diff options
Diffstat (limited to 'lib/libpbm2.c')
| -rw-r--r-- | lib/libpbm2.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/libpbm2.c b/lib/libpbm2.c index 2fec4788..a611bec5 100644 --- a/lib/libpbm2.c +++ b/lib/libpbm2.c @@ -216,6 +216,9 @@ pbm_readpbmrow_bitoffset(FILE * const ifP, Read it into packedBits[], preserving surrounding image data. Logic not tested for negative offsets. + + Because we are reading in packed mode large cols and offset values are + acceptable; dividing by 8 prevents overflows. -----------------------------------------------------------------------------*/ unsigned int const rsh = offset % 8; unsigned int const lsh = (8 - rsh) % 8; @@ -224,13 +227,15 @@ pbm_readpbmrow_bitoffset(FILE * const ifP, Aligned to nearest byte boundary to the left, so the first few bits might contain original data, not output. */ - unsigned int const last = pbm_packed_bytes(cols+rsh) - 1; + unsigned int const last = pbm_packed_bytes((unsigned int)cols + rsh) - 1; /* Position within window of rightmost byte after shift */ /* The original leftmost and rightmost chars. */ unsigned char const origHead = window[0]; unsigned char const origEnd = window[last]; + assert(cols > 0 && pbm_packed_bytes(cols) > 0); + pbm_readpbmrow_packed(ifP, window, cols, format); if (rsh > 0) { |