static void sycc420_to_rgb(opj_image_t *img)
{
    int *d0, *d1, *d2, *r, *g, *b, *nr, *ng, *nb;
    const int *y, *cb, *cr, *ny;
    size_t maxw, maxh, max, offx, loopmaxw, offy, loopmaxh;
    int offset, upb;
    size_t i;

    upb = (int)img->comps[0].prec;
    offset = 1 << (upb - 1);
    upb = (1 << upb) - 1;

    maxw = (size_t)img->comps[0].w;
    maxh = (size_t)img->comps[0].h;
    max = maxw * maxh;

    y = img->comps[0].data;
    cb = img->comps[1].data;
    cr = img->comps[2].data;

    d0 = r = (int*)opj_image_data_alloc(sizeof(int) * max);
    d1 = g = (int*)opj_image_data_alloc(sizeof(int) * max);
    d2 = b = (int*)opj_image_data_alloc(sizeof(int) * max);

    if (r == NULL || g == NULL || b == NULL) {
        goto fails;
    }

    /* if img->x0 is odd, then first column shall use Cb/Cr = 0 */
    offx = img->x0 & 1U;
    loopmaxw = maxw - offx;
    /* if img->y0 is odd, then first line shall use Cb/Cr = 0 */
    offy = img->y0 & 1U;
    loopmaxh = maxh - offy;

    if (offy > 0U) {
        size_t j;

        for (j = 0; j < maxw; ++j) {
            sycc_to_rgb(offset, upb, *y, 0, 0, r, g, b);
            ++y;
            ++r;
            ++g;
            ++b;
        }
    }

    for (i = 0U; i < (loopmaxh & ~(size_t)1U); i += 2U) {
        size_t j;

        ny = y + maxw;
        nr = r + maxw;
        ng = g + maxw;
        nb = b + maxw;

        if (offx > 0U) {
            sycc_to_rgb(offset, upb, *y, 0, 0, r, g, b);
            ++y;
            ++r;
            ++g;
            ++b;
            sycc_to_rgb(offset, upb, *ny, *cb, *cr, nr, ng, nb);
            ++ny;
            ++nr;
            ++ng;
            ++nb;
        }

        for (j = 0; j < (loopmaxw & ~(size_t)1U); j += 2U) {
            sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
            ++y;
            ++r;
            ++g;
            ++b;
            sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
            ++y;
            ++r;
            ++g;
            ++b;

            sycc_to_rgb(offset, upb, *ny, *cb, *cr, nr, ng, nb);
            ++ny;
            ++nr;
            ++ng;
            ++nb;
            sycc_to_rgb(offset, upb, *ny, *cb, *cr, nr, ng, nb);
            ++ny;
            ++nr;
            ++ng;
            ++nb;
            ++cb;
            ++cr;
        }
        if (j < loopmaxw) {
            sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
            ++y;
            ++r;
            ++g;
            ++b;

            sycc_to_rgb(offset, upb, *ny, *cb, *cr, nr, ng, nb);
            ++ny;
            ++nr;
            ++ng;
            ++nb;
            ++cb;
            ++cr;
        }
        y += maxw;
        r += maxw;
        g += maxw;
        b += maxw;
    }
    if (i < loopmaxh) {
        size_t j;

        for (j = 0U; j < (maxw & ~(size_t)1U); j += 2U) {
            sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);

            ++y;
            ++r;
            ++g;
            ++b;

            sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);

            ++y;
            ++r;
            ++g;
            ++b;
            ++cb;
            ++cr;
        }
        if (j < maxw) {
            sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
        }
    }

    opj_image_data_free(img->comps[0].data);
    img->comps[0].data = d0;
    opj_image_data_free(img->comps[1].data);
    img->comps[1].data = d1;
    opj_image_data_free(img->comps[2].data);
    img->comps[2].data = d2;

    img->comps[1].w = img->comps[2].w = img->comps[0].w;
    img->comps[1].h = img->comps[2].h = img->comps[0].h;
    img->comps[1].dx = img->comps[2].dx = img->comps[0].dx;
    img->comps[1].dy = img->comps[2].dy = img->comps[0].dy;
    img->color_space = OPJ_CLRSPC_SRGB;
    return;

fails:
    opj_image_data_free(r);
    opj_image_data_free(g);
    opj_image_data_free(b);
}/* sycc420_to_rgb() */