#include <windows.h>
#include <stdio.h>

HANDLE com=0;

int com_close() {
	if(com)	CloseHandle(com);
	com=0;
	return 0;
}

int com_startup(char *port) {

	DCB params = {0};
	COMMTIMEOUTS timeouts = {0};
FILE* dcbFile;
FILE* timeoutsFile;

	com = CreateFile(port, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

	if(com==INVALID_HANDLE_VALUE) {
		com=0;
		return 0;
	}

    //if (!GetCommTimeouts(com, &?)	    // Save original comm timeouts
		//error

	params.DCBlength=sizeof(params);
	if(!GetCommState(com, &params))
		return com_close();

	params.BaudRate = CBR_115200;
	params.ByteSize = 8;
	params.StopBits = ONESTOPBIT;
	params.Parity = NOPARITY;
    params.fDtrControl     = DTR_CONTROL_DISABLE;
    params.fRtsControl     = RTS_CONTROL_DISABLE;
    params.fOutxCtsFlow    = FALSE;
    params.fOutxDsrFlow    = FALSE;
    params.fDsrSensitivity = FALSE;
    params.fOutX           = FALSE;
    params.fInX            = FALSE;
    params.fTXContinueOnXoff = FALSE;

dcbFile = fopen("dcb.bin", "wb");
fwrite(&params, sizeof(params), 1, dcbFile);
fclose(dcbFile);

	if(!SetCommState(com, &params))
		return com_close();

	//read timeout = chars*multiplier+constant
	timeouts.ReadIntervalTimeout=0;
	timeouts.ReadTotalTimeoutConstant = 50;
	timeouts.ReadTotalTimeoutMultiplier = 10;
	timeouts.WriteTotalTimeoutConstant = 0;
	timeouts.WriteTotalTimeoutMultiplier = 0;

timeoutsFile = fopen("timeouts.bin", "wb");
fwrite(&timeouts, sizeof(timeouts), 1, timeoutsFile);
fclose(timeoutsFile);

	if(!SetCommTimeouts(com, &timeouts))
		return com_close();

	return 1;
}

void com_flush() {
	PurgeComm(com, PURGE_TXABORT | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_RXCLEAR);
}

void com_shutdown() {
	if(com) {
	    //SetCommTimeouts(com, &?);	    // restore original comm timeouts
		com_flush();
		com_close();
	}
}

//write byte to com port
int com_write(int c) {
	int written=0;
	if(com)
		WriteFile(com, &c, 1, &written, NULL);
	return written;
}

//write bytes to com port
//returns # of bytes written
int com_writebuf(char *buf, int size) {
	int written=0;
	if(com)
		WriteFile(com, buf, size, &written, NULL);
	return written;
}

//read bytes from com
//returns # of bytes read
int com_read(char *buf, int size) {
	int read=0;
	if(com)
		ReadFile(com, buf, size, &read, NULL);
	return read;
}