Update README.md

Examples/SwiftSerialExample/Sources/main.swift

@@ -11,7 +11,7 @@ let test3Strings: String = testString + "\n" + testString + "\n" + testString +
 
 let arguments = CommandLine.arguments
 guard arguments.count >= 2 else {
-    print("Need serial port name, e.g. /dev/ttyUSB0 as the first argument.")
+    print("Need serial port name, e.g. /dev/ttyUSB0 or /dev/cu.usbserial as the first argument.")
     exit(1)
 }
 

Examples/SwiftSerialIM/Package.swift

@@ -0,0 +1,8 @@
+import PackageDescription
+
+let package = Package(
+    name: "SwiftSerialIM",
+    dependencies: [
+    	.Package(url: "https://github.com/yeokm1/SwiftSerial.git", majorVersion: 0)
+	]
+)

Examples/SwiftSerialIM/Sources/main.swift

@@ -0,0 +1,127 @@
+import Foundation
+import SwiftSerial
+
+
+let arguments = CommandLine.arguments
+guard arguments.count >= 2 else {
+    print("Need serial port name, e.g. /dev/ttyUSB0 or /dev/cu.usbserial as the first argument.")
+    exit(1)
+}
+
+print("Connect a null modem serial cable between two machines before you continue to use this program")
+
+let portName = arguments[1]
+let serialPort: SerialPort = SerialPort(path: portName)
+
+var myturn = true
+
+// Prepares the stdin so we can getchar() without echoing 
+func prepareStdin() {
+
+    // Set up the control structure
+    var settings = termios()
+
+    // Get options structure for stdin
+    tcgetattr(STDIN_FILENO, &settings)
+
+    //Turn off ICANON and ECHO
+    settings.c_lflag &= ~tcflag_t(ICANON | ECHO)
+
+    tcsetattr(STDIN_FILENO, TCSANOW, &settings)
+}
+
+func getKeyPress () -> UnicodeScalar {
+    let valueRead: Int = Int(getchar())
+
+    guard let charRead = UnicodeScalar(valueRead) else{
+        return UnicodeScalar("")!
+    }
+
+    return charRead
+}
+
+func printToScreenFrom(myself: Bool, characterToPrint: UnicodeScalar){
+
+    if(myturn && !myself){
+        myturn = false
+        print("\nOther: ", terminator:"")
+    } else if (!myturn && myself){
+        myturn = true
+        print("\nMe: ", terminator:"")
+    }
+
+    print(characterToPrint, terminator:"")
+}
+
+func backgroundRead() {
+    while true{
+        do{
+            let readCharacter = try serialPort.readChar()
+            printToScreenFrom(myself: false, characterToPrint: readCharacter)
+        } catch {
+            print("Error: \(error)")
+        }
+    }  
+}
+
+
+
+do {
+
+    print("Attempting to open port: \(portName)")
+    try serialPort.openPort()
+    print("Serial port \(portName) opened successfully.")
+    defer {
+        serialPort.closePort()
+        print("Port Closed")
+    }
+
+    serialPort.setSettings(receiveRate: .baud9600,
+                           transmitRate: .baud9600,
+                           minimumBytesToRead: 1)
+
+    prepareStdin()
+
+
+    //Turn off output buffering if not multiple threads will have problems printing
+    setbuf(stdout, nil);
+
+
+    //Run the serial port reading function in another thread
+#if os(Linux)
+    var readingThread = pthread_t()
+
+    let pthreadFunc: @convention(c) (UnsafeMutableRawPointer?) -> UnsafeMutableRawPointer? = {
+        observer in
+
+        backgroundRead()
+    }
+
+    pthread_create(&readingThread, nil, pthreadFunc, nil)
+
+#elseif os(OSX)
+    DispatchQueue.global(qos: .userInitiated).async { 
+        backgroundRead()
+    }
+
+#endif
+
+
+    print("\nReady to send and receive messages in realtime!")
+    print("\nMe: ", terminator:"")
+
+
+    while true {
+        var enteredKey = getKeyPress()
+        printToScreenFrom(myself: true, characterToPrint: enteredKey)
+        var _ = try serialPort.writeChar(enteredKey)
+    }
+
+
+} catch PortError.failedToOpen {
+    print("Serial port \(portName) failed to open. You might need root permissions.")
+} catch {
+    print("Error: \(error)")
+}
+
+

README.md

@@ -59,8 +59,11 @@ nano ~/.profile
 export PATH=$HOME/swift-3.0/usr/bin:$PATH
 ```
 ## Jumping straight into sample code
+To get started quickly, you can take a look at my example projects [here](Examples/). 
 
-To get started quickly, you can take a look at my example project [here](Examples/SwiftSerialExample). In order to run the example properly, you need to connect one of your (USB/UART) serial ports in a loopback manner. Basically, you short the TX and RX pins of the serial port.
+### Example 1: Loopback Test
+
+In order to run this example properly, you need to connect one of your (USB/UART) serial ports in a loopback manner. Basically, you short the TX and RX pins of the serial port. This library currently only support the `/dev/cu.*` variant on Mac. Read the beginning of the API usage section for more details.
 
 ```bash
 git clone https://github.com/yeokm1/SwiftSerial.git
@@ -71,11 +74,28 @@ swift build
 sudo ./.build/debug/SwiftSerialExample /dev/ttyUSB0
 
 #For Mac: Root is not required
-./.build/debug/SwiftSerialExample /dev/tty.usbserial
+./.build/debug/SwiftSerialExample /dev/cu.usbserial
 
 #If all goes well you should see a series of messages informing you that data transmitted has been received properly.
 ```
 
+### Example 2: A chat app between 2 machines
+
+In order to run this example properly, you need 2 machines connected by a [null-modem cable](https://en.wikipedia.org/wiki/Null_modem) or 2 USB-Serial adapters with the TX-RX pins connected to each other. Run a copy of my program on both machines.
+
+```bash
+git clone https://github.com/yeokm1/SwiftSerial.git
+cd SwiftSerial/Examples/SwiftSerialIM/
+swift build
+
+#For Linux: You need root to access the serial port. Replace /dev/ttyUSB0 with the name of your serial port under test
+sudo ./.build/debug/SwiftSerialIM /dev/ttyUSB0
+
+#For Mac: Root is not required
+./.build/debug/SwiftSerialIM /dev/cu.usbserial
+```
+People at both machines can now "chat" with each other.
+
 ## Integrating with your project
 
 Add SwiftSerial as a dependency to your project by editing the `Package.swift` file.
@@ -102,7 +122,9 @@ Then run `swift build` to download the dependencies and compile your project. Yo
 ```swift
 let serialPort: SerialPort = SerialPort(path: portName)
 ```
-Supply the portname that you wish to open like `/dev/ttyUSB0` or `/dev/tty.usbserial`.
+Supply the portname that you wish to open like `/dev/ttyUSB0` or `/dev/cu.usbserial`. 
+
+For Macs, this library currently only works with the `/dev/cu.*` ports instead of the `/dev/tty.*`. I have enabled blocking on the serial port to prevent high CPU usage which will prevent the `/dev/tty.*` from working. Read more about the differences between the two [here](http://stackoverflow.com/questions/8632586/macos-whats-the-difference-between-dev-tty-and-dev-cu). If there is a problem, open an issue describing your situation and let me look into it.
 
 ### Opening the Serial Port
 
@@ -166,6 +188,11 @@ func readUntilChar(_ terminator: CChar) throws -> String
 ```
 Keep reading until the specified CChar is encountered. Return the string read so far without that value.
 
+```swift
+func readChar() throws -> UnicodeScalar
+```
+Read only one character. This works best if `minimumBytesToRead` has been set to `1` when opening the port. This function internally calls `readBytes()`.
+
 ### Writing data to the port
 
 There are several functions you can use to write data. All functions here are blocking till all the data has been written. All functions can throw `PortError.mustBeOpen`.
@@ -185,6 +212,11 @@ func writeBytes(from buffer: UnsafeMutablePointer<UInt8>, size: Int) throws -> I
 ```
 Function for those that want to mess with unsafe pointers. You have to specify how many bytes have to be written. Will return how many bytes actually written.
 
+```swift
+func writeChar(_ character: UnicodeScalar) throws -> Int{
+```
+Writes only one character. Will return `1` if successful. This function internally calls `writeString()`. Pull requests for a better way of doing this is appreciated.
+
 ### Closing the port
 
 Just do `serialPort.closePort()` to close the port once you are done using it.

Sources/SwiftSerial.swift

@@ -191,7 +191,7 @@ public enum ParityType {
     case even
     case odd
 
-	var parityValue: tcflag_t {
+    var parityValue: tcflag_t {
         switch self {
         case .none:
             return 0
@@ -248,7 +248,7 @@ public class SerialPort {
     #if os(Linux)
         fileDescriptor = open(path, readWriteParam | O_NOCTTY)
     #elseif os(OSX)
-        fileDescriptor = open(path, readWriteParam | O_NOCTTY | O_EXLOCK | O_NONBLOCK)
+        fileDescriptor = open(path, readWriteParam | O_NOCTTY | O_EXLOCK)
     #endif
 
         // Throw error if open() failed
@@ -389,7 +389,7 @@ extension SerialPort {
             data = Data(bytes: buffer, count: bytesRead)
         } else {
             //This is to avoid the case where bytesRead can be negative causing problems allocating the Data buffer
-       	    data = Data(bytes: buffer, count: 0)
+            data = Data(bytes: buffer, count: 0)
         }
 
         return data
@@ -421,17 +421,17 @@ extension SerialPort {
         }
 
         while true {
-        	let bytesRead = try readBytes(into: buffer, size: 1)
+            let bytesRead = try readBytes(into: buffer, size: 1)
 
-        	if bytesRead > 0 {
-        		let character = CChar(buffer[0])
+            if bytesRead > 0 {
+                let character = CChar(buffer[0])
                 
                 if character == terminator {
                     break
                 } else {
                     data.append(buffer, count: 1)
                 }
-        	}
+            }
         }
 
         if let string = String(data: data, encoding: String.Encoding.utf8) {
@@ -445,6 +445,25 @@ extension SerialPort {
         let newlineChar = CChar(10) // Newline/Line feed character `\n` is 10
         return try readUntilChar(newlineChar)
     }
+
+    public func readChar() throws -> UnicodeScalar {
+        let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: 1)
+        
+        defer {
+            buffer.deallocate(capacity: 1)
+        }
+
+        while true {
+            let bytesRead = try readBytes(into: buffer, size: 1)
+
+            if bytesRead > 0 {
+                let character = UnicodeScalar(buffer[0])
+                return character     
+            }
+        }         
+
+    }
+
 }
 
 // MARK: Transmitting
@@ -480,4 +499,10 @@ extension SerialPort {
 
         return try writeData(data)
     }
+
+    public func writeChar(_ character: UnicodeScalar) throws -> Int{
+        let stringEquiv = String(character)
+        let bytesWritten = try writeString(stringEquiv)
+        return bytesWritten
+    }
 }