static int mem_write(jas_stream_obj_t *obj, char *buf, int cnt)
{
	int n;
	int ret;
	jas_stream_memobj_t *m = (jas_stream_memobj_t *)obj;
	long newbufsize;
	long newpos;

	assert(buf);
	assert(cnt >= 0);

	JAS_DBGLOG(100, ("mem_write(%p, %p, %d)\n", obj, buf, cnt));
	newpos = m->pos_ + cnt;
	if (newpos > m->bufsize_ && m->growable_) {
		newbufsize = m->bufsize_;
		while (newbufsize < newpos) {
			newbufsize <<= 1;
			assert(newbufsize >= 0);
		}
		JAS_DBGLOG(100, ("mem_write resizing from %d to %z\n", m->bufsize_,
		  newbufsize));
		JAS_DBGLOG(100, ("mem_write resizing from %d to %ul\n", m->bufsize_,
		  JAS_CAST(unsigned long, newbufsize)));
		if (mem_resize(m, newbufsize)) {
			return -1;
		}
	}
	if (m->pos_ > m->len_) {
		/* The current position is beyond the end of the file, so
		  pad the file to the current position with zeros. */
		n = JAS_MIN(m->pos_, m->bufsize_) - m->len_;
		if (n > 0) {
			memset(&m->buf_[m->len_], 0, n);
			m->len_ += n;
		}
		if (m->pos_ != m->len_) {
			/* The buffer is not big enough. */
			return 0;
		}
	}
	n = m->bufsize_ - m->pos_;
	ret = JAS_MIN(n, cnt);
	if (ret > 0) {
		memcpy(&m->buf_[m->pos_], buf, ret);
		m->pos_ += ret;
	}
	if (m->pos_ > m->len_) {
		m->len_ = m->pos_;
	}
	assert(ret == cnt);
	return ret;
}
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.