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/*

 * Brute Force & Ignorance (BFI) video decoder

 * Copyright (c) 2008 Sisir Koppaka

 *

 * 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

 * @brief Brute Force & Ignorance (.bfi) video decoder

 * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )

 * @see http://wiki.multimedia.cx/index.php?title=BFI

 */

#include "libavutil/common.h"

#include "avcodec.h"

#include "bytestream.h"

#include "internal.h"

typedef struct BFIContext {

    AVCodecContext *avctx;

    uint8_t *dst;

    uint32_t pal[256];

} BFIContext;

static av_cold int bfi_decode_init(AVCodecContext *avctx)

{

    BFIContext *bfi = avctx->priv_data;

    avctx->pix_fmt  = AV_PIX_FMT_PAL8;

    bfi->dst        = av_mallocz(avctx->width * avctx->height);

    if (!bfi->dst)

        return AVERROR(ENOMEM);

    return 0;

}

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

                            int *got_frame, AVPacket *avpkt)

{

    AVFrame *frame = data;

    GetByteContext g;

    int buf_size    = avpkt->size;

    BFIContext *bfi = avctx->priv_data;

    uint8_t *dst    = bfi->dst;

    uint8_t *src, *dst_offset, colour1, colour2;

    uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;

    uint32_t *pal;

    int i, j, ret, height = avctx->height;

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

        return ret;

    bytestream2_init(&g, avpkt->data, buf_size);

    /* Set frame parameters and palette, if necessary */

    if (!avctx->frame_number) {

        frame->pict_type = AV_PICTURE_TYPE_I;

        frame->key_frame = 1;

        /* Setting the palette */

        if (avctx->extradata_size > 768) {

            av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");

            return AVERROR_INVALIDDATA;

        }

        pal = (uint32_t *)frame->data[1];

        for (i = 0; i < avctx->extradata_size / 3; i++) {

            int shift = 16;

            *pal = 0xFFU << 24;

            for (j = 0; j < 3; j++, shift -= 8)

                *pal += ((avctx->extradata[i * 3 + j] << 2) |

                         (avctx->extradata[i * 3 + j] >> 4)) << shift;

            pal++;

        }

        memcpy(bfi->pal, frame->data[1], sizeof(bfi->pal));

        frame->palette_has_changed = 1;

    } else {

        frame->pict_type = AV_PICTURE_TYPE_P;

        frame->key_frame = 0;

        frame->palette_has_changed = 0;

        memcpy(frame->data[1], bfi->pal, sizeof(bfi->pal));

    }

    bytestream2_skip(&g, 4); // Unpacked size, not required.

    while (dst != frame_end) {

        static const uint8_t lentab[4] = { 0, 2, 0, 1 };

        unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);

        unsigned int code   = byte >> 6;

        unsigned int length = byte & ~0xC0;

        if (!bytestream2_get_bytes_left(&g)) {

            av_log(avctx, AV_LOG_ERROR,

                   "Input resolution larger than actual frame.\n");

            return AVERROR_INVALIDDATA;

        }

        /* Get length and offset (if required) */

        if (length == 0) {

            if (code == 1) {

                length = bytestream2_get_byte(&g);

                offset = bytestream2_get_le16(&g);

            } else {

                length = bytestream2_get_le16(&g);

                if (code == 2 && length == 0)

                    break;

            }

        } else {

            if (code == 1)

                offset = bytestream2_get_byte(&g);

        }

        /* Do boundary check */

        if (dst + (length << lentab[code]) > frame_end)

            break;

        switch (code) {

        case 0:                // normal chain

            if (length >= bytestream2_get_bytes_left(&g)) {

                av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");

                return AVERROR_INVALIDDATA;

            }

            bytestream2_get_buffer(&g, dst, length);

            dst += length;

            break;

        case 1:                // back chain

            dst_offset = dst - offset;

            length    *= 4;     // Convert dwords to bytes.

            if (dst_offset < bfi->dst)

                break;

            while (length--)

                *dst++ = *dst_offset++;

            break;

        case 2:                // skip chain

            dst += length;

            break;

        case 3:                // fill chain

            colour1 = bytestream2_get_byte(&g);

            colour2 = bytestream2_get_byte(&g);

            while (length--) {

                *dst++ = colour1;

                *dst++ = colour2;

            }

            break;

        }

    }

    src = bfi->dst;

    dst = frame->data[0];

    while (height--) {

        memcpy(dst, src, avctx->width);

        src += avctx->width;

        dst += frame->linesize[0];

    }

    *got_frame = 1;

    return buf_size;

}

static av_cold int bfi_decode_close(AVCodecContext *avctx)

{

    BFIContext *bfi = avctx->priv_data;

    av_freep(&bfi->dst);

    return 0;

}

AVCodec ff_bfi_decoder = {

    .name           = "bfi",

    .long_name      = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = AV_CODEC_ID_BFI,

    .priv_data_size = sizeof(BFIContext),

    .init           = bfi_decode_init,

    .close          = bfi_decode_close,

    .decode         = bfi_decode_frame,

    .capabilities   = AV_CODEC_CAP_DR1,

};