//******************************************************************************
// Message Object: messages consist of a topic and message text
// both of which are bounded character strings.
// This is a simple, but limited and possibly inefficient solution
// ****** CLASS INVARIANTS
// Thus all messages are subject to the size constraints (SIZE_TOPIC and SIZE_TEXT)
// and thus will not be listed as a PRECONDITION.
// The current implementation will only store up to this maximum size.
// ******* PERSISTANCE OF OBJECTS:
// Interesting feature is the ability of the message to read/write itself
// to an open file - this is reminiscent of the document archiving done
// in MFC's CDocument class.
// This feature supports persistence of objects where the place for storage is controlled
// by the application by the details of storage is arranged by the object itself
// Thus the application can decide to store all objects in one file or in many
// The non-default constructor will initialize a message from an open file.
// AUTHOR: Chris Wild
// DATE: July 25, 1997
//***************************************************************

#ifndef MESSAGE_H	// to keep from doubly defining this header file
#define MESSAGE_H
#include <windows.h>

const int SIZE_TOPIC = 50; // maximum size for topic field
const int SIZE_TEXT = 300; // maximum size for message text field

class CMessage {
public:
//************** constructors and desctructors
	// Default constructor builds an empty message
	CMessage();
	// This constructor initializes messages from file
	// fileHandle: is handle to already open message file
	CMessage(HANDLE fileHandle);
	// Copy constructor
	CMessage(const CMessage& Msg); // Copy constructor
	~CMessage();

//************** Operations
	// Sets the message topic
	//POST: Topic of this message is set to string
	void SetTopic(const char * );
	// Gets the message topic
	// PRE: thisTopic is big enough (maximum SIZE_TOPIC+1 characters)
	// POST: returns topic of this message
	void GetTopic(char * thisTopic) const;
	// Sets text of message
	void SetText(const char *);
	// returns text of message
	// PRE: thisMessage is big enough (maximum SIZE_TEXT+1 characters)
	void GetText(char * thisMessage) const;
	// Read/Write message to already open file
	bool ReadMsg(HANDLE fileHandle);
	bool WriteMsg(HANDLE fileHandle) const;
private:
	char topic[SIZE_TOPIC+1]; // fixed string buffer for convenience
	char text[SIZE_TEXT+1];
};
	
#endif