March 2014 update

Task/Morse-code/Kotlin/morse-code.kotlin

@@ -0,0 +1,55 @@
+import javax.sound.sampled.AudioFormat
+import javax.sound.sampled.AudioSystem
+
+val morseCode = hashMapOf('a' to ".-",   'b' to "-...", 'c' to "-.-.",
+                          'd' to "-..",  'e' to ".",    'f' to "..-.",
+                          'g' to "--.",  'h' to "....", 'i' to "..",
+                          'j' to ".---", 'k' to "-.-",  'l' to ".-..",
+                          'm' to "--",   'n' to "-.",   'o' to "---",
+                          'p' to ".--.", 'q' to "--.-", 'r' to ".-.",
+                          's' to "...",  't' to "-",    'u' to "..-",
+                          'v' to "...-", 'w' to ".--",  'x' to "-..-",
+                          'y' to "-.--", 'z' to "--..",
+
+                          '0' to ".....", '1' to "-....", '2' to "--...",
+                          '3' to "---..", '4' to "----.", '5' to "-----",
+                          '6' to ".----", '7' to "..---", '8' to "...--",
+                          '9' to "....-",
+
+                          ' ' to "/",       ',' to "--..--", '!' to "-.-.--",
+                          '"' to ".-..-.",  '.' to ".-.-.-", '?' to "..--..",
+                          '\'' to ".----.", '/' to "-..-.",  '-' to "-....-",
+                          '(' to "-.--.-",  ')' to "-.--.-")
+
+val symbolDurationInMs = hashMapOf('.' to 200, '-' to 500, '/' to 1000)
+
+fun main(args: Array<String>) {
+    args.forEach { playMorseCode(toMorseCode(it.toLowerCase())) }
+}
+
+fun toMorseCode(message: String) = message.filter { morseCode.containsKey(it) }
+                                          .fold("")  { (acc, ch) -> acc + morseCode[ch]!! }
+
+fun playMorseCode(morseCode: String) = morseCode.forEach { symbol -> beep(symbolDurationInMs[symbol]!!) }
+
+fun beep(durationInMs: Int) {
+    val soundBuffer = ByteArray(durationInMs * 8)
+    for ((i, elem) in soundBuffer.withIndices()) {
+        soundBuffer[i] = (Math.sin(i / 8.0 * 2.0 * Math.PI) * 80.0).toByte()
+    }
+
+    val audioFormat = AudioFormat(/*sampleRate*/ 8000F,
+                                  /*sampleSizeInBits*/ 8,
+                                  /*channels*/ 1,
+                                  /*signed*/ true,
+                                  /*bigEndian*/ false)
+    with (AudioSystem.getSourceDataLine(audioFormat)!!) {
+        open(audioFormat)
+
+        start()
+        write(soundBuffer, 0, soundBuffer.size)
+        drain()
+
+        close()
+    }
+}