//*********************************************************************
// Handles fixed size messages
// Returns strings through reference parameters because of C++'s
// policy on array parameters
// I would prefer to return as value of function for GetTopic and GetText
// but then strings would have to be a first class object
// we will deal with this in later implementations
// AUTHOR: Chris Wild
// DATE: July 25, 1997
//*********************************************************************
#include "message.h"
#include <string.h>
#include <iostream.h>

CMessage::CMessage()
{
	ZeroMemory(topic,sizeof(topic)); // I like clean memoery
	ZeroMemory(text, sizeof(text));

}

// Initializes message from already open file
CMessage::CMessage(HANDLE fileHandle)
{
	DWORD nBytes;

	ReadFile(fileHandle,topic,SIZE_TOPIC+1,&nBytes,0);
	ReadFile(fileHandle,text,SIZE_TEXT+1,&nBytes,0);
}

CMessage::CMessage(const CMessage& msg)
{
	strncpy(topic,msg.topic,SIZE_TOPIC+1);
	strncpy(text,msg.text,SIZE_TEXT+1);
}


CMessage::~CMessage()
{ // nothing to do
}

// Sets the message topic
//POST: Topic of this message is set to Cstring
// I don't assume that the input string "thisTopic" is the
// correct length.
void CMessage::SetTopic(const char* thisTopic)
{
	int size = (strlen(thisTopic)>SIZE_TOPIC?SIZE_TOPIC:strlen(thisTopic));
	strncpy(topic,thisTopic,size);
	topic[size] = '\0';	// force null terminated string
}
// Gets the message topic
// PRE: thisTopic is big enough (maximum SIZE_TOPIC+1 characters)
void CMessage::GetTopic(char* thisTopic) const
{
	strncpy(thisTopic,topic,strlen(topic)+1);
}

// Sets text of message
// I don't assume that the input string "thisMessage" is the
// correct length.

void CMessage::SetText(const char* thisMsg)
{
	int size = (strlen(thisMsg)>SIZE_TEXT?SIZE_TEXT:strlen(thisMsg));
	strncpy(text,thisMsg,size);
	text[size] = '\0';
}


// returns text of message
// PRE: thisMsg is big enough (maximum SIZE_TEXT+1 characters)
void CMessage::GetText(char* thisMsg) const
{
	strncpy(thisMsg,text,strlen(text)+1);
}

bool CMessage::ReadMsg(HANDLE fileHandle) 
{
	DWORD nBytes;

	if(!ReadFile(fileHandle,topic,SIZE_TOPIC+1,&nBytes,0))
		return FALSE;
	if(!ReadFile(fileHandle,text,SIZE_TEXT+1,&nBytes,0))
		return FALSE;
	return TRUE;
}

bool CMessage::WriteMsg(HANDLE fileHandle) 
{
	DWORD nBytes;

	if(!WriteFile(fileHandle, topic, SIZE_TOPIC+1, &nBytes,NULL)) {
		cerr << "Error: " << GetLastError() <<
			" when writing file:" << endl;
		return FALSE;
	}
	if(!WriteFile(fileHandle, text, SIZE_TEXT+1, &nBytes,NULL)) {
		cerr << "Error: " << GetLastError() <<
			" when writing file:" << endl;
		return FALSE;
	}
	return TRUE;

}