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msrledec.c
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msrledec.c
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/*
* Microsoft RLE decoder
* Copyright (C) 2008 Konstantin Shishkov
*
* 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
* MS RLE decoder based on decoder by Mike Melanson and my own for TSCC
* For more information about the MS RLE format, visit:
* http://www.multimedia.cx/msrle.txt
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "msrledec.h"
static int msrle_decode_pal4(AVCodecContext *avctx, AVFrame *pic,
GetByteContext *gb)
{
unsigned char rle_code;
unsigned char extra_byte, odd_pixel;
unsigned char stream_byte;
int pixel_ptr = 0;
int line = avctx->height - 1;
int i;
while (line >= 0 && pixel_ptr <= avctx->width) {
if (bytestream2_get_bytes_left(gb) <= 0) {
av_log(avctx, AV_LOG_ERROR,
"MS RLE: bytestream overrun, %dx%d left\n",
avctx->width - pixel_ptr, line);
return AVERROR_INVALIDDATA;
}
rle_code = stream_byte = bytestream2_get_byteu(gb);
if (rle_code == 0) {
/* fetch the next byte to see how to handle escape code */
stream_byte = bytestream2_get_byte(gb);
if (stream_byte == 0) {
/* line is done, goto the next one */
line--;
pixel_ptr = 0;
} else if (stream_byte == 1) {
/* decode is done */
return 0;
} else if (stream_byte == 2) {
/* reposition frame decode coordinates */
stream_byte = bytestream2_get_byte(gb);
pixel_ptr += stream_byte;
stream_byte = bytestream2_get_byte(gb);
line -= stream_byte;
} else {
// copy pixels from encoded stream
odd_pixel = stream_byte & 1;
rle_code = (stream_byte + 1) / 2;
extra_byte = rle_code & 0x01;
if (pixel_ptr + 2*rle_code - odd_pixel > avctx->width ||
bytestream2_get_bytes_left(gb) < rle_code) {
av_log(avctx, AV_LOG_ERROR,
"MS RLE: frame/stream ptr just went out of bounds (copy)\n");
return AVERROR_INVALIDDATA;
}
for (i = 0; i < rle_code; i++) {
if (pixel_ptr >= avctx->width)
break;
stream_byte = bytestream2_get_byteu(gb);
pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte >> 4;
pixel_ptr++;
if (i + 1 == rle_code && odd_pixel)
break;
if (pixel_ptr >= avctx->width)
break;
pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte & 0x0F;
pixel_ptr++;
}
// if the RLE code is odd, skip a byte in the stream
if (extra_byte)
bytestream2_skip(gb, 1);
}
} else {
// decode a run of data
if (pixel_ptr + rle_code > avctx->width + 1) {
av_log(avctx, AV_LOG_ERROR,
"MS RLE: frame ptr just went out of bounds (run) %d %d %d\n", pixel_ptr, rle_code, avctx->width);
return AVERROR_INVALIDDATA;
}
stream_byte = bytestream2_get_byte(gb);
for (i = 0; i < rle_code; i++) {
if (pixel_ptr >= avctx->width)
break;
if ((i & 1) == 0)
pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte >> 4;
else
pic->data[0][line * pic->linesize[0] + pixel_ptr] = stream_byte & 0x0F;
pixel_ptr++;
}
}
}
/* one last sanity check on the way out */
if (bytestream2_get_bytes_left(gb)) {
av_log(avctx, AV_LOG_ERROR,
"MS RLE: ended frame decode with %d bytes left over\n",
bytestream2_get_bytes_left(gb));
return AVERROR_INVALIDDATA;
}
return 0;
}
static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVFrame *pic,
int depth, GetByteContext *gb)
{
uint8_t *output, *output_end;
int p1, p2, line=avctx->height - 1, pos=0, i;
uint16_t pix16;
uint32_t pix32;
unsigned int width= FFABS(pic->linesize[0]) / (depth >> 3);
output = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
output_end = output + FFABS(pic->linesize[0]);
while (bytestream2_get_bytes_left(gb) > 0) {
p1 = bytestream2_get_byteu(gb);
if(p1 == 0) { //Escape code
p2 = bytestream2_get_byte(gb);
if(p2 == 0) { //End-of-line
if (--line < 0) {
if (bytestream2_get_be16(gb) == 1) { // end-of-picture
return 0;
} else {
av_log(avctx, AV_LOG_ERROR,
"Next line is beyond picture bounds (%d bytes left)\n",
bytestream2_get_bytes_left(gb));
return AVERROR_INVALIDDATA;
}
}
output = pic->data[0] + line * pic->linesize[0];
output_end = output + FFABS(pic->linesize[0]);
pos = 0;
continue;
} else if(p2 == 1) { //End-of-picture
return 0;
} else if(p2 == 2) { //Skip
p1 = bytestream2_get_byte(gb);
p2 = bytestream2_get_byte(gb);
line -= p2;
pos += p1;
if (line < 0 || pos >= width){
av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n");
return -1;
}
output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
output_end = pic->data[0] + line * pic->linesize[0] + FFABS(pic->linesize[0]);
continue;
}
// Copy data
if (output + p2 * (depth >> 3) > output_end) {
bytestream2_skip(gb, 2 * (depth >> 3));
continue;
} else if (bytestream2_get_bytes_left(gb) < p2 * (depth >> 3)) {
av_log(avctx, AV_LOG_ERROR, "bytestream overrun\n");
return AVERROR_INVALIDDATA;
}
if ((depth == 8) || (depth == 24)) {
bytestream2_get_bufferu(gb, output, p2 * (depth >> 3));
output += p2 * (depth >> 3);
// RLE8 copy is actually padded - and runs are not!
if(depth == 8 && (p2 & 1)) {
bytestream2_skip(gb, 1);
}
} else if (depth == 16) {
for(i = 0; i < p2; i++) {
*(uint16_t*)output = bytestream2_get_le16u(gb);
output += 2;
}
} else if (depth == 32) {
for(i = 0; i < p2; i++) {
*(uint32_t*)output = bytestream2_get_le32u(gb);
output += 4;
}
}
pos += p2;
} else { //run of pixels
uint8_t pix[3]; //original pixel
if (output + p1 * (depth >> 3) > output_end)
continue;
switch(depth){
case 8:
pix[0] = bytestream2_get_byte(gb);
memset(output, pix[0], p1);
output += p1;
break;
case 16:
pix16 = bytestream2_get_le16(gb);
for(i = 0; i < p1; i++) {
*(uint16_t*)output = pix16;
output += 2;
}
break;
case 24:
pix[0] = bytestream2_get_byte(gb);
pix[1] = bytestream2_get_byte(gb);
pix[2] = bytestream2_get_byte(gb);
for(i = 0; i < p1; i++) {
*output++ = pix[0];
*output++ = pix[1];
*output++ = pix[2];
}
break;
case 32:
pix32 = bytestream2_get_le32(gb);
for(i = 0; i < p1; i++) {
*(uint32_t*)output = pix32;
output += 4;
}
break;
}
pos += p1;
}
}
av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no end-of-picture code\n");
return 0;
}
int ff_msrle_decode(AVCodecContext *avctx, AVFrame *pic,
int depth, GetByteContext *gb)
{
switch(depth){
case 4:
return msrle_decode_pal4(avctx, pic, gb);
case 8:
case 16:
case 24:
case 32:
return msrle_decode_8_16_24_32(avctx, pic, depth, gb);
default:
av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
return -1;
}
}