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/*
* Autodesc RLE Decoder
* Copyright (C) 2005 the ffmpeg project
*
* 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 aasc.c
* Autodesc RLE Video Decoder by Konstantin Shishkov
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "avcodec.h"
#include "dsputil.h"
typedef struct AascContext {
AVCodecContext *avctx;
AVFrame frame;
} AascContext;
#define FETCH_NEXT_STREAM_BYTE() \
if (stream_ptr >= buf_size) \
{ \
av_log(s->avctx, AV_LOG_ERROR, " AASC: stream ptr just went out of bounds (fetch)\n"); \
break; \
} \
stream_byte = buf[stream_ptr++];
static int aasc_decode_init(AVCodecContext *avctx)
{
AascContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->pix_fmt = PIX_FMT_BGR24;
s->frame.data[0] = NULL;
return 0;
}
static int aasc_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
AascContext *s = avctx->priv_data;
int stream_ptr = 4;
unsigned char rle_code;
unsigned char stream_byte;
int pixel_ptr = 0;
int row_dec, row_ptr;
int frame_size;
int i;
s->frame.reference = 1;
s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
if (avctx->reget_buffer(avctx, &s->frame)) {
av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
return -1;
}
row_dec = s->frame.linesize[0];
row_ptr = (s->avctx->height - 1) * row_dec;
frame_size = row_dec * s->avctx->height;
while (row_ptr >= 0) {
FETCH_NEXT_STREAM_BYTE();
rle_code = stream_byte;
if (rle_code == 0) {
/* fetch the next byte to see how to handle escape code */
FETCH_NEXT_STREAM_BYTE();
if (stream_byte == 0) {
/* line is done, goto the next one */
row_ptr -= row_dec;
pixel_ptr = 0;
} else if (stream_byte == 1) {
/* decode is done */
break;
} else if (stream_byte == 2) {
/* reposition frame decode coordinates */
FETCH_NEXT_STREAM_BYTE();
pixel_ptr += stream_byte;
FETCH_NEXT_STREAM_BYTE();
row_ptr -= stream_byte * row_dec;
} else {
/* copy pixels from encoded stream */
if ((pixel_ptr + stream_byte > avctx->width * 3) ||
(row_ptr < 0)) {
av_log(s->avctx, AV_LOG_ERROR, " AASC: frame ptr just went out of bounds (copy1)\n");
break;
}
rle_code = stream_byte;
if (stream_ptr + rle_code > buf_size) {
av_log(s->avctx, AV_LOG_ERROR, " AASC: stream ptr just went out of bounds (copy2)\n");
break;
}
for (i = 0; i < rle_code; i++) {
FETCH_NEXT_STREAM_BYTE();
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
pixel_ptr++;
}
if (rle_code & 1)
stream_ptr++;
}
} else {
/* decode a run of data */
if ((pixel_ptr + rle_code > avctx->width * 3) ||
(row_ptr < 0)) {
av_log(s->avctx, AV_LOG_ERROR, " AASC: frame ptr just went out of bounds (run1)\n");
break;
}
FETCH_NEXT_STREAM_BYTE();
while(rle_code--) {
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
pixel_ptr++;
}
}
}
/* one last sanity check on the way out */
if (stream_ptr < buf_size)
av_log(s->avctx, AV_LOG_ERROR, " AASC: ended frame decode with bytes left over (%d < %d)\n",
stream_ptr, buf_size);
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
/* report that the buffer was completely consumed */
return buf_size;
}
static int aasc_decode_end(AVCodecContext *avctx)
{
AascContext *s = avctx->priv_data;
/* release the last frame */
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
return 0;
}
AVCodec aasc_decoder = {
"aasc",
CODEC_TYPE_VIDEO,
CODEC_ID_AASC,
sizeof(AascContext),
aasc_decode_init,
NULL,
aasc_decode_end,
aasc_decode_frame,
CODEC_CAP_DR1,
};
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