Define basic design of output streams

lib/filesystem/CStream.h

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+#pragma once
+
+/*
+ * CStream.h, part of VCMI engine
+ *
+ * Authors: listed in file AUTHORS in main folder
+ *
+ * License: GNU General Public License v2.0 or later
+ * Full text of license available in license.txt file, in main folder
+ *
+ */
+
+class DLL_LINKAGE CStream : private boost::noncopyable
+{
+public:
+	/**
+	 * D-tor.
+	 */
+	virtual ~CStream() {}
+
+	/**
+	 * Seeks to the specified position.
+	 *
+	 * @param position The position from the beginning.
+	 * @return the position actually moved to, -1 on error.
+	 */
+	virtual si64 seek(si64 position) = 0;
+
+	/**
+	 * Gets the current position in the stream.
+	 *
+	 * @return the position.
+	 */
+	virtual si64 tell() = 0;
+
+	/**
+	 * Relative seeks to the specified position.
+	 *
+	 * @param delta The count of bytes to seek from current position.
+	 * @return the count of bytes skipped actually.
+	 */
+	virtual si64 skip(si64 delta) = 0;
+
+	/**
+	 * Gets the length in bytes of the stream.
+	 *
+	 * @return the length in bytes of the stream.
+	 */
+	virtual si64 getSize() = 0;	
+};