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diff --git a/common/stream.h b/common/stream.h
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+++ b/common/stream.h
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+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2001  Ludvig Strigeus
+ * Copyright (C) 2001/2002 The ScummVM project
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+
+#ifndef COMMON_STREAM_H
+#define COMMON_STREAM_H
+
+#include "stdafx.h"
+#include "common/scummsys.h"
+
+
+namespace Common {
+
+class WriteStream {
+public:
+	virtual uint32 write(const void *ptr, uint32 size) = 0;
+
+	// The remaining methods all have default implementations
+
+	void writeByte(byte value);
+
+	void writeUint16LE(uint16 value);
+	void writeUint32LE(uint32 value);
+
+	void writeUint16BE(uint16 value);
+	void writeUint32BE(uint32 value);
+
+/*
+	void writeSint16LE(int16 value);
+	void writeSint32LE(int32 value);
+
+	void writeSint16BE(int16 value);
+	void writeSint32BE(int32 value);
+*/
+};
+
+
+class ReadStream {
+public:
+	virtual uint32 read(void *ptr, uint32 size) = 0;
+
+	// The remaining methods all have default implementations
+
+	byte readByte();
+
+	uint16 readUint16LE();
+	uint32 readUint32LE();
+
+	uint16 readUint16BE();
+	uint32 readUint32BE();
+
+/*
+	int16 readSint16LE();
+	int32 readSint32LE();
+
+	int16 readSint16BE();
+	int32 readSint32BE();
+*/
+};
+
+/**
+ * XORReadStream is a wrapper around an arbitrary other ReadStream,
+ * which 'decrypts' the data being read by XORing all data bytes with the given
+ * encryption 'key'.
+ */
+class XORReadStream : public ReadStream {
+private:
+	byte _encbyte;
+	ReadStream *_realStream;
+public:
+	XORReadStream(ReadStream *in, byte enc = 0) : _realStream(in), _encbyte(enc) {}
+	void setEnc(byte value) { _encbyte = value; }
+
+	uint32 read(void *ptr, uint32 size) {
+		uint32 len = _realStream->read(ptr, size);
+		if (_encbyte) {
+			byte *p = (byte *)ptr;
+			byte *end = p + len;
+			while (p < end)
+				*p++ ^= _encbyte;
+		}
+		return len;
+	}
+};
+
+class MemoryReadStream : public ReadStream {
+private:
+	const byte *_ptr;
+	uint32 _size;
+public:
+	MemoryReadStream(const byte *ptr, uint32 size) : _ptr(ptr), _size(size) {}
+
+	uint32 read(void *ptr, uint32 size) {
+		if (size > _size)
+			size = _size;
+		memcpy(ptr, _ptr, size);
+		_size -= size;
+		_ptr += size;
+		return size;
+	}
+};
+
+}	// End of namespace Common
+
+#endif