/*
* 21.04.2004 Original verion. davagin@udm.ru.
*-----------------------------------------------------------------------
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*----------------------------------------------------------------------
*/
package davaguine.jmac.info;
import davaguine.jmac.tools.ByteArrayReader;
import davaguine.jmac.tools.ByteArrayWriter;
import davaguine.jmac.tools.File;
import davaguine.jmac.tools.JMACException;
import java.io.EOFException;
import java.io.IOException;
/**
* Author: Dmitry Vaguine
* Date: 04.03.2004
* Time: 14:51:31
*/
public class APETagFooter {
public String m_cID; // should equal 'APETAGEX' (char[8])
public int m_nVersion; // equals CURRENT_APE_TAG_VERSION (int)
public int m_nSize; // the complete size of the tag, including this footer (int)
public int m_nFields; // the number of fields in the tag (int)
public int m_nFlags; // the tag flags (none currently defined) (int)
public final static int APE_TAG_FOOTER_BYTES = 32;
public final static int CURRENT_APE_TAG_VERSION = 2000;
APETagFooter() {
this(0, 0);
}
APETagFooter(int nFields) {
this(nFields, 0);
}
APETagFooter(int nFields, int nFieldBytes) {
m_cID = "APETAGEX";
m_nFields = nFields;
m_nFlags = APETag.APE_TAG_FLAGS_DEFAULT;
m_nSize = nFieldBytes + APE_TAG_FOOTER_BYTES;
m_nVersion = CURRENT_APE_TAG_VERSION;
}
public int GetTotalTagBytes() {
return m_nSize + (GetHasHeader() ? APE_TAG_FOOTER_BYTES : 0);
}
public int GetFieldBytes() {
return m_nSize - APE_TAG_FOOTER_BYTES;
}
public int GetFieldsOffset() {
return GetHasHeader() ? APE_TAG_FOOTER_BYTES : 0;
}
public int GetNumberFields() {
return m_nFields;
}
public boolean GetHasHeader() {
return (m_nFlags & APETag.APE_TAG_FLAG_CONTAINS_HEADER) > 0;
}
public boolean GetIsHeader() {
return (m_nFlags & APETag.APE_TAG_FLAG_IS_HEADER) > 0;
}
public int GetVersion() {
return m_nVersion;
}
public boolean GetIsValid(boolean bAllowHeader) {
boolean bValid = m_cID.equals("APETAGEX") &&
(m_nVersion <= CURRENT_APE_TAG_VERSION) &&
(m_nFields <= 65536) &&
(GetFieldBytes() <= (1024 * 1024 * 16));
if (bValid && !bAllowHeader && GetIsHeader())
bValid = false;
return bValid;
}
public static APETagFooter read(final File file) throws IOException {
file.seek(file.length() - APE_TAG_FOOTER_BYTES);
APETagFooter tag = new APETagFooter();
try {
final ByteArrayReader reader = new ByteArrayReader(file, APE_TAG_FOOTER_BYTES);
tag.m_cID = reader.readString(8, "US-ASCII");
tag.m_nVersion = reader.readInt();
tag.m_nSize = reader.readInt();
tag.m_nFields = reader.readInt();
tag.m_nFlags = reader.readInt();
return tag;
} catch (EOFException e) {
throw new JMACException("Unsupported Format");
}
}
public void write(final ByteArrayWriter writer) {
writer.writeString(m_cID, 8, "US-ASCII");
writer.writeInt(m_nVersion);
writer.writeInt(m_nSize);
writer.writeInt(m_nFields);
writer.writeInt(m_nFlags);
writer.writeInt(0);
writer.writeInt(0);
}
}