/*
 * Windows 16 (& 32 & 64?) compatible serial port library
 * Uses 8 databits, no parity, 1 stop bit, no handshaking
 * By: Thomas Buck <taucher.bodensee@gmail.com>
 * Visit: www.xythobuz.org
 */

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

#define BAUD CBR_19200;

HANDLE hSerial = INVALID_HANDLE_VALUE;

// Open the serial port
int serialOpen(char *port) {
	DCB dcbSerialParams = {0};
	COMMTIMEOUTS timeouts = {0};

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

	if (hSerial == INVALID_HANDLE_VALUE) {
		return -1;
	}
	

	dcbSerial.DCBlength = sizeof(dcbSerialParams);
	if (!GetCommState(hSerial, &dcbSerialParams)) {
		CloseHandle(hSerial);
		hSerial = INVALID_HANDLE_VALUE;
		return -1;
	}
	dcbSerialParams.BaudRate = BAUD;
	dcbSerialParams.ByteSize = 8;
	dcbSerialParams.StopBits = ONESTOPBIT;
	dcbSerialParams.Parity = NOPARITY;
	if (!SetCommState(hSerial, &dcbSerialParams)) {
		CloseHandle(hSerial);
		hSerial = INVALID_HANDLE_VALUE;
		return -1;
	}
	
	timeouts.ReadIntervalTimeout = 50;
	timeouts.ReadTotalTimeoutConstant = 50;
	timeouts.ReadTotalTimeoutMultiplier = 10;
	timeouts.WriteTotalTimeoutConstant = 50;
	timeouts.WriteTotalTimeoutMultiplier = 10;

	if (!SetCommTimeouts(hSerial, &timeouts)) {
		CloseHandle(hSerial);
		hSerial = INVALID_HANDLE_VALUE;
		return -1;
	}

	return 0;
}

// Write to port. Returns number of characters sent, -1 on error
ssize_t serialWrite(char *data, size_t length) {
	DWORD dwBytesWritten = 0;
	if (!WriteFile(hSerial, data, length, &dwBytesWritten, NULL)) {
		return -1;
	}
	return dwBytesWritten;

}

// Read from port. Return number of characters read, 0 if none available, -1 on error
ssize_t serialRead(char *data, size_t length) {
	DWORD dwBytesRead = 0;
	if (!ReadFile(hSerial, data, length, &dwBytesRead, NULL)) {
		return -1;
	}
	return dwBytesRead;
}

// Close the serial Port
void serialClose(void) {
	CloseHandle(hSerial);
	hSerial = INVALID_HANDLE_VALUE;
}