rfid-credential-provider/Provider/RfidCredentialProvider/Serial.cpp

#include "Serial.h"
#include "Registry.h"
#include <iostream>

Serial::Serial()
{
	//We're not yet connected
	this->connected = false;

	HKEY hKey;
	if(RegOpenKeyExW(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Tyler Menezes\\Rfid Login", 0, KEY_READ, &hKey) != ERROR_SUCCESS){
		delete hKey;
		return; // Token not recognized.
	}

	std::wstring port;
	GetStringRegKey(hKey, L"Port", port, L"COM3");

	//Try to connect to the given port throuh CreateFile
	this->hSerial = CreateFile(port.c_str(),
			GENERIC_READ | GENERIC_WRITE,
			0,
			NULL,
			OPEN_EXISTING,
			FILE_ATTRIBUTE_NORMAL,
			NULL);

	//Check if the connection was successfull
	if(this->hSerial==INVALID_HANDLE_VALUE)
	{
		//If not success full display an Error
		if(GetLastError()==ERROR_FILE_NOT_FOUND){

			//Print Error if neccessary
			printf("ERROR: Handle was not attached. Reason: %s not available.\n");

		}
		else
		{
			printf("ERROR!!!");
		}
	}
	else
	{
		//If connected we try to set the comm parameters
		DCB dcbSerialParams = {0};

		//Try to get the current
		if (!GetCommState(this->hSerial, &dcbSerialParams))
		{
			//If impossible, show an error
			printf("failed to get current serial parameters!");
		}
		else
		{
			//Define serial connection parameters for the arduino board
			dcbSerialParams.BaudRate=CBR_9600;
			dcbSerialParams.ByteSize=8;
			dcbSerialParams.StopBits=ONESTOPBIT;
			dcbSerialParams.Parity=NOPARITY;

			 //Set the parameters and check for their proper application
			 if(!SetCommState(hSerial, &dcbSerialParams))
			 {
				printf("ALERT: Could not set Serial Port parameters");
			 }
			 else
			 {
				 //If everything went fine we're connected
				 this->connected = true;
				 //We wait 2s as the arduino board will be reseting
				 Sleep(ARDUINO_WAIT_TIME);
			 }
		}
	}

}

Serial::~Serial()
{
	//Check if we are connected before trying to disconnect
	if(this->connected)
	{
		//We're no longer connected
		this->connected = false;
		//Close the serial handler
		CloseHandle(this->hSerial);
	}
}

int Serial::ReadData(char *buffer, unsigned int nbChar)
{
	//Number of bytes we'll have read
	DWORD bytesRead;
	//Number of bytes we'll really ask to read
	unsigned int toRead;

	//Use the ClearCommError function to get status info on the Serial port
	ClearCommError(this->hSerial, &this->errors, &this->status);

	//Check if there is something to read
	if(this->status.cbInQue>0)
	{
		//If there is we check if there is enough data to read the required number
		//of characters, if not we'll read only the available characters to prevent
		//locking of the application.
		if(this->status.cbInQue>nbChar)
		{
			toRead = nbChar;
		}
		else
		{
			toRead = this->status.cbInQue;
		}

		//Try to read the require number of chars, and return the number of read bytes on success
		if(ReadFile(this->hSerial, buffer, toRead, &bytesRead, NULL) && bytesRead != 0)
		{
			return bytesRead;
		}

	}

	//If nothing has been read, or that an error was detected return -1
	return -1;

}


bool Serial::WriteData(char *buffer, unsigned int nbChar)
{
	DWORD bytesSend;

	//Try to write the buffer on the Serial port
	if(!WriteFile(this->hSerial, (void *)buffer, nbChar, &bytesSend, 0))
	{
		//In case it don't work get comm error and return false
		ClearCommError(this->hSerial, &this->errors, &this->status);

		return false;
	}
	else
		return true;
}

bool Serial::IsConnected()
{
	//Simply return the connection status
	return this->connected;
}