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A fix for a bug where large files containing the same non-zero bytes which requires a sliding window, courtesy of Serge Belyshev.

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This commit is contained in:
Con Kolivas 2013-03-18 23:50:32 +11:00
parent ccf225f710
commit 2df8968e75
1 changed files with 22 additions and 13 deletions
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35
rzip.c
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@ -189,6 +189,22 @@ static uchar *single_get_sb(__maybe_unused rzip_control *control, i64 p)
return (control->sb.buf_low + p);
}
/* The length of continous range of the sliding buffer,
* starting from the offset P.
*/
static i64 sliding_get_sb_range(rzip_control *control, i64 p)
{
struct sliding_buffer *sb = &control->sb;
if (p >= sb->offset_low && p < sb->offset_low + sb->size_low)
return (sb->size_low - (p - sb->offset_low));
if (p >= sb->offset_high && p < (sb->offset_high + sb->size_high))
return (sb->size_high - (p - sb->offset_high));
fatal("sliding_get_sb_range: the pointer is out of range\n");
return 0;
}
/* Since the sliding get_sb only allows us to access one byte at a time, we
* do the same as we did with get_sb with the memcpy since one memcpy is much
* faster than numerous memcpys 1 byte at a time */
@ -199,22 +215,15 @@ static void single_mcpy(rzip_control *control, unsigned char *buf, i64 offset, i
static void sliding_mcpy(rzip_control *control, unsigned char *buf, i64 offset, i64 len)
{
struct sliding_buffer *sb = &control->sb;
i64 i, offdiff = offset - sb->offset_low;
i64 n = 0;
/* See if we fit in the low buffer first and use the faster function
* where possible */
if (offdiff >= 0 && offdiff < sb->size_low) {
i64 minlen = MIN(len, sb->size_low - offdiff);
while (n < len) {
uchar *srcbuf = sliding_get_sb(control, offset + n);
i64 m = MIN(sliding_get_sb_range(control, offset + n), len - n);
memcpy(buf, control->sb.buf_low + offdiff, minlen);
len -= minlen;
memcpy(buf + n, srcbuf, m);
n += m;
}
/* We have no choice but to go fine-grained if there's any len left
* since we will be paging */
for (i = 0; i < len; i++)
memcpy(buf + i, sliding_get_sb(control, offset + i), 1);
}
/* All put_u8/u32/vchars go to stream 0 */