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https://github.com/FFmpeg/FFmpeg.git
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262 lines
9.7 KiB
C
262 lines
9.7 KiB
C
/*
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* Microsoft RLE decoder
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* Copyright (C) 2008 Konstantin Shishkov
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* MS RLE decoder based on decoder by Mike Melanson and my own for TSCC
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* For more information about the MS RLE format, visit:
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* http://www.multimedia.cx/msrle.txt
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*/
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "msrledec.h"
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static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic,
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GetByteContext *gb)
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{
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unsigned char rle_code;
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unsigned char extra_byte, odd_pixel;
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unsigned char stream_byte;
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unsigned int pixel_ptr = 0;
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int row_dec = pic->linesize[0];
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int row_ptr = (avctx->height - 1) * row_dec;
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int frame_size = row_dec * avctx->height;
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int i;
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while (row_ptr >= 0) {
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if (bytestream2_get_bytes_left(gb) <= 0) {
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av_log(avctx, AV_LOG_ERROR,
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"MS RLE: bytestream overrun, %d rows left\n",
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row_ptr);
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return AVERROR_INVALIDDATA;
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}
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rle_code = stream_byte = bytestream2_get_byteu(gb);
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if (rle_code == 0) {
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/* fetch the next byte to see how to handle escape code */
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stream_byte = bytestream2_get_byte(gb);
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if (stream_byte == 0) {
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/* line is done, goto the next one */
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row_ptr -= row_dec;
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pixel_ptr = 0;
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} else if (stream_byte == 1) {
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/* decode is done */
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return 0;
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} else if (stream_byte == 2) {
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/* reposition frame decode coordinates */
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stream_byte = bytestream2_get_byte(gb);
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pixel_ptr += stream_byte;
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stream_byte = bytestream2_get_byte(gb);
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row_ptr -= stream_byte * row_dec;
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} else {
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// copy pixels from encoded stream
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odd_pixel = stream_byte & 1;
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rle_code = (stream_byte + 1) / 2;
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extra_byte = rle_code & 0x01;
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if (row_ptr + pixel_ptr + stream_byte > frame_size ||
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bytestream2_get_bytes_left(gb) < rle_code) {
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av_log(avctx, AV_LOG_ERROR,
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"MS RLE: frame/stream ptr just went out of bounds (copy)\n");
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return AVERROR_INVALIDDATA;
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}
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for (i = 0; i < rle_code; i++) {
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if (pixel_ptr >= avctx->width)
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break;
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stream_byte = bytestream2_get_byteu(gb);
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pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
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pixel_ptr++;
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if (i + 1 == rle_code && odd_pixel)
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break;
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if (pixel_ptr >= avctx->width)
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break;
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pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
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pixel_ptr++;
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}
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// if the RLE code is odd, skip a byte in the stream
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if (extra_byte)
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bytestream2_skip(gb, 1);
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}
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} else {
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// decode a run of data
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if (row_ptr + pixel_ptr + stream_byte > frame_size) {
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av_log(avctx, AV_LOG_ERROR,
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"MS RLE: frame ptr just went out of bounds (run)\n");
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return AVERROR_INVALIDDATA;
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}
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stream_byte = bytestream2_get_byte(gb);
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for (i = 0; i < rle_code; i++) {
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if (pixel_ptr >= avctx->width)
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break;
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if ((i & 1) == 0)
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pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
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else
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pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
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pixel_ptr++;
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}
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}
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}
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/* one last sanity check on the way out */
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if (bytestream2_get_bytes_left(gb)) {
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av_log(avctx, AV_LOG_ERROR,
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"MS RLE: ended frame decode with %d bytes left over\n",
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bytestream2_get_bytes_left(gb));
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return AVERROR_INVALIDDATA;
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}
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return 0;
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}
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static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic,
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int depth, GetByteContext *gb)
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{
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uint8_t *output, *output_end;
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int p1, p2, line=avctx->height - 1, pos=0, i;
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uint16_t pix16;
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uint32_t pix32;
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unsigned int width= FFABS(pic->linesize[0]) / (depth >> 3);
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output = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
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output_end = pic->data[0] + avctx->height * pic->linesize[0];
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while (bytestream2_get_bytes_left(gb) > 0) {
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p1 = bytestream2_get_byteu(gb);
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if(p1 == 0) { //Escape code
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p2 = bytestream2_get_byte(gb);
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if(p2 == 0) { //End-of-line
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if (--line < 0) {
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if (bytestream2_get_be16(gb) == 1) { // end-of-picture
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return 0;
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} else {
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av_log(avctx, AV_LOG_ERROR,
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"Next line is beyond picture bounds (%d bytes left)\n",
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bytestream2_get_bytes_left(gb));
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return AVERROR_INVALIDDATA;
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}
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}
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output = pic->data[0] + line * pic->linesize[0];
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pos = 0;
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continue;
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} else if(p2 == 1) { //End-of-picture
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return 0;
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} else if(p2 == 2) { //Skip
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p1 = bytestream2_get_byte(gb);
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p2 = bytestream2_get_byte(gb);
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line -= p2;
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pos += p1;
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if (line < 0 || pos >= width){
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av_log(avctx, AV_LOG_ERROR, "Skip beyond picture bounds\n");
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return -1;
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}
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output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
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continue;
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}
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// Copy data
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if ((pic->linesize[0] > 0 && output + p2 * (depth >> 3) > output_end) ||
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(pic->linesize[0] < 0 && output + p2 * (depth >> 3) < output_end)) {
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bytestream2_skip(gb, 2 * (depth >> 3));
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continue;
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} else if (bytestream2_get_bytes_left(gb) < p2 * (depth >> 3)) {
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av_log(avctx, AV_LOG_ERROR, "bytestream overrun\n");
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return AVERROR_INVALIDDATA;
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}
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if ((depth == 8) || (depth == 24)) {
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for(i = 0; i < p2 * (depth >> 3); i++) {
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*output++ = bytestream2_get_byteu(gb);
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}
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// RLE8 copy is actually padded - and runs are not!
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if(depth == 8 && (p2 & 1)) {
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bytestream2_skip(gb, 1);
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}
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} else if (depth == 16) {
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for(i = 0; i < p2; i++) {
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*(uint16_t*)output = bytestream2_get_le16u(gb);
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output += 2;
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}
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} else if (depth == 32) {
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for(i = 0; i < p2; i++) {
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*(uint32_t*)output = bytestream2_get_le32u(gb);
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output += 4;
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}
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}
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pos += p2;
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} else { //run of pixels
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uint8_t pix[3]; //original pixel
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switch(depth){
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case 8: pix[0] = bytestream2_get_byte(gb);
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break;
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case 16: pix16 = bytestream2_get_le16(gb);
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break;
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case 24: pix[0] = bytestream2_get_byte(gb);
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pix[1] = bytestream2_get_byte(gb);
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pix[2] = bytestream2_get_byte(gb);
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break;
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case 32: pix32 = bytestream2_get_le32(gb);
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break;
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}
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if ((pic->linesize[0] > 0 && output + p1 * (depth >> 3) > output_end) ||
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(pic->linesize[0] < 0 && output + p1 * (depth >> 3) < output_end))
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continue;
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for(i = 0; i < p1; i++) {
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switch(depth){
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case 8: *output++ = pix[0];
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break;
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case 16: *(uint16_t*)output = pix16;
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output += 2;
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break;
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case 24: *output++ = pix[0];
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*output++ = pix[1];
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*output++ = pix[2];
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break;
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case 32: *(uint32_t*)output = pix32;
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output += 4;
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break;
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}
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}
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pos += p1;
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}
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}
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av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no end-of-picture code\n");
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return 0;
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}
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int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic,
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int depth, GetByteContext *gb)
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{
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switch(depth){
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case 4:
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return msrle_decode_pal4(avctx, pic, gb);
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case 8:
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case 16:
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case 24:
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case 32:
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return msrle_decode_8_16_24_32(avctx, pic, depth, gb);
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default:
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av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
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return -1;
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}
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}
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