static void run_burl_normalize (buffer *psrc, buffer *ptmp, int flags, int line, const char *in, size_t in_len, const char *out, size_t out_len) {
    int qs;
    buffer_copy_string_len(psrc, in, in_len);
    qs = burl_normalize(psrc, ptmp, flags);
    if (out_len == (size_t)-2) {
        if (-2 == qs) return;
        fprintf(stderr,
                "%s.%d: %s('%s') failed: expected error, got '%s'\n",
                __FILE__, line, __func__+4, in, psrc->ptr);
    }
    else {
        if (buffer_is_equal_string(psrc, out, out_len)) return;
        fprintf(stderr,
                "%s.%d: %s('%s') failed: expected '%s', got '%s'\n",
                __FILE__, line, __func__+4, in, out, psrc->ptr);
    }
    fflush(stderr);
    abort();
}

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.