Function decode_entropy_coded_image

libavcodec/webp.c:552–756

}

static int decode_entropy_coded_image(WebPContext *s, enum ImageRole role,
                                      int w, int h)
{
    ImageContext *img;
    HuffReader *hg;
    int i, j, ret, x, y, width;

    img       = &s->image[role];
    img->role = role;

    if (!img->frame) {
        img->frame = av_frame_alloc();
        if (!img->frame)
            return AVERROR(ENOMEM);
    }

    img->frame->format = AV_PIX_FMT_ARGB;
    img->frame->width  = w;
    img->frame->height = h;

    if (role == IMAGE_ROLE_ARGB && !img->is_alpha_primary) {
        ret = ff_thread_get_buffer(s->avctx, img->frame, 0);
    } else
        ret = av_frame_get_buffer(img->frame, 1);
    if (ret < 0)
        return ret;

    if (get_bits1(&s->gb)) {
        img->color_cache_bits = get_bits(&s->gb, 4);
        if (img->color_cache_bits < 1 || img->color_cache_bits > 11) {
            av_log(s->avctx, AV_LOG_ERROR, "invalid color cache bits: %d\n",
                   img->color_cache_bits);
            return AVERROR_INVALIDDATA;
        }
        img->color_cache = av_calloc(1 << img->color_cache_bits,
                                     sizeof(*img->color_cache));
        if (!img->color_cache)
            return AVERROR(ENOMEM);
    } else {
        img->color_cache_bits = 0;
    }

    img->nb_huffman_groups = 1;
    if (role == IMAGE_ROLE_ARGB && get_bits1(&s->gb)) {
        ret = decode_entropy_image(s);
        if (ret < 0)
            return ret;
        img->nb_huffman_groups = s->nb_huffman_groups;
    }
    img->huffman_groups = av_calloc(img->nb_huffman_groups,
                                    HUFFMAN_CODES_PER_META_CODE *
                                    sizeof(*img->huffman_groups));
    if (!img->huffman_groups)
        return AVERROR(ENOMEM);

    for (i = 0; i < img->nb_huffman_groups; i++) {
        hg = &img->huffman_groups[i * HUFFMAN_CODES_PER_META_CODE];
        for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; j++) {