c
<     *outptr++ = colormap[0][t];
---
>     int validated_t = validate_index(t, cmaplen);
>     if (validated_t != -1) {
>         *outptr++ = colormap[0][validated_t];
>     } else {
>         // Handle out-of-bounds error
>         *outptr++ = 0; // or some other default value
>     }

// ...

int validate_index(int t, int cmaplen) {
    if (t >= 0 && t < cmaplen) {
        return t;
    } else {
        return -1;
    }
}
