X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Flzx-decompress.c;h=4047f956c376abf0e2d35dbe02d5a0ef37adc6ec;hb=1c19875f1bcbfe341014b20b9bbbc9b5fa0cea4d;hp=935c6367e9bc769bba03a88fd53e058d2a6de9a2;hpb=9bec19341aac9190cd0bd80a6937b02d923dd566;p=wimlib diff --git a/src/lzx-decompress.c b/src/lzx-decompress.c index 935c6367..4047f956 100644 --- a/src/lzx-decompress.c +++ b/src/lzx-decompress.c @@ -38,13 +38,13 @@ * * A compressed WIM resource consists of a table of chunk offsets followed by * the compressed chunks themselves. All compressed chunks except possibly the - * last decompress to WIM_CHUNK_SIZE (= 32768) bytes. This is quite similar to - * the cabinet (.cab) file format, but they are not the same. According to the - * cabinet format documentation, the LZX block size is independent from the - * CFDATA blocks, and a LZX block may span several CFDATA blocks. However, in - * WIMs, LZX blocks do not appear to ever span multiple WIM chunks. Note that - * this means any WIM chunk may be decompressed or compressed independently from - * any other chunk, which is convenient. + * last decompress to 32768 bytes. This is quite similar to the cabinet (.cab) + * file format, but they are not the same. According to the cabinet format + * documentation, the LZX block size is independent from the CFDATA blocks, and + * a LZX block may span several CFDATA blocks. However, in WIMs, LZX blocks do + * not appear to ever span multiple WIM chunks. Note that this means any WIM + * chunk may be decompressed or compressed independently from any other chunk, + * which is convenient. * * A LZX compressed WIM chunk contains one or more LZX blocks of the aligned, * verbatim, or uncompressed block types. For aligned and verbatim blocks, the @@ -121,9 +121,9 @@ struct lzx_tables { u16 maintree_decode_table[(1 << LZX_MAINCODE_TABLEBITS) + - (LZX_MAINCODE_NUM_SYMBOLS * 2)] + (LZX_MAINCODE_MAX_NUM_SYMBOLS * 2)] _aligned_attribute(DECODE_TABLE_ALIGNMENT); - u8 maintree_lens[LZX_MAINCODE_NUM_SYMBOLS]; + u8 maintree_lens[LZX_MAINCODE_MAX_NUM_SYMBOLS]; u16 lentree_decode_table[(1 << LZX_LENCODE_TABLEBITS) + @@ -156,10 +156,11 @@ read_huffsym_using_pretree(struct input_bitstream *istream, static inline int read_huffsym_using_maintree(struct input_bitstream *istream, const struct lzx_tables *tables, - unsigned *n) + unsigned *n, + unsigned num_main_syms) { return read_huffsym(istream, tables->maintree_decode_table, - tables->maintree_lens, LZX_MAINCODE_NUM_SYMBOLS, + tables->maintree_lens, num_main_syms, LZX_MAINCODE_TABLEBITS, n, LZX_MAX_MAIN_CODEWORD_LEN); } @@ -324,6 +325,8 @@ lzx_read_code_lens(struct input_bitstream *istream, u8 lens[], */ static int lzx_read_block_header(struct input_bitstream *istream, + unsigned num_main_syms, + unsigned max_window_size, unsigned *block_size_ret, unsigned *block_type_ret, struct lzx_tables *tables, @@ -336,7 +339,7 @@ lzx_read_block_header(struct input_bitstream *istream, unsigned i; unsigned len; - ret = bitstream_ensure_bits(istream, LZX_BLOCKTYPE_NBITS + 1); + ret = bitstream_ensure_bits(istream, 4); if (ret) { LZX_DEBUG("LZX input stream overrun"); return ret; @@ -344,20 +347,36 @@ lzx_read_block_header(struct input_bitstream *istream, /* The first three bits tell us what kind of block it is, and are one * of the LZX_BLOCKTYPE_* values. */ - block_type = bitstream_read_bits_nocheck(istream, LZX_BLOCKTYPE_NBITS); + block_type = bitstream_read_bits_nocheck(istream, 3); - /* The next bit indicates whether the block size is the default (32768), - * indicated by a 1 bit, or whether the block size is given by the next - * 16 bits, indicated by a 0 bit. */ + /* Read the block size. This mirrors the behavior + * lzx_write_compressed_block() in lzx-compress.c; see that for more + * details. */ s = bitstream_read_bits_nocheck(istream, 1); - if (s) { - block_size = 32768; + block_size = LZX_DEFAULT_BLOCK_SIZE; } else { - ret = bitstream_read_bits(istream, LZX_BLOCKSIZE_NBITS, &block_size); + unsigned tmp; + block_size = 0; + + ret = bitstream_read_bits(istream, 8, &tmp); if (ret) return ret; - block_size = le16_to_cpu(block_size); + block_size |= tmp; + + ret = bitstream_read_bits(istream, 8, &tmp); + if (ret) + return ret; + block_size <<= 8; + block_size |= tmp; + + if (max_window_size >= 65536) { + ret = bitstream_read_bits(istream, 8, &tmp); + if (ret) + return ret; + block_size <<= 8; + block_size |= tmp; + } } switch (block_type) { @@ -408,10 +427,10 @@ lzx_read_block_header(struct input_bitstream *istream, * tree. */ LZX_DEBUG("Reading path lengths for remaining elements of " "main tree (%d elements).", - LZX_MAINCODE_NUM_SYMBOLS - LZX_NUM_CHARS); + num_main_syms - LZX_NUM_CHARS); ret = lzx_read_code_lens(istream, tables->maintree_lens + LZX_NUM_CHARS, - LZX_MAINCODE_NUM_SYMBOLS - LZX_NUM_CHARS); + num_main_syms - LZX_NUM_CHARS); if (ret) { LZX_DEBUG("Failed to read the path lengths for the " "remaining elements of the main tree"); @@ -422,7 +441,7 @@ lzx_read_block_header(struct input_bitstream *istream, "table for the main tree."); ret = make_huffman_decode_table(tables->maintree_decode_table, - LZX_MAINCODE_NUM_SYMBOLS, + num_main_syms, LZX_MAINCODE_TABLEBITS, tables->maintree_lens, LZX_MAX_MAIN_CODEWORD_LEN); @@ -754,6 +773,7 @@ undo_call_insn_preprocessing(u8 uncompressed_data[], int uncompressed_data_len) * @block_type: The type of the block (LZX_BLOCKTYPE_VERBATIM or * LZX_BLOCKTYPE_ALIGNED) * @block_size: The size of the block, in bytes. + * @num_main_syms: Number of symbols in the main alphabet. * @window: Pointer to the decompression window. * @window_pos: The current position in the window. Will be 0 for the first * block. @@ -764,6 +784,7 @@ undo_call_insn_preprocessing(u8 uncompressed_data[], int uncompressed_data_len) */ static int lzx_decompress_block(int block_type, unsigned block_size, + unsigned num_main_syms, u8 *window, unsigned window_pos, const struct lzx_tables *tables, @@ -778,7 +799,8 @@ lzx_decompress_block(int block_type, unsigned block_size, end = window_pos + block_size; while (window_pos < end) { ret = read_huffsym_using_maintree(istream, tables, - &main_element); + &main_element, + num_main_syms); if (ret) return ret; @@ -786,7 +808,7 @@ lzx_decompress_block(int block_type, unsigned block_size, /* literal: 0 to LZX_NUM_CHARS - 1 */ window[window_pos++] = main_element; } else { - /* match: LZX_NUM_CHARS to LZX_MAINCODE_NUM_SYMBOLS - 1 */ + /* match: LZX_NUM_CHARS to num_main_syms - 1 */ match_len = lzx_decode_match(main_element, block_type, end - window_pos, @@ -803,10 +825,10 @@ lzx_decompress_block(int block_type, unsigned block_size, return 0; } -/* API function documented in wimlib.h */ WIMLIBAPI int -wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, - void *uncompressed_data, unsigned uncompressed_len) +wimlib_lzx_decompress2(const void *compressed_data, unsigned compressed_len, + void *uncompressed_data, unsigned uncompressed_len, + u32 max_window_size) { struct lzx_tables tables; struct input_bitstream istream; @@ -814,15 +836,30 @@ wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, unsigned window_pos; unsigned block_size; unsigned block_type; + unsigned num_main_syms; int ret; bool e8_preprocessing_done; - LZX_DEBUG("lzx_decompress (compressed_data = %p, compressed_len = %d, " - "uncompressed_data = %p, uncompressed_len = %d).", + LZX_DEBUG("compressed_data = %p, compressed_len = %u, " + "uncompressed_data = %p, uncompressed_len = %u, " + "max_window_size=%u).", compressed_data, compressed_len, - uncompressed_data, uncompressed_len); + uncompressed_data, uncompressed_len, max_window_size); + + if (!lzx_window_size_valid(max_window_size)) { + LZX_DEBUG("Window size of %u is invalid!", + max_window_size); + return -1; + } - wimlib_assert(uncompressed_len <= 32768); + num_main_syms = lzx_get_num_main_syms(max_window_size); + + if (uncompressed_len > max_window_size) { + LZX_DEBUG("Uncompressed chunk size of %u exceeds " + "window size of %u!", + uncompressed_len, max_window_size); + return -1; + } memset(tables.maintree_lens, 0, sizeof(tables.maintree_lens)); memset(tables.lentree_lens, 0, sizeof(tables.lentree_lens)); @@ -842,7 +879,8 @@ wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, window_pos += block_size) { LZX_DEBUG("Reading block header."); - ret = lzx_read_block_header(&istream, &block_size, + ret = lzx_read_block_header(&istream, num_main_syms, + max_window_size, &block_size, &block_type, &tables, &queue); if (ret) return ret; @@ -866,6 +904,7 @@ wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, LZX_DEBUG("LZX_BLOCKTYPE_ALIGNED"); ret = lzx_decompress_block(block_type, block_size, + num_main_syms, uncompressed_data, window_pos, &tables, @@ -873,6 +912,7 @@ wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, &istream); if (ret) return ret; + if (tables.maintree_lens[0xe8] != 0) e8_preprocessing_done = true; break; @@ -903,3 +943,13 @@ wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, undo_call_insn_preprocessing(uncompressed_data, uncompressed_len); return 0; } + +/* API function documented in wimlib.h */ +WIMLIBAPI int +wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len, + void *uncompressed_data, unsigned uncompressed_len) +{ + return wimlib_lzx_decompress2(compressed_data, compressed_len, + uncompressed_data, uncompressed_len, + 32768); +}