From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Thu, 14 Mar 2013 21:29:51 +0000 (+0100)
Subject: Add input stream that identifies its content.
X-Git-Url: https://git.pterodactylus.net/?a=commitdiff_plain;h=fae468e1da8a64ae76bde4fd2f37ed7b468dc390;p=sonitus.git

Add input stream that identifies its content.
---

diff --git a/src/main/java/net/pterodactylus/sonitus/io/IdentifyingInputStream.java b/src/main/java/net/pterodactylus/sonitus/io/IdentifyingInputStream.java
new file mode 100644
index 0000000..537c9a4
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/io/IdentifyingInputStream.java
@@ -0,0 +1,96 @@
+/*
+ * Sonitus - IdentifyingStream.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.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import net.pterodactylus.sonitus.data.Format;
+
+import com.google.common.base.Optional;
+
+/**
+ * Wrapper around an {@link InputStream} that identifies the {@link Format} of
+ * the wrapped stream.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class IdentifyingInputStream extends FilterInputStream {
+
+	/** The identified format. */
+	private final Format format;
+
+	/**
+	 * Creates a new identifying input stream.
+	 *
+	 * @param inputStream
+	 * 		The input stream to wrap
+	 * @param format
+	 * 		The format of the stream
+	 */
+	private IdentifyingInputStream(InputStream inputStream, Format format) {
+		super(inputStream);
+		this.format = format;
+	}
+
+	//
+	// ACCESSORS
+	//
+
+	/**
+	 * Returns the identified format.
+	 *
+	 * @return The identified format
+	 */
+	public Format format() {
+		return format;
+	}
+
+	//
+	// STATIC METHODS
+	//
+
+	/**
+	 * Tries to identify the given input stream.
+	 *
+	 * @param inputStream
+	 * 		The input stream to identify
+	 * @return An identifying input stream that delivers the original stream and
+	 *         the format it detected, or {@link com.google.common.base.Optional#absent()}
+	 *         if no format could be identified
+	 * @throws IOException
+	 * 		if an I/O error occurs
+	 */
+	public static Optional<IdentifyingInputStream> create(InputStream inputStream) throws IOException {
+
+		/* remember everything we read here. */
+		RememberingInputStream rememberingInputStream = new RememberingInputStream(inputStream);
+
+		/* try Ogg Vorbis first. */
+		try {
+			Format format = OggVorbisIdentifier.identify(rememberingInputStream);
+			return Optional.of(new IdentifyingInputStream(rememberingInputStream.remembered(), format));
+		} catch (IdentifierException ie1) {
+			rememberingInputStream = new RememberingInputStream(rememberingInputStream.remembered());
+		}
+
+		return Optional.absent();
+	}
+
+}