Function stbi__extend_receive

lite/example/cpp_example/mge/cv/stb_image.h:2300–2313

combined JPEG 'receive' and JPEG 'extend', since baseline always extends everything it receives.

// combined JPEG 'receive' and JPEG 'extend', since baseline
// always extends everything it receives.
stbi_inline static int stbi__extend_receive(stbi__jpeg* j, int n) {
    unsigned int k;
    int sgn;
    if (j->code_bits < n)
        stbi__grow_buffer_unsafe(j);

    sgn = j->code_buffer >> 31;  // sign bit always in MSB; 0 if MSB clear (positive), 1
                                 // if MSB set (negative)
    k = stbi_lrot(j->code_buffer, n);
    j->code_buffer = k & ~stbi__bmask[n];
    k &= stbi__bmask[n];
    j->code_bits -= n;
    return k + (stbi__jbias[n] & (sgn - 1));
}

// get some unsigned bits
stbi_inline static int stbi__jpeg_get_bits(stbi__jpeg* j, int n) {