Add parser for FLAC metadata.

[sonitus.git] / src / main / java / net / pterodactylus / sonitus / io / flac / Header.java

diff --git a/src/main/java/net/pterodactylus/sonitus/io/flac/Header.java b/src/main/java/net/pterodactylus/sonitus/io/flac/Header.java
new file mode 100644 (file)
index 0000000..bd6770e
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/io/flac/Header.java
@@ -0,0 +1,114 @@
+/*
+ * Sonitus - Header.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.flac;
+
+import static com.google.common.io.ByteStreams.readFully;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Header for a {@link MetadataBlock}.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class Header {
+
+       /** Whether this metadata block is the last metadata block. */
+       private final boolean lastMetadataBlock;
+
+       /** The type of the metadata block. */
+       private final BlockType blockType;
+
+       /** The length of the metadata block. */
+       private final int length;
+
+       /**
+        * Creates a new metadata block header.
+        *
+        * @param lastMetadataBlock
+        *              {@code true} if this metadata block is the last metadata block in the FLAC
+        *              stream, {@code false} otherwise
+        * @param blockType
+        *              The type of the metadata block
+        * @param length
+        *              The length of the metadata block
+        */
+       private Header(boolean lastMetadataBlock, BlockType blockType, int length) {
+               this.lastMetadataBlock = lastMetadataBlock;
+               this.blockType = blockType;
+               this.length = length;
+       }
+
+       //
+       // ACCESSORS
+       //
+
+       /**
+        * Returns whether this metadata block is the last metadata block in the FLAC
+        * {@link Stream}.
+        *
+        * @return {@code true} if this metadata block is last metadata block in the
+        *         FLAC stream, {@code false} otherwise
+        */
+       public boolean isLastMetadataBlock() {
+               return lastMetadataBlock;
+       }
+
+       /**
+        * Returns the type of the metadata block.
+        *
+        * @return The type of the metadata block
+        */
+       public BlockType blockType() {
+               return blockType;
+       }
+
+       /**
+        * Returns the length of the metadata block.
+        *
+        * @return The length of the metadata block
+        */
+       public int length() {
+               return length;
+       }
+
+       //
+       // STATIC METHODS
+       //
+
+       /**
+        * Parses a metadata block header from the current position of the given input
+        * stream.
+        *
+        * @param inputStream
+        *              The input stream to parse the header from
+        * @return The parsed header
+        * @throws IOException
+        *              if an I/O error occurs
+        */
+       public static Header parse(InputStream inputStream) throws IOException {
+               byte[] buffer = new byte[4];
+               readFully(inputStream, buffer);
+               boolean lastMetadataBlock = ((buffer[0] >> 7) & 0x01) != 0;
+               BlockType blockType = BlockType.valueOf(buffer[0] & 0x7f);
+               int length = ((buffer[1] & 0xff) << 16) | ((buffer[2] & 0xff) << 8) | (buffer[3] & 0xff);
+               return new Header(lastMetadataBlock, blockType, length);
+       }
+
+}