos_slot >= 14);
+ assert(direct_bits >= 6);
+ direct_bits -= ALIGN_BITS;
+ assert(direct_bits >= 2);
+ do {
+ rc_normalize();
+ rc_range >>= 1;
+ const uint32_t t
+ = (rc_code - rc_range)
+ >> 31;
+ rc_code -= rc_range & (t - 1);
+ rep0 = (rep0 << 1) | (1 - t);
+ } while (--direct_bits > 0);
+ rep0 <<= ALIGN_BITS;
+
+ bittree_reverse_decode(rep0,
+ coder->pos_align_decoder,
+ ALIGN_BITS);
+
+ if (rep0 == UINT32_MAX) {
+ // End of Payload Marker found.
+ coder->lz.eopm_detected = true;
+ break;
+ }
+ }
+ } else {
+ rep0 = pos_slot;
+ }
+
+ } else {
+ update_bit_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.
+
+ if_bit_0(coder->is_rep0[state]) {
+ update_bit_0(coder->is_rep0[state]);
+
+ // The distance is rep0.
+
+ if_bit_0(coder->is_rep0_long[state][
+ pos_state]) {
+ update_bit_0(coder->is_rep0_long[
+ state][pos_state]);
+
+ // Repeating exactly one byte. For
+ // simplicity, it is done here inline
+ // instead of at the end of the main
+ // loop.
+
+ update_short_rep(state);
+
+ // Security/sanity checks. See the end
+ // of the main loop for explanation
+ // of these.
+ if ((rep0 >= coder->lz.pos
+ && !coder->lz.is_full)
+ || in_pos_local
+ > in_size)
+ goto error;
+
+ // Repeat one byte and start a new
+ // decoding loop.
+ coder->lz.dict[coder->lz.pos]
+ = lz_get_byte(
+ coder->lz, rep0);
+ ++coder->lz.pos;
+ ++now_pos;
+ continue;
+
+ } else {
+ update_bit_1(coder->is_rep0_long[
+ state][pos_state]);
+
+ // Repeating more than one byte at
+ // distance of rep0.
+ }
+
+ } else {
+ update_bit_1(coder->is_rep0[state]);
+
+ // 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.
+
+ uint32_t distance;
+
+ if_bit_0(coder->is_rep1[state]) {
+ update_bit_0(coder->is_rep1[state]);
+ distance = rep1;
+ } else {
+ update_bit_1(coder->is_rep1[state]);
+
+ if_bit_0(coder->is_rep2[state]) {
+ update_bit_0(coder->is_rep2[
+ state]);
+ distance = rep2;
+ } else {
+ update_bit_1(coder->is_rep2[
+ state]);
+ distance = rep3;
+ rep3 = rep2;
+ }
+
+ rep2 = rep1;
+ }
+
+ rep1 = rep0;
+ rep0 = distance;
+ }
+
+ // Decode the length of the repeated match.
+ length_decode(len, coder->rep_match_len_decoder,
+ pos_state);
+
+ update_rep(state);
+ }
+
+
+ /////////////////////////////////
+ // 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_MIN_LEN);
+ assert(len <= MATCH_MAX_LEN);
+
+ now_pos += len;
+
+ // Validate the buffer position to avoid buffer overflows
+ // on corrupted input data.
+ if (in_pos_local > in_size)
+ goto error;
+
+ // Repeat len bytes from distance of rep0.
+ if (!lzma_lz_out_repeat(&coder->lz, rep0, len))
+ goto error;
+ }
+
+ rc_normalize();
+
+
+ /////////////////////////////////
+ // Update the *data structure. //
+ /////////////////////////////////
+
+ // Range decoder
+ rc_from_local(coder->rc);
+
+ // State
+ coder->state = state;
+ coder->rep0 = rep0;
+ coder->rep1 = rep1;
+ coder->rep2 = rep2;
+ coder->rep3 = rep3;
+
+ // Misc
+ coder->now_pos = now_pos;
+ *in_pos = in_pos_local;
+
+ return false;
+
+error:
+ return true;
+}
+
+
+static void
+lzma_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+ lzma_next_coder_end(&coder->next, allocator);
+ lzma_lz_decoder_end(&coder->lz, allocator);
+ lzma_literal_end(&coder->literal_coder, allocator);
+ lzma_free(coder, allocator);
+ return;
+}
+
+
+extern lzma_ret
+lzma_lzma_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+ const lzma_filter_info *filters)
+{
+ // Validate pos_bits. Other options are validated by the
+ // respective initialization functions.
+ const lzma_options_lzma *options = filters[0].options;
+ if (options->pos_bits > LZMA_POS_BITS_MAX)
+ return LZMA_HEADER_ERROR;
+
+ // Allocate memory for the decoder if needed.
+ if (next->coder == NULL) {
+ next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+ if (next->coder == NULL)
+ return LZMA_MEM_ERROR;
+
+ // Initialize variables so that we know later that we don't
+ // have an existing decoder initialized.
+ next->coder->next = LZMA_NEXT_CODER_INIT;
+ next->coder->lz = LZMA_LZ_DECODER_INIT;
+ next->coder->literal_coder = NULL;
+ }
+
+ // Store the pos_bits and calculate pos_mask.
+ next->coder->pos_bits = options->pos_bits;
+ next->coder->pos_mask = (1U << next->coder->pos_bits) - 1;
+
+ // Allocate (if needed) and initialize the literal decoder.
+ {
+ const lzma_ret ret = lzma_literal_init(
+ &next->coder->literal_coder, allocator,
+ options->literal_context_bits,
+ options->literal_pos_bits);
+ if (ret != LZMA_OK) {
+ lzma_free(next->coder, allocator);
+ next->coder = NULL;
+ return ret;
+ }
+ }
+
+ // Allocate and initialize the LZ decoder.
+ {
+ const lzma_ret ret = lzma_lz_decoder_reset(
+ &next->coder->lz, allocator, &decode_real,
+ filters[0].uncompressed_size,
+ options->dictionary_size, MATCH_MAX_LEN);
+ if (ret != LZMA_OK) {
+ lzma_literal_end(&next->coder->literal_coder,
+ allocator);
+ lzma_free(next->coder, allocator);
+ next->coder = NULL;
+ return ret;
+ }
+ }
+
+ // State
+ next->coder->state = 0;
+ next->coder->rep0 = 0;
+ next->coder->rep1 = 0;
+ next->coder->rep2 = 0;
+ next->coder->rep3 = 0;
+ next->coder->pos_bits = options->pos_bits;
+ next->coder->pos_mask = (1 << next->coder->pos_bits) - 1;
+ next->coder->now_pos = 0;
+ next->coder->init_bytes_left = 5;
+
+ // Range decoder
+ rc_reset(next->coder->rc);
+
+ // Bit and bittree decoders
+ for (uint32_t i = 0; i < STATES; ++i) {
+ for (uint32_t j = 0; j <= next->coder->pos_mask; ++j) {
+ bit_reset(next->coder->is_match[i][j]);
+ bit_reset(next->coder->is_rep0_long[i][j]);
+ }
+
+ bit_reset(next->coder->is_rep[i]);
+ bit_reset(next->coder->is_rep0[i]);
+ bit_reset(next->coder->is_rep1[i]);
+ bit_reset(next->coder->is_rep2[i]);
+ }
+
+ for (uint32_t i = 0; i < LEN_TO_POS_STATES; ++i)
+ bittree_reset(next->coder->pos_slot_decoder[i], POS_SLOT_BITS);
+
+ for (uint32_t i = 0; i < FULL_DISTANCES - END_POS_MODEL_INDEX; ++i)
+ bit_reset(next->coder->pos_decoders[i]);
+
+ bittree_reset(next->coder->pos_align_decoder, ALIGN_BITS);
+
+ // Len decoders (also bit/bittree)
+ const uint32_t num_pos_states = 1 << next->coder->pos_bits;
+ bit_reset(next->coder->len_decoder.choice);
+ bit_reset(next->coder->len_decoder.choice2);
+ bit_reset(next->coder->rep_match_len_decoder.choice);
+ bit_reset(next->coder->rep_match_len_decoder.choice2);
+
+ for (uint32_t pos_state = 0; pos_state < num_pos_states; ++pos_state) {
+ bittree_reset(next->coder->len_decoder.low[pos_state],
+ LEN_LOW_BITS);
+ bittree_reset(next->coder->len_decoder.mid[pos_state],
+ LEN_MID_BITS);
+
+ bittree_reset(next->coder->rep_match_len_decoder.low[
+ pos_state], LEN_LOW_BITS);
+ bittree_reset(next->coder->rep_match_len_decoder.mid[
+ pos_state], LEN_MID_BITS);
+ }
+
+ bittree_reset(next->coder->len_decoder.high, LEN_HIGH_BITS);
+ bittree_reset(next->coder->rep_match_len_decoder.high, LEN_HIGH_BITS);
+
+ // Initialize the next decoder in the chain, if any.
+ {
+ const lzma_ret ret = lzma_next_filter_init(&next->coder->next,
+ allocator, filters + 1);
+ if (ret != LZMA_OK) {
+ lzma_decoder_end(next->coder, allocator);
+ return ret;
+ }
+ }
+
+ // Initialization successful. Set the function pointers.
+ next->code = &lzma_lz_decode;
+ next->end = &lzma_decoder_end;
+
+ return LZMA_OK;
+}
+
+
+extern bool
+lzma_lzma_decode_properties(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->pos_bits = byte / (9 * 5);
+ byte -= options->pos_bits * 9 * 5;
+ options->literal_pos_bits = byte / 9;
+ options->literal_context_bits = byte - options->literal_pos_bits * 9;
+
+ return false;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-20 10:44:32 +0000