/*

 * Electronic Arts Madcow Video Decoder

 * Copyright (c) 2007-2009 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 Madcow Video Decoder

 * @author Peter Ross <pross@xvid.org>

 *

 * @see technical details at

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

 */

#include "libavutil/mem.h"

#include "libavutil/mem_internal.h"

#include "avcodec.h"

#include "blockdsp.h"

#include "bytestream.h"

#include "bswapdsp.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

#include "aandcttab.h"

#include "eaidct.h"

#include "mpeg12data.h"

#include "mpeg12vlc.h"

#define EA_PREAMBLE_SIZE    8

#define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD I-frame */

#define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD P-frame */

#define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */

typedef struct MadContext {

    AVCodecContext *avctx;

    BlockDSPContext bdsp;

    BswapDSPContext bbdsp;

    AVFrame *last_frame;

    GetBitContext gb;

    void *bitstream_buf;

    unsigned int bitstream_buf_size;

    DECLARE_ALIGNED(32, int16_t, block)[64];

    uint16_t quant_matrix[64];

} MadContext;

static av_cold int decode_init(AVCodecContext *avctx)

{

    MadContext *s = avctx->priv_data;

    s->avctx = avctx;

    avctx->pix_fmt = AV_PIX_FMT_YUV420P;

    ff_blockdsp_init(&s->bdsp);

    ff_bswapdsp_init(&s->bbdsp);

    ff_mpeg12_init_vlcs();

    s->last_frame = av_frame_alloc();

    if (!s->last_frame)

        return AVERROR(ENOMEM);

    return 0;

}

static inline void comp(unsigned char *dst, ptrdiff_t dst_stride,

                        unsigned char *src, ptrdiff_t src_stride, int add)

{

    int j, i;

    for (j=0; j<8; j++)

        for (i=0; i<8; i++)

            dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);

}

static inline void comp_block(MadContext *t, AVFrame *frame,

                              int mb_x, int mb_y,

                              int j, int mv_x, int mv_y, int add)

{

    if (j < 4) {

        unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame->linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;

        if (offset >= (t->avctx->height - 7) * t->last_frame->linesize[0] - 7)

            return;

        comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),

             frame->linesize[0],

             t->last_frame->data[0] + offset,

             t->last_frame->linesize[0], add);

    } else if (!(t->avctx->flags & AV_CODEC_FLAG_GRAY)) {

        int index = j - 3;

        unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame->linesize[index] + mb_x * 8 + (mv_x/2);

        if (offset >= (t->avctx->height/2 - 7) * t->last_frame->linesize[index] - 7)

            return;

        comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,

             frame->linesize[index],

             t->last_frame->data[index] + offset,

             t->last_frame->linesize[index], add);

    }

}

static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,

                            int mb_x, int mb_y, int j)

{

    if (j < 4) {

        ff_ea_idct_put_c(

            frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),

            frame->linesize[0], block);

    } else if (!(t->avctx->flags & AV_CODEC_FLAG_GRAY)) {

        int index = j - 3;

        ff_ea_idct_put_c(

            frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,

            frame->linesize[index], block);

    }

}

static inline int decode_block_intra(MadContext *s, int16_t * block)

{

    int level, i, j, run;

    const uint8_t *scantable = ff_zigzag_direct;

    int16_t *quant_matrix = s->quant_matrix;

    block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];

    /* The RL decoder is derived from mpeg1_decode_block_intra;

       Escaped level and run values a decoded differently */

    i = 0;

    {

        OPEN_READER(re, &s->gb);

        /* now quantify & encode AC coefficients */

        for (;;) {

            UPDATE_CACHE(re, &s->gb);

            GET_RL_VLC(level, run, re, &s->gb, ff_mpeg1_rl_vlc, TEX_VLC_BITS, 2, 0);

            if (level == 127) {

                break;

            } else if (level != 0) {

                i += run;

                if (i > 63)

                    return -1;

                j = scantable[i];

                level = (level*quant_matrix[j]) >> 4;

                level = (level-1)|1;

                level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);

                LAST_SKIP_BITS(re, &s->gb, 1);

            } else {

                /* escape */

                level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);

                run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);

                i += run;

                if (i > 63)

                    return -1;

                j = scantable[i];

                if (level < 0) {

                    level = -level;

                    level = (level*quant_matrix[j]) >> 4;

                    level = (level-1)|1;

                    level = -level;

                } else {

                    level = (level*quant_matrix[j]) >> 4;

                    level = (level-1)|1;

                }

            }

            block[j] = level;

        }

        CLOSE_READER(re, &s->gb);

    }

    return 0;

}

static int decode_motion(GetBitContext *gb)

{

    int value = 0;

    if (get_bits1(gb)) {

        if (get_bits1(gb))

            value = -17;

        value += get_bits(gb, 4) + 1;

    }

    return value;

}

static int decode_mb(MadContext *s, AVFrame *frame, int inter, int mb_x, int mb_y)

{

    int mv_map = 0;

    int av_uninit(mv_x), av_uninit(mv_y);

    int j;

    if (inter) {

        int v = decode210(&s->gb);

        if (v < 2) {

            mv_map = v ? get_bits(&s->gb, 6) : 63;

            mv_x = decode_motion(&s->gb);

            mv_y = decode_motion(&s->gb);

        }

    }

    for (j=0; j<6; j++) {

        if (mv_map & (1<<j)) {  // mv_x and mv_y are guarded by mv_map

            int add = 2*decode_motion(&s->gb);

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

                comp_block(s, frame, mb_x, mb_y, j, mv_x, mv_y, add);

        } else {

            s->bdsp.clear_block(s->block);

            if (decode_block_intra(s, s->block) < 0) {

                av_log(s->avctx, AV_LOG_ERROR,

                        "ac-tex damaged at %d %d\n", mb_x, mb_y);

                return -1;

            }

            idct_put(s, frame, s->block, mb_x, mb_y, j);

        }

    }

    return 0;

}

static void calc_quant_matrix(MadContext *s, int qscale)

{

    int i;

    s->quant_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;

    for (i=1; i<64; i++)

        s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;

}

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

                        int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size       = avpkt->size;

    MadContext *s     = avctx->priv_data;

    GetByteContext gb;

    int width, height;

    int chunk_type;

    int inter, ret;

    bytestream2_init(&gb, buf, buf_size);

    chunk_type = bytestream2_get_le32(&gb);

    inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);

    bytestream2_skip(&gb, 10);

    av_reduce(&avctx->framerate.den, &avctx->framerate.num,

              bytestream2_get_le16(&gb), 1000, 1<<30);

    width  = bytestream2_get_le16(&gb);

    height = bytestream2_get_le16(&gb);

    bytestream2_skip(&gb, 1);

    calc_quant_matrix(s, bytestream2_get_byte(&gb));

    bytestream2_skip(&gb, 2);

    if (bytestream2_get_bytes_left(&gb) < 2) {

        av_log(avctx, AV_LOG_ERROR, "Input data too small\n");

        return AVERROR_INVALIDDATA;

    }

    if (width < 16 || height < 16) {

        av_log(avctx, AV_LOG_ERROR, "Dimensions too small\n");

        return AVERROR_INVALIDDATA;

    }

    if (avctx->width != width || avctx->height != height) {

        av_frame_unref(s->last_frame);

        if((width * (int64_t)height)/2048*7 > bytestream2_get_bytes_left(&gb))

            return AVERROR_INVALIDDATA;

        if ((ret = ff_set_dimensions(avctx, width, height)) < 0)

            return ret;

    }

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

        return ret;

    if (inter && !s->last_frame->data[0]) {

        av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");

        ret = ff_get_buffer(avctx, s->last_frame, AV_GET_BUFFER_FLAG_REF);

        if (ret < 0)

            return ret;

        memset(s->last_frame->data[0], 0, s->last_frame->height *

               s->last_frame->linesize[0]);

        memset(s->last_frame->data[1], 0x80, s->last_frame->height / 2 *

               s->last_frame->linesize[1]);

        memset(s->last_frame->data[2], 0x80, s->last_frame->height / 2 *

               s->last_frame->linesize[2]);

    }

    av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size,

                          bytestream2_get_bytes_left(&gb));

    if (!s->bitstream_buf)

        return AVERROR(ENOMEM);

    s->bbdsp.bswap16_buf(s->bitstream_buf, (const uint16_t *)(buf + bytestream2_tell(&gb)),

                         bytestream2_get_bytes_left(&gb) / 2);

    memset((uint8_t*)s->bitstream_buf + bytestream2_get_bytes_left(&gb), 0, AV_INPUT_BUFFER_PADDING_SIZE);

    init_get_bits(&s->gb, s->bitstream_buf, 8*(bytestream2_get_bytes_left(&gb)));

    for (int mb_y = 0; mb_y < (avctx->height + 15) / 16; mb_y++)

        for (int mb_x = 0; mb_x < (avctx->width + 15) / 16; mb_x++)

            if (decode_mb(s, frame, inter, mb_x, mb_y) < 0)

                return AVERROR_INVALIDDATA;

    *got_frame = 1;

    if (chunk_type != MADe_TAG) {

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

            return ret;

    }

    return buf_size;

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    MadContext *t = avctx->priv_data;

    av_frame_free(&t->last_frame);

    av_freep(&t->bitstream_buf);

    return 0;

}

const FFCodec ff_eamad_decoder = {

    .p.name         = "eamad",

    CODEC_LONG_NAME("Electronic Arts Madcow Video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_MAD,

    .priv_data_size = sizeof(MadContext),

    .init           = decode_init,

    .close          = decode_end,

    FF_CODEC_DECODE_CB(decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};