Add filter that tracks the time.

diff --git a/src/main/java/net/pterodactylus/sonitus/data/filter/TimeCounterFilter.java b/src/main/java/net/pterodactylus/sonitus/data/filter/TimeCounterFilter.java
new file mode 100644 (file)
index 0000000..3bb4415
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/data/filter/TimeCounterFilter.java
@@ -0,0 +1,102 @@
+/*
+ * Sonitus - TimeCounterFilter.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 java.io.IOException;
+import java.util.concurrent.atomic.AtomicLong;
+
+import net.pterodactylus.sonitus.data.Filter;
+import net.pterodactylus.sonitus.data.Metadata;
+
+/**
+ * {@link Filter} implementation that uses the number of bytes that have been
+ * {@link #process(byte[]) processed} together with the {@link Metadata} to
+ * calculate how long a source is already playing.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class TimeCounterFilter extends DummyFilter {
+
+       /** The byte counter. */
+       private final AtomicLong counter = new AtomicLong();
+
+       /** Whether to reset the counter on a metadata update. */
+       private final boolean resetOnMetadataUpdate;
+
+       /**
+        * Creates a new time counter filter that automatically resets the counter when
+        * the metadata is {@link #metadataUpdated(Metadata) updated}.
+        */
+       public TimeCounterFilter() {
+               this(true);
+       }
+
+       /**
+        * Creates a new time counter filter.
+        *
+        * @param resetOnMetadataUpdate
+        *              {@code true} if the counter should automatically be reset if the metadata
+        *              is updated, {@code false} otherwise
+        */
+       public TimeCounterFilter(boolean resetOnMetadataUpdate) {
+               this.resetOnMetadataUpdate = resetOnMetadataUpdate;
+       }
+
+       //
+       // ACTIONS
+       //
+
+       /**
+        * Returns the number of milliseconds worth of data that has been passed into
+        * {@link #process(byte[])}. If no metadata has yet been set, {@code 0} is
+        * returned.
+        *
+        * @return The number of milliseconds the current source is already playing
+        */
+       public long getMillis() {
+               Metadata metadata = super.metadata();
+               if (metadata == null) {
+                       return 0;
+               }
+               return 1000 * counter.get() / (metadata.channels() * metadata.frequency() * 2);
+       }
+
+       /** Resets the counter to 0. */
+       public void reset() {
+               counter.set(0);
+       }
+
+       //
+       // DUMMYFILTER METHODS
+       //
+
+       @Override
+       public void metadataUpdated(Metadata metadata) {
+               super.metadataUpdated(metadata);
+               if (resetOnMetadataUpdate) {
+                       reset();
+               }
+       }
+
+       @Override
+       public void process(byte[] buffer) throws IOException {
+               super.process(buffer);
+               counter.getAndAdd(buffer.length);
+       }
+
+}