1 files changed, 128 insertions, 0 deletions
diff --git a/engines/sherlock/decompress.cpp b/engines/sherlock/decompress.cpp
new file mode 100644
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+++ b/engines/sherlock/decompress.cpp
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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.
+ *
+ */
+
+#include "sherlock/decompress.h"
+
+namespace Sherlock {
+
+/**
+ * Decompresses an LZW compressed resource. If no outSize is specified, it will
+ * decompress the entire resource. If, however, an explicit size is specified,
+ * then it means we're already within a resource, and only want to decompress
+ * part of it.
+ */
+Common::SeekableReadStream *decompressLZ(Common::SeekableReadStream &source, int32 outSize) {
+	if (outSize == -1) {
+		source.seek(5);
+		outSize = source.readSint32LE();
+	}
+
+	byte lzWindow[4096];
+	uint16 lzWindowPos;
+	uint16 cmd;
+
+	byte *outBuffer = new byte[outSize];
+	byte *outBufferEnd = outBuffer + outSize;
+	Common::MemoryReadStream *outS = new Common::MemoryReadStream(outBuffer, outSize, DisposeAfterUse::YES);
+
+	memset(lzWindow, 0xFF, 0xFEE);
+	lzWindowPos = 0xFEE;
+	cmd = 0;
+
+	do {
+		cmd >>= 1;
+		if (!(cmd & 0x100))
+			cmd = source.readByte() | 0xFF00;
+
+		if (cmd & 1) {
+			byte literal = source.readByte();
+			*outBuffer++ = literal;
+			lzWindow[lzWindowPos] = literal;
+			lzWindowPos = (lzWindowPos + 1) & 0x0FFF;
+		} else {
+			int copyPos, copyLen;
+			copyPos = source.readByte();
+			copyLen = source.readByte();
+			copyPos = copyPos | ((copyLen & 0xF0) << 4);
+			copyLen = (copyLen & 0x0F) + 3;
+			while (copyLen--) {
+				byte literal = lzWindow[copyPos];
+				copyPos = (copyPos + 1) & 0x0FFF;
+				*outBuffer++ = literal;
+				lzWindow[lzWindowPos] = literal;
+				lzWindowPos = (lzWindowPos + 1) & 0x0FFF;
+			}
+		}
+	} while (outBuffer < outBufferEnd);
+
+	return outS;
+}
+
+
+/**
+ * Decompresses a Rose Tattoo resource
+ *
+Common::SeekableReadStream *decompress32(Common::SeekableReadStream &source, int32 outSize) {
+	if (outSize == -1) {
+		outSize = source.readSint32LE();
+	}
+
+	byte lzWindow[8192];
+	byte *outBuffer = new byte[outSize];
+	byte *outBufferEnd = outBuffer + outSize;
+	Common::MemoryReadStream *outS = new Common::MemoryReadStream(outBuffer, outSize, DisposeAfterUse::YES);
+
+	memset(lzWindow, 0xFF, 8192);
+	int lzWindowPos = 0xFEE;
+	int cmd = 0;
+
+	do {
+		cmd >>= 1;
+		if (!(cmd & 0x100))
+			cmd = source.readByte() | 0xFF00;
+
+		if (cmd & 1) {
+			byte literal = source.readByte();
+			*outBuffer++ = literal;
+			lzWindow[lzWindowPos] = literal;
+			lzWindowPos = (lzWindowPos + 1) & 0x0FFF;
+		} else {
+			int copyPos, copyLen;
+			copyPos = source.readByte();
+			copyLen = source.readByte();
+			copyPos = copyPos | ((copyLen & 0xF0) << 4);
+			copyLen = (copyLen & 0x0F) + 3;
+			while (copyLen--) {
+				byte literal = lzWindow[copyPos];
+				copyPos = (copyPos + 1) & 0x0FFF;
+				*outBuffer++ = literal;
+				lzWindow[lzWindowPos] = literal;
+				lzWindowPos = (lzWindowPos + 1) & 0x0FFF;
+			}
+		}
+	} while (outBuffer < outBufferEnd);
+
+	return outS;
+}
+*/
+
+} // namespace Sherlock