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/*

 * Deluxe Paint Animation decoder

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

 */

/**

 * @file

 * Deluxe Paint Animation decoder

 */

#include "avcodec.h"

#include "bytestream.h"

#include "internal.h"

typedef struct AnmContext {

    AVFrame *frame;

    int palette[AVPALETTE_COUNT];

    GetByteContext gb;

    int x;  ///< x coordinate position

} AnmContext;

static av_cold int decode_init(AVCodecContext *avctx)

{

    AnmContext *s = avctx->priv_data;

    int i;

    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    s->frame = av_frame_alloc();

    if (!s->frame)

        return AVERROR(ENOMEM);

    bytestream2_init(&s->gb, avctx->extradata, avctx->extradata_size);

    if (bytestream2_get_bytes_left(&s->gb) < 16 * 8 + 4 * 256)

        return AVERROR_INVALIDDATA;

    bytestream2_skipu(&s->gb, 16 * 8);

    for (i = 0; i < 256; i++)

        s->palette[i] = bytestream2_get_le32u(&s->gb);

    return 0;

}

/**

 * Perform decode operation

 * @param dst     pointer to destination image buffer

 * @param dst_end pointer to end of destination image buffer

 * @param gb GetByteContext (optional, see below)

 * @param pixel Fill color (optional, see below)

 * @param count Pixel count

 * @param x Pointer to x-axis counter

 * @param width Image width

 * @param linesize Destination image buffer linesize

 * @return non-zero if destination buffer is exhausted

 *

 * a copy operation is achieved when 'gb' is set

 * a fill operation is achieved when 'gb' is null and pixel is >= 0

 * a skip operation is achieved when 'gb' is null and pixel is < 0

 */

static inline int op(uint8_t **dst, const uint8_t *dst_end,

                     GetByteContext *gb,

                     int pixel, int count,

                     int *x, int width, int linesize)

{

    int remaining = width - *x;

    while(count > 0) {

        int striplen = FFMIN(count, remaining);

        if (gb) {

            if (bytestream2_get_bytes_left(gb) < striplen)

                goto exhausted;

            bytestream2_get_bufferu(gb, *dst, striplen);

        } else if (pixel >= 0)

            memset(*dst, pixel, striplen);

        *dst      += striplen;

        remaining -= striplen;

        count     -= striplen;

        if (remaining <= 0) {

            *dst      += linesize - width;

            remaining  = width;

        }

        if (linesize > 0) {

            if (*dst >= dst_end) goto exhausted;

        } else {

            if (*dst <= dst_end) goto exhausted;

        }

    }

    *x = width - remaining;

    return 0;

exhausted:

    *x = width - remaining;

    return 1;

}

static int decode_frame(AVCodecContext *avctx,

                        void *data, int *got_frame,

                        AVPacket *avpkt)

{

    AnmContext *s = avctx->priv_data;

    const int buf_size = avpkt->size;

    uint8_t *dst, *dst_end;

    int count, ret;

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

        return ret;

    dst     = s->frame->data[0];

    dst_end = s->frame->data[0] + s->frame->linesize[0]*avctx->height;

    bytestream2_init(&s->gb, avpkt->data, buf_size);

    if (bytestream2_get_byte(&s->gb) != 0x42) {

        avpriv_request_sample(avctx, "Unknown record type");

        return AVERROR_INVALIDDATA;

    }

    if (bytestream2_get_byte(&s->gb)) {

        avpriv_request_sample(avctx, "Padding bytes");

        return AVERROR_PATCHWELCOME;

    }

    bytestream2_skip(&s->gb, 2);

    s->x = 0;

    do {

        /* if statements are ordered by probability */

#define OP(gb, pixel, count) \

    op(&dst, dst_end, (gb), (pixel), (count), &s->x, avctx->width, s->frame->linesize[0])

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

        count = type & 0x7F;

        type >>= 7;

        if (count) {

            if (OP(type ? NULL : &s->gb, -1, count)) break;

        } else if (!type) {

            int pixel;

            count = bytestream2_get_byte(&s->gb);  /* count==0 gives nop */

            pixel = bytestream2_get_byte(&s->gb);

            if (OP(NULL, pixel, count)) break;

        } else {

            int pixel;

            type = bytestream2_get_le16(&s->gb);

            count = type & 0x3FFF;

            type >>= 14;

            if (!count) {

                if (type == 0)

                    break; // stop

                if (type == 2) {

                    avpriv_request_sample(avctx, "Unknown opcode");

                    return AVERROR_PATCHWELCOME;

                }

                continue;

            }

            pixel = type == 3 ? bytestream2_get_byte(&s->gb) : -1;

            if (type == 1) count += 0x4000;

            if (OP(type == 2 ? &s->gb : NULL, pixel, count)) break;

        }

    } while (bytestream2_get_bytes_left(&s->gb) > 0);

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

    *got_frame = 1;

    if ((ret = av_frame_ref(data, s->frame)) < 0)

        return ret;

    return buf_size;

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    AnmContext *s = avctx->priv_data;

    av_frame_free(&s->frame);

    return 0;

}

AVCodec ff_anm_decoder = {

    .name           = "anm",

    .long_name      = NULL_IF_CONFIG_SMALL("Deluxe Paint Animation"),

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = AV_CODEC_ID_ANM,

    .priv_data_size = sizeof(AnmContext),

    .init           = decode_init,

    .close          = decode_end,

    .decode         = decode_frame,

    .capabilities   = CODEC_CAP_DR1,

};