/*

 * American Laser Games MM Video Decoder

 * Copyright (c) 2006,2008 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 Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * American Laser Games MM Video Decoder

 * by Peter Ross (pross@xvid.org)

 *

 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,

 * including Mad Dog McCree and Crime Patrol.

 *

 * Technical details here:

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

 */

#include "libavutil/intreadwrite.h"

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "decode.h"

#define MM_PREAMBLE_SIZE    6

#define MM_TYPE_RAW         0x2

#define MM_TYPE_INTER       0x5

#define MM_TYPE_INTRA       0x8

#define MM_TYPE_INTRA_HH    0xc

#define MM_TYPE_INTER_HH    0xd

#define MM_TYPE_INTRA_HHV   0xe

#define MM_TYPE_INTER_HHV   0xf

#define MM_TYPE_PALETTE     0x31

typedef struct MmContext {

    AVCodecContext *avctx;

    AVFrame *frame;

    unsigned int palette[AVPALETTE_COUNT];

    GetByteContext gb;

} MmContext;

static av_cold int mm_decode_init(AVCodecContext *avctx)

{

    MmContext *s = avctx->priv_data;

    s->avctx = avctx;

    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    if (!avctx->width || !avctx->height ||

        (avctx->width & 1) || (avctx->height & 1)) {

        av_log(avctx, AV_LOG_ERROR, "Invalid video dimensions: %dx%d\n",

               avctx->width, avctx->height);

        return AVERROR(EINVAL);

    }

    s->frame = av_frame_alloc();

    if (!s->frame)

        return AVERROR(ENOMEM);

    return 0;

}

static int mm_decode_raw(MmContext * s)

{

    if (bytestream2_get_bytes_left(&s->gb) < s->avctx->width * s->avctx->height)

        return AVERROR_INVALIDDATA;

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

        bytestream2_get_buffer(&s->gb, s->frame->data[0] + y*s->frame->linesize[0], s->avctx->width);

    return 0;

}

static void mm_decode_pal(MmContext *s)

{

    int start = bytestream2_get_le16(&s->gb);

    int count = bytestream2_get_le16(&s->gb);

    for (int i = 0; i < count; i++)

        s->palette[(start+i)&0xFF] = 0xFFU << 24 | (bytestream2_get_be24(&s->gb) << 2);

}

/**

 * @param half_horiz Half horizontal resolution (0 or 1)

 * @param half_vert Half vertical resolution (0 or 1)

 */

static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)

{

    int x = 0, y = 0;

    while (bytestream2_get_bytes_left(&s->gb) > 0) {

        int run_length, color;

        if (y >= s->avctx->height)

            return 0;

        color = bytestream2_get_byte(&s->gb);

        if (color & 0x80) {

            run_length = 1;

        }else{

            run_length = (color & 0x7f) + 2;

            color = bytestream2_get_byte(&s->gb);

        }

        if (half_horiz)

            run_length *=2;

        if (run_length > s->avctx->width - x)

            return AVERROR_INVALIDDATA;

        if (color) {

            memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);

            if (half_vert && y + half_vert < s->avctx->height)

                memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);

        }

        x+= run_length;

        if (x >= s->avctx->width) {

            x=0;

            y += 1 + half_vert;

        }

    }

    return 0;

}

/**

 * @param half_horiz Half horizontal resolution (0 or 1)

 * @param half_vert Half vertical resolution (0 or 1)

 */

static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)

{

    int data_off = bytestream2_get_le16(&s->gb);

    int y = 0;

    GetByteContext data_ptr;

    if (bytestream2_get_bytes_left(&s->gb) < data_off)

        return AVERROR_INVALIDDATA;

    bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);

    while (s->gb.buffer < data_ptr.buffer_start) {

        int i, j;

        int length = bytestream2_get_byte(&s->gb);

        int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);

        length &= 0x7F;

        if (length==0) {

            y += x;

            continue;

        }

        if (y + half_vert >= s->avctx->height)

            return 0;

        for(i=0; i<length; i++) {

            int replace_array = bytestream2_get_byte(&s->gb);

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

                int replace = (replace_array >> (7-j)) & 1;

                if (x + half_horiz >= s->avctx->width)

                    break;

                if (replace) {

                    int color = bytestream2_get_byte(&data_ptr);

                    s->frame->data[0][y*s->frame->linesize[0] + x] = color;

                    if (half_horiz)

                        s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;

                    if (half_vert) {

                        s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;

                        if (half_horiz)

                            s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;

                    }

                }

                x += 1 + half_horiz;

            }

        }

        y += 1 + half_vert;

    }

    return 0;

}

static int mm_decode_frame(AVCodecContext *avctx, AVFrame *rframe,

                           int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    MmContext *s = avctx->priv_data;

    int type, res;

    if (buf_size < MM_PREAMBLE_SIZE)

        return AVERROR_INVALIDDATA;

    type = AV_RL16(&buf[0]);

    buf += MM_PREAMBLE_SIZE;

    buf_size -= MM_PREAMBLE_SIZE;

    bytestream2_init(&s->gb, buf, buf_size);

    if ((res = ff_reget_buffer(avctx, s->frame, 0)) < 0)

        return res;

    switch(type) {

    case MM_TYPE_RAW       : res = mm_decode_raw(s); break;

    case MM_TYPE_PALETTE   : mm_decode_pal(s); return avpkt->size;

    case MM_TYPE_INTRA     : res = mm_decode_intra(s, 0, 0); break;

    case MM_TYPE_INTRA_HH  : res = mm_decode_intra(s, 1, 0); break;

    case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;

    case MM_TYPE_INTER     : res = mm_decode_inter(s, 0, 0); break;

    case MM_TYPE_INTER_HH  : res = mm_decode_inter(s, 1, 0); break;

    case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;

    default:

        res = AVERROR_INVALIDDATA;

        break;

    }

    if (res < 0)

        return res;

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

    if ((res = av_frame_ref(rframe, s->frame)) < 0)

        return res;

    *got_frame      = 1;

    return avpkt->size;

}

static av_cold int mm_decode_end(AVCodecContext *avctx)

{

    MmContext *s = avctx->priv_data;

    av_frame_free(&s->frame);

    return 0;

}

const FFCodec ff_mmvideo_decoder = {

    .p.name         = "mmvideo",

    CODEC_LONG_NAME("American Laser Games MM Video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_MMVIDEO,

    .priv_data_size = sizeof(MmContext),

    .init           = mm_decode_init,

    .close          = mm_decode_end,

    FF_CODEC_DECODE_CB(mm_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};