static inline int ok_png_paeth_predictor(int a, int b, int c) {
    int p = a + b - c;
    int pa = abs(p - a);
    int pb = abs(p - b);
    int pc = abs(p - c);
    if (pa <= pb && pa <= pc) {
        return a;
    } else if (pb <= pc) {
        return b;
    } else {
        return c;
    }
}