From 305a3bfdb929e13027c3db1638f9930261ace9e7 Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?=
 <bombe@pterodactylus.net>
Date: Sat, 16 Mar 2013 12:28:02 +0100
Subject: [PATCH] Add rate limiting filter.

---
 .../sonitus/data/filter/RateLimitingFilter.java    | 130 +++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 src/main/java/net/pterodactylus/sonitus/data/filter/RateLimitingFilter.java

diff --git a/src/main/java/net/pterodactylus/sonitus/data/filter/RateLimitingFilter.java b/src/main/java/net/pterodactylus/sonitus/data/filter/RateLimitingFilter.java
new file mode 100644
index 0000000..c40f90f
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/data/filter/RateLimitingFilter.java
@@ -0,0 +1,130 @@
+/*
+ * Sonitus - DelayFilter.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.data.filter;
+
+import static com.google.common.io.Closeables.close;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.PipedInputStream;
+import java.io.PipedOutputStream;
+import java.util.Arrays;
+import java.util.logging.Logger;
+
+import net.pterodactylus.sonitus.data.ConnectException;
+import net.pterodactylus.sonitus.data.Connection;
+import net.pterodactylus.sonitus.data.Filter;
+import net.pterodactylus.sonitus.data.Format;
+import net.pterodactylus.sonitus.data.Source;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * Rate limiting filter that only passes a specified amount of data per second
+ * from its {@link Source} to its {@link net.pterodactylus.sonitus.data.Sink}.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class RateLimitingFilter implements Filter {
+
+	/** The logger. */
+	private static final Logger logger = Logger.getLogger(RateLimitingFilter.class.getName());
+
+	/** The limiting rate in bytes/second. */
+	private final int rate;
+
+	/** The source’s format. */
+	private Format format;
+
+	/** The input stream to read from. */
+	private PipedInputStream pipedInputStream = new PipedInputStream();
+
+	/**
+	 * Creates a new rate limiting filter.
+	 *
+	 * @param rate
+	 * 		The limiting rate (in bytes/second)
+	 */
+	public RateLimitingFilter(int rate) {
+		this.rate = rate;
+	}
+
+	//
+	// FILTER METHODS
+	//
+
+	@Override
+	public Format format() {
+		return format;
+	}
+
+	@Override
+	public byte[] get(int bufferSize) throws EOFException, IOException {
+		byte[] buffer = new byte[bufferSize];
+		int read = pipedInputStream.read(buffer);
+		if (read == -1) {
+			throw new EOFException();
+		}
+		return Arrays.copyOf(buffer, read);
+	}
+
+	@Override
+	public void connect(Source source) throws ConnectException {
+		Preconditions.checkNotNull(source, "source must not be null");
+
+		format = source.format();
+		final long start = System.currentTimeMillis();
+		try {
+			pipedInputStream = new PipedInputStream();
+			final PipedOutputStream pipedOutputStream = new PipedOutputStream(pipedInputStream);
+			new Thread(new Connection(source) {
+
+				@Override
+				protected int bufferSize() {
+					return rate;
+				}
+
+				@Override
+				protected void feed(byte[] buffer) throws IOException {
+					long waitTime = 1000 * buffer.length / rate;
+					long now = System.currentTimeMillis();
+					pipedOutputStream.write(buffer);
+					pipedOutputStream.flush();
+					while ((System.currentTimeMillis() - now) < waitTime) {
+						try {
+							long limitDelay = waitTime - (System.currentTimeMillis() - now);
+							logger.finest(String.format("Waiting %d ms...", limitDelay));
+							Thread.sleep(limitDelay);
+						} catch (InterruptedException ie1) {
+							/* ignore, keep looping. */
+						}
+					}
+				}
+
+				@Override
+				protected void finish() throws IOException {
+					close(pipedInputStream, true);
+					close(pipedOutputStream, true);
+				}
+			}).start();
+		} catch (IOException ioe1) {
+			throw new ConnectException(ioe1);
+		}
+	}
+
+}
-- 
2.7.4