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https://github.com/topjohnwu/Magisk.git
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1172 lines
33 KiB
C
Vendored
1172 lines
33 KiB
C
Vendored
/*
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* LZMA2 decoder
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*
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* Authors: Lasse Collin <lasse.collin@tukaani.org>
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* Igor Pavlov <http://7-zip.org/>
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*
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* This file has been put into the public domain.
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* You can do whatever you want with this file.
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*/
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#include "xz_private.h"
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#include "xz_lzma2.h"
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/*
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* Range decoder initialization eats the first five bytes of each LZMA chunk.
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*/
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#define RC_INIT_BYTES 5
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/*
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* Minimum number of usable input buffer to safely decode one LZMA symbol.
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* The worst case is that we decode 22 bits using probabilities and 26
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* direct bits. This may decode at maximum of 20 bytes of input. However,
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* lzma_main() does an extra normalization before returning, thus we
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* need to put 21 here.
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*/
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#define LZMA_IN_REQUIRED 21
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/*
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* Dictionary (history buffer)
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*
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* These are always true:
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* start <= pos <= full <= end
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* pos <= limit <= end
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*
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* In multi-call mode, also these are true:
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* end == size
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* size <= size_max
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* allocated <= size
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*
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* Most of these variables are size_t to support single-call mode,
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* in which the dictionary variables address the actual output
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* buffer directly.
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*/
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struct dictionary {
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/* Beginning of the history buffer */
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uint8_t *buf;
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/* Old position in buf (before decoding more data) */
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size_t start;
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/* Position in buf */
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size_t pos;
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/*
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* How full dictionary is. This is used to detect corrupt input that
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* would read beyond the beginning of the uncompressed stream.
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*/
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size_t full;
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/* Write limit; we don't write to buf[limit] or later bytes. */
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size_t limit;
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/*
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* End of the dictionary buffer. In multi-call mode, this is
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* the same as the dictionary size. In single-call mode, this
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* indicates the size of the output buffer.
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*/
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size_t end;
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/*
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* Size of the dictionary as specified in Block Header. This is used
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* together with "full" to detect corrupt input that would make us
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* read beyond the beginning of the uncompressed stream.
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*/
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uint32_t size;
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/*
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* Maximum allowed dictionary size in multi-call mode.
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* This is ignored in single-call mode.
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*/
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uint32_t size_max;
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/*
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* Amount of memory currently allocated for the dictionary.
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* This is used only with XZ_DYNALLOC. (With XZ_PREALLOC,
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* size_max is always the same as the allocated size.)
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*/
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uint32_t allocated;
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/* Operation mode */
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enum xz_mode mode;
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};
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/* Range decoder */
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struct rc_dec {
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uint32_t range;
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uint32_t code;
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/*
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* Number of initializing bytes remaining to be read
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* by rc_read_init().
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*/
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uint32_t init_bytes_left;
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/*
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* Buffer from which we read our input. It can be either
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* temp.buf or the caller-provided input buffer.
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*/
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const uint8_t *in;
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size_t in_pos;
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size_t in_limit;
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};
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/* Probabilities for a length decoder. */
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struct lzma_len_dec {
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/* Probability of match length being at least 10 */
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uint16_t choice;
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/* Probability of match length being at least 18 */
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uint16_t choice2;
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/* Probabilities for match lengths 2-9 */
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uint16_t low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
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/* Probabilities for match lengths 10-17 */
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uint16_t mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
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/* Probabilities for match lengths 18-273 */
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uint16_t high[LEN_HIGH_SYMBOLS];
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};
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struct lzma_dec {
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/* Distances of latest four matches */
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uint32_t rep0;
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uint32_t rep1;
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uint32_t rep2;
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uint32_t rep3;
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/* Types of the most recently seen LZMA symbols */
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enum lzma_state state;
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/*
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* Length of a match. This is updated so that dict_repeat can
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* be called again to finish repeating the whole match.
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*/
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uint32_t len;
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/*
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* LZMA properties or related bit masks (number of literal
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* context bits, a mask dervied from the number of literal
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* position bits, and a mask dervied from the number
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* position bits)
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*/
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uint32_t lc;
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uint32_t literal_pos_mask; /* (1 << lp) - 1 */
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uint32_t pos_mask; /* (1 << pb) - 1 */
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/* If 1, it's a match. Otherwise it's a single 8-bit literal. */
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uint16_t is_match[STATES][POS_STATES_MAX];
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/* If 1, it's a repeated match. The distance is one of rep0 .. rep3. */
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uint16_t is_rep[STATES];
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/*
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* If 0, distance of a repeated match is rep0.
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* Otherwise check is_rep1.
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*/
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uint16_t is_rep0[STATES];
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/*
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* If 0, distance of a repeated match is rep1.
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* Otherwise check is_rep2.
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*/
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uint16_t is_rep1[STATES];
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/* If 0, distance of a repeated match is rep2. Otherwise it is rep3. */
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uint16_t is_rep2[STATES];
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/*
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* If 1, the repeated match has length of one byte. Otherwise
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* the length is decoded from rep_len_decoder.
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*/
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uint16_t is_rep0_long[STATES][POS_STATES_MAX];
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/*
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* Probability tree for the highest two bits of the match
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* distance. There is a separate probability tree for match
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* lengths of 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273].
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*/
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uint16_t dist_slot[DIST_STATES][DIST_SLOTS];
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/*
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* Probility trees for additional bits for match distance
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* when the distance is in the range [4, 127].
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*/
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uint16_t dist_special[FULL_DISTANCES - DIST_MODEL_END];
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/*
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* Probability tree for the lowest four bits of a match
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* distance that is equal to or greater than 128.
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*/
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uint16_t dist_align[ALIGN_SIZE];
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/* Length of a normal match */
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struct lzma_len_dec match_len_dec;
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/* Length of a repeated match */
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struct lzma_len_dec rep_len_dec;
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/* Probabilities of literals */
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uint16_t literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE];
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};
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struct lzma2_dec {
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/* Position in xz_dec_lzma2_run(). */
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enum lzma2_seq {
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SEQ_CONTROL,
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SEQ_UNCOMPRESSED_1,
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SEQ_UNCOMPRESSED_2,
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SEQ_COMPRESSED_0,
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SEQ_COMPRESSED_1,
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SEQ_PROPERTIES,
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SEQ_LZMA_PREPARE,
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SEQ_LZMA_RUN,
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SEQ_COPY
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} sequence;
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/* Next position after decoding the compressed size of the chunk. */
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enum lzma2_seq next_sequence;
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/* Uncompressed size of LZMA chunk (2 MiB at maximum) */
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uint32_t uncompressed;
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/*
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* Compressed size of LZMA chunk or compressed/uncompressed
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* size of uncompressed chunk (64 KiB at maximum)
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*/
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uint32_t compressed;
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/*
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* True if dictionary reset is needed. This is false before
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* the first chunk (LZMA or uncompressed).
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*/
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bool need_dict_reset;
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/*
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* True if new LZMA properties are needed. This is false
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* before the first LZMA chunk.
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*/
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bool need_props;
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};
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struct xz_dec_lzma2 {
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/*
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* The order below is important on x86 to reduce code size and
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* it shouldn't hurt on other platforms. Everything up to and
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* including lzma.pos_mask are in the first 128 bytes on x86-32,
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* which allows using smaller instructions to access those
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* variables. On x86-64, fewer variables fit into the first 128
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* bytes, but this is still the best order without sacrificing
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* the readability by splitting the structures.
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*/
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struct rc_dec rc;
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struct dictionary dict;
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struct lzma2_dec lzma2;
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struct lzma_dec lzma;
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/*
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* Temporary buffer which holds small number of input bytes between
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* decoder calls. See lzma2_lzma() for details.
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*/
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struct {
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uint32_t size;
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uint8_t buf[3 * LZMA_IN_REQUIRED];
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} temp;
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};
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/**************
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* Dictionary *
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**************/
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/*
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* Reset the dictionary state. When in single-call mode, set up the beginning
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* of the dictionary to point to the actual output buffer.
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*/
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static void dict_reset(struct dictionary *dict, struct xz_buf *b)
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{
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if (DEC_IS_SINGLE(dict->mode)) {
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dict->buf = b->out + b->out_pos;
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dict->end = b->out_size - b->out_pos;
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}
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dict->start = 0;
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dict->pos = 0;
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dict->limit = 0;
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dict->full = 0;
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}
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/* Set dictionary write limit */
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static void dict_limit(struct dictionary *dict, size_t out_max)
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{
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if (dict->end - dict->pos <= out_max)
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dict->limit = dict->end;
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else
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dict->limit = dict->pos + out_max;
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}
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/* Return true if at least one byte can be written into the dictionary. */
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static inline bool dict_has_space(const struct dictionary *dict)
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{
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return dict->pos < dict->limit;
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}
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/*
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* Get a byte from the dictionary at the given distance. The distance is
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* assumed to valid, or as a special case, zero when the dictionary is
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* still empty. This special case is needed for single-call decoding to
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* avoid writing a '\0' to the end of the destination buffer.
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*/
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static inline uint32_t dict_get(const struct dictionary *dict, uint32_t dist)
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{
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size_t offset = dict->pos - dist - 1;
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if (dist >= dict->pos)
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offset += dict->end;
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return dict->full > 0 ? dict->buf[offset] : 0;
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}
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/*
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* Put one byte into the dictionary. It is assumed that there is space for it.
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*/
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static inline void dict_put(struct dictionary *dict, uint8_t byte)
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{
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dict->buf[dict->pos++] = byte;
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if (dict->full < dict->pos)
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dict->full = dict->pos;
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}
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/*
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* Repeat given number of bytes from the given distance. If the distance is
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* invalid, false is returned. On success, true is returned and *len is
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* updated to indicate how many bytes were left to be repeated.
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*/
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static bool dict_repeat(struct dictionary *dict, uint32_t *len, uint32_t dist)
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{
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size_t back;
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uint32_t left;
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if (dist >= dict->full || dist >= dict->size)
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return false;
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left = min_t(size_t, dict->limit - dict->pos, *len);
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*len -= left;
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back = dict->pos - dist - 1;
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if (dist >= dict->pos)
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back += dict->end;
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do {
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dict->buf[dict->pos++] = dict->buf[back++];
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if (back == dict->end)
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back = 0;
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} while (--left > 0);
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if (dict->full < dict->pos)
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dict->full = dict->pos;
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return true;
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}
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/* Copy uncompressed data as is from input to dictionary and output buffers. */
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static void dict_uncompressed(struct dictionary *dict, struct xz_buf *b,
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uint32_t *left)
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{
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size_t copy_size;
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while (*left > 0 && b->in_pos < b->in_size
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&& b->out_pos < b->out_size) {
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copy_size = min(b->in_size - b->in_pos,
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b->out_size - b->out_pos);
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if (copy_size > dict->end - dict->pos)
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copy_size = dict->end - dict->pos;
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if (copy_size > *left)
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copy_size = *left;
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*left -= copy_size;
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memcpy(dict->buf + dict->pos, b->in + b->in_pos, copy_size);
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dict->pos += copy_size;
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if (dict->full < dict->pos)
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dict->full = dict->pos;
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if (DEC_IS_MULTI(dict->mode)) {
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if (dict->pos == dict->end)
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dict->pos = 0;
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memcpy(b->out + b->out_pos, b->in + b->in_pos,
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copy_size);
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}
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dict->start = dict->pos;
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b->out_pos += copy_size;
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b->in_pos += copy_size;
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}
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}
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/*
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* Flush pending data from dictionary to b->out. It is assumed that there is
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* enough space in b->out. This is guaranteed because caller uses dict_limit()
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* before decoding data into the dictionary.
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*/
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static uint32_t dict_flush(struct dictionary *dict, struct xz_buf *b)
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{
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size_t copy_size = dict->pos - dict->start;
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if (DEC_IS_MULTI(dict->mode)) {
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if (dict->pos == dict->end)
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dict->pos = 0;
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memcpy(b->out + b->out_pos, dict->buf + dict->start,
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copy_size);
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}
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dict->start = dict->pos;
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b->out_pos += copy_size;
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return copy_size;
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}
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/*****************
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* Range decoder *
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*****************/
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/* Reset the range decoder. */
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static void rc_reset(struct rc_dec *rc)
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{
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rc->range = (uint32_t)-1;
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rc->code = 0;
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rc->init_bytes_left = RC_INIT_BYTES;
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}
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/*
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* Read the first five initial bytes into rc->code if they haven't been
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* read already. (Yes, the first byte gets completely ignored.)
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*/
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static bool rc_read_init(struct rc_dec *rc, struct xz_buf *b)
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{
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while (rc->init_bytes_left > 0) {
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if (b->in_pos == b->in_size)
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return false;
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rc->code = (rc->code << 8) + b->in[b->in_pos++];
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--rc->init_bytes_left;
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}
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return true;
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}
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/* Return true if there may not be enough input for the next decoding loop. */
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static inline bool rc_limit_exceeded(const struct rc_dec *rc)
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{
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return rc->in_pos > rc->in_limit;
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}
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/*
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* Return true if it is possible (from point of view of range decoder) that
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* we have reached the end of the LZMA chunk.
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*/
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static inline bool rc_is_finished(const struct rc_dec *rc)
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{
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return rc->code == 0;
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}
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/* Read the next input byte if needed. */
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static __always_inline void rc_normalize(struct rc_dec *rc)
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{
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if (rc->range < RC_TOP_VALUE) {
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rc->range <<= RC_SHIFT_BITS;
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rc->code = (rc->code << RC_SHIFT_BITS) + rc->in[rc->in_pos++];
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}
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}
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/*
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* Decode one bit. In some versions, this function has been splitted in three
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* functions so that the compiler is supposed to be able to more easily avoid
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* an extra branch. In this particular version of the LZMA decoder, this
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* doesn't seem to be a good idea (tested with GCC 3.3.6, 3.4.6, and 4.3.3
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* on x86). Using a non-splitted version results in nicer looking code too.
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*
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* NOTE: This must return an int. Do not make it return a bool or the speed
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* of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care,
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* and it generates 10-20 % faster code than GCC 3.x from this file anyway.)
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*/
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static __always_inline int rc_bit(struct rc_dec *rc, uint16_t *prob)
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{
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uint32_t bound;
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int bit;
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rc_normalize(rc);
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bound = (rc->range >> RC_BIT_MODEL_TOTAL_BITS) * *prob;
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if (rc->code < bound) {
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rc->range = bound;
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*prob += (RC_BIT_MODEL_TOTAL - *prob) >> RC_MOVE_BITS;
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bit = 0;
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} else {
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rc->range -= bound;
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rc->code -= bound;
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*prob -= *prob >> RC_MOVE_BITS;
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bit = 1;
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}
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return bit;
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}
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/* Decode a bittree starting from the most significant bit. */
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static __always_inline uint32_t rc_bittree(struct rc_dec *rc,
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uint16_t *probs, uint32_t limit)
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{
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uint32_t symbol = 1;
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do {
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if (rc_bit(rc, &probs[symbol]))
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symbol = (symbol << 1) + 1;
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else
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symbol <<= 1;
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} while (symbol < limit);
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return symbol;
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}
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/* Decode a bittree starting from the least significant bit. */
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static __always_inline void rc_bittree_reverse(struct rc_dec *rc,
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uint16_t *probs,
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uint32_t *dest, uint32_t limit)
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{
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uint32_t symbol = 1;
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uint32_t i = 0;
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do {
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if (rc_bit(rc, &probs[symbol])) {
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symbol = (symbol << 1) + 1;
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*dest += 1 << i;
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} else {
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symbol <<= 1;
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|
}
|
|
} while (++i < limit);
|
|
}
|
|
|
|
/* Decode direct bits (fixed fifty-fifty probability) */
|
|
static inline void rc_direct(struct rc_dec *rc, uint32_t *dest, uint32_t limit)
|
|
{
|
|
uint32_t mask;
|
|
|
|
do {
|
|
rc_normalize(rc);
|
|
rc->range >>= 1;
|
|
rc->code -= rc->range;
|
|
mask = (uint32_t)0 - (rc->code >> 31);
|
|
rc->code += rc->range & mask;
|
|
*dest = (*dest << 1) + (mask + 1);
|
|
} while (--limit > 0);
|
|
}
|
|
|
|
/********
|
|
* LZMA *
|
|
********/
|
|
|
|
/* Get pointer to literal coder probability array. */
|
|
static uint16_t *lzma_literal_probs(struct xz_dec_lzma2 *s)
|
|
{
|
|
uint32_t prev_byte = dict_get(&s->dict, 0);
|
|
uint32_t low = prev_byte >> (8 - s->lzma.lc);
|
|
uint32_t high = (s->dict.pos & s->lzma.literal_pos_mask) << s->lzma.lc;
|
|
return s->lzma.literal[low + high];
|
|
}
|
|
|
|
/* Decode a literal (one 8-bit byte) */
|
|
static void lzma_literal(struct xz_dec_lzma2 *s)
|
|
{
|
|
uint16_t *probs;
|
|
uint32_t symbol;
|
|
uint32_t match_byte;
|
|
uint32_t match_bit;
|
|
uint32_t offset;
|
|
uint32_t i;
|
|
|
|
probs = lzma_literal_probs(s);
|
|
|
|
if (lzma_state_is_literal(s->lzma.state)) {
|
|
symbol = rc_bittree(&s->rc, probs, 0x100);
|
|
} else {
|
|
symbol = 1;
|
|
match_byte = dict_get(&s->dict, s->lzma.rep0) << 1;
|
|
offset = 0x100;
|
|
|
|
do {
|
|
match_bit = match_byte & offset;
|
|
match_byte <<= 1;
|
|
i = offset + match_bit + symbol;
|
|
|
|
if (rc_bit(&s->rc, &probs[i])) {
|
|
symbol = (symbol << 1) + 1;
|
|
offset &= match_bit;
|
|
} else {
|
|
symbol <<= 1;
|
|
offset &= ~match_bit;
|
|
}
|
|
} while (symbol < 0x100);
|
|
}
|
|
|
|
dict_put(&s->dict, (uint8_t)symbol);
|
|
lzma_state_literal(&s->lzma.state);
|
|
}
|
|
|
|
/* Decode the length of the match into s->lzma.len. */
|
|
static void lzma_len(struct xz_dec_lzma2 *s, struct lzma_len_dec *l,
|
|
uint32_t pos_state)
|
|
{
|
|
uint16_t *probs;
|
|
uint32_t limit;
|
|
|
|
if (!rc_bit(&s->rc, &l->choice)) {
|
|
probs = l->low[pos_state];
|
|
limit = LEN_LOW_SYMBOLS;
|
|
s->lzma.len = MATCH_LEN_MIN;
|
|
} else {
|
|
if (!rc_bit(&s->rc, &l->choice2)) {
|
|
probs = l->mid[pos_state];
|
|
limit = LEN_MID_SYMBOLS;
|
|
s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS;
|
|
} else {
|
|
probs = l->high;
|
|
limit = LEN_HIGH_SYMBOLS;
|
|
s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS
|
|
+ LEN_MID_SYMBOLS;
|
|
}
|
|
}
|
|
|
|
s->lzma.len += rc_bittree(&s->rc, probs, limit) - limit;
|
|
}
|
|
|
|
/* Decode a match. The distance will be stored in s->lzma.rep0. */
|
|
static void lzma_match(struct xz_dec_lzma2 *s, uint32_t pos_state)
|
|
{
|
|
uint16_t *probs;
|
|
uint32_t dist_slot;
|
|
uint32_t limit;
|
|
|
|
lzma_state_match(&s->lzma.state);
|
|
|
|
s->lzma.rep3 = s->lzma.rep2;
|
|
s->lzma.rep2 = s->lzma.rep1;
|
|
s->lzma.rep1 = s->lzma.rep0;
|
|
|
|
lzma_len(s, &s->lzma.match_len_dec, pos_state);
|
|
|
|
probs = s->lzma.dist_slot[lzma_get_dist_state(s->lzma.len)];
|
|
dist_slot = rc_bittree(&s->rc, probs, DIST_SLOTS) - DIST_SLOTS;
|
|
|
|
if (dist_slot < DIST_MODEL_START) {
|
|
s->lzma.rep0 = dist_slot;
|
|
} else {
|
|
limit = (dist_slot >> 1) - 1;
|
|
s->lzma.rep0 = 2 + (dist_slot & 1);
|
|
|
|
if (dist_slot < DIST_MODEL_END) {
|
|
s->lzma.rep0 <<= limit;
|
|
probs = s->lzma.dist_special + s->lzma.rep0
|
|
- dist_slot - 1;
|
|
rc_bittree_reverse(&s->rc, probs,
|
|
&s->lzma.rep0, limit);
|
|
} else {
|
|
rc_direct(&s->rc, &s->lzma.rep0, limit - ALIGN_BITS);
|
|
s->lzma.rep0 <<= ALIGN_BITS;
|
|
rc_bittree_reverse(&s->rc, s->lzma.dist_align,
|
|
&s->lzma.rep0, ALIGN_BITS);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Decode a repeated match. The distance is one of the four most recently
|
|
* seen matches. The distance will be stored in s->lzma.rep0.
|
|
*/
|
|
static void lzma_rep_match(struct xz_dec_lzma2 *s, uint32_t pos_state)
|
|
{
|
|
uint32_t tmp;
|
|
|
|
if (!rc_bit(&s->rc, &s->lzma.is_rep0[s->lzma.state])) {
|
|
if (!rc_bit(&s->rc, &s->lzma.is_rep0_long[
|
|
s->lzma.state][pos_state])) {
|
|
lzma_state_short_rep(&s->lzma.state);
|
|
s->lzma.len = 1;
|
|
return;
|
|
}
|
|
} else {
|
|
if (!rc_bit(&s->rc, &s->lzma.is_rep1[s->lzma.state])) {
|
|
tmp = s->lzma.rep1;
|
|
} else {
|
|
if (!rc_bit(&s->rc, &s->lzma.is_rep2[s->lzma.state])) {
|
|
tmp = s->lzma.rep2;
|
|
} else {
|
|
tmp = s->lzma.rep3;
|
|
s->lzma.rep3 = s->lzma.rep2;
|
|
}
|
|
|
|
s->lzma.rep2 = s->lzma.rep1;
|
|
}
|
|
|
|
s->lzma.rep1 = s->lzma.rep0;
|
|
s->lzma.rep0 = tmp;
|
|
}
|
|
|
|
lzma_state_long_rep(&s->lzma.state);
|
|
lzma_len(s, &s->lzma.rep_len_dec, pos_state);
|
|
}
|
|
|
|
/* LZMA decoder core */
|
|
static bool lzma_main(struct xz_dec_lzma2 *s)
|
|
{
|
|
uint32_t pos_state;
|
|
|
|
/*
|
|
* If the dictionary was reached during the previous call, try to
|
|
* finish the possibly pending repeat in the dictionary.
|
|
*/
|
|
if (dict_has_space(&s->dict) && s->lzma.len > 0)
|
|
dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0);
|
|
|
|
/*
|
|
* Decode more LZMA symbols. One iteration may consume up to
|
|
* LZMA_IN_REQUIRED - 1 bytes.
|
|
*/
|
|
while (dict_has_space(&s->dict) && !rc_limit_exceeded(&s->rc)) {
|
|
pos_state = s->dict.pos & s->lzma.pos_mask;
|
|
|
|
if (!rc_bit(&s->rc, &s->lzma.is_match[
|
|
s->lzma.state][pos_state])) {
|
|
lzma_literal(s);
|
|
} else {
|
|
if (rc_bit(&s->rc, &s->lzma.is_rep[s->lzma.state]))
|
|
lzma_rep_match(s, pos_state);
|
|
else
|
|
lzma_match(s, pos_state);
|
|
|
|
if (!dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0))
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Having the range decoder always normalized when we are outside
|
|
* this function makes it easier to correctly handle end of the chunk.
|
|
*/
|
|
rc_normalize(&s->rc);
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Reset the LZMA decoder and range decoder state. Dictionary is nore reset
|
|
* here, because LZMA state may be reset without resetting the dictionary.
|
|
*/
|
|
static void lzma_reset(struct xz_dec_lzma2 *s)
|
|
{
|
|
uint16_t *probs;
|
|
size_t i;
|
|
|
|
s->lzma.state = STATE_LIT_LIT;
|
|
s->lzma.rep0 = 0;
|
|
s->lzma.rep1 = 0;
|
|
s->lzma.rep2 = 0;
|
|
s->lzma.rep3 = 0;
|
|
|
|
/*
|
|
* All probabilities are initialized to the same value. This hack
|
|
* makes the code smaller by avoiding a separate loop for each
|
|
* probability array.
|
|
*
|
|
* This could be optimized so that only that part of literal
|
|
* probabilities that are actually required. In the common case
|
|
* we would write 12 KiB less.
|
|
*/
|
|
probs = s->lzma.is_match[0];
|
|
for (i = 0; i < PROBS_TOTAL; ++i)
|
|
probs[i] = RC_BIT_MODEL_TOTAL / 2;
|
|
|
|
rc_reset(&s->rc);
|
|
}
|
|
|
|
/*
|
|
* Decode and validate LZMA properties (lc/lp/pb) and calculate the bit masks
|
|
* from the decoded lp and pb values. On success, the LZMA decoder state is
|
|
* reset and true is returned.
|
|
*/
|
|
static bool lzma_props(struct xz_dec_lzma2 *s, uint8_t props)
|
|
{
|
|
if (props > (4 * 5 + 4) * 9 + 8)
|
|
return false;
|
|
|
|
s->lzma.pos_mask = 0;
|
|
while (props >= 9 * 5) {
|
|
props -= 9 * 5;
|
|
++s->lzma.pos_mask;
|
|
}
|
|
|
|
s->lzma.pos_mask = (1 << s->lzma.pos_mask) - 1;
|
|
|
|
s->lzma.literal_pos_mask = 0;
|
|
while (props >= 9) {
|
|
props -= 9;
|
|
++s->lzma.literal_pos_mask;
|
|
}
|
|
|
|
s->lzma.lc = props;
|
|
|
|
if (s->lzma.lc + s->lzma.literal_pos_mask > 4)
|
|
return false;
|
|
|
|
s->lzma.literal_pos_mask = (1 << s->lzma.literal_pos_mask) - 1;
|
|
|
|
lzma_reset(s);
|
|
|
|
return true;
|
|
}
|
|
|
|
/*********
|
|
* LZMA2 *
|
|
*********/
|
|
|
|
/*
|
|
* The LZMA decoder assumes that if the input limit (s->rc.in_limit) hasn't
|
|
* been exceeded, it is safe to read up to LZMA_IN_REQUIRED bytes. This
|
|
* wrapper function takes care of making the LZMA decoder's assumption safe.
|
|
*
|
|
* As long as there is plenty of input left to be decoded in the current LZMA
|
|
* chunk, we decode directly from the caller-supplied input buffer until
|
|
* there's LZMA_IN_REQUIRED bytes left. Those remaining bytes are copied into
|
|
* s->temp.buf, which (hopefully) gets filled on the next call to this
|
|
* function. We decode a few bytes from the temporary buffer so that we can
|
|
* continue decoding from the caller-supplied input buffer again.
|
|
*/
|
|
static bool lzma2_lzma(struct xz_dec_lzma2 *s, struct xz_buf *b)
|
|
{
|
|
size_t in_avail;
|
|
uint32_t tmp;
|
|
|
|
in_avail = b->in_size - b->in_pos;
|
|
if (s->temp.size > 0 || s->lzma2.compressed == 0) {
|
|
tmp = 2 * LZMA_IN_REQUIRED - s->temp.size;
|
|
if (tmp > s->lzma2.compressed - s->temp.size)
|
|
tmp = s->lzma2.compressed - s->temp.size;
|
|
if (tmp > in_avail)
|
|
tmp = in_avail;
|
|
|
|
memcpy(s->temp.buf + s->temp.size, b->in + b->in_pos, tmp);
|
|
|
|
if (s->temp.size + tmp == s->lzma2.compressed) {
|
|
memzero(s->temp.buf + s->temp.size + tmp,
|
|
sizeof(s->temp.buf)
|
|
- s->temp.size - tmp);
|
|
s->rc.in_limit = s->temp.size + tmp;
|
|
} else if (s->temp.size + tmp < LZMA_IN_REQUIRED) {
|
|
s->temp.size += tmp;
|
|
b->in_pos += tmp;
|
|
return true;
|
|
} else {
|
|
s->rc.in_limit = s->temp.size + tmp - LZMA_IN_REQUIRED;
|
|
}
|
|
|
|
s->rc.in = s->temp.buf;
|
|
s->rc.in_pos = 0;
|
|
|
|
if (!lzma_main(s) || s->rc.in_pos > s->temp.size + tmp)
|
|
return false;
|
|
|
|
s->lzma2.compressed -= s->rc.in_pos;
|
|
|
|
if (s->rc.in_pos < s->temp.size) {
|
|
s->temp.size -= s->rc.in_pos;
|
|
memmove(s->temp.buf, s->temp.buf + s->rc.in_pos,
|
|
s->temp.size);
|
|
return true;
|
|
}
|
|
|
|
b->in_pos += s->rc.in_pos - s->temp.size;
|
|
s->temp.size = 0;
|
|
}
|
|
|
|
in_avail = b->in_size - b->in_pos;
|
|
if (in_avail >= LZMA_IN_REQUIRED) {
|
|
s->rc.in = b->in;
|
|
s->rc.in_pos = b->in_pos;
|
|
|
|
if (in_avail >= s->lzma2.compressed + LZMA_IN_REQUIRED)
|
|
s->rc.in_limit = b->in_pos + s->lzma2.compressed;
|
|
else
|
|
s->rc.in_limit = b->in_size - LZMA_IN_REQUIRED;
|
|
|
|
if (!lzma_main(s))
|
|
return false;
|
|
|
|
in_avail = s->rc.in_pos - b->in_pos;
|
|
if (in_avail > s->lzma2.compressed)
|
|
return false;
|
|
|
|
s->lzma2.compressed -= in_avail;
|
|
b->in_pos = s->rc.in_pos;
|
|
}
|
|
|
|
in_avail = b->in_size - b->in_pos;
|
|
if (in_avail < LZMA_IN_REQUIRED) {
|
|
if (in_avail > s->lzma2.compressed)
|
|
in_avail = s->lzma2.compressed;
|
|
|
|
memcpy(s->temp.buf, b->in + b->in_pos, in_avail);
|
|
s->temp.size = in_avail;
|
|
b->in_pos += in_avail;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Take care of the LZMA2 control layer, and forward the job of actual LZMA
|
|
* decoding or copying of uncompressed chunks to other functions.
|
|
*/
|
|
XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
|
|
struct xz_buf *b)
|
|
{
|
|
uint32_t tmp;
|
|
|
|
while (b->in_pos < b->in_size || s->lzma2.sequence == SEQ_LZMA_RUN) {
|
|
switch (s->lzma2.sequence) {
|
|
case SEQ_CONTROL:
|
|
/*
|
|
* LZMA2 control byte
|
|
*
|
|
* Exact values:
|
|
* 0x00 End marker
|
|
* 0x01 Dictionary reset followed by
|
|
* an uncompressed chunk
|
|
* 0x02 Uncompressed chunk (no dictionary reset)
|
|
*
|
|
* Highest three bits (s->control & 0xE0):
|
|
* 0xE0 Dictionary reset, new properties and state
|
|
* reset, followed by LZMA compressed chunk
|
|
* 0xC0 New properties and state reset, followed
|
|
* by LZMA compressed chunk (no dictionary
|
|
* reset)
|
|
* 0xA0 State reset using old properties,
|
|
* followed by LZMA compressed chunk (no
|
|
* dictionary reset)
|
|
* 0x80 LZMA chunk (no dictionary or state reset)
|
|
*
|
|
* For LZMA compressed chunks, the lowest five bits
|
|
* (s->control & 1F) are the highest bits of the
|
|
* uncompressed size (bits 16-20).
|
|
*
|
|
* A new LZMA2 stream must begin with a dictionary
|
|
* reset. The first LZMA chunk must set new
|
|
* properties and reset the LZMA state.
|
|
*
|
|
* Values that don't match anything described above
|
|
* are invalid and we return XZ_DATA_ERROR.
|
|
*/
|
|
tmp = b->in[b->in_pos++];
|
|
|
|
if (tmp == 0x00)
|
|
return XZ_STREAM_END;
|
|
|
|
if (tmp >= 0xE0 || tmp == 0x01) {
|
|
s->lzma2.need_props = true;
|
|
s->lzma2.need_dict_reset = false;
|
|
dict_reset(&s->dict, b);
|
|
} else if (s->lzma2.need_dict_reset) {
|
|
return XZ_DATA_ERROR;
|
|
}
|
|
|
|
if (tmp >= 0x80) {
|
|
s->lzma2.uncompressed = (tmp & 0x1F) << 16;
|
|
s->lzma2.sequence = SEQ_UNCOMPRESSED_1;
|
|
|
|
if (tmp >= 0xC0) {
|
|
/*
|
|
* When there are new properties,
|
|
* state reset is done at
|
|
* SEQ_PROPERTIES.
|
|
*/
|
|
s->lzma2.need_props = false;
|
|
s->lzma2.next_sequence
|
|
= SEQ_PROPERTIES;
|
|
|
|
} else if (s->lzma2.need_props) {
|
|
return XZ_DATA_ERROR;
|
|
|
|
} else {
|
|
s->lzma2.next_sequence
|
|
= SEQ_LZMA_PREPARE;
|
|
if (tmp >= 0xA0)
|
|
lzma_reset(s);
|
|
}
|
|
} else {
|
|
if (tmp > 0x02)
|
|
return XZ_DATA_ERROR;
|
|
|
|
s->lzma2.sequence = SEQ_COMPRESSED_0;
|
|
s->lzma2.next_sequence = SEQ_COPY;
|
|
}
|
|
|
|
break;
|
|
|
|
case SEQ_UNCOMPRESSED_1:
|
|
s->lzma2.uncompressed
|
|
+= (uint32_t)b->in[b->in_pos++] << 8;
|
|
s->lzma2.sequence = SEQ_UNCOMPRESSED_2;
|
|
break;
|
|
|
|
case SEQ_UNCOMPRESSED_2:
|
|
s->lzma2.uncompressed
|
|
+= (uint32_t)b->in[b->in_pos++] + 1;
|
|
s->lzma2.sequence = SEQ_COMPRESSED_0;
|
|
break;
|
|
|
|
case SEQ_COMPRESSED_0:
|
|
s->lzma2.compressed
|
|
= (uint32_t)b->in[b->in_pos++] << 8;
|
|
s->lzma2.sequence = SEQ_COMPRESSED_1;
|
|
break;
|
|
|
|
case SEQ_COMPRESSED_1:
|
|
s->lzma2.compressed
|
|
+= (uint32_t)b->in[b->in_pos++] + 1;
|
|
s->lzma2.sequence = s->lzma2.next_sequence;
|
|
break;
|
|
|
|
case SEQ_PROPERTIES:
|
|
if (!lzma_props(s, b->in[b->in_pos++]))
|
|
return XZ_DATA_ERROR;
|
|
|
|
s->lzma2.sequence = SEQ_LZMA_PREPARE;
|
|
|
|
case SEQ_LZMA_PREPARE:
|
|
if (s->lzma2.compressed < RC_INIT_BYTES)
|
|
return XZ_DATA_ERROR;
|
|
|
|
if (!rc_read_init(&s->rc, b))
|
|
return XZ_OK;
|
|
|
|
s->lzma2.compressed -= RC_INIT_BYTES;
|
|
s->lzma2.sequence = SEQ_LZMA_RUN;
|
|
|
|
case SEQ_LZMA_RUN:
|
|
/*
|
|
* Set dictionary limit to indicate how much we want
|
|
* to be encoded at maximum. Decode new data into the
|
|
* dictionary. Flush the new data from dictionary to
|
|
* b->out. Check if we finished decoding this chunk.
|
|
* In case the dictionary got full but we didn't fill
|
|
* the output buffer yet, we may run this loop
|
|
* multiple times without changing s->lzma2.sequence.
|
|
*/
|
|
dict_limit(&s->dict, min_t(size_t,
|
|
b->out_size - b->out_pos,
|
|
s->lzma2.uncompressed));
|
|
if (!lzma2_lzma(s, b))
|
|
return XZ_DATA_ERROR;
|
|
|
|
s->lzma2.uncompressed -= dict_flush(&s->dict, b);
|
|
|
|
if (s->lzma2.uncompressed == 0) {
|
|
if (s->lzma2.compressed > 0 || s->lzma.len > 0
|
|
|| !rc_is_finished(&s->rc))
|
|
return XZ_DATA_ERROR;
|
|
|
|
rc_reset(&s->rc);
|
|
s->lzma2.sequence = SEQ_CONTROL;
|
|
|
|
} else if (b->out_pos == b->out_size
|
|
|| (b->in_pos == b->in_size
|
|
&& s->temp.size
|
|
< s->lzma2.compressed)) {
|
|
return XZ_OK;
|
|
}
|
|
|
|
break;
|
|
|
|
case SEQ_COPY:
|
|
dict_uncompressed(&s->dict, b, &s->lzma2.compressed);
|
|
if (s->lzma2.compressed > 0)
|
|
return XZ_OK;
|
|
|
|
s->lzma2.sequence = SEQ_CONTROL;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return XZ_OK;
|
|
}
|
|
|
|
XZ_EXTERN struct xz_dec_lzma2 *xz_dec_lzma2_create(enum xz_mode mode,
|
|
uint32_t dict_max)
|
|
{
|
|
struct xz_dec_lzma2 *s = kmalloc(sizeof(*s), GFP_KERNEL);
|
|
if (s == NULL)
|
|
return NULL;
|
|
|
|
s->dict.mode = mode;
|
|
s->dict.size_max = dict_max;
|
|
|
|
if (DEC_IS_PREALLOC(mode)) {
|
|
s->dict.buf = vmalloc(dict_max);
|
|
if (s->dict.buf == NULL) {
|
|
kfree(s);
|
|
return NULL;
|
|
}
|
|
} else if (DEC_IS_DYNALLOC(mode)) {
|
|
s->dict.buf = NULL;
|
|
s->dict.allocated = 0;
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
XZ_EXTERN enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s, uint8_t props)
|
|
{
|
|
/* This limits dictionary size to 3 GiB to keep parsing simpler. */
|
|
if (props > 39)
|
|
return XZ_OPTIONS_ERROR;
|
|
|
|
s->dict.size = 2 + (props & 1);
|
|
s->dict.size <<= (props >> 1) + 11;
|
|
|
|
if (DEC_IS_MULTI(s->dict.mode)) {
|
|
if (s->dict.size > s->dict.size_max)
|
|
return XZ_MEMLIMIT_ERROR;
|
|
|
|
s->dict.end = s->dict.size;
|
|
|
|
if (DEC_IS_DYNALLOC(s->dict.mode)) {
|
|
if (s->dict.allocated < s->dict.size) {
|
|
vfree(s->dict.buf);
|
|
s->dict.buf = vmalloc(s->dict.size);
|
|
if (s->dict.buf == NULL) {
|
|
s->dict.allocated = 0;
|
|
return XZ_MEM_ERROR;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
s->lzma.len = 0;
|
|
|
|
s->lzma2.sequence = SEQ_CONTROL;
|
|
s->lzma2.need_dict_reset = true;
|
|
|
|
s->temp.size = 0;
|
|
|
|
return XZ_OK;
|
|
}
|
|
|
|
XZ_EXTERN void xz_dec_lzma2_end(struct xz_dec_lzma2 *s)
|
|
{
|
|
if (DEC_IS_MULTI(s->dict.mode))
|
|
vfree(s->dict.buf);
|
|
|
|
kfree(s);
|
|
}
|