static int pnm_getdata(jas_stream_t *in, pnm_hdr_t *hdr, jas_image_t *image)
{
	int ret;
#if 0
	int numcmpts;
#endif
	int cmptno;
	int fmt;
	jas_matrix_t *data[3];
	int x;
	int y;
	int_fast64_t v;
	int depth;
	int type;
	int c;
	int n;

	ret = -1;

#if 0
	numcmpts = jas_image_numcmpts(image);
#endif
	fmt = pnm_fmt(hdr->magic);
	type = pnm_type(hdr->magic);
	assert(type != PNM_TYPE_INVALID);
	depth = pnm_maxvaltodepth(hdr->maxval);

	data[0] = 0;
	data[1] = 0;
	data[2] = 0;
	for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
		if (!(data[cmptno] = jas_matrix_create(1, hdr->width))) {
			goto done;
		}
	}

	for (y = 0; y < hdr->height; ++y) {
		if (type == PNM_TYPE_PBM) {
			if (fmt == PNM_FMT_BIN) {
				for (x = 0; x < hdr->width;) {
					if ((c = jas_stream_getc(in)) == EOF) {
						goto done;
					}
					n = 8;
					while (n > 0 && x < hdr->width) {
						jas_matrix_set(data[0], 0, x, 1 - ((c >> 7) & 1));
						c <<= 1;
						--n;
						++x;
					}
				}
			} else {
				for (x = 0; x < hdr->width; ++x) {
					int uv;
					if (pnm_getbitstr(in, &uv)) {
						goto done;
					}
					jas_matrix_set(data[0], 0, x, 1 - uv);
				}
			}
		} else {
			for (x = 0; x < hdr->width; ++x) {
				for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
					if (fmt == PNM_FMT_BIN) {
						/* The sample data is in binary format. */
						if (hdr->sgnd) {
							/* The sample data is signed. */
							int_fast32_t sv;
							if (pnm_getsint(in, depth, &sv)) {
								if (!pnm_allowtrunc) {
									goto done;
								}
								jas_eprintf("bad sample data\n");
								sv = 0;
							}
							v = sv;
						} else {
							/* The sample data is unsigned. */
							uint_fast32_t uv;
							if (pnm_getuint(in, depth, &uv)) {
								if (!pnm_allowtrunc) {
									goto done;
								}
								jas_eprintf("bad sample data\n");
								uv = 0;
							}
							v = uv;
						}
					} else {
						/* The sample data is in text format. */
						if (hdr->sgnd) {
							/* The sample data is signed. */
							int_fast32_t sv;
							if (pnm_getsintstr(in, &sv)) {
								if (!pnm_allowtrunc) {
									goto done;
								}
								jas_eprintf("bad sample data\n");
								sv = 0;
							}
							v = sv;
						} else {
							/* The sample data is unsigned. */
							uint_fast32_t uv;
							if (pnm_getuintstr(in, &uv)) {
								if (!pnm_allowtrunc) {
									goto done;
								}
								jas_eprintf("bad sample data\n");
								uv = 0;
							}
							v = uv;
						}
					}
					jas_matrix_set(data[cmptno], 0, x, v);
				}
			}
		}
		for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
			if (jas_image_writecmpt(image, cmptno, 0, y, hdr->width, 1,
			  data[cmptno])) {
				goto done;
			}
		}
	}

	ret = 0;

done:

	for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
		if (data[cmptno]) {
			jas_matrix_destroy(data[cmptno]);
		}
	}

	return ret;
}

The product 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 occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.