static int iwgif_read(struct iwgifrcontext *rctx,
		iw_byte *buf, size_t buflen)
{
	int ret;
	size_t bytesread = 0;

	ret = (*rctx->iodescr->read_fn)(rctx->ctx,rctx->iodescr,
		buf,buflen,&bytesread);
	if(!ret || bytesread!=buflen) {
		return 0;
	}
	return 1;
}

The product divides a value by zero.