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- /*
- * Simple XZ decoder command line tool
- *
- * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
- * Modified for toybox by Isaac Dunham
- USE_XZCAT(NEWTOY(xzcat, NULL, TOYFLAG_USR|TOYFLAG_BIN))
- config XZCAT
- bool "xzcat"
- default n
- help
- usage: xzcat [filename...]
-
- Decompress listed files to stdout. Use stdin if no files listed.
- */
- #define FOR_xzcat
- #include "toys.h"
- // BEGIN xz.h
- /**
- * enum xz_ret - Return codes
- * @XZ_OK: Everything is OK so far. More input or more
- * output space is required to continue.
- * @XZ_STREAM_END: Operation finished successfully.
- * @XZ_UNSUPPORTED_CHECK: Integrity check type is not supported. Decoding
- * is still possible in multi-call mode by simply
- * calling xz_dec_run() again.
- * Note that this return value is used only if
- * XZ_DEC_ANY_CHECK was defined at build time,
- * which is not used in the kernel. Unsupported
- * check types return XZ_OPTIONS_ERROR if
- * XZ_DEC_ANY_CHECK was not defined at build time.
- * @XZ_MEM_ERROR: Allocating memory failed. The amount of memory
- * that was tried to be allocated was no more than the
- * dict_max argument given to xz_dec_init().
- * @XZ_MEMLIMIT_ERROR: A bigger LZMA2 dictionary would be needed than
- * allowed by the dict_max argument given to
- * xz_dec_init().
- * @XZ_FORMAT_ERROR: File format was not recognized (wrong magic
- * bytes).
- * @XZ_OPTIONS_ERROR: This implementation doesn't support the requested
- * compression options. In the decoder this means
- * that the header CRC32 matches, but the header
- * itself specifies something that we don't support.
- * @XZ_DATA_ERROR: Compressed data is corrupt.
- * @XZ_BUF_ERROR: Cannot make any progress. Details are slightly
- * different between multi-call and single-call
- * mode; more information below.
- *
- * XZ_BUF_ERROR is returned when two consecutive calls to XZ code cannot
- * consume any input and cannot produce any new output. This happens when
- * there is no new input available, or the output buffer is full while at
- * least one output byte is still pending. Assuming your code is not buggy,
- * you can get this error only when decoding a compressed stream that is
- * truncated or otherwise corrupt.
- */
- enum xz_ret {
- XZ_OK,
- XZ_STREAM_END,
- XZ_UNSUPPORTED_CHECK,
- XZ_MEM_ERROR,
- XZ_MEMLIMIT_ERROR,
- XZ_FORMAT_ERROR,
- XZ_OPTIONS_ERROR,
- XZ_DATA_ERROR,
- XZ_BUF_ERROR
- };
- /**
- * struct xz_buf - Passing input and output buffers to XZ code
- * @in: Beginning of the input buffer. This may be NULL if and only
- * if in_pos is equal to in_size.
- * @in_pos: Current position in the input buffer. This must not exceed
- * in_size.
- * @in_size: Size of the input buffer
- * @out: Beginning of the output buffer. This may be NULL if and only
- * if out_pos is equal to out_size.
- * @out_pos: Current position in the output buffer. This must not exceed
- * out_size.
- * @out_size: Size of the output buffer
- *
- * Only the contents of the output buffer from out[out_pos] onward, and
- * the variables in_pos and out_pos are modified by the XZ code.
- */
- struct xz_buf {
- const uint8_t *in;
- size_t in_pos;
- size_t in_size;
- uint8_t *out;
- size_t out_pos;
- size_t out_size;
- };
- /**
- * struct xz_dec - Opaque type to hold the XZ decoder state
- */
- struct xz_dec;
- /**
- * xz_dec_init() - Allocate and initialize a XZ decoder state
- * @mode: Operation mode
- * @dict_max: Maximum size of the LZMA2 dictionary (history buffer) for
- * multi-call decoding. LZMA2 dictionary is always 2^n bytes
- * or 2^n + 2^(n-1) bytes (the latter sizes are less common
- * in practice), so other values for dict_max don't make sense.
- * In the kernel, dictionary sizes of 64 KiB, 128 KiB, 256 KiB,
- * 512 KiB, and 1 MiB are probably the only reasonable values,
- * except for kernel and initramfs images where a bigger
- * dictionary can be fine and useful.
- *
- * dict_max specifies the maximum allowed dictionary size that xz_dec_run()
- * may allocate once it has parsed the dictionary size from the stream
- * headers. This way excessive allocations can be avoided while still
- * limiting the maximum memory usage to a sane value to prevent running the
- * system out of memory when decompressing streams from untrusted sources.
- *
- * On success, xz_dec_init() returns a pointer to struct xz_dec, which is
- * ready to be used with xz_dec_run(). If memory allocation fails,
- * xz_dec_init() returns NULL.
- */
- struct xz_dec *xz_dec_init(uint32_t dict_max);
- /**
- * xz_dec_run() - Run the XZ decoder
- * @s: Decoder state allocated using xz_dec_init()
- * @b: Input and output buffers
- *
- * The possible return values depend on build options and operation mode.
- * See enum xz_ret for details.
- *
- * Note that if an error occurs in single-call mode (return value is not
- * XZ_STREAM_END), b->in_pos and b->out_pos are not modified and the
- * contents of the output buffer from b->out[b->out_pos] onward are
- * undefined. This is true even after XZ_BUF_ERROR, because with some filter
- * chains, there may be a second pass over the output buffer, and this pass
- * cannot be properly done if the output buffer is truncated. Thus, you
- * cannot give the single-call decoder a too small buffer and then expect to
- * get that amount valid data from the beginning of the stream. You must use
- * the multi-call decoder if you don't want to uncompress the whole stream.
- */
- enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b);
- /**
- * xz_dec_reset() - Reset an already allocated decoder state
- * @s: Decoder state allocated using xz_dec_init()
- *
- * This function can be used to reset the multi-call decoder state without
- * freeing and reallocating memory with xz_dec_end() and xz_dec_init().
- *
- * In single-call mode, xz_dec_reset() is always called in the beginning of
- * xz_dec_run(). Thus, explicit call to xz_dec_reset() is useful only in
- * multi-call mode.
- */
- void xz_dec_reset(struct xz_dec *s);
- /**
- * xz_dec_end() - Free the memory allocated for the decoder state
- * @s: Decoder state allocated using xz_dec_init(). If s is NULL,
- * this function does nothing.
- */
- void xz_dec_end(struct xz_dec *s);
- /*
- * Update CRC32 value using the polynomial from IEEE-802.3. To start a new
- * calculation, the third argument must be zero. To continue the calculation,
- * the previously returned value is passed as the third argument.
- */
- static uint32_t xz_crc32_table[256];
- uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
- {
- crc = ~crc;
- while (size != 0) {
- crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
- --size;
- }
- return ~crc;
- }
- static uint64_t xz_crc64_table[256];
- // END xz.h
- static uint8_t in[BUFSIZ];
- static uint8_t out[BUFSIZ];
- void do_xzcat(int fd, char *name)
- {
- struct xz_buf b;
- struct xz_dec *s;
- enum xz_ret ret;
- const char *msg;
- crc_init(xz_crc32_table, 1);
- const uint64_t poly = 0xC96C5795D7870F42ULL;
- uint32_t i;
- uint32_t j;
- uint64_t r;
- /* initialize CRC64 table*/
- for (i = 0; i < 256; ++i) {
- r = i;
- for (j = 0; j < 8; ++j)
- r = (r >> 1) ^ (poly & ~((r & 1) - 1));
- xz_crc64_table[i] = r;
- }
- /*
- * Support up to 64 MiB dictionary. The actually needed memory
- * is allocated once the headers have been parsed.
- */
- s = xz_dec_init(1 << 26);
- if (s == NULL) {
- msg = "Memory allocation failed\n";
- goto error;
- }
- b.in = in;
- b.in_pos = 0;
- b.in_size = 0;
- b.out = out;
- b.out_pos = 0;
- b.out_size = BUFSIZ;
- for (;;) {
- if (b.in_pos == b.in_size) {
- b.in_size = read(fd, in, sizeof(in));
- b.in_pos = 0;
- }
- ret = xz_dec_run(s, &b);
- if (b.out_pos == sizeof(out)) {
- if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos) {
- msg = "Write error\n";
- goto error;
- }
- b.out_pos = 0;
- }
- if (ret == XZ_OK)
- continue;
- if (ret == XZ_UNSUPPORTED_CHECK)
- continue;
- if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos) {
- msg = "Write error\n";
- goto error;
- }
- switch (ret) {
- case XZ_STREAM_END:
- xz_dec_end(s);
- return;
- case XZ_MEM_ERROR:
- msg = "Memory allocation failed\n";
- goto error;
- case XZ_MEMLIMIT_ERROR:
- msg = "Memory usage limit reached\n";
- goto error;
- case XZ_FORMAT_ERROR:
- msg = "Not a .xz file\n";
- goto error;
- case XZ_OPTIONS_ERROR:
- msg = "Unsupported options in the .xz headers\n";
- goto error;
- case XZ_DATA_ERROR:
- case XZ_BUF_ERROR:
- msg = "File is corrupt\n";
- goto error;
- default:
- msg = "Bug!\n";
- goto error;
- }
- }
- error:
- xz_dec_end(s);
- error_exit("%s", msg);
- }
- void xzcat_main(void)
- {
- loopfiles(toys.optargs, do_xzcat);
- }
- // BEGIN xz_private.h
- /* Uncomment as needed to enable BCJ filter decoders.
- * These cost about 2.5 k when all are enabled; SPARC and IA64 make 0.7 k
- * */
- #define XZ_DEC_X86
- #define XZ_DEC_POWERPC
- #define XZ_DEC_IA64
- #define XZ_DEC_ARM
- #define XZ_DEC_ARMTHUMB
- #define XZ_DEC_SPARC
- #define memeq(a, b, size) (memcmp(a, b, size) == 0)
- /* Inline functions to access unaligned unsigned 32-bit integers */
- #ifndef get_unaligned_le32
- static inline uint32_t get_unaligned_le32(const uint8_t *buf)
- {
- return (uint32_t)buf[0]
- | ((uint32_t)buf[1] << 8)
- | ((uint32_t)buf[2] << 16)
- | ((uint32_t)buf[3] << 24);
- }
- #endif
- #ifndef get_unaligned_be32
- static inline uint32_t get_unaligned_be32(const uint8_t *buf)
- {
- return (uint32_t)(buf[0] << 24)
- | ((uint32_t)buf[1] << 16)
- | ((uint32_t)buf[2] << 8)
- | (uint32_t)buf[3];
- }
- #endif
- #ifndef put_unaligned_le32
- static inline void put_unaligned_le32(uint32_t val, uint8_t *buf)
- {
- buf[0] = (uint8_t)val;
- buf[1] = (uint8_t)(val >> 8);
- buf[2] = (uint8_t)(val >> 16);
- buf[3] = (uint8_t)(val >> 24);
- }
- #endif
- #ifndef put_unaligned_be32
- static inline void put_unaligned_be32(uint32_t val, uint8_t *buf)
- {
- buf[0] = (uint8_t)(val >> 24);
- buf[1] = (uint8_t)(val >> 16);
- buf[2] = (uint8_t)(val >> 8);
- buf[3] = (uint8_t)val;
- }
- #endif
- /*
- * Use get_unaligned_le32() also for aligned access for simplicity. On
- * little endian systems, #define get_le32(ptr) (*(const uint32_t *)(ptr))
- * could save a few bytes in code size.
- */
- #ifndef get_le32
- # define get_le32 get_unaligned_le32
- #endif
- /*
- * If any of the BCJ filter decoders are wanted, define XZ_DEC_BCJ.
- * XZ_DEC_BCJ is used to enable generic support for BCJ decoders.
- */
- #ifndef XZ_DEC_BCJ
- # if defined(XZ_DEC_X86) || defined(XZ_DEC_POWERPC) \
- || defined(XZ_DEC_IA64) || defined(XZ_DEC_ARM) \
- || defined(XZ_DEC_ARM) || defined(XZ_DEC_ARMTHUMB) \
- || defined(XZ_DEC_SPARC)
- # define XZ_DEC_BCJ
- # endif
- #endif
- /*
- * Allocate memory for LZMA2 decoder. xz_dec_lzma2_reset() must be used
- * before calling xz_dec_lzma2_run().
- */
- struct xz_dec_lzma2 *xz_dec_lzma2_create(uint32_t dict_max);
- /*
- * Decode the LZMA2 properties (one byte) and reset the decoder. Return
- * XZ_OK on success, XZ_MEMLIMIT_ERROR if the preallocated dictionary is not
- * big enough, and XZ_OPTIONS_ERROR if props indicates something that this
- * decoder doesn't support.
- */
- enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s,
- uint8_t props);
- /* Decode raw LZMA2 stream from b->in to b->out. */
- enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
- struct xz_buf *b);
- // END "xz_private.h"
- /*
- * Branch/Call/Jump (BCJ) filter decoders
- * The rest of the code is inside this ifdef. It makes things a little more
- * convenient when building without support for any BCJ filters.
- */
- #ifdef XZ_DEC_BCJ
- struct xz_dec_bcj {
- /* Type of the BCJ filter being used */
- enum {
- BCJ_X86 = 4, /* x86 or x86-64 */
- BCJ_POWERPC = 5, /* Big endian only */
- BCJ_IA64 = 6, /* Big or little endian */
- BCJ_ARM = 7, /* Little endian only */
- BCJ_ARMTHUMB = 8, /* Little endian only */
- BCJ_SPARC = 9 /* Big or little endian */
- } type;
- /*
- * Return value of the next filter in the chain. We need to preserve
- * this information across calls, because we must not call the next
- * filter anymore once it has returned XZ_STREAM_END.
- */
- enum xz_ret ret;
- /*
- * Absolute position relative to the beginning of the uncompressed
- * data (in a single .xz Block). We care only about the lowest 32
- * bits so this doesn't need to be uint64_t even with big files.
- */
- uint32_t pos;
- /* x86 filter state */
- uint32_t x86_prev_mask;
- /* Temporary space to hold the variables from struct xz_buf */
- uint8_t *out;
- size_t out_pos;
- size_t out_size;
- struct {
- /* Amount of already filtered data in the beginning of buf */
- size_t filtered;
- /* Total amount of data currently stored in buf */
- size_t size;
- /*
- * Buffer to hold a mix of filtered and unfiltered data. This
- * needs to be big enough to hold Alignment + 2 * Look-ahead:
- *
- * Type Alignment Look-ahead
- * x86 1 4
- * PowerPC 4 0
- * IA-64 16 0
- * ARM 4 0
- * ARM-Thumb 2 2
- * SPARC 4 0
- */
- uint8_t buf[16];
- } temp;
- };
- /*
- * Decode the Filter ID of a BCJ filter. This implementation doesn't
- * support custom start offsets, so no decoding of Filter Properties
- * is needed. Returns XZ_OK if the given Filter ID is supported.
- * Otherwise XZ_OPTIONS_ERROR is returned.
- */
- enum xz_ret xz_dec_bcj_reset(struct xz_dec_bcj *s, uint8_t id);
- /*
- * Decode raw BCJ + LZMA2 stream. This must be used only if there actually is
- * a BCJ filter in the chain. If the chain has only LZMA2, xz_dec_lzma2_run()
- * must be called directly.
- */
- enum xz_ret xz_dec_bcj_run(struct xz_dec_bcj *s,
- struct xz_dec_lzma2 *lzma2,
- struct xz_buf *b);
- #ifdef XZ_DEC_X86
- /*
- * This is used to test the most significant byte of a memory address
- * in an x86 instruction.
- */
- static inline int bcj_x86_test_msbyte(uint8_t b)
- {
- return b == 0x00 || b == 0xFF;
- }
- static size_t bcj_x86(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
- {
- static const int mask_to_allowed_status[8]
- = { 1,1,1,0,1,0,0,0 };
- static const uint8_t mask_to_bit_num[8] = { 0, 1, 2, 2, 3, 3, 3, 3 };
- size_t i;
- size_t prev_pos = (size_t)-1;
- uint32_t prev_mask = s->x86_prev_mask;
- uint32_t src;
- uint32_t dest;
- uint32_t j;
- uint8_t b;
- if (size <= 4)
- return 0;
- size -= 4;
- for (i = 0; i < size; ++i) {
- if ((buf[i] & 0xFE) != 0xE8)
- continue;
- prev_pos = i - prev_pos;
- if (prev_pos > 3) {
- prev_mask = 0;
- } else {
- prev_mask = (prev_mask << (prev_pos - 1)) & 7;
- if (prev_mask != 0) {
- b = buf[i + 4 - mask_to_bit_num[prev_mask]];
- if (!mask_to_allowed_status[prev_mask]
- || bcj_x86_test_msbyte(b)) {
- prev_pos = i;
- prev_mask = (prev_mask << 1) | 1;
- continue;
- }
- }
- }
- prev_pos = i;
- if (bcj_x86_test_msbyte(buf[i + 4])) {
- src = get_unaligned_le32(buf + i + 1);
- for (;;) {
- dest = src - (s->pos + (uint32_t)i + 5);
- if (prev_mask == 0)
- break;
- j = mask_to_bit_num[prev_mask] * 8;
- b = (uint8_t)(dest >> (24 - j));
- if (!bcj_x86_test_msbyte(b))
- break;
- src = dest ^ (((uint32_t)1 << (32 - j)) - 1);
- }
- dest &= 0x01FFFFFF;
- dest |= (uint32_t)0 - (dest & 0x01000000);
- put_unaligned_le32(dest, buf + i + 1);
- i += 4;
- } else {
- prev_mask = (prev_mask << 1) | 1;
- }
- }
- prev_pos = i - prev_pos;
- s->x86_prev_mask = prev_pos > 3 ? 0 : prev_mask << (prev_pos - 1);
- return i;
- }
- #endif
- #ifdef XZ_DEC_POWERPC
- static size_t bcj_powerpc(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
- {
- size_t i;
- uint32_t instr;
- for (i = 0; i + 4 <= size; i += 4) {
- instr = get_unaligned_be32(buf + i);
- if ((instr & 0xFC000003) == 0x48000001) {
- instr &= 0x03FFFFFC;
- instr -= s->pos + (uint32_t)i;
- instr &= 0x03FFFFFC;
- instr |= 0x48000001;
- put_unaligned_be32(instr, buf + i);
- }
- }
- return i;
- }
- #endif
- #ifdef XZ_DEC_IA64
- static size_t bcj_ia64(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
- {
- static const uint8_t branch_table[32] = {
- 0, 0, 0, 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0, 0, 0, 0,
- 4, 4, 6, 6, 0, 0, 7, 7,
- 4, 4, 0, 0, 4, 4, 0, 0
- };
- /*
- * The local variables take a little bit stack space, but it's less
- * than what LZMA2 decoder takes, so it doesn't make sense to reduce
- * stack usage here without doing that for the LZMA2 decoder too.
- */
- /* Loop counters */
- size_t i;
- size_t j;
- /* Instruction slot (0, 1, or 2) in the 128-bit instruction word */
- uint32_t slot;
- /* Bitwise offset of the instruction indicated by slot */
- uint32_t bit_pos;
- /* bit_pos split into byte and bit parts */
- uint32_t byte_pos;
- uint32_t bit_res;
- /* Address part of an instruction */
- uint32_t addr;
- /* Mask used to detect which instructions to convert */
- uint32_t mask;
- /* 41-bit instruction stored somewhere in the lowest 48 bits */
- uint64_t instr;
- /* Instruction normalized with bit_res for easier manipulation */
- uint64_t norm;
- for (i = 0; i + 16 <= size; i += 16) {
- mask = branch_table[buf[i] & 0x1F];
- for (slot = 0, bit_pos = 5; slot < 3; ++slot, bit_pos += 41) {
- if (((mask >> slot) & 1) == 0)
- continue;
- byte_pos = bit_pos >> 3;
- bit_res = bit_pos & 7;
- instr = 0;
- for (j = 0; j < 6; ++j)
- instr |= (uint64_t)(buf[i + j + byte_pos])
- << (8 * j);
- norm = instr >> bit_res;
- if (((norm >> 37) & 0x0F) == 0x05
- && ((norm >> 9) & 0x07) == 0) {
- addr = (norm >> 13) & 0x0FFFFF;
- addr |= ((uint32_t)(norm >> 36) & 1) << 20;
- addr <<= 4;
- addr -= s->pos + (uint32_t)i;
- addr >>= 4;
- norm &= ~((uint64_t)0x8FFFFF << 13);
- norm |= (uint64_t)(addr & 0x0FFFFF) << 13;
- norm |= (uint64_t)(addr & 0x100000)
- << (36 - 20);
- instr &= (1 << bit_res) - 1;
- instr |= norm << bit_res;
- for (j = 0; j < 6; j++)
- buf[i + j + byte_pos]
- = (uint8_t)(instr >> (8 * j));
- }
- }
- }
- return i;
- }
- #endif
- #ifdef XZ_DEC_ARM
- static size_t bcj_arm(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
- {
- size_t i;
- uint32_t addr;
- for (i = 0; i + 4 <= size; i += 4) {
- if (buf[i + 3] == 0xEB) {
- addr = (uint32_t)buf[i] | ((uint32_t)buf[i + 1] << 8)
- | ((uint32_t)buf[i + 2] << 16);
- addr <<= 2;
- addr -= s->pos + (uint32_t)i + 8;
- addr >>= 2;
- buf[i] = (uint8_t)addr;
- buf[i + 1] = (uint8_t)(addr >> 8);
- buf[i + 2] = (uint8_t)(addr >> 16);
- }
- }
- return i;
- }
- #endif
- #ifdef XZ_DEC_ARMTHUMB
- static size_t bcj_armthumb(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
- {
- size_t i;
- uint32_t addr;
- for (i = 0; i + 4 <= size; i += 2) {
- if ((buf[i + 1] & 0xF8) == 0xF0
- && (buf[i + 3] & 0xF8) == 0xF8) {
- addr = (((uint32_t)buf[i + 1] & 0x07) << 19)
- | ((uint32_t)buf[i] << 11)
- | (((uint32_t)buf[i + 3] & 0x07) << 8)
- | (uint32_t)buf[i + 2];
- addr <<= 1;
- addr -= s->pos + (uint32_t)i + 4;
- addr >>= 1;
- buf[i + 1] = (uint8_t)(0xF0 | ((addr >> 19) & 0x07));
- buf[i] = (uint8_t)(addr >> 11);
- buf[i + 3] = (uint8_t)(0xF8 | ((addr >> 8) & 0x07));
- buf[i + 2] = (uint8_t)addr;
- i += 2;
- }
- }
- return i;
- }
- #endif
- #ifdef XZ_DEC_SPARC
- static size_t bcj_sparc(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
- {
- size_t i;
- uint32_t instr;
- for (i = 0; i + 4 <= size; i += 4) {
- instr = get_unaligned_be32(buf + i);
- if ((instr >> 22) == 0x100 || (instr >> 22) == 0x1FF) {
- instr <<= 2;
- instr -= s->pos + (uint32_t)i;
- instr >>= 2;
- instr = ((uint32_t)0x40000000 - (instr & 0x400000))
- | 0x40000000 | (instr & 0x3FFFFF);
- put_unaligned_be32(instr, buf + i);
- }
- }
- return i;
- }
- #endif
- /*
- * Apply the selected BCJ filter. Update *pos and s->pos to match the amount
- * of data that got filtered.
- *
- * NOTE: This is implemented as a switch statement to avoid using function
- * pointers, which could be problematic in the kernel boot code, which must
- * avoid pointers to static data (at least on x86).
- */
- static void bcj_apply(struct xz_dec_bcj *s,
- uint8_t *buf, size_t *pos, size_t size)
- {
- size_t filtered;
- buf += *pos;
- size -= *pos;
- switch (s->type) {
- #ifdef XZ_DEC_X86
- case BCJ_X86:
- filtered = bcj_x86(s, buf, size);
- break;
- #endif
- #ifdef XZ_DEC_POWERPC
- case BCJ_POWERPC:
- filtered = bcj_powerpc(s, buf, size);
- break;
- #endif
- #ifdef XZ_DEC_IA64
- case BCJ_IA64:
- filtered = bcj_ia64(s, buf, size);
- break;
- #endif
- #ifdef XZ_DEC_ARM
- case BCJ_ARM:
- filtered = bcj_arm(s, buf, size);
- break;
- #endif
- #ifdef XZ_DEC_ARMTHUMB
- case BCJ_ARMTHUMB:
- filtered = bcj_armthumb(s, buf, size);
- break;
- #endif
- #ifdef XZ_DEC_SPARC
- case BCJ_SPARC:
- filtered = bcj_sparc(s, buf, size);
- break;
- #endif
- default:
- /* Never reached but silence compiler warnings. */
- filtered = 0;
- break;
- }
- *pos += filtered;
- s->pos += filtered;
- }
- /*
- * Flush pending filtered data from temp to the output buffer.
- * Move the remaining mixture of possibly filtered and unfiltered
- * data to the beginning of temp.
- */
- static void bcj_flush(struct xz_dec_bcj *s, struct xz_buf *b)
- {
- size_t copy_size;
- copy_size = minof(s->temp.filtered, b->out_size - b->out_pos);
- memcpy(b->out + b->out_pos, s->temp.buf, copy_size);
- b->out_pos += copy_size;
- s->temp.filtered -= copy_size;
- s->temp.size -= copy_size;
- memmove(s->temp.buf, s->temp.buf + copy_size, s->temp.size);
- }
- /*
- * The BCJ filter functions are primitive in sense that they process the
- * data in chunks of 1-16 bytes. To hide this issue, this function does
- * some buffering.
- */
- enum xz_ret xz_dec_bcj_run(struct xz_dec_bcj *s,
- struct xz_dec_lzma2 *lzma2,
- struct xz_buf *b)
- {
- size_t out_start;
- /*
- * Flush pending already filtered data to the output buffer. Return
- * immediatelly if we couldn't flush everything, or if the next
- * filter in the chain had already returned XZ_STREAM_END.
- */
- if (s->temp.filtered > 0) {
- bcj_flush(s, b);
- if (s->temp.filtered > 0)
- return XZ_OK;
- if (s->ret == XZ_STREAM_END)
- return XZ_STREAM_END;
- }
- /*
- * If we have more output space than what is currently pending in
- * temp, copy the unfiltered data from temp to the output buffer
- * and try to fill the output buffer by decoding more data from the
- * next filter in the chain. Apply the BCJ filter on the new data
- * in the output buffer. If everything cannot be filtered, copy it
- * to temp and rewind the output buffer position accordingly.
- *
- * This needs to be always run when temp.size == 0 to handle a special
- * case where the output buffer is full and the next filter has no
- * more output coming but hasn't returned XZ_STREAM_END yet.
- */
- if (s->temp.size < b->out_size - b->out_pos || s->temp.size == 0) {
- out_start = b->out_pos;
- memcpy(b->out + b->out_pos, s->temp.buf, s->temp.size);
- b->out_pos += s->temp.size;
- s->ret = xz_dec_lzma2_run(lzma2, b);
- if (s->ret != XZ_STREAM_END
- && (s->ret != XZ_OK ))
- return s->ret;
- bcj_apply(s, b->out, &out_start, b->out_pos);
- /*
- * As an exception, if the next filter returned XZ_STREAM_END,
- * we can do that too, since the last few bytes that remain
- * unfiltered are meant to remain unfiltered.
- */
- if (s->ret == XZ_STREAM_END)
- return XZ_STREAM_END;
- s->temp.size = b->out_pos - out_start;
- b->out_pos -= s->temp.size;
- memcpy(s->temp.buf, b->out + b->out_pos, s->temp.size);
- /*
- * If there wasn't enough input to the next filter to fill
- * the output buffer with unfiltered data, there's no point
- * to try decoding more data to temp.
- */
- if (b->out_pos + s->temp.size < b->out_size)
- return XZ_OK;
- }
- /*
- * We have unfiltered data in temp. If the output buffer isn't full
- * yet, try to fill the temp buffer by decoding more data from the
- * next filter. Apply the BCJ filter on temp. Then we hopefully can
- * fill the actual output buffer by copying filtered data from temp.
- * A mix of filtered and unfiltered data may be left in temp; it will
- * be taken care on the next call to this function.
- */
- if (b->out_pos < b->out_size) {
- /* Make b->out{,_pos,_size} temporarily point to s->temp. */
- s->out = b->out;
- s->out_pos = b->out_pos;
- s->out_size = b->out_size;
- b->out = s->temp.buf;
- b->out_pos = s->temp.size;
- b->out_size = sizeof(s->temp.buf);
- s->ret = xz_dec_lzma2_run(lzma2, b);
- s->temp.size = b->out_pos;
- b->out = s->out;
- b->out_pos = s->out_pos;
- b->out_size = s->out_size;
- if (s->ret != XZ_OK && s->ret != XZ_STREAM_END)
- return s->ret;
- bcj_apply(s, s->temp.buf, &s->temp.filtered, s->temp.size);
- /*
- * If the next filter returned XZ_STREAM_END, we mark that
- * everything is filtered, since the last unfiltered bytes
- * of the stream are meant to be left as is.
- */
- if (s->ret == XZ_STREAM_END)
- s->temp.filtered = s->temp.size;
- bcj_flush(s, b);
- if (s->temp.filtered > 0)
- return XZ_OK;
- }
- return s->ret;
- }
- enum xz_ret xz_dec_bcj_reset(struct xz_dec_bcj *s, uint8_t id)
- {
- switch (id) {
- #ifdef XZ_DEC_X86
- case BCJ_X86:
- #endif
- #ifdef XZ_DEC_POWERPC
- case BCJ_POWERPC:
- #endif
- #ifdef XZ_DEC_IA64
- case BCJ_IA64:
- #endif
- #ifdef XZ_DEC_ARM
- case BCJ_ARM:
- #endif
- #ifdef XZ_DEC_ARMTHUMB
- case BCJ_ARMTHUMB:
- #endif
- #ifdef XZ_DEC_SPARC
- case BCJ_SPARC:
- #endif
- break;
- default:
- /* Unsupported Filter ID */
- return XZ_OPTIONS_ERROR;
- }
- s->type = id;
- s->ret = XZ_OK;
- s->pos = 0;
- s->x86_prev_mask = 0;
- s->temp.filtered = 0;
- s->temp.size = 0;
- return XZ_OK;
- }
- #endif
- /*
- * LZMA2 decoder
- */
- // BEGIN xz_lzma2.h
- /*
- * LZMA2 definitions
- *
- */
- /* Range coder constants */
- #define RC_SHIFT_BITS 8
- #define RC_TOP_BITS 24
- #define RC_TOP_VALUE (1 << RC_TOP_BITS)
- #define RC_BIT_MODEL_TOTAL_BITS 11
- #define RC_BIT_MODEL_TOTAL (1 << RC_BIT_MODEL_TOTAL_BITS)
- #define RC_MOVE_BITS 5
- /*
- * Maximum number of position states. A position state is the lowest pb
- * number of bits of the current uncompressed offset. In some places there
- * are different sets of probabilities for different position states.
- */
- #define POS_STATES_MAX (1 << 4)
- /*
- * This enum is used to track which LZMA symbols have occurred most recently
- * and in which order. This information is used to predict the next symbol.
- *
- * Symbols:
- * - Literal: One 8-bit byte
- * - Match: Repeat a chunk of data at some distance
- * - Long repeat: Multi-byte match at a recently seen distance
- * - Short repeat: One-byte repeat at a recently seen distance
- *
- * The symbol names are in from STATE_oldest_older_previous. REP means
- * either short or long repeated match, and NONLIT means any non-literal.
- */
- enum lzma_state {
- 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_LIT_MATCH,
- STATE_LIT_LONGREP,
- STATE_LIT_SHORTREP,
- STATE_NONLIT_MATCH,
- STATE_NONLIT_REP
- };
- /* Total number of states */
- #define STATES 12
- /* The lowest 7 states indicate that the previous state was a literal. */
- #define LIT_STATES 7
- /* Indicate that the latest symbol was a literal. */
- static inline void lzma_state_literal(enum lzma_state *state)
- {
- if (*state <= STATE_SHORTREP_LIT_LIT)
- *state = STATE_LIT_LIT;
- else if (*state <= STATE_LIT_SHORTREP)
- *state -= 3;
- else
- *state -= 6;
- }
- /* Indicate that the latest symbol was a match. */
- static inline void lzma_state_match(enum lzma_state *state)
- {
- *state = *state < LIT_STATES ? STATE_LIT_MATCH : STATE_NONLIT_MATCH;
- }
- /* Indicate that the latest state was a long repeated match. */
- static inline void lzma_state_long_rep(enum lzma_state *state)
- {
- *state = *state < LIT_STATES ? STATE_LIT_LONGREP : STATE_NONLIT_REP;
- }
- /* Indicate that the latest symbol was a short match. */
- static inline void lzma_state_short_rep(enum lzma_state *state)
- {
- *state = *state < LIT_STATES ? STATE_LIT_SHORTREP : STATE_NONLIT_REP;
- }
- /* Test if the previous symbol was a literal. */
- static inline int lzma_state_is_literal(enum lzma_state state)
- {
- return state < LIT_STATES;
- }
- /* Each literal coder is divided in three sections:
- * - 0x001-0x0FF: Without match byte
- * - 0x101-0x1FF: With match byte; match bit is 0
- * - 0x201-0x2FF: With match byte; match bit is 1
- *
- * Match byte is used when the previous LZMA symbol was something else than
- * a literal (that is, it was some kind of match).
- */
- #define LITERAL_CODER_SIZE 0x300
- /* Maximum number of literal coders */
- #define LITERAL_CODERS_MAX (1 << 4)
- /* Minimum length of a match is two bytes. */
- #define MATCH_LEN_MIN 2
- /* Match length is encoded with 4, 5, or 10 bits.
- *
- * Length Bits
- * 2-9 4 = Choice=0 + 3 bits
- * 10-17 5 = Choice=1 + Choice2=0 + 3 bits
- * 18-273 10 = Choice=1 + Choice2=1 + 8 bits
- */
- #define LEN_LOW_BITS 3
- #define LEN_LOW_SYMBOLS (1 << LEN_LOW_BITS)
- #define LEN_MID_BITS 3
- #define LEN_MID_SYMBOLS (1 << LEN_MID_BITS)
- #define LEN_HIGH_BITS 8
- #define LEN_HIGH_SYMBOLS (1 << LEN_HIGH_BITS)
- #define LEN_SYMBOLS (LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS + LEN_HIGH_SYMBOLS)
- /*
- * Maximum length of a match is 273 which is a result of the encoding
- * described above.
- */
- #define MATCH_LEN_MAX (MATCH_LEN_MIN + LEN_SYMBOLS - 1)
- /*
- * Different sets of probabilities are used for match distances that have
- * very short match length: Lengths of 2, 3, and 4 bytes have a separate
- * set of probabilities for each length. The matches with longer length
- * use a shared set of probabilities.
- */
- #define DIST_STATES 4
- /*
- * Get the index of the appropriate probability array for decoding
- * the distance slot.
- */
- static inline uint32_t lzma_get_dist_state(uint32_t len)
- {
- return len < DIST_STATES + MATCH_LEN_MIN
- ? len - MATCH_LEN_MIN : DIST_STATES - 1;
- }
- /*
- * The highest two bits of a 32-bit match distance are encoded using six bits.
- * This six-bit value is called a distance slot. This way encoding a 32-bit
- * value takes 6-36 bits, larger values taking more bits.
- */
- #define DIST_SLOT_BITS 6
- #define DIST_SLOTS (1 << DIST_SLOT_BITS)
- /* Match distances up to 127 are fully encoded using probabilities. Since
- * the highest two bits (distance slot) are always encoded using six bits,
- * the distances 0-3 don't need any additional bits to encode, since the
- * distance slot itself is the same as the actual distance. DIST_MODEL_START
- * indicates the first distance slot where at least one additional bit is
- * needed.
- */
- #define DIST_MODEL_START 4
- /*
- * Match distances greater than 127 are encoded in three pieces:
- * - distance slot: the highest two bits
- * - direct bits: 2-26 bits below the highest two bits
- * - alignment bits: four lowest bits
- *
- * Direct bits don't use any probabilities.
- *
- * The distance slot value of 14 is for distances 128-191.
- */
- #define DIST_MODEL_END 14
- /* Distance slots that indicate a distance <= 127. */
- #define FULL_DISTANCES_BITS (DIST_MODEL_END / 2)
- #define FULL_DISTANCES (1 << FULL_DISTANCES_BITS)
- /*
- * For match distances greater than 127, only the highest two bits and the
- * lowest four bits (alignment) is encoded using probabilities.
- */
- #define ALIGN_BITS 4
- #define ALIGN_SIZE (1 << ALIGN_BITS)
- #define ALIGN_MASK (ALIGN_SIZE - 1)
- /* Total number of all probability variables */
- #define PROBS_TOTAL (1846 + LITERAL_CODERS_MAX * LITERAL_CODER_SIZE)
- /*
- * LZMA remembers the four most recent match distances. Reusing these
- * distances tends to take less space than re-encoding the actual
- * distance value.
- */
- #define REPS 4
- // END xz_lzma2.h
- /*
- * Range decoder initialization eats the first five bytes of each LZMA chunk.
- */
- #define RC_INIT_BYTES 5
- /*
- * Minimum number of usable input buffer to safely decode one LZMA symbol.
- * The worst case is that we decode 22 bits using probabilities and 26
- * direct bits. This may decode at maximum of 20 bytes of input. However,
- * lzma_main() does an extra normalization before returning, thus we
- * need to put 21 here.
- */
- #define LZMA_IN_REQUIRED 21
- /*
- * Dictionary (history buffer)
- *
- * These are always true:
- * start <= pos <= full <= end
- * pos <= limit <= end
- * end == size
- * size <= size_max
- * allocated <= size
- *
- * Most of these variables are size_t as a relic of single-call mode,
- * in which the dictionary variables address the actual output
- * buffer directly.
- */
- struct dictionary {
- /* Beginning of the history buffer */
- uint8_t *buf;
- /* Old position in buf (before decoding more data) */
- size_t start;
- /* Position in buf */
- size_t pos;
- /*
- * How full dictionary is. This is used to detect corrupt input that
- * would read beyond the beginning of the uncompressed stream.
- */
- size_t full;
- /* Write limit; we don't write to buf[limit] or later bytes. */
- size_t limit;
- /* End of the dictionary buffer. This is the same as the dictionary size. */
- size_t end;
- /*
- * Size of the dictionary as specified in Block Header. This is used
- * together with "full" to detect corrupt input that would make us
- * read beyond the beginning of the uncompressed stream.
- */
- uint32_t size;
- /*
- * Maximum allowed dictionary size.
- */
- uint32_t size_max;
- /*
- * Amount of memory currently allocated for the dictionary.
- */
- uint32_t allocated;
- };
- /* Range decoder */
- struct rc_dec {
- uint32_t range;
- uint32_t code;
- /*
- * Number of initializing bytes remaining to be read
- * by rc_read_init().
- */
- uint32_t init_bytes_left;
- /*
- * Buffer from which we read our input. It can be either
- * temp.buf or the caller-provided input buffer.
- */
- const uint8_t *in;
- size_t in_pos;
- size_t in_limit;
- };
- /* Probabilities for a length decoder. */
- struct lzma_len_dec {
- /* Probability of match length being at least 10 */
- uint16_t choice;
- /* Probability of match length being at least 18 */
- uint16_t choice2;
- /* Probabilities for match lengths 2-9 */
- uint16_t low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
- /* Probabilities for match lengths 10-17 */
- uint16_t mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
- /* Probabilities for match lengths 18-273 */
- uint16_t high[LEN_HIGH_SYMBOLS];
- };
- struct lzma_dec {
- /* Distances of latest four matches */
- uint32_t rep0;
- uint32_t rep1;
- uint32_t rep2;
- uint32_t rep3;
- /* Types of the most recently seen LZMA symbols */
- enum lzma_state state;
- /*
- * Length of a match. This is updated so that dict_repeat can
- * be called again to finish repeating the whole match.
- */
- uint32_t len;
- /*
- * LZMA properties or related bit masks (number of literal
- * context bits, a mask dervied from the number of literal
- * position bits, and a mask dervied from the number
- * position bits)
- */
- uint32_t lc;
- uint32_t literal_pos_mask; /* (1 << lp) - 1 */
- uint32_t pos_mask; /* (1 << pb) - 1 */
- /* If 1, it's a match. Otherwise it's a single 8-bit literal. */
- uint16_t is_match[STATES][POS_STATES_MAX];
- /* If 1, it's a repeated match. The distance is one of rep0 .. rep3. */
- uint16_t is_rep[STATES];
- /*
- * If 0, distance of a repeated match is rep0.
- * Otherwise check is_rep1.
- */
- uint16_t is_rep0[STATES];
- /*
- * If 0, distance of a repeated match is rep1.
- * Otherwise check is_rep2.
- */
- uint16_t is_rep1[STATES];
- /* If 0, distance of a repeated match is rep2. Otherwise it is rep3. */
- uint16_t is_rep2[STATES];
- /*
- * If 1, the repeated match has length of one byte. Otherwise
- * the length is decoded from rep_len_decoder.
- */
- uint16_t 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].
- */
- uint16_t dist_slot[DIST_STATES][DIST_SLOTS];
- /*
- * Probility trees for additional bits for match distance
- * when the distance is in the range [4, 127].
- */
- uint16_t dist_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.
- */
- uint16_t dist_align[ALIGN_SIZE];
- /* Length of a normal match */
- struct lzma_len_dec match_len_dec;
- /* Length of a repeated match */
- struct lzma_len_dec rep_len_dec;
- /* Probabilities of literals */
- uint16_t literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE];
- };
- struct lzma2_dec {
- /* Position in xz_dec_lzma2_run(). */
- enum lzma2_seq {
- SEQ_CONTROL,
- SEQ_UNCOMPRESSED_1,
- SEQ_UNCOMPRESSED_2,
- SEQ_COMPRESSED_0,
- SEQ_COMPRESSED_1,
- SEQ_PROPERTIES,
- SEQ_LZMA_PREPARE,
- SEQ_LZMA_RUN,
- SEQ_COPY
- } sequence;
- /* Next position after decoding the compressed size of the chunk. */
- enum lzma2_seq next_sequence;
- /* Uncompressed size of LZMA chunk (2 MiB at maximum) */
- uint32_t uncompressed;
- /*
- * Compressed size of LZMA chunk or compressed/uncompressed
- * size of uncompressed chunk (64 KiB at maximum)
- */
- uint32_t compressed;
- /*
- * True if dictionary reset is needed. This is false before
- * the first chunk (LZMA or uncompressed).
- */
- int need_dict_reset;
- /*
- * True if new LZMA properties are needed. This is false
- * before the first LZMA chunk.
- */
- int need_props;
- };
- struct xz_dec_lzma2 {
- /*
- * The order below is important on x86 to reduce code size and
- * it shouldn't hurt on other platforms. Everything up to and
- * including lzma.pos_mask are in the first 128 bytes on x86-32,
- * which allows using smaller instructions to access those
- * variables. On x86-64, fewer variables fit into the first 128
- * bytes, but this is still the best order without sacrificing
- * the readability by splitting the structures.
- */
- struct rc_dec rc;
- struct dictionary dict;
- struct lzma2_dec lzma2;
- struct lzma_dec lzma;
- /*
- * Temporary buffer which holds small number of input bytes between
- * decoder calls. See lzma2_lzma() for details.
- */
- struct {
- uint32_t size;
- uint8_t buf[3 * LZMA_IN_REQUIRED];
- } temp;
- };
- /**************
- * Dictionary *
- **************/
- /* Reset the dictionary state. */
- static void dict_reset(struct dictionary *dict)
- {
- dict->start = 0;
- dict->pos = 0;
- dict->limit = 0;
- dict->full = 0;
- }
- /* Set dictionary write limit */
- static void dict_limit(struct dictionary *dict, size_t out_max)
- {
- if (dict->end - dict->pos <= out_max)
- dict->limit = dict->end;
- else
- dict->limit = dict->pos + out_max;
- }
- /* Return true if at least one byte can be written into the dictionary. */
- static inline int dict_has_space(const struct dictionary *dict)
- {
- return dict->pos < dict->limit;
- }
- /*
- * Get a byte from the dictionary at the given distance. The distance is
- * assumed to valid, or as a special case, zero when the dictionary is
- * still empty. This special case is needed for single-call decoding to
- * avoid writing a '\0' to the end of the destination buffer.
- */
- static inline uint32_t dict_get(const struct dictionary *dict, uint32_t dist)
- {
- size_t offset = dict->pos - dist - 1;
- if (dist >= dict->pos)
- offset += dict->end;
- return dict->full > 0 ? dict->buf[offset] : 0;
- }
- /*
- * Put one byte into the dictionary. It is assumed that there is space for it.
- */
- static inline void dict_put(struct dictionary *dict, uint8_t byte)
- {
- dict->buf[dict->pos++] = byte;
- if (dict->full < dict->pos)
- dict->full = dict->pos;
- }
- /*
- * Repeat given number of bytes from the given distance. If the distance is
- * invalid, false is returned. On success, true is returned and *len is
- * updated to indicate how many bytes were left to be repeated.
- */
- static int dict_repeat(struct dictionary *dict, uint32_t *len, uint32_t dist)
- {
- size_t back;
- uint32_t left;
- if (dist >= dict->full || dist >= dict->size) return 0;
- left = minof(dict->limit - dict->pos, *len);
- *len -= left;
- back = dict->pos - dist - 1;
- if (dist >= dict->pos)
- back += dict->end;
- do {
- dict->buf[dict->pos++] = dict->buf[back++];
- if (back == dict->end)
- back = 0;
- } while (--left > 0);
- if (dict->full < dict->pos)
- dict->full = dict->pos;
- return 1;
- }
- /* Copy uncompressed data as is from input to dictionary and output buffers. */
- static void dict_uncompressed(struct dictionary *dict, struct xz_buf *b,
- uint32_t *left)
- {
- size_t copy_size;
- while (*left > 0 && b->in_pos < b->in_size
- && b->out_pos < b->out_size) {
- copy_size = minof(b->in_size - b->in_pos,
- b->out_size - b->out_pos);
- if (copy_size > dict->end - dict->pos)
- copy_size = dict->end - dict->pos;
- if (copy_size > *left)
- copy_size = *left;
- *left -= copy_size;
- memcpy(dict->buf + dict->pos, b->in + b->in_pos, copy_size);
- dict->pos += copy_size;
- if (dict->full < dict->pos)
- dict->full = dict->pos;
- if (dict->pos == dict->end)
- dict->pos = 0;
- memcpy(b->out + b->out_pos, b->in + b->in_pos,
- copy_size);
- dict->start = dict->pos;
- b->out_pos += copy_size;
- b->in_pos += copy_size;
- }
- }
- /*
- * Flush pending data from dictionary to b->out. It is assumed that there is
- * enough space in b->out. This is guaranteed because caller uses dict_limit()
- * before decoding data into the dictionary.
- */
- static uint32_t dict_flush(struct dictionary *dict, struct xz_buf *b)
- {
- size_t copy_size = dict->pos - dict->start;
- if (dict->pos == dict->end)
- dict->pos = 0;
- memcpy(b->out + b->out_pos, dict->buf + dict->start,
- copy_size);
- dict->start = dict->pos;
- b->out_pos += copy_size;
- return copy_size;
- }
- /*****************
- * Range decoder *
- *****************/
- /* Reset the range decoder. */
- static void rc_reset(struct rc_dec *rc)
- {
- rc->range = (uint32_t)-1;
- rc->code = 0;
- rc->init_bytes_left = RC_INIT_BYTES;
- }
- /*
- * Read the first five initial bytes into rc->code if they haven't been
- * read already. (Yes, the first byte gets completely ignored.)
- */
- static int rc_read_init(struct rc_dec *rc, struct xz_buf *b)
- {
- while (rc->init_bytes_left > 0) {
- if (b->in_pos == b->in_size) return 0;
- rc->code = (rc->code << 8) + b->in[b->in_pos++];
- --rc->init_bytes_left;
- }
- return 1;
- }
- /* Return true if there may not be enough input for the next decoding loop. */
- static inline int rc_limit_exceeded(const struct rc_dec *rc)
- {
- return rc->in_pos > rc->in_limit;
- }
- /*
- * Return true if it is possible (from point of view of range decoder) that
- * we have reached the end of the LZMA chunk.
- */
- static inline int rc_is_finished(const struct rc_dec *rc)
- {
- return rc->code == 0;
- }
- /* Read the next input byte if needed. */
- static inline void rc_normalize(struct rc_dec *rc)
- {
- if (rc->range < RC_TOP_VALUE) {
- rc->range <<= RC_SHIFT_BITS;
- rc->code = (rc->code << RC_SHIFT_BITS) + rc->in[rc->in_pos++];
- }
- }
- /*
- * Decode one bit. In some versions, this function has been splitted in three
- * functions so that the compiler is supposed to be able to more easily avoid
- * an extra branch. In this particular version of the LZMA decoder, this
- * doesn't seem to be a good idea (tested with GCC 3.3.6, 3.4.6, and 4.3.3
- * on x86). Using a non-splitted version results in nicer looking code too.
- *
- * NOTE: This must return an int. Do not make it return a bool or the speed
- * of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care,
- * and it generates 10-20 % faster code than GCC 3.x from this file anyway.)
- */
- static inline int rc_bit(struct rc_dec *rc, uint16_t *prob)
- {
- uint32_t bound;
- int bit;
- rc_normalize(rc);
- bound = (rc->range >> RC_BIT_MODEL_TOTAL_BITS) * *prob;
- if (rc->code < bound) {
- rc->range = bound;
- *prob += (RC_BIT_MODEL_TOTAL - *prob) >> RC_MOVE_BITS;
- bit = 0;
- } else {
- rc->range -= bound;
- rc->code -= bound;
- *prob -= *prob >> RC_MOVE_BITS;
- bit = 1;
- }
- return bit;
- }
- /* Decode a bittree starting from the most significant bit. */
- static inline uint32_t rc_bittree(struct rc_dec *rc,
- uint16_t *probs, uint32_t limit)
- {
- uint32_t symbol = 1;
- do {
- if (rc_bit(rc, &probs[symbol]))
- symbol = (symbol << 1) + 1;
- else
- symbol <<= 1;
- } while (symbol < limit);
- return symbol;
- }
- /* Decode a bittree starting from the least significant bit. */
- static inline void rc_bittree_reverse(struct rc_dec *rc,
- uint16_t *probs,
- uint32_t *dest, uint32_t limit)
- {
- uint32_t symbol = 1;
- uint32_t i = 0;
- do {
- if (rc_bit(rc, &probs[symbol])) {
- symbol = (symbol << 1) + 1;
- *dest += 1 << i;
- } else {
- symbol <<= 1;
- }
- } 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 int 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 0;
- }
- }
- /*
- * 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 1;
- }
- /*
- * 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 int lzma_props(struct xz_dec_lzma2 *s, uint8_t props)
- {
- if (props > (4 * 5 + 4) * 9 + 8)
- return 0;
- 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 0;
- s->lzma.literal_pos_mask = (1 << s->lzma.literal_pos_mask) - 1;
- lzma_reset(s);
- return 1;
- }
- /*********
- * 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 int 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) {
- memset(s->temp.buf + s->temp.size + tmp, 0,
- 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 1;
- } 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 0;
- 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 1;
- }
- 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 0;
- in_avail = s->rc.in_pos - b->in_pos;
- if (in_avail > s->lzma2.compressed) return 0;
- 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 1;
- }
- /*
- * Take care of the LZMA2 control layer, and forward the job of actual LZMA
- * decoding or copying of uncompressed chunks to other functions.
- */
- 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 = 1;
- s->lzma2.need_dict_reset = 0;
- dict_reset(&s->dict);
- } 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 = 0;
- 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, minof(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;
- }
- struct xz_dec_lzma2 *xz_dec_lzma2_create(uint32_t dict_max)
- {
- struct xz_dec_lzma2 *s = malloc(sizeof(*s));
- if (s == NULL)
- return NULL;
- s->dict.size_max = dict_max;
- s->dict.buf = NULL;
- s->dict.allocated = 0;
- return s;
- }
- 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 (s->dict.size > s->dict.size_max)
- return XZ_MEMLIMIT_ERROR;
- s->dict.end = s->dict.size;
- if (s->dict.allocated < s->dict.size) {
- free(s->dict.buf);
- s->dict.buf = malloc(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 = 1;
- s->temp.size = 0;
- return XZ_OK;
- }
- /*
- * .xz Stream decoder
- */
- // BEGIN xz_stream.h
- /*
- * Definitions for handling the .xz file format
- */
- /*
- * See the .xz file format specification at
- * http://tukaani.org/xz/xz-file-format.txt
- * to understand the container format.
- */
- #define STREAM_HEADER_SIZE 12
- #define HEADER_MAGIC "\3757zXZ"
- #define HEADER_MAGIC_SIZE 6
- #define FOOTER_MAGIC "YZ"
- #define FOOTER_MAGIC_SIZE 2
- /*
- * Variable-length integer can hold a 63-bit unsigned integer or a special
- * value indicating that the value is unknown.
- *
- * Experimental: vli_type can be defined to uint32_t to save a few bytes
- * in code size (no effect on speed). Doing so limits the uncompressed and
- * compressed size of the file to less than 256 MiB and may also weaken
- * error detection slightly.
- */
- typedef uint64_t vli_type;
- #define VLI_MAX ((vli_type)-1 / 2)
- #define VLI_UNKNOWN ((vli_type)-1)
- /* Maximum encoded size of a VLI */
- #define VLI_BYTES_MAX (sizeof(vli_type) * 8 / 7)
- /* Integrity Check types */
- enum xz_check {
- XZ_CHECK_NONE = 0,
- XZ_CHECK_CRC32 = 1,
- XZ_CHECK_CRC64 = 4,
- XZ_CHECK_SHA256 = 10
- };
- /* Maximum possible Check ID */
- #define XZ_CHECK_MAX 15
- // END xz_stream.h
- #define IS_CRC64(check_type) ((check_type) == XZ_CHECK_CRC64)
- /* Hash used to validate the Index field */
- struct xz_dec_hash {
- vli_type unpadded;
- vli_type uncompressed;
- uint32_t crc32;
- };
- struct xz_dec {
- /* Position in dec_main() */
- enum {
- SEQ_STREAM_HEADER,
- SEQ_BLOCK_START,
- SEQ_BLOCK_HEADER,
- SEQ_BLOCK_UNCOMPRESS,
- SEQ_BLOCK_PADDING,
- SEQ_BLOCK_CHECK,
- SEQ_INDEX,
- SEQ_INDEX_PADDING,
- SEQ_INDEX_CRC32,
- SEQ_STREAM_FOOTER
- } sequence;
- /* Position in variable-length integers and Check fields */
- uint32_t pos;
- /* Variable-length integer decoded by dec_vli() */
- vli_type vli;
- /* Saved in_pos and out_pos */
- size_t in_start;
- size_t out_start;
- /* CRC32 or CRC64 value in Block or CRC32 value in Index */
- uint64_t crc;
- /* Type of the integrity check calculated from uncompressed data */
- enum xz_check check_type;
- /*
- * True if the next call to xz_dec_run() is allowed to return
- * XZ_BUF_ERROR.
- */
- int allow_buf_error;
- /* Information stored in Block Header */
- struct {
- /*
- * Value stored in the Compressed Size field, or
- * VLI_UNKNOWN if Compressed Size is not present.
- */
- vli_type compressed;
- /*
- * Value stored in the Uncompressed Size field, or
- * VLI_UNKNOWN if Uncompressed Size is not present.
- */
- vli_type uncompressed;
- /* Size of the Block Header field */
- uint32_t size;
- } block_header;
- /* Information collected when decoding Blocks */
- struct {
- /* Observed compressed size of the current Block */
- vli_type compressed;
- /* Observed uncompressed size of the current Block */
- vli_type uncompressed;
- /* Number of Blocks decoded so far */
- vli_type count;
- /*
- * Hash calculated from the Block sizes. This is used to
- * validate the Index field.
- */
- struct xz_dec_hash hash;
- } block;
- /* Variables needed when verifying the Index field */
- struct {
- /* Position in dec_index() */
- enum {
- SEQ_INDEX_COUNT,
- SEQ_INDEX_UNPADDED,
- SEQ_INDEX_UNCOMPRESSED
- } sequence;
- /* Size of the Index in bytes */
- vli_type size;
- /* Number of Records (matches block.count in valid files) */
- vli_type count;
- /*
- * Hash calculated from the Records (matches block.hash in
- * valid files).
- */
- struct xz_dec_hash hash;
- } index;
- /*
- * Temporary buffer needed to hold Stream Header, Block Header,
- * and Stream Footer. The Block Header is the biggest (1 KiB)
- * so we reserve space according to that. buf[] has to be aligned
- * to a multiple of four bytes; the size_t variables before it
- * should guarantee this.
- */
- struct {
- size_t pos;
- size_t size;
- uint8_t buf[1024];
- } temp;
- struct xz_dec_lzma2 *lzma2;
- #ifdef XZ_DEC_BCJ
- struct xz_dec_bcj *bcj;
- int bcj_active;
- #endif
- };
- /* Sizes of the Check field with different Check IDs */
- static const uint8_t check_sizes[16] = {
- 0,
- 4, 4, 4,
- 8, 8, 8,
- 16, 16, 16,
- 32, 32, 32,
- 64, 64, 64
- };
- /*
- * Fill s->temp by copying data starting from b->in[b->in_pos]. Caller
- * must have set s->temp.pos to indicate how much data we are supposed
- * to copy into s->temp.buf. Return true once s->temp.pos has reached
- * s->temp.size.
- */
- static int fill_temp(struct xz_dec *s, struct xz_buf *b)
- {
- size_t copy_size = minof(b->in_size - b->in_pos, s->temp.size - s->temp.pos);
- memcpy(s->temp.buf + s->temp.pos, b->in + b->in_pos, copy_size);
- b->in_pos += copy_size;
- s->temp.pos += copy_size;
- if (s->temp.pos == s->temp.size) {
- s->temp.pos = 0;
- return 1;
- }
- return 0;
- }
- /* Decode a variable-length integer (little-endian base-128 encoding) */
- static enum xz_ret dec_vli(struct xz_dec *s, const uint8_t *in,
- size_t *in_pos, size_t in_size)
- {
- uint8_t byte;
- if (s->pos == 0)
- s->vli = 0;
- while (*in_pos < in_size) {
- byte = in[*in_pos];
- ++*in_pos;
- s->vli |= (vli_type)(byte & 0x7F) << s->pos;
- if ((byte & 0x80) == 0) {
- /* Don't allow non-minimal encodings. */
- if (byte == 0 && s->pos != 0)
- return XZ_DATA_ERROR;
- s->pos = 0;
- return XZ_STREAM_END;
- }
- s->pos += 7;
- if (s->pos == 7 * VLI_BYTES_MAX)
- return XZ_DATA_ERROR;
- }
- return XZ_OK;
- }
- /*
- * Decode the Compressed Data field from a Block. Update and validate
- * the observed compressed and uncompressed sizes of the Block so that
- * they don't exceed the values possibly stored in the Block Header
- * (validation assumes that no integer overflow occurs, since vli_type
- * is normally uint64_t). Update the CRC32 or CRC64 value if presence of
- * the CRC32 or CRC64 field was indicated in Stream Header.
- *
- * Once the decoding is finished, validate that the observed sizes match
- * the sizes possibly stored in the Block Header. Update the hash and
- * Block count, which are later used to validate the Index field.
- */
- static enum xz_ret dec_block(struct xz_dec *s, struct xz_buf *b)
- {
- enum xz_ret ret;
- s->in_start = b->in_pos;
- s->out_start = b->out_pos;
- #ifdef XZ_DEC_BCJ
- if (s->bcj_active)
- ret = xz_dec_bcj_run(s->bcj, s->lzma2, b);
- else
- #endif
- ret = xz_dec_lzma2_run(s->lzma2, b);
- s->block.compressed += b->in_pos - s->in_start;
- s->block.uncompressed += b->out_pos - s->out_start;
- /*
- * There is no need to separately check for VLI_UNKNOWN, since
- * the observed sizes are always smaller than VLI_UNKNOWN.
- */
- if (s->block.compressed > s->block_header.compressed
- || s->block.uncompressed
- > s->block_header.uncompressed)
- return XZ_DATA_ERROR;
- if (s->check_type == XZ_CHECK_CRC32)
- s->crc = xz_crc32(b->out + s->out_start,
- b->out_pos - s->out_start, s->crc);
- else if (s->check_type == XZ_CHECK_CRC64) {
- s->crc = ~(s->crc);
- size_t size = b->out_pos - s->out_start;
- uint8_t *buf = b->out + s->out_start;
- while (size) {
- s->crc = xz_crc64_table[*buf++ ^ (s->crc & 0xFF)] ^ (s->crc >> 8);
- --size;
- }
- s->crc=~(s->crc);
- }
- if (ret == XZ_STREAM_END) {
- if (s->block_header.compressed != VLI_UNKNOWN
- && s->block_header.compressed
- != s->block.compressed)
- return XZ_DATA_ERROR;
- if (s->block_header.uncompressed != VLI_UNKNOWN
- && s->block_header.uncompressed
- != s->block.uncompressed)
- return XZ_DATA_ERROR;
- s->block.hash.unpadded += s->block_header.size
- + s->block.compressed;
- s->block.hash.unpadded += check_sizes[s->check_type];
- s->block.hash.uncompressed += s->block.uncompressed;
- s->block.hash.crc32 = xz_crc32(
- (const uint8_t *)&s->block.hash,
- sizeof(s->block.hash), s->block.hash.crc32);
- ++s->block.count;
- }
- return ret;
- }
- /* Update the Index size and the CRC32 value. */
- static void index_update(struct xz_dec *s, const struct xz_buf *b)
- {
- size_t in_used = b->in_pos - s->in_start;
- s->index.size += in_used;
- s->crc = xz_crc32(b->in + s->in_start, in_used, s->crc);
- }
- /*
- * Decode the Number of Records, Unpadded Size, and Uncompressed Size
- * fields from the Index field. That is, Index Padding and CRC32 are not
- * decoded by this function.
- *
- * This can return XZ_OK (more input needed), XZ_STREAM_END (everything
- * successfully decoded), or XZ_DATA_ERROR (input is corrupt).
- */
- static enum xz_ret dec_index(struct xz_dec *s, struct xz_buf *b)
- {
- enum xz_ret ret;
- do {
- ret = dec_vli(s, b->in, &b->in_pos, b->in_size);
- if (ret != XZ_STREAM_END) {
- index_update(s, b);
- return ret;
- }
- switch (s->index.sequence) {
- case SEQ_INDEX_COUNT:
- s->index.count = s->vli;
- /*
- * Validate that the Number of Records field
- * indicates the same number of Records as
- * there were Blocks in the Stream.
- */
- if (s->index.count != s->block.count)
- return XZ_DATA_ERROR;
- s->index.sequence = SEQ_INDEX_UNPADDED;
- break;
- case SEQ_INDEX_UNPADDED:
- s->index.hash.unpadded += s->vli;
- s->index.sequence = SEQ_INDEX_UNCOMPRESSED;
- break;
- case SEQ_INDEX_UNCOMPRESSED:
- s->index.hash.uncompressed += s->vli;
- s->index.hash.crc32 = xz_crc32(
- (const uint8_t *)&s->index.hash,
- sizeof(s->index.hash),
- s->index.hash.crc32);
- --s->index.count;
- s->index.sequence = SEQ_INDEX_UNPADDED;
- break;
- }
- } while (s->index.count > 0);
- return XZ_STREAM_END;
- }
- /*
- * Validate that the next four or eight input bytes match the value
- * of s->crc. s->pos must be zero when starting to validate the first byte.
- * The "bits" argument allows using the same code for both CRC32 and CRC64.
- */
- static enum xz_ret crc_validate(struct xz_dec *s, struct xz_buf *b,
- uint32_t bits)
- {
- do {
- if (b->in_pos == b->in_size)
- return XZ_OK;
- if (((s->crc >> s->pos) & 0xFF) != b->in[b->in_pos++])
- return XZ_DATA_ERROR;
- s->pos += 8;
- } while (s->pos < bits);
- s->crc = 0;
- s->pos = 0;
- return XZ_STREAM_END;
- }
- /*
- * Skip over the Check field when the Check ID is not supported.
- * Returns true once the whole Check field has been skipped over.
- */
- static int check_skip(struct xz_dec *s, struct xz_buf *b)
- {
- while (s->pos < check_sizes[s->check_type]) {
- if (b->in_pos == b->in_size) return 0;
- ++b->in_pos;
- ++s->pos;
- }
- s->pos = 0;
- return 1;
- }
- /* Decode the Stream Header field (the first 12 bytes of the .xz Stream). */
- static enum xz_ret dec_stream_header(struct xz_dec *s)
- {
- if (!memeq(s->temp.buf, HEADER_MAGIC, HEADER_MAGIC_SIZE))
- return XZ_FORMAT_ERROR;
- if (xz_crc32(s->temp.buf + HEADER_MAGIC_SIZE, 2, 0)
- != get_le32(s->temp.buf + HEADER_MAGIC_SIZE + 2))
- return XZ_DATA_ERROR;
- if (s->temp.buf[HEADER_MAGIC_SIZE] != 0)
- return XZ_OPTIONS_ERROR;
- /*
- * Of integrity checks, we support none (Check ID = 0),
- * CRC32 (Check ID = 1), and optionally CRC64 (Check ID = 4).
- * However, if XZ_DEC_ANY_CHECK is defined, we will accept other
- * check types too, but then the check won't be verified and
- * a warning (XZ_UNSUPPORTED_CHECK) will be given.
- */
- s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1];
- if (s->check_type > XZ_CHECK_MAX)
- return XZ_OPTIONS_ERROR;
- if (s->check_type > XZ_CHECK_CRC32 && !IS_CRC64(s->check_type))
- return XZ_UNSUPPORTED_CHECK;
- return XZ_OK;
- }
- /* Decode the Stream Footer field (the last 12 bytes of the .xz Stream) */
- static enum xz_ret dec_stream_footer(struct xz_dec *s)
- {
- if (!memeq(s->temp.buf + 10, FOOTER_MAGIC, FOOTER_MAGIC_SIZE))
- return XZ_DATA_ERROR;
- if (xz_crc32(s->temp.buf + 4, 6, 0) != get_le32(s->temp.buf))
- return XZ_DATA_ERROR;
- /*
- * Validate Backward Size. Note that we never added the size of the
- * Index CRC32 field to s->index.size, thus we use s->index.size / 4
- * instead of s->index.size / 4 - 1.
- */
- if ((s->index.size >> 2) != get_le32(s->temp.buf + 4))
- return XZ_DATA_ERROR;
- if (s->temp.buf[8] != 0 || s->temp.buf[9] != s->check_type)
- return XZ_DATA_ERROR;
- /*
- * Use XZ_STREAM_END instead of XZ_OK to be more convenient
- * for the caller.
- */
- return XZ_STREAM_END;
- }
- /* Decode the Block Header and initialize the filter chain. */
- static enum xz_ret dec_block_header(struct xz_dec *s)
- {
- enum xz_ret ret;
- /*
- * Validate the CRC32. We know that the temp buffer is at least
- * eight bytes so this is safe.
- */
- s->temp.size -= 4;
- if (xz_crc32(s->temp.buf, s->temp.size, 0)
- != get_le32(s->temp.buf + s->temp.size))
- return XZ_DATA_ERROR;
- s->temp.pos = 2;
- /*
- * Catch unsupported Block Flags. We support only one or two filters
- * in the chain, so we catch that with the same test.
- */
- #ifdef XZ_DEC_BCJ
- if (s->temp.buf[1] & 0x3E)
- #else
- if (s->temp.buf[1] & 0x3F)
- #endif
- return XZ_OPTIONS_ERROR;
- /* Compressed Size */
- if (s->temp.buf[1] & 0x40) {
- if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
- != XZ_STREAM_END)
- return XZ_DATA_ERROR;
- s->block_header.compressed = s->vli;
- } else {
- s->block_header.compressed = VLI_UNKNOWN;
- }
- /* Uncompressed Size */
- if (s->temp.buf[1] & 0x80) {
- if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
- != XZ_STREAM_END)
- return XZ_DATA_ERROR;
- s->block_header.uncompressed = s->vli;
- } else {
- s->block_header.uncompressed = VLI_UNKNOWN;
- }
- #ifdef XZ_DEC_BCJ
- /* If there are two filters, the first one must be a BCJ filter. */
- s->bcj_active = s->temp.buf[1] & 0x01;
- if (s->bcj_active) {
- if (s->temp.size - s->temp.pos < 2)
- return XZ_OPTIONS_ERROR;
- ret = xz_dec_bcj_reset(s->bcj, s->temp.buf[s->temp.pos++]);
- if (ret != XZ_OK)
- return ret;
- /*
- * We don't support custom start offset,
- * so Size of Properties must be zero.
- */
- if (s->temp.buf[s->temp.pos++] != 0x00)
- return XZ_OPTIONS_ERROR;
- }
- #endif
- /* Valid Filter Flags always take at least two bytes. */
- if (s->temp.size - s->temp.pos < 2)
- return XZ_DATA_ERROR;
- /* Filter ID = LZMA2 */
- if (s->temp.buf[s->temp.pos++] != 0x21)
- return XZ_OPTIONS_ERROR;
- /* Size of Properties = 1-byte Filter Properties */
- if (s->temp.buf[s->temp.pos++] != 0x01)
- return XZ_OPTIONS_ERROR;
- /* Filter Properties contains LZMA2 dictionary size. */
- if (s->temp.size - s->temp.pos < 1)
- return XZ_DATA_ERROR;
- ret = xz_dec_lzma2_reset(s->lzma2, s->temp.buf[s->temp.pos++]);
- if (ret != XZ_OK)
- return ret;
- /* The rest must be Header Padding. */
- while (s->temp.pos < s->temp.size)
- if (s->temp.buf[s->temp.pos++] != 0x00)
- return XZ_OPTIONS_ERROR;
- s->temp.pos = 0;
- s->block.compressed = 0;
- s->block.uncompressed = 0;
- return XZ_OK;
- }
- static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
- {
- enum xz_ret ret;
- /*
- * Store the start position for the case when we are in the middle
- * of the Index field.
- */
- s->in_start = b->in_pos;
- for (;;) {
- switch (s->sequence) {
- case SEQ_STREAM_HEADER:
- /*
- * Stream Header is copied to s->temp, and then
- * decoded from there. This way if the caller
- * gives us only little input at a time, we can
- * still keep the Stream Header decoding code
- * simple. Similar approach is used in many places
- * in this file.
- */
- if (!fill_temp(s, b))
- return XZ_OK;
- /*
- * If dec_stream_header() returns
- * XZ_UNSUPPORTED_CHECK, it is still possible
- * to continue decoding if working in multi-call
- * mode. Thus, update s->sequence before calling
- * dec_stream_header().
- */
- s->sequence = SEQ_BLOCK_START;
- ret = dec_stream_header(s);
- if (ret != XZ_OK)
- return ret;
- case SEQ_BLOCK_START:
- /* We need one byte of input to continue. */
- if (b->in_pos == b->in_size)
- return XZ_OK;
- /* See if this is the beginning of the Index field. */
- if (b->in[b->in_pos] == 0) {
- s->in_start = b->in_pos++;
- s->sequence = SEQ_INDEX;
- break;
- }
- /*
- * Calculate the size of the Block Header and
- * prepare to decode it.
- */
- s->block_header.size
- = ((uint32_t)b->in[b->in_pos] + 1) * 4;
- s->temp.size = s->block_header.size;
- s->temp.pos = 0;
- s->sequence = SEQ_BLOCK_HEADER;
- case SEQ_BLOCK_HEADER:
- if (!fill_temp(s, b))
- return XZ_OK;
- ret = dec_block_header(s);
- if (ret != XZ_OK)
- return ret;
- s->sequence = SEQ_BLOCK_UNCOMPRESS;
- case SEQ_BLOCK_UNCOMPRESS:
- ret = dec_block(s, b);
- if (ret != XZ_STREAM_END)
- return ret;
- s->sequence = SEQ_BLOCK_PADDING;
- case SEQ_BLOCK_PADDING:
- /*
- * Size of Compressed Data + Block Padding
- * must be a multiple of four. We don't need
- * s->block.compressed for anything else
- * anymore, so we use it here to test the size
- * of the Block Padding field.
- */
- while (s->block.compressed & 3) {
- if (b->in_pos == b->in_size)
- return XZ_OK;
- if (b->in[b->in_pos++] != 0)
- return XZ_DATA_ERROR;
- ++s->block.compressed;
- }
- s->sequence = SEQ_BLOCK_CHECK;
- case SEQ_BLOCK_CHECK:
- if (s->check_type == XZ_CHECK_CRC32) {
- ret = crc_validate(s, b, 32);
- if (ret != XZ_STREAM_END)
- return ret;
- }
- else if (IS_CRC64(s->check_type)) {
- ret = crc_validate(s, b, 64);
- if (ret != XZ_STREAM_END)
- return ret;
- }
- else if (!check_skip(s, b)) {
- return XZ_OK;
- }
- s->sequence = SEQ_BLOCK_START;
- break;
- case SEQ_INDEX:
- ret = dec_index(s, b);
- if (ret != XZ_STREAM_END)
- return ret;
- s->sequence = SEQ_INDEX_PADDING;
- case SEQ_INDEX_PADDING:
- while ((s->index.size + (b->in_pos - s->in_start))
- & 3) {
- if (b->in_pos == b->in_size) {
- index_update(s, b);
- return XZ_OK;
- }
- if (b->in[b->in_pos++] != 0)
- return XZ_DATA_ERROR;
- }
- /* Finish the CRC32 value and Index size. */
- index_update(s, b);
- /* Compare the hashes to validate the Index field. */
- if (!memeq(&s->block.hash, &s->index.hash,
- sizeof(s->block.hash)))
- return XZ_DATA_ERROR;
- s->sequence = SEQ_INDEX_CRC32;
- case SEQ_INDEX_CRC32:
- ret = crc_validate(s, b, 32);
- if (ret != XZ_STREAM_END)
- return ret;
- s->temp.size = STREAM_HEADER_SIZE;
- s->sequence = SEQ_STREAM_FOOTER;
- case SEQ_STREAM_FOOTER:
- if (!fill_temp(s, b))
- return XZ_OK;
- return dec_stream_footer(s);
- }
- }
- /* Never reached */
- }
- /*
- * xz_dec_run() is a wrapper for dec_main() to handle some special cases in
- * multi-call and single-call decoding.
- *
- * In multi-call mode, we must return XZ_BUF_ERROR when it seems clear that we
- * are not going to make any progress anymore. This is to prevent the caller
- * from calling us infinitely when the input file is truncated or otherwise
- * corrupt. Since zlib-style API allows that the caller fills the input buffer
- * only when the decoder doesn't produce any new output, we have to be careful
- * to avoid returning XZ_BUF_ERROR too easily: XZ_BUF_ERROR is returned only
- * after the second consecutive call to xz_dec_run() that makes no progress.
- *
- * In single-call mode, if we couldn't decode everything and no error
- * occurred, either the input is truncated or the output buffer is too small.
- * Since we know that the last input byte never produces any output, we know
- * that if all the input was consumed and decoding wasn't finished, the file
- * must be corrupt. Otherwise the output buffer has to be too small or the
- * file is corrupt in a way that decoding it produces too big output.
- *
- * If single-call decoding fails, we reset b->in_pos and b->out_pos back to
- * their original values. This is because with some filter chains there won't
- * be any valid uncompressed data in the output buffer unless the decoding
- * actually succeeds (that's the price to pay of using the output buffer as
- * the workspace).
- */
- enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b)
- {
- size_t in_start;
- size_t out_start;
- enum xz_ret ret;
- in_start = b->in_pos;
- out_start = b->out_pos;
- ret = dec_main(s, b);
- if (ret == XZ_OK && in_start == b->in_pos && out_start == b->out_pos) {
- if (s->allow_buf_error)
- ret = XZ_BUF_ERROR;
- s->allow_buf_error = 1;
- } else {
- s->allow_buf_error = 0;
- }
- return ret;
- }
- struct xz_dec *xz_dec_init(uint32_t dict_max)
- {
- struct xz_dec *s = malloc(sizeof(*s));
- if (!s)
- return NULL;
- #ifdef XZ_DEC_BCJ
- s->bcj = malloc(sizeof(*s->bcj));
- if (!s->bcj)
- goto error_bcj;
- #endif
- s->lzma2 = xz_dec_lzma2_create(dict_max);
- if (s->lzma2 == NULL)
- goto error_lzma2;
- xz_dec_reset(s);
- return s;
- error_lzma2:
- #ifdef XZ_DEC_BCJ
- free(s->bcj);
- error_bcj:
- #endif
- free(s);
- return NULL;
- }
- void xz_dec_reset(struct xz_dec *s)
- {
- s->sequence = SEQ_STREAM_HEADER;
- s->allow_buf_error = 0;
- s->pos = 0;
- s->crc = 0;
- memset(&s->block, 0, sizeof(s->block));
- memset(&s->index, 0, sizeof(s->index));
- s->temp.pos = 0;
- s->temp.size = STREAM_HEADER_SIZE;
- }
- void xz_dec_end(struct xz_dec *s)
- {
- if (s != NULL) {
- free((s->lzma2)->dict.buf);
- free(s->lzma2);
- #ifdef XZ_DEC_BCJ
- free(s->bcj);
- #endif
- free(s);
- }
- }
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