Added classes for reading vorbis comment chapters

1 files changed, 194 insertions, 0 deletions

diff --git a/src/de/danoeh/antennapod/util/vorbiscommentreader/VorbisCommentReader.java b/src/de/danoeh/antennapod/util/vorbiscommentreader/VorbisCommentReader.java
new file mode 100644
index 000000000..2ffe3c05f
--- /dev/null
+++ b/src/de/danoeh/antennapod/util/vorbiscommentreader/VorbisCommentReader.java
@@ -0,0 +1,194 @@
+package de.danoeh.antennapod.util.vorbiscommentreader;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.util.Arrays;
+
+import org.apache.commons.io.EndianUtils;
+import org.apache.commons.io.IOUtils;
+
+
+public abstract class VorbisCommentReader {
+	/** Length of first page in an ogg file in bytes. */
+	private static final int FIRST_PAGE_LENGTH = 58;
+	private static final int SECOND_PAGE_MAX_LENGTH = 64 * 1024 * 1024;
+	private static final int PACKET_TYPE_IDENTIFICATION = 1;
+	private static final int PACKET_TYPE_COMMENT = 3;
+
+	/** Called when Reader finds identification header. */
+	public abstract void onVorbisCommentFound();
+
+	public abstract void onVorbisCommentHeaderFound(VorbisCommentHeader header);
+
+	/**
+	 * Is called every time the Reader finds a content vector. The handler
+	 * should return true if it wants to handle the content vector.
+	 */
+	public abstract boolean onContentVectorKey(String content);
+
+	/**
+	 * Is called if onContentVectorKey returned true for the key.
+	 * 
+	 * @throws VorbisCommentReaderException
+	 */
+	public abstract void onContentVectorValue(String key, String value)
+			throws VorbisCommentReaderException;
+
+	public abstract void onNoVorbisCommentFound();
+
+	public abstract void onEndOfComment();
+
+	public abstract void onError(VorbisCommentReaderException exception);
+
+	public void readInputStream(InputStream input)
+			throws VorbisCommentReaderException {
+		try {
+			// look for identification header
+			if (findIdentificationHeader(input)) {
+				
+				onVorbisCommentFound();
+				input = new OggInputStream(input);
+				if (findCommentHeader(input)) {
+					VorbisCommentHeader commentHeader = readCommentHeader(input);
+					if (commentHeader != null) {
+						onVorbisCommentHeaderFound(commentHeader);
+						for (int i = 0; i < commentHeader
+								.getUserCommentLength(); i++) {
+							try {
+								long vectorLength = EndianUtils
+										.readSwappedUnsignedInteger(input);
+								String key = readContentVectorKey(input,
+										vectorLength).toLowerCase();
+								boolean readValue = onContentVectorKey(key);
+								if (readValue) {
+									String value = readUTF8String(
+											input,
+											(int) (vectorLength - key.length() - 1))
+											.toLowerCase();
+									onContentVectorValue(key, value);
+								} else {
+									IOUtils.skipFully(input,
+											vectorLength - key.length() - 1);
+								}
+							} catch (IOException e) {
+								e.printStackTrace();
+							}
+						}
+						onEndOfComment();
+					}
+
+				} else {
+					onError(new VorbisCommentReaderException(
+							"No comment header found"));
+				}
+			} else {
+				onNoVorbisCommentFound();
+			}
+		} catch (IOException e) {
+			onError(new VorbisCommentReaderException(e));
+		}
+	}
+
+	private String readUTF8String(InputStream input, long length)
+			throws IOException {
+		StringBuffer buffer = new StringBuffer();
+		for (int i = 0; i < length; i++) {
+			char c = (char) input.read();
+			buffer.append(c);
+		}
+		return buffer.toString();
+	}
+
+	/**
+	 * Looks for an identification header in the first page of the file. If an
+	 * identification header is found, it will be skipped completely and the
+	 * method will return true, otherwise false.
+	 * 
+	 * @throws IOException
+	 */
+	private boolean findIdentificationHeader(InputStream input)
+			throws IOException {
+		byte[] buffer = new byte[FIRST_PAGE_LENGTH];
+		IOUtils.readFully(input, buffer);
+		int i;
+		for (i = 6; i < buffer.length; i++) {
+			if (buffer[i - 5] == 'v' && buffer[i - 4] == 'o'
+					&& buffer[i - 3] == 'r' && buffer[i - 2] == 'b'
+					&& buffer[i - 1] == 'i' && buffer[i] == 's'
+					&& buffer[i - 6] == PACKET_TYPE_IDENTIFICATION) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	private boolean findCommentHeader(InputStream input) throws IOException {
+		char[] buffer = new char["vorbis".length() + 1];
+		for (int bytesRead = 0; bytesRead < SECOND_PAGE_MAX_LENGTH; bytesRead++) {
+			char c = (char) input.read();
+			int dest = -1;
+			switch (c) {
+			case PACKET_TYPE_COMMENT:
+				dest = 0;
+				break;
+			case 'v':
+				dest = 1;
+				break;
+			case 'o':
+				dest = 2;
+				break;
+			case 'r':
+				dest = 3;
+				break;
+			case 'b':
+				dest = 4;
+				break;
+			case 'i':
+				dest = 5;
+				break;
+			case 's':
+				dest = 6;
+				break;
+			}
+			if (dest >= 0) {
+				buffer[dest] = c;
+				if (buffer[1] == 'v' && buffer[2] == 'o' && buffer[3] == 'r'
+						&& buffer[4] == 'b' && buffer[5] == 'i'
+						&& buffer[6] == 's' && buffer[0] == PACKET_TYPE_COMMENT) {
+					return true;
+				}
+			} else {
+				Arrays.fill(buffer, (char) 0);
+			}
+		}
+		return false;
+	}
+
+	private VorbisCommentHeader readCommentHeader(InputStream input)
+			throws IOException, VorbisCommentReaderException {
+		try {
+			long vendorLength = EndianUtils.readSwappedUnsignedInteger(input);
+			String vendorName = readUTF8String(input, vendorLength);
+			long userCommentLength = EndianUtils
+					.readSwappedUnsignedInteger(input);
+			return new VorbisCommentHeader(vendorName, userCommentLength);
+		} catch (UnsupportedEncodingException e) {
+			throw new VorbisCommentReaderException(e);
+		}
+	}
+
+	private String readContentVectorKey(InputStream input, long vectorLength)
+			throws IOException {
+		StringBuffer buffer = new StringBuffer();
+		for (int i = 0; i < vectorLength; i++) {
+			char c = (char) input.read();
+			if (c == '=') {
+				return buffer.toString();
+			} else {
+				buffer.append(c);
+			}
+		}
+		return null; // no key found
+	}
+}