mirror of
https://github.com/libretro/scummvm.git
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226 lines
8.1 KiB
C++
226 lines
8.1 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; 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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// Based off ffmpeg's msvideo.cpp
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#include "image/codecs/msvideo1.h"
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#include "common/stream.h"
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#include "common/textconsole.h"
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namespace Image {
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#define CHECK_STREAM_PTR(n) \
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if ((stream.pos() + n) > stream.size() ) { \
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warning ("MS Video-1: Stream out of bounds (%d >= %d) d%d", stream.pos() + n, stream.size(), n); \
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return; \
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}
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MSVideo1Decoder::MSVideo1Decoder(uint16 width, uint16 height, byte bitsPerPixel) : Codec() {
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_surface = new Graphics::Surface();
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_surface->create(width, height, (bitsPerPixel == 8) ? Graphics::PixelFormat::createFormatCLUT8() :
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Graphics::PixelFormat(2, 5, 5, 5, 0, 10, 5, 0, 0));
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_bitsPerPixel = bitsPerPixel;
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}
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MSVideo1Decoder::~MSVideo1Decoder() {
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_surface->free();
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delete _surface;
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}
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void MSVideo1Decoder::decode8(Common::SeekableReadStream &stream) {
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byte colors[8];
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byte *pixels = (byte *)_surface->getPixels();
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uint16 stride = _surface->w;
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int skipBlocks = 0;
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uint16 blocks_wide = _surface->w / 4;
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uint16 blocks_high = _surface->h / 4;
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uint32 totalBlocks = blocks_wide * blocks_high;
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uint32 blockInc = 4;
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uint16 rowDec = stride + 4;
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for (uint16 block_y = blocks_high; block_y > 0; block_y--) {
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uint32 blockPtr = (block_y * 4 - 1) * stride;
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for (uint16 block_x = blocks_wide; block_x > 0; block_x--) {
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// check if this block should be skipped
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if (skipBlocks > 0) {
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blockPtr += blockInc;
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skipBlocks--;
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totalBlocks--;
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continue;
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}
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uint32 pixelPtr = blockPtr;
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/* get the next two bytes in the encoded data stream */
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CHECK_STREAM_PTR(2);
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byte byte_a = stream.readByte();
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byte byte_b = stream.readByte();
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/* check if the decode is finished */
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if (byte_a == 0 && byte_b == 0 && totalBlocks == 0) {
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return;
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} else if ((byte_b & 0xFC) == 0x84) {
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// skip code, but don't count the current block
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skipBlocks = ((byte_b - 0x84) << 8) + byte_a - 1;
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} else if (byte_b < 0x80) {
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// 2-color encoding
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uint16 flags = (byte_b << 8) | byte_a;
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CHECK_STREAM_PTR(2);
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colors[0] = stream.readByte();
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colors[1] = stream.readByte();
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for (byte pixel_y = 0; pixel_y < 4; pixel_y++) {
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for (byte pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
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pixels[pixelPtr++] = colors[(flags & 0x1) ^ 1];
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pixelPtr -= rowDec;
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}
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} else if (byte_b >= 0x90) {
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// 8-color encoding
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uint16 flags = (byte_b << 8) | byte_a;
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CHECK_STREAM_PTR(8);
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for (byte i = 0; i < 8; i++)
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colors[i] = stream.readByte();
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for (byte pixel_y = 0; pixel_y < 4; pixel_y++) {
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for (byte pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
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pixels[pixelPtr++] = colors[((pixel_y & 0x2) << 1) + (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
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pixelPtr -= rowDec;
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}
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} else {
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// 1-color encoding
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colors[0] = byte_a;
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for (byte pixel_y = 0; pixel_y < 4; pixel_y++) {
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for (byte pixel_x = 0; pixel_x < 4; pixel_x++)
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pixels[pixelPtr++] = colors[0];
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pixelPtr -= rowDec;
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}
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}
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blockPtr += blockInc;
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totalBlocks--;
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}
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}
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}
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void MSVideo1Decoder::decode16(Common::SeekableReadStream &stream) {
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/* decoding parameters */
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uint16 colors[8];
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uint16 *pixels = (uint16 *)_surface->getPixels();
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int32 stride = _surface->w;
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int32 skip_blocks = 0;
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int32 blocks_wide = _surface->w / 4;
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int32 blocks_high = _surface->h / 4;
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int32 total_blocks = blocks_wide * blocks_high;
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int32 block_inc = 4;
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int32 row_dec = stride + 4;
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for (int32 block_y = blocks_high; block_y > 0; block_y--) {
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int32 block_ptr = ((block_y * 4) - 1) * stride;
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for (int32 block_x = blocks_wide; block_x > 0; block_x--) {
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/* check if this block should be skipped */
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if (skip_blocks) {
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block_ptr += block_inc;
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skip_blocks--;
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total_blocks--;
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continue;
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}
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int32 pixel_ptr = block_ptr;
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/* get the next two bytes in the encoded data stream */
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CHECK_STREAM_PTR(2);
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byte byte_a = stream.readByte();
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byte byte_b = stream.readByte();
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/* check if the decode is finished */
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if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
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return;
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} else if ((byte_b & 0xFC) == 0x84) {
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/* skip code, but don't count the current block */
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skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
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} else if (byte_b < 0x80) {
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/* 2- or 8-color encoding modes */
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uint16 flags = (byte_b << 8) | byte_a;
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CHECK_STREAM_PTR(4);
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colors[0] = stream.readUint16LE();
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colors[1] = stream.readUint16LE();
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if (colors[0] & 0x8000) {
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/* 8-color encoding */
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CHECK_STREAM_PTR(12);
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colors[2] = stream.readUint16LE();
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colors[3] = stream.readUint16LE();
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colors[4] = stream.readUint16LE();
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colors[5] = stream.readUint16LE();
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colors[6] = stream.readUint16LE();
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colors[7] = stream.readUint16LE();
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for (int pixel_y = 0; pixel_y < 4; pixel_y++) {
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for (int pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
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pixels[pixel_ptr++] =
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colors[((pixel_y & 0x2) << 1) +
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(pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
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pixel_ptr -= row_dec;
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}
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} else {
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/* 2-color encoding */
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for (int pixel_y = 0; pixel_y < 4; pixel_y++) {
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for (int pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
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pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
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pixel_ptr -= row_dec;
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}
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}
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} else {
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/* otherwise, it's a 1-color block */
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colors[0] = (byte_b << 8) | byte_a;
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for (int pixel_y = 0; pixel_y < 4; pixel_y++) {
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for (int pixel_x = 0; pixel_x < 4; pixel_x++)
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pixels[pixel_ptr++] = colors[0];
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pixel_ptr -= row_dec;
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}
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}
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block_ptr += block_inc;
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total_blocks--;
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}
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}
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}
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const Graphics::Surface *MSVideo1Decoder::decodeFrame(Common::SeekableReadStream &stream) {
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if (_bitsPerPixel == 8)
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decode8(stream);
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else
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decode16(stream);
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return _surface;
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}
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} // End of namespace Image
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