39 - WIP - incorporates the latest P25 C4FM decoder from master and

updates the LSM decoder to follow the same design pattern.  Adds LSM
decoder support to the demodulator viewer application.  The current
symbol timing gain for LSM is set too high -- is using the C4FM gain
and causes too much fluctuation in the timing error.

src/main/java/io/github/dsheirer/buffer/FloatCircularBuffer.java

@@ -0,0 +1,120 @@
+/*******************************************************************************
+ *     SDR Trunk 
+ *     Copyright (C) 2014 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.buffer;
+
+import java.util.Arrays;
+
+/**
+ * Circular sample buffer - allocates a buffer and stores samples in a circular
+ * fashion, overwriting older samples with newly arrived samples.  Initially
+ * fills buffer with 0-valued samples
+ *
+ * Can be used as a delay-type buffer, to delay samples by the 'size' amount
+ *
+ * @author denny
+ */
+public class FloatCircularBuffer
+{
+    float[] mBuffer;
+    int mBufferPointer = 0;
+
+    /**
+     * Creates a circular double buffer of the specified size and all entries filled with the specified initial value.
+     *
+     * @param size of the buffer
+     * @param initialFillValue to fill the buffer entries
+     */
+    public FloatCircularBuffer(int size, float initialFillValue)
+    {
+        mBuffer = new float[size];
+        Arrays.fill(mBuffer, initialFillValue);
+    }
+
+    /**
+     * Creates a circular double buffer of the specified size and all entries filled with an initial value of zero.
+     *
+     * @param size of the buffer
+     */
+    public FloatCircularBuffer(int size)
+    {
+        this(size, 0.0f);
+    }
+
+    public float[] getBuffer()
+    {
+        return mBuffer;
+    }
+
+    /**
+     * Puts the new value into the buffer and returns the oldest buffer value that it replaced
+     *
+     * @param newValue to add to the buffer
+     * @return oldest value that was overwritten by the new value
+     */
+    public float get(float newValue)
+    {
+        float oldestSample = mBuffer[mBufferPointer];
+
+        mBuffer[mBufferPointer] = newValue;
+
+        mBufferPointer++;
+
+        if(mBufferPointer >= mBuffer.length)
+        {
+            mBufferPointer = 0;
+        }
+
+        return oldestSample;
+    }
+
+    public float[] getAll()
+    {
+        int valuePointer = 0;
+        float[] values = new float[mBuffer.length];
+        int bufferPointer = mBufferPointer;
+
+        while(valuePointer < values.length)
+        {
+            values[valuePointer++] = mBuffer[bufferPointer++];
+
+            if(bufferPointer >= mBuffer.length)
+            {
+                bufferPointer = 0;
+            }
+        }
+
+        return values;
+    }
+
+    /**
+     * Places the new value into the buffer, overwriting the oldest value
+     *
+     * @param newValue to add to the buffer
+     */
+    public void put(float newValue)
+    {
+        mBuffer[mBufferPointer] = newValue;
+
+        mBufferPointer++;
+
+        if(mBufferPointer >= mBuffer.length)
+        {
+            mBufferPointer = 0;
+        }
+    }
+}