/*
*
- * Copyright (C) 2012 Eric Biggers
+ * Copyright (C) 2012, 2013 Eric Biggers
*
* This file is part of wimlib, a library for working with WIM files.
*
*
* Note: taking the low 8 bits of the symbol is the same as subtracting 256, the
* number of symbols reserved for literals.
+ *
+ * Returns the match length, or -1 on error.
*/
-static int xpress_decode_match(int huffsym, unsigned window_pos,
- unsigned window_len, u8 window[],
- struct input_bitstream *istream)
+static int
+xpress_decode_match(unsigned huffsym, unsigned window_pos,
+ unsigned window_len, u8 window[],
+ struct input_bitstream *istream)
{
unsigned match_len;
unsigned match_offset;
ret = bitstream_read_bits(istream, offset_bsr, &match_offset);
if (ret != 0)
- return -1;
+ return ret;
match_offset |= (1 << offset_bsr);
if (len_hdr == 0xf) {
ret = bitstream_read_byte(istream);
- if (ret == -1)
- return -1;
+ if (ret < 0)
+ return ret;
match_len = ret;
if (match_len == 0xff) {
ret = bitstream_read_byte(istream);
- if (ret == -1)
- return -1;
+ if (ret < 0)
+ return ret;
match_len = ret;
ret = bitstream_read_byte(istream);
- if (ret == -1)
- return -1;
+ if (ret < 0)
+ return ret;
match_len |= (ret << 8);
- if (match_len < 0xf)
- return -1;
} else {
match_len += 0xf;
}
match_src = match_dest - match_offset;
if (window_pos + match_len > window_len) {
- ERROR("XPRESS decompression error: match of length %d "
+ ERROR("XPRESS decompression error: match of length %u "
"bytes overflows window", match_len);
return -1;
}
if (match_src < window) {
- ERROR("XPRESS decompression error: match of length %d bytes "
- "references data before window (match_offset = %d, "
- "window_pos = %d)", match_len, match_offset, window_pos);
+ ERROR("XPRESS decompression error: match of length %u bytes "
+ "references data before window (match_offset = %u, "
+ "window_pos = %u)", match_len, match_offset, window_pos);
return -1;
}
/* Decodes the Huffman-encoded matches and literal bytes in a block of
* XPRESS-encoded data. */
-static int xpress_decompress_literals(struct input_bitstream *istream,
- u8 uncompressed_data[],
- unsigned uncompressed_len,
- const u8 lens[],
- const u16 decode_table[])
+static int
+xpress_decompress_block(struct input_bitstream *istream,
+ u8 uncompressed_data[],
+ unsigned uncompressed_len,
+ const u8 lens[],
+ const u16 decode_table[])
{
- unsigned curpos = 0;
+ unsigned curpos;
unsigned huffsym;
+ int ret;
int match_len;
- int ret = 0;
+ curpos = 0;
while (curpos < uncompressed_len) {
ret = read_huffsym(istream, decode_table, lens,
XPRESS_NUM_SYMBOLS, XPRESS_TABLEBITS,
&huffsym, XPRESS_MAX_CODEWORD_LEN);
if (ret != 0)
- break;
+ return ret;
if (huffsym < XPRESS_NUM_CHARS) {
uncompressed_data[curpos++] = huffsym;
uncompressed_len,
uncompressed_data,
istream);
- if (match_len == -1) {
- ret = 1;
- break;
- }
+ if (match_len < 0)
+ return match_len;
curpos += match_len;
}
}
- return ret;
+ return 0;
}
-int xpress_decompress(const void *__compressed_data, unsigned compressed_len,
- void *uncompressed_data, unsigned uncompressed_len)
+int
+xpress_decompress(const void *__compressed_data, unsigned compressed_len,
+ void *uncompressed_data, unsigned uncompressed_len)
{
u8 lens[XPRESS_NUM_SYMBOLS];
u16 decode_table[(1 << XPRESS_TABLEBITS) + 2 * XPRESS_NUM_SYMBOLS];
* in the first 256 bytes of the compressed data.
*/
if (compressed_len < XPRESS_NUM_SYMBOLS / 2)
- return WIMLIB_ERR_DECOMPRESSION;
+ return -1;
for (i = 0; i < XPRESS_NUM_SYMBOLS / 2; i++) {
*lens_p++ = compressed_data[i] & 0xf;
init_input_bitstream(&istream, compressed_data + XPRESS_NUM_SYMBOLS / 2,
compressed_len - XPRESS_NUM_SYMBOLS / 2);
- return xpress_decompress_literals(&istream, uncompressed_data,
- uncompressed_len, lens,
- decode_table);
+ return xpress_decompress_block(&istream, uncompressed_data,
+ uncompressed_len, lens,
+ decode_table);
}