Add new functionality to set custom XON/XOFF characters

src/main/c/Posix/SerialPort_Posix.c

@@ -2,7 +2,7 @@
  * SerialPort_Posix.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Nov 14, 2021
+ *  Last Updated on:  Nov 19, 2021
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2021 Fazecast, Inc.
@@ -66,6 +66,8 @@ jfieldID rs485EnableTerminationField;
 jfieldID rs485RxDuringTxField;
 jfieldID rs485DelayBeforeField;
 jfieldID rs485DelayAfterField;
+jfieldID xonStartCharField;
+jfieldID xoffStopCharField;
 jfieldID timeoutModeField;
 jfieldID readTimeoutField;
 jfieldID writeTimeoutField;
@@ -147,6 +149,8 @@ JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_initializeLibrar
 	rs485RxDuringTxField = (*env)->GetFieldID(env, serialCommClass, "rs485RxDuringTx", "Z");
 	rs485DelayBeforeField = (*env)->GetFieldID(env, serialCommClass, "rs485DelayBefore", "I");
 	rs485DelayAfterField = (*env)->GetFieldID(env, serialCommClass, "rs485DelayAfter", "I");
+	xonStartCharField = (*env)->GetFieldID(env, serialCommClass, "xonStartChar", "B");
+	xoffStopCharField = (*env)->GetFieldID(env, serialCommClass, "xoffStopChar", "B");
 	timeoutModeField = (*env)->GetFieldID(env, serialCommClass, "timeoutMode", "I");
 	readTimeoutField = (*env)->GetFieldID(env, serialCommClass, "readTimeout", "I");
 	writeTimeoutField = (*env)->GetFieldID(env, serialCommClass, "writeTimeout", "I");
@@ -248,10 +252,14 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	unsigned char rs485RxDuringTx = (*env)->GetBooleanField(env, obj, rs485RxDuringTxField);
 	unsigned char isDtrEnabled = (*env)->GetBooleanField(env, obj, isDtrEnabledField);
 	unsigned char isRtsEnabled = (*env)->GetBooleanField(env, obj, isRtsEnabledField);
+	char xonStartChar = (*env)->GetByteField(env, obj, xonStartCharField);
+	char xoffStopChar = (*env)->GetByteField(env, obj, xoffStopCharField);
 
 	// Clear any serial port flags and set up raw non-canonical port parameters
 	struct termios options = { 0 };
 	tcgetattr(port->handle, &options);
+	options.c_cc[VSTART] = (unsigned char)xonStartChar;
+	options.c_cc[VSTOP] = (unsigned char)xoffStopChar;
 	options.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | INPCK | IGNPAR | IGNCR | ICRNL | IXON | IXOFF);
 	options.c_oflag &= ~OPOST;
 	options.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
@@ -423,6 +431,18 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_waitForEvent(JNI
 	// TODO: START THREAD TO HANDLE ALL OF THIS IN C
 	// TODO: LISTEN FOR ERROR EVENTS IN CASE SERIAL PORT GETS UNPLUGGED? TEST IF WORKS?
 	// TODO: STORE ALL AVAILABLE PORTS IN C, RECHECK AVAILABLE PORTS UPON RESCAN SO ALREADY OPEN PORTS DON'T GET MESSED UP
+	/*
+	ioctl: TIOCMIWAIT
+	ioctl: TIOCGICOUNT
+	static final public int LISTENING_EVENT_BREAK_INTERRUPT = 0x00010000;
+	static final public int LISTENING_EVENT_CARRIER_DETECT = 0x00020000;
+	static final public int LISTENING_EVENT_CTS = 0x00040000;
+	static final public int LISTENING_EVENT_DSR = 0x00080000;
+	static final public int LISTENING_EVENT_RING_INDICATOR = 0x00100000;
+	static final public int LISTENING_EVENT_FRAMING_ERROR = 0x00200000;
+	static final public int LISTENING_EVENT_OVERRUN_ERROR = 0x00400000;
+	static final public int LISTENING_EVENT_PARITY_ERROR = 0x00800000;
+	static final public int LISTENING_EVENT_OUTPUT_EMPTY = 0x01000000;*/
 
 	// Wait for a serial port event
 	if (poll(&waitingSet, 1, 500) <= 0)

src/main/c/Posix/com_fazecast_jSerialComm_SerialPort.h

@@ -47,12 +47,32 @@ extern "C" {
 #define com_fazecast_jSerialComm_SerialPort_TIMEOUT_WRITE_BLOCKING 256L
 #undef com_fazecast_jSerialComm_SerialPort_TIMEOUT_SCANNER
 #define com_fazecast_jSerialComm_SerialPort_TIMEOUT_SCANNER 4096L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_TIMED_OUT
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_TIMED_OUT 0L
 #undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DATA_AVAILABLE
 #define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DATA_AVAILABLE 1L
 #undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DATA_RECEIVED
 #define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DATA_RECEIVED 16L
 #undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DATA_WRITTEN
 #define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DATA_WRITTEN 256L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_BREAK_INTERRUPT
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_BREAK_INTERRUPT 65536L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_CARRIER_DETECT
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_CARRIER_DETECT 131072L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_CTS
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_CTS 262144L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DSR
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_DSR 524288L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_RING_INDICATOR
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_RING_INDICATOR 1048576L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_FRAMING_ERROR
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_FRAMING_ERROR 2097152L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_OVERRUN_ERROR
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_OVERRUN_ERROR 4194304L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_PARITY_ERROR
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_PARITY_ERROR 8388608L
+#undef com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_OUTPUT_EMPTY
+#define com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_OUTPUT_EMPTY 16777216L
 /*
  * Class:     com_fazecast_jSerialComm_SerialPort
  * Method:    getCommPorts

src/main/c/Windows/SerialPort_Windows.c

@@ -2,7 +2,7 @@
  * SerialPort_Windows.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Nov 12, 2021
+ *  Last Updated on:  Nov 19, 2021
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2021 Fazecast, Inc.
@@ -59,6 +59,8 @@ jfieldID receiveDeviceQueueSizeField;
 jfieldID rs485ModeField;
 jfieldID rs485DelayBeforeField;
 jfieldID rs485DelayAfterField;
+jfieldID xonStartCharField;
+jfieldID xoffStopCharField;
 jfieldID timeoutModeField;
 jfieldID readTimeoutField;
 jfieldID writeTimeoutField;
@@ -374,6 +376,8 @@ JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_initializeLibrar
 	rs485ModeField = env->GetFieldID(serialCommClass, "rs485Mode", "Z");
 	rs485DelayBeforeField = env->GetFieldID(serialCommClass, "rs485DelayBefore", "I");
 	rs485DelayAfterField = env->GetFieldID(serialCommClass, "rs485DelayAfter", "I");
+	xonStartCharField = env->GetFieldID(serialCommClass, "xonStartChar", "B");
+	xoffStopCharField = env->GetFieldID(serialCommClass, "xoffStopChar", "B");
 	timeoutModeField = env->GetFieldID(serialCommClass, "timeoutMode", "I");
 	readTimeoutField = env->GetFieldID(serialCommClass, "readTimeout", "I");
 	writeTimeoutField = env->GetFieldID(serialCommClass, "writeTimeout", "I");
@@ -443,6 +447,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	int readTimeout = env->GetIntField(obj, readTimeoutField);
 	int writeTimeout = env->GetIntField(obj, writeTimeoutField);
 	int eventsToMonitor = env->GetIntField(obj, eventFlagsField);
+	char xonStartChar = env->GetByteField(obj, xonStartCharField);
+	char xoffStopChar = env->GetByteField(obj, xoffStopCharField);
 	DWORD sendDeviceQueueSize = (DWORD)env->GetIntField(obj, sendDeviceQueueSizeField);
 	DWORD receiveDeviceQueueSize = (DWORD)env->GetIntField(obj, receiveDeviceQueueSizeField);
 	BYTE rs485ModeEnabled = (BYTE)env->GetBooleanField(obj, rs485ModeField);
@@ -487,8 +493,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configPort(J
 	dcbSerialParams.fNull = FALSE;
 	dcbSerialParams.XonLim = 2048;
 	dcbSerialParams.XoffLim = 512;
-	dcbSerialParams.XonChar = (char)17;
-	dcbSerialParams.XoffChar = (char)19;
+	dcbSerialParams.XonChar = xonStartChar;
+	dcbSerialParams.XoffChar = xoffStopChar;
 
 	// Apply changes
 	return (SetCommState(port->handle, &dcbSerialParams) && Java_com_fazecast_jSerialComm_SerialPort_configTimeouts(env, obj, serialPortPointer, timeoutMode, readTimeout, writeTimeout, eventsToMonitor));

src/main/java/com/fazecast/jSerialComm/SerialPort.java

@@ -385,6 +385,7 @@ public final class SerialPort
 	static final public int TIMEOUT_SCANNER = 0x00001000;
 
 	// Serial Port Listening Events
+	static final public int LISTENING_EVENT_TIMED_OUT = 0x00000000;
 	static final public int LISTENING_EVENT_DATA_AVAILABLE = 0x00000001;
 	static final public int LISTENING_EVENT_DATA_RECEIVED = 0x00000010;
 	static final public int LISTENING_EVENT_DATA_WRITTEN = 0x00000100;
@@ -395,6 +396,7 @@ public final class SerialPort
 	private volatile int timeoutMode = TIMEOUT_NONBLOCKING, readTimeout = 0, writeTimeout = 0, flowControl = 0;
 	private volatile int sendDeviceQueueSize = 4096, receiveDeviceQueueSize = 4096;
 	private volatile int safetySleepTimeMS = 200, rs485DelayBefore = 0, rs485DelayAfter = 0;
+	private volatile byte xonStartChar = 17, xoffStopChar = 19;
 	private volatile SerialPortDataListener userDataListener = null;
 	private volatile SerialPortEventListener serialEventListener = null;
 	private volatile String comPort, friendlyName, portDescription;
@@ -1299,6 +1301,31 @@ public final class SerialPort
 		return true;
 	}
 
+	/**
+	 * Sets custom XON/XOFF flow control characters for the device.
+	 * <p>
+	 * Custom characters should almost never be used, as most devices expect the XON/START character to be 17 and the
+	 * XOFF/STOP character to be 13. If your device expects different flow control characters, they may be changed using
+	 * this function.
+	 *
+	 * @param xonStartCharacter The decimal-based character to use as an XON signal.
+	 * @param xoffStopCharacter The decimal-based character to use as an XOFF signal.
+	 * @return Whether the port configuration is valid or disallowed on this system (only meaningful after the port is already opened).
+	 */
+	public final synchronized boolean setXonXoffCharacters(byte xonStartCharacter, byte xoffStopCharacter)
+	{
+		xonStartChar = xonStartCharacter;
+		xoffStopChar = xoffStopCharacter;
+
+		if (portHandle > 0)
+		{
+			if (safetySleepTimeMS > 0)
+				try { Thread.sleep(safetySleepTimeMS); } catch (Exception e) { Thread.currentThread().interrupt(); }
+			return configPort(portHandle);
+		}
+		return true;
+	}
+
 	/**
 	 * Gets a descriptive string representing this serial port or the device connected to it.
 	 * <p>