diff options
Diffstat (limited to 'fitz')
| -rw-r--r-- | fitz/filt_faxd.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/fitz/filt_faxd.c b/fitz/filt_faxd.c index d5d636f6..463d9de1 100644 --- a/fitz/filt_faxd.c +++ b/fitz/filt_faxd.c @@ -218,11 +218,23 @@ find_changing(const unsigned char *line, int x, int w) * we started from) */ m = mask[x & 7]; } + /* We have 'w' pixels (bits) in line. The last pixel that can be + * safely accessed is the (w-1)th bit of line. + * By taking W = w>>3, we know that the first W bytes of line are + * full, with w&7 stray bits following. */ W = w>>3; x >>= 3; - a = line[x]; + a = line[x]; /* Safe as x < w => x <= w-1 => x>>3 <= (w-1)>>3 */ b = a ^ (a>>1); b &= m; + if (x >= W) + { + /* Within the last byte already */ + x = (x<<3) + clz[b]; + if (x > w) + x = w; + return x; + } while (b == 0) { if (++x >= W) |