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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
// Based off ffmpeg's msrledec.c
#include "common/debug.h"
#include "image/codecs/msrle4.h"
#include "common/stream.h"
#include "common/textconsole.h"
#include "common/util.h"
namespace Image {
MSRLE4Decoder::MSRLE4Decoder(uint16 width, uint16 height, byte bitsPerPixel) {
_surface = new Graphics::Surface();
_surface->create(width, height, Graphics::PixelFormat::createFormatCLUT8());
_bitsPerPixel = bitsPerPixel;
}
MSRLE4Decoder::~MSRLE4Decoder() {
_surface->free();
delete _surface;
}
const Graphics::Surface *MSRLE4Decoder::decodeFrame(Common::SeekableReadStream &stream) {
if (_bitsPerPixel == 4) {
decode4(stream);
} else
error("Unhandled %d bit Microsoft RLE encoding", _bitsPerPixel);
return _surface;
}
void MSRLE4Decoder::decode4(Common::SeekableReadStream &stream) {
int x = 0;
int y = _surface->h - 1;
byte *output = (byte *)_surface->getBasePtr(x, y);
byte *output_end = (byte *)_surface->getBasePtr(_surface->w, y);
while (!stream.eos()) {
byte count = stream.readByte();
if (count == 0) {
byte value = stream.readByte();
if (value == 0) {
// End of line
x = 0;
y--;
output = (byte *)_surface->getBasePtr(x, y);
} else if (value == 1) {
// End of image
return;
} else if (value == 2) {
// Skip
count = stream.readByte();
value = stream.readByte();
x += count;
y -= value;
if (y < 0) {
warning("MS RLE Codec: Skip beyond picture bounds");
return;
}
output = (byte *)_surface->getBasePtr(x, y);
} else {
// Copy data
int odd_pixel = value & 1;
int rle_code = (value + 1) / 2;
int extra_byte = rle_code & 0x01;
if (output + value > output_end) {
stream.skip(rle_code + extra_byte);
continue;
}
for (int i = 0; i < rle_code; i++) {
byte color = stream.readByte();
*output++ = (color & 0xf0) >> 4;
if (i + 1 == rle_code && odd_pixel) {
break;
}
*output++ = color & 0x0f;
}
if (extra_byte)
stream.skip(1);
x += value;
}
} else {
// Run data
if (output + count > output_end)
continue;
byte color = stream.readByte();
for (int i = 0; i < count; i++, x++) {
*output++ = (color & 0xf0) >> 4;
i++;
x++;
if (i == count)
break;
*output++ = color & 0x0f;
}
}
}
warning("MS RLE Codec: No end-of-picture code");
}
} // End of namespace Image
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