X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;ds=sidebyside;f=src%2Fxpress-decompress.c;h=ebe0d23b73d6c1eccf23c9b4ee023d0172a13b3d;hb=32614c9f026be20f0336df3053b91090dc53297f;hp=b71f6be23e1c6f8a502564fda9b29e966d33a5fa;hpb=4757f17833c96b8c83a7e17cbc6f374c449d60db;p=wimlib diff --git a/src/xpress-decompress.c b/src/xpress-decompress.c index b71f6be2..ebe0d23b 100644 --- a/src/xpress-decompress.c +++ b/src/xpress-decompress.c @@ -55,10 +55,10 @@ * * Also, a caveat--- according to Microsoft's documentation for XPRESS, * - * "Some implementation of the decompression algorithm expect an extra - * symbol to mark the end of the data. Specifically, some implementations - * fail during decompression if the Huffman symbol 256 is not found after - * the actual data." + * "Some implementation of the decompression algorithm expect an extra + * symbol to mark the end of the data. Specifically, some implementations + * fail during decompression if the Huffman symbol 256 is not found after + * the actual data." * * This is the case for the implementation in WIMGAPI. However, wimlib's * decompressor in this file currently does not care if this extra symbol is @@ -69,8 +69,8 @@ # include "config.h" #endif -#include "wimlib.h" -#include "wimlib/decompress.h" +#include "wimlib/decompressor_ops.h" +#include "wimlib/decompress_common.h" #include "wimlib/xpress.h" /* @@ -84,17 +84,12 @@ * Returns the match length, or -1 if the data is invalid. */ static int -xpress_decode_match(unsigned sym, input_idx_t window_pos, - input_idx_t window_len, u8 window[restrict], +xpress_decode_match(unsigned sym, u32 window_pos, + u32 window_len, u8 window[restrict], struct input_bitstream * restrict istream) { - - u8 len_hdr; - u8 offset_bsr; - int ret; - u8 *match_dest; - u8 *match_src; - unsigned i; + unsigned len_hdr; + unsigned offset_bsr; unsigned match_len; unsigned match_offset; @@ -102,27 +97,15 @@ xpress_decode_match(unsigned sym, input_idx_t window_pos, len_hdr = sym & 0xf; offset_bsr = sym >> 4; - if (bitstream_ensure_bits(istream, 16)) - return -1; + bitstream_ensure_bits(istream, 16); match_offset = (1U << offset_bsr) | bitstream_pop_bits(istream, offset_bsr); if (len_hdr == 0xf) { - ret = bitstream_read_byte(istream); - if (ret < 0) - return ret; - match_len = ret; + match_len = bitstream_read_byte(istream); if (unlikely(match_len == 0xff)) { - ret = bitstream_read_byte(istream); - if (ret < 0) - return ret; - match_len = ret; - - ret = bitstream_read_byte(istream); - if (ret < 0) - return ret; - - match_len |= (ret << 8); + match_len = bitstream_read_byte(istream); + match_len |= (unsigned)bitstream_read_byte(istream) << 8; } else { match_len += 0xf; } @@ -131,21 +114,14 @@ xpress_decode_match(unsigned sym, input_idx_t window_pos, } match_len += XPRESS_MIN_MATCH_LEN; - - /* Verify the match is in bounds, then copy its data to the the current - * position. */ - - if (window_pos + match_len > window_len) + if (unlikely(match_len > window_len - window_pos)) return -1; - if (match_offset > window_pos) + if (unlikely(match_offset > window_pos)) return -1; - match_dest = window + window_pos; - match_src = match_dest - match_offset; - - for (i = 0; i < match_len; i++) - match_dest[i] = match_src[i]; + lz_copy(&window[window_pos], match_len, match_offset, + &window[window_len]); return match_len; } @@ -156,24 +132,19 @@ static int xpress_lz_decode(struct input_bitstream * restrict istream, u8 uncompressed_data[restrict], unsigned uncompressed_len, - const u8 lens[restrict], const u16 decode_table[restrict]) { - input_idx_t curpos; + u32 curpos; unsigned match_len; for (curpos = 0; curpos < uncompressed_len; curpos += match_len) { unsigned sym; int ret; - if (unlikely(bitstream_ensure_bits(istream, 16))) - return -1; - - if (unlikely(read_huffsym(istream, decode_table, lens, - XPRESS_NUM_SYMBOLS, XPRESS_TABLEBITS, - &sym, XPRESS_MAX_CODEWORD_LEN))) - return -1; + bitstream_ensure_bits(istream, 16); + sym = read_huffsym(istream, decode_table, + XPRESS_TABLEBITS, XPRESS_MAX_CODEWORD_LEN); if (sym < XPRESS_NUM_CHARS) { /* Literal */ uncompressed_data[curpos] = sym; @@ -194,14 +165,11 @@ xpress_lz_decode(struct input_bitstream * restrict istream, } -/* API function documented in wimlib.h */ -WIMLIBAPI int -wimlib_xpress_decompress(const void * const restrict _compressed_data, - const unsigned compressed_len, - void * const restrict uncompressed_data, - const unsigned uncompressed_len) +static int +xpress_decompress(const void *compressed_data, size_t compressed_size, + void *uncompressed_data, size_t uncompressed_size, void *_ctx) { - const u8 *compressed_data = _compressed_data; + const u8 *cdata = compressed_data; u8 lens[XPRESS_NUM_SYMBOLS]; u8 *lens_p; u16 decode_table[(1 << XPRESS_TABLEBITS) + 2 * XPRESS_NUM_SYMBOLS] @@ -211,13 +179,13 @@ wimlib_xpress_decompress(const void * const restrict _compressed_data, /* XPRESS uses only one Huffman code. It contains 512 symbols, and the * code lengths of these symbols are given literally as 4-bit integers * in the first 256 bytes of the compressed data. */ - if (compressed_len < XPRESS_NUM_SYMBOLS / 2) + if (compressed_size < XPRESS_NUM_SYMBOLS / 2) return -1; lens_p = lens; for (unsigned i = 0; i < XPRESS_NUM_SYMBOLS / 2; i++) { - *lens_p++ = compressed_data[i] & 0xf; - *lens_p++ = compressed_data[i] >> 4; + *lens_p++ = cdata[i] & 0xf; + *lens_p++ = cdata[i] >> 4; } if (make_huffman_decode_table(decode_table, XPRESS_NUM_SYMBOLS, @@ -225,9 +193,13 @@ wimlib_xpress_decompress(const void * const restrict _compressed_data, XPRESS_MAX_CODEWORD_LEN)) return -1; - init_input_bitstream(&istream, compressed_data + XPRESS_NUM_SYMBOLS / 2, - compressed_len - XPRESS_NUM_SYMBOLS / 2); + init_input_bitstream(&istream, cdata + XPRESS_NUM_SYMBOLS / 2, + compressed_size - XPRESS_NUM_SYMBOLS / 2); return xpress_lz_decode(&istream, uncompressed_data, - uncompressed_len, lens, decode_table); + uncompressed_size, decode_table); } + +const struct decompressor_ops xpress_decompressor_ops = { + .decompress = xpress_decompress, +};