File	Doc	Category	Size	Date	Package
OggPageHeader.java	API Doc	Jaudiotagger 2.0.4	13646	Thu Apr 28 13:34:48 BST 2011	org.jaudiotagger.audio.ogg.util

OggPageHeader

• java.lang.Object

Fields Summary
public static Logger	logger
public static final byte[]	CAPTURE_PATTERN
public static final int	OGG_PAGE_HEADER_FIXED_LENGTH
public static final int	MAXIMUM_NO_OF_SEGMENT_SIZE
public static final int	MAXIMUM_SEGMENT_SIZE
public static final int	MAXIMUM_PAGE_HEADER_SIZE
public static final int	MAXIMUM_PAGE_DATA_SIZE
public static final int	MAXIMUM_PAGE_SIZE
public static final int	FIELD_CAPTURE_PATTERN_POS
public static final int	FIELD_STREAM_STRUCTURE_VERSION_POS
public static final int	FIELD_HEADER_TYPE_FLAG_POS
public static final int	FIELD_ABSOLUTE_GRANULE_POS
public static final int	FIELD_STREAM_SERIAL_NO_POS
public static final int	FIELD_PAGE_SEQUENCE_NO_POS
public static final int	FIELD_PAGE_CHECKSUM_POS
public static final int	FIELD_PAGE_SEGMENTS_POS
public static final int	FIELD_SEGMENT_TABLE_POS
public static final int	FIELD_CAPTURE_PATTERN_LENGTH
public static final int	FIELD_STREAM_STRUCTURE_VERSION_LENGTH
public static final int	FIELD_HEADER_TYPE_FLAG_LENGTH
public static final int	FIELD_ABSOLUTE_GRANULE_LENGTH
public static final int	FIELD_STREAM_SERIAL_NO_LENGTH
public static final int	FIELD_PAGE_SEQUENCE_NO_LENGTH
public static final int	FIELD_PAGE_CHECKSUM_LENGTH
public static final int	FIELD_PAGE_SEGMENTS_LENGTH
private byte[]	rawHeaderData
private double	absoluteGranulePosition
private int	checksum
private byte	headerTypeFlag
private boolean	isValid
private int	pageLength
private int	pageSequenceNumber
private int	streamSerialNumber
private byte[]	segmentTable
private List	packetList
private boolean	lastPacketIncomplete
private long	startByte

Constructors Summary

public OggPageHeader(byte[] b) this.rawHeaderData = b; int streamStructureRevision = b[FIELD_STREAM_STRUCTURE_VERSION_POS]; headerTypeFlag = b[FIELD_HEADER_TYPE_FLAG_POS]; if (streamStructureRevision == 0) { this.absoluteGranulePosition = 0; for (int i = 0; i < FIELD_ABSOLUTE_GRANULE_LENGTH; i++) { this.absoluteGranulePosition += u(b[i + FIELD_ABSOLUTE_GRANULE_POS]) * Math.pow(2, 8 * i); } streamSerialNumber = Utils.getIntLE(b, FIELD_STREAM_SERIAL_NO_POS, 17); pageSequenceNumber = Utils.getIntLE(b, FIELD_PAGE_SEQUENCE_NO_POS, 21); checksum = Utils.getIntLE(b, FIELD_PAGE_CHECKSUM_POS, 25); int pageSegments = u(b[FIELD_PAGE_SEGMENTS_POS]); this.segmentTable = new byte[b.length - OGG_PAGE_HEADER_FIXED_LENGTH]; int packetLength = 0; Integer segmentLength = null; for (int i = 0; i < segmentTable.length; i++) { segmentTable[i] = b[OGG_PAGE_HEADER_FIXED_LENGTH + i]; segmentLength = u(segmentTable[i]); this.pageLength += segmentLength; packetLength += segmentLength; if (segmentLength < MAXIMUM_SEGMENT_SIZE) { packetList.add(new PacketStartAndLength(pageLength - packetLength, packetLength)); packetLength = 0; } } //If last segment value is 255 this packet continues onto next page //and will not have been added to the packetStartAndEnd list yet if(segmentLength!=null) { if (segmentLength == MAXIMUM_SEGMENT_SIZE) { packetList.add(new PacketStartAndLength(pageLength - packetLength, packetLength)); lastPacketIncomplete = true; } } isValid = true; } if(logger.isLoggable(Level.CONFIG)) { logger.config("Constructed OggPage:" + this.toString()); }

Methods Summary
public double	getAbsoluteGranulePosition() logger.fine("Number Of Samples: " + absoluteGranulePosition); return this.absoluteGranulePosition;
public int	getCheckSum() return checksum;
public byte	getHeaderType() return headerTypeFlag;
public java.util.List	getPacketList() return a list of packet start position and size within this page. return packetList;
public int	getPageLength() logger.fine("This page length: " + pageLength); return this.pageLength;
public int	getPageSequence() return pageSequenceNumber;
public byte[]	getRawHeaderData() return the raw header data that this pageheader is derived from return rawHeaderData;
public byte[]	getSegmentTable() return this.segmentTable;
public int	getSerialNumber() return streamSerialNumber;
public long	getStartByte() Startbyte of this pageHeader in the file This is useful for Ogg files that contain unsupported additional data at the start of the file such as ID3 data return startByte;
public boolean	isLastPacketIncomplete() return true if the last packet on this page extends to the next page return lastPacketIncomplete;
public boolean	isValid() return isValid;
public static org.jaudiotagger.audio.ogg.util.OggPageHeader	read(java.nio.ByteBuffer byteBuffer) Read next PageHeader from Buffer param byteBuffer return throws IOException throws CannotReadException //byteBuffer int start = byteBuffer.position(); logger.fine("Trying to read OggPage at:" + start); byte[] b = new byte[OggPageHeader.CAPTURE_PATTERN.length]; byteBuffer.get(b); if (!(Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN))) { throw new CannotReadException(ErrorMessage.OGG_HEADER_CANNOT_BE_FOUND.getMsg(new String(b))); } byteBuffer.position(start + OggPageHeader.FIELD_PAGE_SEGMENTS_POS); int pageSegments = byteBuffer.get() & 0xFF; //unsigned byteBuffer.position(start); b = new byte[OggPageHeader.OGG_PAGE_HEADER_FIXED_LENGTH + pageSegments]; byteBuffer.get(b); OggPageHeader pageHeader = new OggPageHeader(b); //Now just after PageHeader, ready for Packet Data return pageHeader;
public static org.jaudiotagger.audio.ogg.util.OggPageHeader	read(java.io.RandomAccessFile raf) Read next PageHeader from file param raf return throws IOException throws CannotReadException long start = raf.getFilePointer(); logger.fine("Trying to read OggPage at:" + start); byte[] b = new byte[OggPageHeader.CAPTURE_PATTERN.length]; raf.read(b); if (!(Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN))) { raf.seek(start); if(AbstractID3v2Tag.isId3Tag(raf)) { logger.warning(ErrorMessage.OGG_CONTAINS_ID3TAG.getMsg(raf.getFilePointer() - start)); raf.read(b); if ((Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN))) { //Go to the end of the ID3 header start=raf.getFilePointer() - OggPageHeader.CAPTURE_PATTERN.length; } } else { throw new CannotReadException(ErrorMessage.OGG_HEADER_CANNOT_BE_FOUND.getMsg(new String(b))); } } raf.seek(start + OggPageHeader.FIELD_PAGE_SEGMENTS_POS); int pageSegments = raf.readByte() & 0xFF; //unsigned raf.seek(start); b = new byte[OggPageHeader.OGG_PAGE_HEADER_FIXED_LENGTH + pageSegments]; raf.read(b); OggPageHeader pageHeader = new OggPageHeader(b); pageHeader.setStartByte(start); //Now just after PageHeader, ready for Packet Data return pageHeader;
public void	setStartByte(long startByte) this.startByte = startByte;
public java.lang.String	toString() String out = "Ogg Page Header:isValid:" + isValid + ":type:" + headerTypeFlag + ":oggPageHeaderLength:" + rawHeaderData.length + ":length:" + pageLength + ":seqNo:" + getPageSequence() + ":packetIncomplete:" + isLastPacketIncomplete() + ":serNum:" + this.getSerialNumber(); for (PacketStartAndLength packet : getPacketList()) { out += packet.toString(); } return out;
private int	u(int i) return i & 0xFF;