ProtoStream added

git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1240 8c4709b5-6ec9-48aa-a5cd-a96041d1645a

core/util/ProtoStream.hpp

@@ -0,0 +1,69 @@
+#ifndef __PROTOSTREAM_HPP__
+#define __PROTOSTREAM_HPP__
+
+#include <iostream>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <google/protobuf/message.h>
+
+#include "Logger.hpp"
+
+using namespace std;
+
+/**
+ * \class ProtoStream
+ * 
+ * 
+ * \brief One way to manage large protobuf-messages
+ * 
+ *	Google protobuf is not designed for large messages.
+ * 	That leads to much memory which is consumed by processing large messages.
+ *	To solve this problem the ProtoStream class stores the protobuf-messages in an other way.
+ *	Instead of using the repeat-function the data is written sequentially in a file.
+ *	Written in the format: 
+ * |4 bytes length-information of the first message| first message | 4 bytes length-information of second message | second message | ...
+ *
+ */
+class ProtoStream
+{
+	private:
+		bool m_write_mode;
+		uint32_t m_size;
+		
+		Logger m_log;
+		ostream* m_outfile;
+		istream* m_infile;
+		
+		
+	public:
+		ProtoStream(ostream * outfile);
+		ProtoStream(istream * infile);
+		virtual ~ProtoStream() {};
+		/**
+		 *	Writes a message to a file. 
+		 * 	This works only if the constructor was called wit a pointer 
+		 *  of an ostream.
+		 *  @param m The protobuf-message to be written.
+		 *  @return Returns true if data was written.
+		 */
+		bool writeMessage(google::protobuf::Message* m);
+		/**
+		 *	Resets the position of the get pointer. After that getNext 
+		 *  delivers the first message again.
+		 * 	This works only if the constructor was called wit a pointer 
+		 *  of an istream.
+		 *  @return Returns true if the pointer is reset.
+		 */
+		bool reset();
+		/**
+		 *	Delivers the protobuf-messages sequentially from file.
+		 * 	This works only if the constructor was called wit a pointer 
+		 *  of an istream.
+		 *  @param m The protobuf-message in which, the data should be 
+		 * 	written.
+		 *  @return Returns true if data was written to protobuf-message.
+		 */
+		bool getNext(google::protobuf::Message* m);
+};
+
+#endif