[WIP] Updates the AM decoder module.

Removes a number of unused classes in an effort to remove RealBuffer
usage across the codebase (has been replaced by ReusableBuffers).

src/main/java/io/github/dsheirer/dsp/am/AMDemodulator.java

@@ -1,22 +1,83 @@
+/*******************************************************************************
+ * sdr-trunk
+ * Copyright (C) 2014-2018 Dennis Sheirer
+ *
+ * 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/>
+ *
+ ******************************************************************************/
 package io.github.dsheirer.dsp.am;
 
-public abstract class AMDemodulator
+import io.github.dsheirer.sample.buffer.ReusableBuffer;
+import io.github.dsheirer.sample.buffer.ReusableBufferQueue;
+import io.github.dsheirer.sample.buffer.ReusableComplexBuffer;
+
+/**
+ * Performs AM demodulation on baseband I/Q samples to produce demodulated float output.
+ */
+public class AMDemodulator
 {
-	private float mGain;
-	
-	public AMDemodulator( float gain )
-	{
-		mGain = gain;
-	}
-	
-    public float demodulate( float inphase, float quadrature )
+    private ReusableBufferQueue mReusableBufferQueue = new ReusableBufferQueue("AMDemodulator");
+    private int mOutputBufferPointer;
+    private float mGain;
+
+    /**
+     * Constructs this demodulator where the specified gain is applied to demodulated output samples.
+     *
+     * @param gain to apply to demodulated output samples.
+     */
+    public AMDemodulator(float gain)
     {
-    	return (float)Math.sqrt( ( inphase * inphase ) + 
-    							 ( quadrature * quadrature ) ) * mGain; 
+        mGain = gain;
+    }
+
+    /**
+     * Sets the gain to the specified level.
+     */
+    public void setGain(float gain)
+    {
+        mGain = gain;
+    }
+
+    /**
+     * Demodulates the comples I/Q sample and returns the demodulated output sample.
+     *
+     * @param inphase sample
+     * @param quadrature sample
+     * @return AM demodulated sample
+     */
+    public float demodulate(float inphase, float quadrature)
+    {
+        return (float)Math.sqrt((inphase * inphase) + (quadrature * quadrature)) * mGain;
+    }
+
+    /**
+     * Demodulates the reusable comples sample buffer and returns a demodulated audio buffer.
+     * @param complexBuffer to demodulate
+     * @return demodulated audio buffer.
+     */
+    public ReusableBuffer demodulate(ReusableComplexBuffer complexBuffer)
+    {
+        ReusableBuffer reusableBuffer = mReusableBufferQueue.getBuffer(complexBuffer.getSampleCount());
+        float[] input = complexBuffer.getSamples();
+        float[] output = reusableBuffer.getSamples();
+        mOutputBufferPointer = 0;
+
+        for(int x= 0; x < complexBuffer.getSamples().length; x += 2)
+        {
+            output[mOutputBufferPointer++] = demodulate(input[x], input[x + 1]);
+        }
+
+        complexBuffer.decrementUserCount();
+        reusableBuffer.incrementUserCount();
+
+        return reusableBuffer;
     }
-    
-	public void setGain( float gain )
-	{
-		mGain = gain;
-	}
 }