Function xan_decode_frame

libavcodec/xan.c:539–635

#endif

static int xan_decode_frame(AVCodecContext *avctx, AVFrame *frame,
                            int *got_frame, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int ret, buf_size = avpkt->size;
    XanContext *s = avctx->priv_data;
    GetByteContext ctx;
    int tag = 0;

    bytestream2_init(&ctx, buf, buf_size);
    while (bytestream2_get_bytes_left(&ctx) > 8 && tag != VGA__TAG) {
        unsigned *tmpptr;
        uint32_t new_pal;
        int size;
        int i;
        tag  = bytestream2_get_le32(&ctx);
        size = bytestream2_get_be32(&ctx);
        if (size < 0) {
            av_log(avctx, AV_LOG_ERROR, "Invalid tag size %d\n", size);
            return AVERROR_INVALIDDATA;
        }
        size = FFMIN(size, bytestream2_get_bytes_left(&ctx));
        switch (tag) {
        case PALT_TAG:
            if (size < PALETTE_SIZE)
                return AVERROR_INVALIDDATA;
            if (s->palettes_count >= PALETTES_MAX)
                return AVERROR_INVALIDDATA;
            tmpptr = av_realloc_array(s->palettes,
                                      s->palettes_count + 1, AVPALETTE_SIZE);
            if (!tmpptr)
                return AVERROR(ENOMEM);
            s->palettes = tmpptr;
            tmpptr += s->palettes_count * AVPALETTE_COUNT;
            for (i = 0; i < PALETTE_COUNT; i++) {
#if RUNTIME_GAMMA
                int r = gamma_corr(bytestream2_get_byteu(&ctx));
                int g = gamma_corr(bytestream2_get_byteu(&ctx));
                int b = gamma_corr(bytestream2_get_byteu(&ctx));
#else
                int r = gamma_lookup[bytestream2_get_byteu(&ctx)];
                int g = gamma_lookup[bytestream2_get_byteu(&ctx)];
                int b = gamma_lookup[bytestream2_get_byteu(&ctx)];
#endif
                *tmpptr++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;
            }
            s->palettes_count++;
            break;
        case SHOT_TAG:
            if (size < 4)
                return AVERROR_INVALIDDATA;
            new_pal = bytestream2_get_le32(&ctx);
            if (new_pal < s->palettes_count) {
                s->cur_palette = new_pal;
            } else
                av_log(avctx, AV_LOG_ERROR, "Invalid palette selected\n");
            break;
        case VGA__TAG: