/*

 * Electronic Arts CMV Video Decoder

 * Copyright (c) 2007-2008 Peter Ross

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

/**

 * @file

 * Electronic Arts CMV Video Decoder

 * by Peter Ross (pross@xvid.org)

 *

 * Technical details here:

 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV

 */

#include "libavutil/common.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/imgutils.h"

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

typedef struct CmvContext {

    AVCodecContext *avctx;

    AVFrame *last_frame;   ///< last

    AVFrame *last2_frame;  ///< second-last

    int width, height;

    unsigned int palette[AVPALETTE_COUNT];

} CmvContext;

static av_cold int cmv_decode_init(AVCodecContext *avctx){

    CmvContext *s = avctx->priv_data;

    s->avctx = avctx;

    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    s->last_frame  = av_frame_alloc();

    s->last2_frame = av_frame_alloc();

    if (!s->last_frame || !s->last2_frame)

        return AVERROR(ENOMEM);

    return 0;

}

static void cmv_decode_intra(CmvContext * s, AVFrame *frame,

                             const uint8_t *buf, const uint8_t *buf_end)

{

    unsigned char *dst = frame->data[0];

    int i;

    for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {

        memcpy(dst, buf, s->avctx->width);

        dst += frame->linesize[0];

        buf += s->avctx->width;

    }

}

static void cmv_motcomp(unsigned char *dst, ptrdiff_t dst_stride,

                        const unsigned char *src, ptrdiff_t src_stride,

                        int x, int y,

                        int xoffset, int yoffset,

                        int width, int height){

    int i,j;

    for(j=y;j<y+4;j++)

    for(i=x;i<x+4;i++)

    {

        if (i+xoffset>=0 && i+xoffset<width &&

            j+yoffset>=0 && j+yoffset<height) {

            dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];

        }else{

            dst[j*dst_stride + i] = 0;

        }

    }

}

static void cmv_decode_inter(CmvContext *s, AVFrame *frame, const uint8_t *buf,

                             const uint8_t *buf_end)

{

    const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);

    int x,y,i;

    i = 0;

    for(y=0; y<s->avctx->height/4; y++)

    for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {

        if (buf[i]==0xFF) {

            unsigned char *dst = frame->data[0] + (y*4)*frame->linesize[0] + x*4;

            if (raw+16<buf_end && *raw==0xFF) { /* intra */

                raw++;

                memcpy(dst, raw, 4);

                memcpy(dst +     frame->linesize[0], raw+4, 4);

                memcpy(dst + 2 * frame->linesize[0], raw+8, 4);

                memcpy(dst + 3 * frame->linesize[0], raw+12, 4);

                raw+=16;

            }else if(raw<buf_end) {  /* inter using second-last frame as reference */

                int xoffset = (*raw & 0xF) - 7;

                int yoffset = ((*raw >> 4)) - 7;

                if (s->last2_frame->data[0])

                    cmv_motcomp(frame->data[0], frame->linesize[0],

                                s->last2_frame->data[0], s->last2_frame->linesize[0],

                                x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

                raw++;

            }

        }else{  /* inter using last frame as reference */

            int xoffset = (buf[i] & 0xF) - 7;

            int yoffset = ((buf[i] >> 4)) - 7;

            if (s->last_frame->data[0])

                cmv_motcomp(frame->data[0], frame->linesize[0],

                            s->last_frame->data[0], s->last_frame->linesize[0],

                            x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

        }

        i++;

    }

}

static int cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)

{

    int pal_start, pal_count, i, ret, fps;

    if(buf_end - buf < 16) {

        av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");

        return AVERROR_INVALIDDATA;

    }

    s->width  = AV_RL16(&buf[4]);

    s->height = AV_RL16(&buf[6]);

    if (s->width  != s->avctx->width ||

        s->height != s->avctx->height) {

        av_frame_unref(s->last_frame);

        av_frame_unref(s->last2_frame);

    }

    ret = ff_set_dimensions(s->avctx, s->width, s->height);

    if (ret < 0)

        return ret;

    fps = AV_RL16(&buf[10]);

    if (fps > 0)

        s->avctx->framerate = (AVRational){ fps, 1 };

    pal_start = AV_RL16(&buf[12]);

    pal_count = AV_RL16(&buf[14]);

    buf += 16;

    for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {

        s->palette[i] = 0xFFU << 24 | AV_RB24(buf);

        buf += 3;

    }

    return 0;

}

#define EA_PREAMBLE_SIZE 8

#define MVIh_TAG MKTAG('M', 'V', 'I', 'h')

static int cmv_decode_frame(AVCodecContext *avctx, AVFrame *frame,

                            int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    CmvContext *s = avctx->priv_data;

    const uint8_t *buf_end = buf + buf_size;

    int ret;

    if (buf_end - buf < EA_PREAMBLE_SIZE)

        return AVERROR_INVALIDDATA;

    if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {

        unsigned size = AV_RL32(buf + 4);

        ret = cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);

        if (ret < 0)

            return ret;

        if (size > buf_end - buf - EA_PREAMBLE_SIZE)

            return AVERROR_INVALIDDATA;

        buf += size;

    }

    if ((ret = av_image_check_size(s->width, s->height, 0, s->avctx)) < 0)

        return ret;

    buf += EA_PREAMBLE_SIZE;

    if (!(buf[0]&1) && buf_end - buf < s->width * s->height * (int64_t)(100 - s->avctx->discard_damaged_percentage) / 100)

        return AVERROR_INVALIDDATA;

    if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)

        return ret;

    memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);

    if ((buf[0]&1)) {  // subtype

        cmv_decode_inter(s, frame, buf+2, buf_end);

        frame->flags &= ~AV_FRAME_FLAG_KEY;

        frame->pict_type = AV_PICTURE_TYPE_P;

    }else{

        frame->flags |= AV_FRAME_FLAG_KEY;

        frame->pict_type = AV_PICTURE_TYPE_I;

        cmv_decode_intra(s, frame, buf+2, buf_end);

    }

    FFSWAP(AVFrame*, s->last2_frame, s->last_frame);

    if ((ret = av_frame_replace(s->last_frame, frame)) < 0)

        return ret;

    *got_frame = 1;

    return buf_size;

}

static av_cold int cmv_decode_end(AVCodecContext *avctx){

    CmvContext *s = avctx->priv_data;

    av_frame_free(&s->last_frame);

    av_frame_free(&s->last2_frame);

    return 0;

}

const FFCodec ff_eacmv_decoder = {

    .p.name         = "eacmv",

    CODEC_LONG_NAME("Electronic Arts CMV video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_CMV,

    .priv_data_size = sizeof(CmvContext),

    .init           = cmv_decode_init,

    .close          = cmv_decode_end,

    FF_CODEC_DECODE_CB(cmv_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};