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\\KORNET\\WinLogin", 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, nullptr) && 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, nullptr))
	{
		// 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;
}