Updates pull request from Roman Tsypuk to convert the build system from

ant to gradle.  Removes linux and windows application launch scripts and
produces an executable jar with all resources included.

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

@@ -0,0 +1,87 @@
+/*******************************************************************************
+ *     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 io.github.dsheirer.sample.complex.Complex;
+
+/**
+ * Implements a FIFO circular buffer for complex samples that provides access
+ * to each complex sample by index number, where index 0 is the newest/latest
+ * complex sample and index (length - 1) is the oldest sample in the buffer.
+ */
+public class ComplexTappedCircularBuffer
+{
+	private Complex[] mBuffer;
+	private int mBufferPointer = 0;
+	
+	public ComplexTappedCircularBuffer( int length )
+	{
+		mBuffer = new Complex[ length ];
+
+		//Pre-load the buffer with 0-valued samples
+		for( int x = 0; x < length; x++ )
+		{
+			mBuffer[ x ] = new Complex( 0, 0 );
+		}
+	}
+
+	/**
+	 * Adds the sample to the buffer and removes the oldest sample
+	 * @param sample
+	 */
+    public void add( Complex sample )
+    {
+		mBuffer[ mBufferPointer++ ] = sample;
+
+		//Reset the buffer pointer once it points past the end of the buffer
+		if( mBufferPointer >= mBuffer.length )
+		{
+			mBufferPointer = 0;
+		}
+    }
+
+	/**
+	 * Retrieves a sample currently in the buffer by index position.
+	 * 
+	 * Index 0 is the newest/latest sample in the buffer and index (length - 1)
+	 * is the oldest.
+	 * 
+	 * Note: the buffer is preloaded with complex samples of 0,0 value.
+	 * 
+	 * @param index where 0 is the newest/latest sample and length-1 is the oldest
+	 * @return complex sample from the buffer.
+	 * @throws ArrayIndexOutOfBoundsException if you attempt to access a sample
+	 * outside of the buffer size
+	 */
+	public Complex get( int index )
+	{
+		/* Since the samples are stored in a forward fashion, we have to access
+		 * the samples in reverse to comply with the access contract, where
+		 * index 0 is the newest and index (length -1) is the oldest, all 
+		 * relative to the current buffer pointer */
+		
+		int pointer = mBuffer.length - 1 + mBufferPointer - index;
+
+		if( pointer >= mBuffer.length )
+		{
+			pointer -= mBuffer.length;
+		}
+
+		return mBuffer[ pointer ];
+	}
+}