static int sunrast_decode_frame(AVCodecContext *avctx, void *data,

                                int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf       = avpkt->data;

    const uint8_t *buf_end   = avpkt->data + avpkt->size;

    AVFrame * const p        = data;

    unsigned int w, h, depth, type, maptype, maplength, stride, x, y, len, alen;

    uint8_t *ptr, *ptr2 = NULL;

    const uint8_t *bufstart = buf;

    int ret;



    if (avpkt->size < 32)

        return AVERROR_INVALIDDATA;



    if (AV_RB32(buf) != RAS_MAGIC) {

        av_log(avctx, AV_LOG_ERROR, "this is not sunras encoded data\n");

        return AVERROR_INVALIDDATA;

    }



    w         = AV_RB32(buf + 4);

    h         = AV_RB32(buf + 8);

    depth     = AV_RB32(buf + 12);

    type      = AV_RB32(buf + 20);

    maptype   = AV_RB32(buf + 24);

    maplength = AV_RB32(buf + 28);

    buf      += 32;



    if (type == RT_EXPERIMENTAL) {

        avpriv_request_sample(avctx, "TIFF/IFF/EXPERIMENTAL (compression) type");

        return AVERROR_PATCHWELCOME;

    }

    if (type > RT_FORMAT_IFF) {

        av_log(avctx, AV_LOG_ERROR, "invalid (compression) type\n");

        return AVERROR_INVALIDDATA;

    }

    if (maptype == RMT_RAW) {

        avpriv_request_sample(avctx, "Unknown colormap type");

        return AVERROR_PATCHWELCOME;

    }

    if (maptype > RMT_RAW) {

        av_log(avctx, AV_LOG_ERROR, "invalid colormap type\n");

        return AVERROR_INVALIDDATA;

    }



    if (type == RT_FORMAT_TIFF || type == RT_FORMAT_IFF) {

        av_log(avctx, AV_LOG_ERROR, "unsupported (compression) type\n");

        return -1;

    }



    switch (depth) {

        case 1:

            avctx->pix_fmt = maplength ? AV_PIX_FMT_PAL8 : AV_PIX_FMT_MONOWHITE;

            break;

        case 4:

            avctx->pix_fmt = maplength ? AV_PIX_FMT_PAL8 : AV_PIX_FMT_NONE;

            break;

        case 8:

            avctx->pix_fmt = maplength ? AV_PIX_FMT_PAL8 : AV_PIX_FMT_GRAY8;

            break;

        case 24:

            avctx->pix_fmt = (type == RT_FORMAT_RGB) ? AV_PIX_FMT_RGB24 : AV_PIX_FMT_BGR24;

            break;

        case 32:

            avctx->pix_fmt = (type == RT_FORMAT_RGB) ? AV_PIX_FMT_0RGB : AV_PIX_FMT_0BGR;

            break;

        default:

            av_log(avctx, AV_LOG_ERROR, "invalid depth\n");

            return AVERROR_INVALIDDATA;

    }



    ret = ff_set_dimensions(avctx, w, h);

    if (ret < 0)

        return ret;



    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)

        return ret;



    p->pict_type = AV_PICTURE_TYPE_I;



    if (buf_end - buf < maplength)

        return AVERROR_INVALIDDATA;



    if (depth > 8 && maplength) {

        av_log(avctx, AV_LOG_WARNING, "useless colormap found or file is corrupted, trying to recover\n");



    } else if (maplength) {

        unsigned int len = maplength / 3;



        if (maplength % 3 || maplength > 768) {

            av_log(avctx, AV_LOG_WARNING, "invalid colormap length\n");

            return AVERROR_INVALIDDATA;

        }



        ptr = p->data[1];

        for (x = 0; x < len; x++, ptr += 4)

            *(uint32_t *)ptr = (0xFFU<<24) + (buf[x]<<16) + (buf[len+x]<<8) + buf[len+len+x];

    }



    buf += maplength;



    if (maplength && depth < 8) {

        ptr = ptr2 = av_malloc_array((w + 15), h);

        if (!ptr)

            return AVERROR(ENOMEM);

        stride = (w + 15 >> 3) * depth;

    } else {

    ptr    = p->data[0];

    stride = p->linesize[0];

    }



    

    len  = (depth * w + 7) >> 3;

    alen = len + (len & 1);



    if (type == RT_BYTE_ENCODED) {

        int value, run;

        uint8_t *end = ptr + h * stride;



        x = 0;

        while (ptr != end && buf < buf_end) {

            run = 1;

            if (buf_end - buf < 1)

                return AVERROR_INVALIDDATA;



            if ((value = *buf++) == RLE_TRIGGER) {

                run = *buf++ + 1;

                if (run != 1)

                    value = *buf++;

            }

            while (run--) {

                if (x < len)

                    ptr[x] = value;

                if (++x >= alen) {

                    x = 0;

                    ptr += stride;

                    if (ptr == end)

                        break;

                }

            }

        }

    } else {

        for (y = 0; y < h; y++) {

            if (buf_end - buf < len)

                break;

            memcpy(ptr, buf, len);

            ptr += stride;

            buf += alen;

        }

    }

    if (avctx->pix_fmt == AV_PIX_FMT_PAL8 && depth < 8) {

        uint8_t *ptr_free = ptr2;

        ptr = p->data[0];

        for (y=0; y<h; y++) {

            for (x = 0; x < (w + 7 >> 3) * depth; x++) {

                if (depth == 1) {

                    ptr[8*x]   = ptr2[x] >> 7;

                    ptr[8*x+1] = ptr2[x] >> 6 & 1;

                    ptr[8*x+2] = ptr2[x] >> 5 & 1;

                    ptr[8*x+3] = ptr2[x] >> 4 & 1;

                    ptr[8*x+4] = ptr2[x] >> 3 & 1;

                    ptr[8*x+5] = ptr2[x] >> 2 & 1;

                    ptr[8*x+6] = ptr2[x] >> 1 & 1;

                    ptr[8*x+7] = ptr2[x]      & 1;

                } else {

                    ptr[2*x]   = ptr2[x] >> 4;

                    ptr[2*x+1] = ptr2[x] & 0xF;

                }

            }

            ptr  += p->linesize[0];

            ptr2 += (w + 15 >> 3) * depth;

        }

        av_freep(&ptr_free);

    }



    *got_frame = 1;



    return buf - bufstart;

}
