/*
* Entagged Audio Tag library
* Copyright (c) 2003-2005 Raphael Slinckx <raphael@slinckx.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.jaudiotagger.audio.ogg.util;
import org.jaudiotagger.audio.exceptions.CannotReadException;
import org.jaudiotagger.audio.generic.Utils;
import org.jaudiotagger.logging.ErrorMessage;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.logging.Logger;
import java.util.logging.Level;
import java.nio.ByteBuffer;
/**
* $Id: OggPageHeader.java 822 2009-10-27 08:52:55Z paultaylor $
* <p/>
* reference:http://xiph.org/ogg/doc/framing.html
*
* @author Raphael Slinckx (KiKiDonK)
* @version 16 d�cembre 2003
*/
public class OggPageHeader {
// Logger Object
public static Logger logger = Logger.getLogger("org.jaudiotagger.audio.ogg.atom");
//Capture pattern at start of header
public static final byte[] CAPTURE_PATTERN = {'O', 'g', 'g', 'S'};
//Ogg Page header is always 27 bytes plus the size of the segment table which is variable
public static final int OGG_PAGE_HEADER_FIXED_LENGTH = 27;
//Can have upto 255 segments in a page
public static final int MAXIMUM_NO_OF_SEGMENT_SIZE = 255;
//Each segment can be upto 255 bytes
public static final int MAXIMUM_SEGMENT_SIZE = 255;
//Maximum size of pageheader (27 + 255 = 282)
public static final int MAXIMUM_PAGE_HEADER_SIZE = OGG_PAGE_HEADER_FIXED_LENGTH + MAXIMUM_NO_OF_SEGMENT_SIZE;
//Maximum size of page data following the page header (255 * 255 = 65025)
public static final int MAXIMUM_PAGE_DATA_SIZE = MAXIMUM_NO_OF_SEGMENT_SIZE * MAXIMUM_SEGMENT_SIZE;
//Maximum size of page includes header and data (282 + 65025 = 65307 bytes)
public static final int MAXIMUM_PAGE_SIZE = MAXIMUM_PAGE_HEADER_SIZE + MAXIMUM_PAGE_DATA_SIZE;
//Starting positions of the various attributes
public static final int FIELD_CAPTURE_PATTERN_POS = 0;
public static final int FIELD_STREAM_STRUCTURE_VERSION_POS = 4;
public static final int FIELD_HEADER_TYPE_FLAG_POS = 5;
public static final int FIELD_ABSOLUTE_GRANULE_POS = 6;
public static final int FIELD_STREAM_SERIAL_NO_POS = 14;
public static final int FIELD_PAGE_SEQUENCE_NO_POS = 18;
public static final int FIELD_PAGE_CHECKSUM_POS = 22;
public static final int FIELD_PAGE_SEGMENTS_POS = 26;
public static final int FIELD_SEGMENT_TABLE_POS = 27;
//Length of various attributes
public static final int FIELD_CAPTURE_PATTERN_LENGTH = 4;
public static final int FIELD_STREAM_STRUCTURE_VERSION_LENGTH = 1;
public static final int FIELD_HEADER_TYPE_FLAG_LENGTH = 1;
public static final int FIELD_ABSOLUTE_GRANULE_LENGTH = 8;
public static final int FIELD_STREAM_SERIAL_NO_LENGTH = 4;
public static final int FIELD_PAGE_SEQUENCE_NO_LENGTH = 4;
public static final int FIELD_PAGE_CHECKSUM_LENGTH = 4;
public static final int FIELD_PAGE_SEGMENTS_LENGTH = 1;
private byte[] rawHeaderData;
private double absoluteGranulePosition;
private int checksum;
private byte headerTypeFlag;
private boolean isValid = false;
private int pageLength = 0;
private int pageSequenceNumber, streamSerialNumber;
private byte[] segmentTable;
private List<PacketStartAndLength> packetList = new ArrayList<PacketStartAndLength>();
private boolean lastPacketIncomplete = false;
/**
* Read next PageHeader from Buffer
*
* @param byteBuffer
* @return
* @throws IOException
* @throws CannotReadException
*/
public static OggPageHeader read(ByteBuffer byteBuffer) throws IOException, 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;
}
/**
* Read next PageHeader from file
*
* @param raf
* @return
* @throws IOException
* @throws CannotReadException
*/
public static OggPageHeader read(RandomAccessFile raf) throws IOException, 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))) {
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);
//Now just after PageHeader, ready for Packet Data
return pageHeader;
}
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());
// }
}
private int u(int i) {
return i & 0xFF;
}
/**
* @return true if the last packet on this page extends to the next page
*/
public boolean isLastPacketIncomplete() {
return lastPacketIncomplete;
}
public double getAbsoluteGranulePosition() {
// logger.fine("Number Of Samples: " + absoluteGranulePosition);
return this.absoluteGranulePosition;
}
public int getCheckSum() {
return checksum;
}
public byte getHeaderType() {
return headerTypeFlag;
}
public int getPageLength() {
// logger.fine("This page length: " + pageLength);
return this.pageLength;
}
public int getPageSequence() {
return pageSequenceNumber;
}
public int getSerialNumber() {
return streamSerialNumber;
}
public byte[] getSegmentTable() {
return this.segmentTable;
}
public boolean isValid() {
return isValid;
}
/**
* @return a list of packet start position and size within this page.
*/
public List<PacketStartAndLength> getPacketList() {
return packetList;
}
/**
* @return the raw header data that this pageheader is derived from
*/
public byte[] getRawHeaderData() {
return rawHeaderData;
}
public 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;
}
/**
* Within the page specifies the start and length of each packet
* in the page offset from the end of the pageheader (after the segment table)
*/
public static class PacketStartAndLength {
private Integer startPosition = 0;
private Integer length = 0;
public PacketStartAndLength(int startPosition, int length) {
this.startPosition = startPosition;
this.length = length;
}
public int getStartPosition() {
return startPosition;
}
public void setStartPosition(int startPosition) {
this.startPosition = startPosition;
}
public int getLength() {
return length;
}
public void setLength(int length) {
this.length = length;
}
public String toString() {
return "NextPkt(start:" + startPosition + ":length:" + length + "),";
}
}
/**
* This represents all the flags that can be set in the headerType field.
* Note these values can be ORED together. For example the last packet in
* a file would normally have a value of 0x5 because both the CONTINUED_PACKET
* bit and the END_OF_BITSTREAM bit would be set.
*/
public static enum HeaderTypeFlag {
FRESH_PACKET((byte) 0x0),
CONTINUED_PACKET((byte) 0x1),
START_OF_BITSTREAM((byte) 0x2),
END_OF_BITSTREAM((byte) 0x4);
byte fileValue;
HeaderTypeFlag(byte fileValue) {
this.fileValue = fileValue;
}
/**
* @return the value that should be written to file to enable this flag
*/
public byte getFileValue() {
return fileValue;
}
}
}