Simulator first commit

node_modules/speaker/examples/sine.js

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+'use strict'
+
+/**
+ * Code adapted from:
+ * http://blogs.msdn.com/b/dawate/archive/2009/06/24/intro-to-audio-programming-part-3-synthesizing-simple-wave-audio-using-c.aspx
+ */
+
+const Readable = require('stream').Readable
+const bufferAlloc = require('buffer-alloc')
+const Speaker = require('../')
+
+// the frequency to play
+const freq = parseFloat(process.argv[2], 10) || 440.0 // Concert A, default tone
+
+// seconds worth of audio data to generate before emitting "end"
+const duration = parseFloat(process.argv[3], 10) || 2.0
+
+console.log('generating a %dhz sine wave for %d seconds', freq, duration)
+
+// A SineWaveGenerator readable stream
+const sine = new Readable()
+sine.bitDepth = 16
+sine.channels = 2
+sine.sampleRate = 44100
+sine.samplesGenerated = 0
+sine._read = read
+
+// create a SineWaveGenerator instance and pipe it to the speaker
+sine.pipe(new Speaker())
+
+// the Readable "_read()" callback function
+function read (n) {
+  const sampleSize = this.bitDepth / 8
+  const blockAlign = sampleSize * this.channels
+  const numSamples = n / blockAlign | 0
+  const buf = bufferAlloc(numSamples * blockAlign)
+  const amplitude = 32760 // Max amplitude for 16-bit audio
+
+  // the "angle" used in the function, adjusted for the number of
+  // channels and sample rate. This value is like the period of the wave.
+  const t = (Math.PI * 2 * freq) / this.sampleRate
+
+  for (let i = 0; i < numSamples; i++) {
+    // fill with a simple sine wave at max amplitude
+    for (let channel = 0; channel < this.channels; channel++) {
+      const s = this.samplesGenerated + i
+      const val = Math.round(amplitude * Math.sin(t * s)) // sine wave
+      const offset = (i * sampleSize * this.channels) + (channel * sampleSize)
+      buf[`writeInt${this.bitDepth}LE`](val, offset)
+    }
+  }
+
+  this.push(buf)
+
+  this.samplesGenerated += numSamples
+  if (this.samplesGenerated >= this.sampleRate * duration) {
+    // after generating "duration" second of audio, emit "end"
+    this.push(null)
+  }
+}

node_modules/speaker/examples/stdin.js

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+'use strict'
+
+/**
+ * Pipe data to stdin and it will be played through your speakers.
+ */
+
+const Speaker = require('../')
+
+const speaker = new Speaker()
+process.stdin.pipe(speaker)