From dfaceff35b847c9f2f9fe6fef22eb29c14be94c7 Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?=
 <bombe@pterodactylus.net>
Date: Sun, 26 May 2013 17:51:08 +0200
Subject: [PATCH] Add sample-aware output stream wrapper and processor.

---
 .../sonitus/io/ProcessingOutputStream.java         | 109 +++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 src/main/java/net/pterodactylus/sonitus/io/ProcessingOutputStream.java

diff --git a/src/main/java/net/pterodactylus/sonitus/io/ProcessingOutputStream.java b/src/main/java/net/pterodactylus/sonitus/io/ProcessingOutputStream.java
new file mode 100644
index 0000000..ded9df1
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/io/ProcessingOutputStream.java
@@ -0,0 +1,109 @@
+/*
+ * Sonitus - SampleOutputStream.java - Copyright © 2013 David Roden
+ *
+ * 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 net.pterodactylus.sonitus.io;
+
+import java.io.FilterOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * {@link OutputStream} wrapper that is aware of channels and samples and can
+ * process samples before forwarding them to the wrapped output stream.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public abstract class ProcessingOutputStream extends FilterOutputStream {
+
+	/** The number of channels. */
+	private final int channels;
+
+	/** The current sample’s channel values. */
+	private int[] currentSamples;
+
+	/** The index of the current channel. */
+	private int currentSampleIndex;
+
+	/** The byte ofset of the current sample’s current channel. */
+	private int currentOffset;
+
+	/** The current sample’s channel value. */
+	private int currentSample;
+
+	/**
+	 * Creates a new processing output stream. Sample values are always assumed to
+	 * be 16 bits wide little-ending signed integers.
+	 *
+	 * @param outputStream
+	 * 		The output stream to wrap
+	 * @param channels
+	 * 		The number of channels
+	 */
+	public ProcessingOutputStream(OutputStream outputStream, int channels) {
+		super(outputStream);
+		this.channels = channels;
+		currentSamples = new int[channels];
+	}
+
+	//
+	// OUTPUTSTREAM METHODS
+	//
+
+	@Override
+	public void write(int data) throws IOException {
+		currentSample = ((currentSample >> 8) & 0xff) | (data << 8);
+		if (++currentOffset == 2) {
+			currentOffset = 0;
+			currentSamples[currentSampleIndex++] = currentSample;
+			currentSample = 0;
+			if (currentSampleIndex == channels) {
+				currentSampleIndex = 0;
+				int[] newSamples = processSamples(currentSamples);
+				for (int sampleIndex = 0; sampleIndex < newSamples.length; ++sampleIndex) {
+					super.write(newSamples[sampleIndex] & 0xff);
+					super.write(newSamples[sampleIndex] >> 8);
+				}
+			}
+		}
+	}
+
+	@Override
+	public void write(byte[] buffer) throws IOException {
+		write(buffer, 0, buffer.length);
+	}
+
+	@Override
+	public void write(byte[] buffer, int offset, int length) throws IOException {
+		for (int index = 0; index < length; ++index) {
+			write(buffer[offset + index]);
+		}
+	}
+
+	//
+	// SUBCLASS METHODS
+	//
+
+	/**
+	 * Processes the given sample.
+	 *
+	 * @param samples
+	 * 		The channel values for a single sample
+	 * @return The processed sample’s channel values
+	 */
+	protected abstract int[] processSamples(int[] samples);
+
+}
-- 
2.7.4