Function stbi__getn

lite/example/cpp_example/mge/cv/stb_image.h:1704–1725

// nothing
#else
static int stbi__getn(stbi__context* s, stbi_uc* buffer, int n) {
    if (s->io.read) {
        int blen = (int)(s->img_buffer_end - s->img_buffer);
        if (blen < n) {
            int res, count;

            memcpy(buffer, s->img_buffer, blen);

            count = (s->io.read)(s->io_user_data, (char*)buffer + blen, n - blen);
            res = (count == (n - blen));
            s->img_buffer = s->img_buffer_end;
            return res;
        }
    }

    if (s->img_buffer + n <= s->img_buffer_end) {
        memcpy(buffer, s->img_buffer, n);
        s->img_buffer += n;
        return 1;
    } else
        return 0;
}
#endif

#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && \