WIP - correctly implements the 2x oversampled polyphase channelizer.

src/buffer/ReverseFloatCircularBuffer.java

@@ -0,0 +1,89 @@
+/*******************************************************************************
+ * sdrtrunk
+ * Copyright (C) 2014-2017 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 buffer;
+
+/**
+ * Circular sample buffer - allocates a buffer and stores samples in a circular
+ * fashion, overwriting older samples with newly arrived samples.
+ */
+public class ReverseFloatCircularBuffer
+{
+    private float[] mBuffer;
+    private int mBufferPointer = 0;
+
+    public ReverseFloatCircularBuffer(int size)
+    {
+        mBuffer = new float[size];
+        mBufferPointer = mBuffer.length - 1;
+    }
+
+    /**
+     * Size of the buffer
+     * @return
+     */
+    public int getSize()
+    {
+        return mBuffer.length;
+    }
+
+    public float[] getBuffer()
+    {
+        return mBuffer;
+    }
+
+    /**
+     * Adds the new value to this buffer.
+     */
+    public void put(float newValue)
+    {
+        mBuffer[mBufferPointer--] = newValue;
+
+        if(mBufferPointer < 0)
+        {
+            mBufferPointer = mBuffer.length - 1;
+        }
+    }
+
+    /**
+     * Returns the sample at the specified index, where index 0 is the newest sample and index (length - 1) is the
+     * oldest sample.
+     * @param index in range of 0 to length-1
+     * @return value at indexed position
+     */
+
+    public float get(int index)
+    {
+        if(index < mBuffer.length)
+        {
+            int pointer = mBufferPointer + 1 + index;
+
+            if(pointer >= mBuffer.length)
+            {
+                pointer -= mBuffer.length;
+            }
+
+            return mBuffer[pointer];
+        }
+        else
+        {
+            throw new ArrayIndexOutOfBoundsException("Index [" + index + "] is not valid for the buffer size of [" +
+                mBuffer.length + "]");
+        }
+    }
+}