Descent3/ddio_win/serial.cpp

/*
* Descent 3 
* Copyright (C) 2024 Parallax Software
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
 * $Source: $
 * $Revision: 2 $
 * $Author: Jeff $
 * $Date: 5/11/99 11:28a $
 *
 * COM port interface
 *
 * $Log: /DescentIII/Main/ddio_win/serial.cpp $
 *
 * 2     5/11/99 11:28a Jeff
 * added serial support (SAMIR)
 *
 * 1     5/10/99 9:27p Jeff
 *
 */

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include "ddio_win.h"
#include "mem.h"
#include "pserror.h"
#include "ddio.h"

#include <stdio.h>

#define ASCII_XON 0x11
#define ASCII_XOFF 0x13

#define N_SERIAL_PORTS 4

// internal struct
typedef struct tWin32SerialPort {
  sbyte port;
  sbyte connect;
  HANDLE hFile;
  DCB dcb;
} tWin32SerialPort;

// takes port number 1-4, returns a port object
tSerialPort ddio_SerialOpenPort(int port_number, int baud) {
  COMMTIMEOUTS ctimeouts;
  char filename[16];
  tWin32SerialPort port_obj;

  ASSERT(port_number >= 1 && port_number <= N_SERIAL_PORTS);

  if (port_number < 1 || port_number > N_SERIAL_PORTS) {
    return NULL;
  }

  sprintf(filename, "COM%d", port_number);

  port_obj.hFile =
      CreateFile(filename, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

  if (port_obj.hFile == INVALID_HANDLE_VALUE) {
    return NULL;
  }
  port_obj.port = (sbyte)port_number;

  //	 Modem COMport is open.
  SetCommMask(port_obj.hFile, 0);
  SetupComm(port_obj.hFile, 1024, 1024);
  PurgeComm(port_obj.hFile, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR);

  //	Timeout after 10 sec.
  ctimeouts.ReadIntervalTimeout = 0xffffffff;
  ctimeouts.ReadTotalTimeoutMultiplier = 0;
  ctimeouts.ReadTotalTimeoutConstant = 10000;
  ctimeouts.WriteTotalTimeoutMultiplier = 0;
  ctimeouts.WriteTotalTimeoutConstant = 10000;
  SetCommTimeouts(port_obj.hFile, &ctimeouts);

  //	Setup parameters for Connection
  //	38400 8N1
  port_obj.dcb.DCBlength = sizeof(DCB);
  GetCommState(port_obj.hFile, &port_obj.dcb);

  port_obj.dcb.BaudRate = baud;

  mprintf((0, "COM%d (%d) is opened.\n", port_obj.port, baud));

  port_obj.dcb.fBinary = 1;
  port_obj.dcb.Parity = NOPARITY;
  port_obj.dcb.fNull = 0;
  port_obj.dcb.XonChar = ASCII_XON;
  port_obj.dcb.XoffChar = ASCII_XOFF;
  port_obj.dcb.XonLim = 1024;
  port_obj.dcb.XoffLim = 1024;
  port_obj.dcb.EofChar = 0;
  port_obj.dcb.EvtChar = 0;
  port_obj.dcb.fDtrControl = DTR_CONTROL_ENABLE; // dtr=on
  port_obj.dcb.fRtsControl = RTS_CONTROL_ENABLE;

  port_obj.dcb.ByteSize = 8;
  port_obj.dcb.StopBits = ONESTOPBIT;
  port_obj.dcb.fParity = FALSE;

  port_obj.dcb.fOutxDsrFlow = FALSE;
  port_obj.dcb.fOutxCtsFlow = FALSE; // rts/cts off

  // obj->dcb.fInX = obj->dcb.fOutX = 1;				// Software flow control XON/XOFF

  if (SetCommState(port_obj.hFile, &port_obj.dcb) == TRUE) {
    //	Send DTR
    EscapeCommFunction(port_obj.hFile, SETDTR);
    port_obj.connect = 1;
  } else {
    mprintf((1, "COMM: Unable to set CommState: (%x)\n", GetLastError()));
    CloseHandle(port_obj.hFile);
    port_obj.connect = 0;

    return NULL;
  }

  tWin32SerialPort *obj = (tWin32SerialPort *)mem_malloc(sizeof(tWin32SerialPort));
  if (obj) {
    memcpy(obj, &port_obj, sizeof(port_obj));
  } else {
    CloseHandle(port_obj.hFile);
    port_obj.connect = 0;
    return NULL;
  }

  return obj;
}

// takes port structure
void ddio_SerialClosePort(tSerialPort port) {
  tWin32SerialPort *obj = (tWin32SerialPort *)port;

  if (!port)
    return;

  if (obj->connect) {
    SetCommMask(obj->hFile, 0);
    EscapeCommFunction(obj->hFile, CLRDTR);
    PurgeComm(obj->hFile, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR);
    CloseHandle(obj->hFile);

    obj->connect = 0;
  }

  obj->hFile = NULL;
  mprintf((0, "COM%d closed.\n", obj->port));

  mem_free(obj);
}

bool ddio_SerialWriteByte(tSerialPort port, ubyte b) {
  tWin32SerialPort *obj = (tWin32SerialPort *)port;
  DWORD length;

  if (!obj->connect)
    return false;

  if (!WriteFile(obj->hFile, &b, 1, &length, NULL)) {
    mprintf((0, "Failed to write byte to COM%d\n", obj->port));
    return false;
  }

  return true;
}