/*
** Authored by Timothy Gerard Endres
** <mailto:[email protected]> <http://www.trustice.com>
**
** This work has been placed into the public domain.
** You may use this work in any way and for any purpose you wish.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE.
**
*/
package installer;
/**
* This class encapsulates the Tar Entry Header used in Tar Archives.
* The class also holds a number of tar constants, used mostly in headers.
*/
public class
TarHeader extends Object
{
/**
* The length of the name field in a header buffer.
*/
public static final int NAMELEN = 100;
/**
* The length of the mode field in a header buffer.
*/
public static final int MODELEN = 8;
/**
* The length of the user id field in a header buffer.
*/
public static final int UIDLEN = 8;
/**
* The length of the group id field in a header buffer.
*/
public static final int GIDLEN = 8;
/**
* The length of the checksum field in a header buffer.
*/
public static final int CHKSUMLEN = 8;
/**
* The length of the size field in a header buffer.
*/
public static final int SIZELEN = 12;
/**
* The length of the magic field in a header buffer.
*/
public static final int MAGICLEN = 8;
/**
* The length of the modification time field in a header buffer.
*/
public static final int MODTIMELEN = 12;
/**
* The length of the user name field in a header buffer.
*/
public static final int UNAMELEN = 32;
/**
* The length of the group name field in a header buffer.
*/
public static final int GNAMELEN = 32;
/**
* The length of the devices field in a header buffer.
*/
public static final int DEVLEN = 8;
/**
* LF_ constants represent the "link flag" of an entry, or more commonly,
* the "entry type". This is the "old way" of indicating a normal file.
*/
public static final byte LF_OLDNORM = 0;
/**
* Normal file type.
*/
public static final byte LF_NORMAL = (byte) '0';
/**
* Link file type.
*/
public static final byte LF_LINK = (byte) '1';
/**
* Symbolic link file type.
*/
public static final byte LF_SYMLINK = (byte) '2';
/**
* Character device file type.
*/
public static final byte LF_CHR = (byte) '3';
/**
* Block device file type.
*/
public static final byte LF_BLK = (byte) '4';
/**
* Directory file type.
*/
public static final byte LF_DIR = (byte) '5';
/**
* FIFO (pipe) file type.
*/
public static final byte LF_FIFO = (byte) '6';
/**
* Contiguous file type.
*/
public static final byte LF_CONTIG = (byte) '7';
/**
* The magic tag representing a POSIX tar archive.
*/
public static final String TMAGIC = "ustar";
/**
* The magic tag representing a GNU tar archive.
*/
public static final String GNU_TMAGIC = "ustar ";
/**
* The entry's name.
*/
public StringBuffer name;
/**
* The entry's permission mode.
*/
public int mode;
/**
* The entry's user id.
*/
public int userId;
/**
* The entry's group id.
*/
public int groupId;
/**
* The entry's size.
*/
public long size;
/**
* The entry's modification time.
*/
public long modTime;
/**
* The entry's checksum.
*/
public int checkSum;
/**
* The entry's link flag.
*/
public byte linkFlag;
/**
* The entry's link name.
*/
public StringBuffer linkName;
/**
* The entry's magic tag.
*/
public StringBuffer magic;
/**
* The entry's user name.
*/
public StringBuffer userName;
/**
* The entry's group name.
*/
public StringBuffer groupName;
/**
* The entry's major device number.
*/
public int devMajor;
/**
* The entry's minor device number.
*/
public int devMinor;
public
TarHeader()
{
this.magic = new StringBuffer( TarHeader.TMAGIC );
this.name = new StringBuffer();
this.linkName = new StringBuffer();
String user =
System.getProperty( "user.name", "" );
if ( user.length() > 31 )
user = user.substring( 0, 31 );
this.userId = 0;
this.groupId = 0;
this.userName = new StringBuffer( user );
this.groupName = new StringBuffer( "" );
}
/**
* TarHeaders can be cloned.
*/
public Object
clone()
{
TarHeader hdr = null;
try {
hdr = (TarHeader) super.clone();
hdr.name =
(this.name == null ) ? null
: new StringBuffer( this.name.toString() );
hdr.mode = this.mode;
hdr.userId = this.userId;
hdr.groupId = this.groupId;
hdr.size = this.size;
hdr.modTime = this.modTime;
hdr.checkSum = this.checkSum;
hdr.linkFlag = this.linkFlag;
hdr.linkName =
(this.linkName == null ) ? null
: new StringBuffer( this.linkName.toString() );
hdr.magic =
(this.magic == null ) ? null
: new StringBuffer( this.magic.toString() );
hdr.userName =
(this.userName == null ) ? null
: new StringBuffer( this.userName.toString() );
hdr.groupName =
(this.groupName == null ) ? null
: new StringBuffer( this.groupName.toString() );
hdr.devMajor = this.devMajor;
hdr.devMinor = this.devMinor;
}
catch ( CloneNotSupportedException ex )
{
ex.printStackTrace();
}
return hdr;
}
/**
* Get the name of this entry.
*
* @return Teh entry's name.
*/
public String
getName()
{
return this.name.toString();
}
/**
* Parse an octal string from a header buffer. This is used for the
* file permission mode value.
*
* @param header The header buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The number of header bytes to parse.
* @return The long value of the octal string.
*/
public static long
parseOctal( byte[] header, int offset, int length )
throws InvalidHeaderException
{
long result = 0;
boolean stillPadding = true;
int end = offset + length;
for ( int i = offset ; i < end ; ++i )
{
if ( header[i] == 0 )
break;
if ( header[i] == (byte) ' ' || header[i] == '0' )
{
if ( stillPadding )
continue;
if ( header[i] == (byte) ' ' )
break;
}
stillPadding = false;
result =
(result << 3)
+ (header[i] - '0');
}
return result;
}
/**
* Parse an entry name from a header buffer.
*
* @param header The header buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The number of header bytes to parse.
* @return The header's entry name.
*/
public static StringBuffer
parseName( byte[] header, int offset, int length )
throws InvalidHeaderException
{
StringBuffer result = new StringBuffer( length );
int end = offset + length;
for ( int i = offset ; i < end ; ++i )
{
if ( header[i] == 0 )
break;
result.append( (char)header[i] );
}
return result;
}
/**
* Determine the number of bytes in an entry name.
*
* @param header The header buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The number of header bytes to parse.
* @return The number of bytes in a header's entry name.
*/
public static int
getNameBytes( StringBuffer name, byte[] buf, int offset, int length )
{
int i;
for ( i = 0 ; i < length && i < name.length() ; ++i )
{
buf[ offset + i ] = (byte) name.charAt( i );
}
for ( ; i < length ; ++i )
{
buf[ offset + i ] = 0;
}
return offset + length;
}
/**
* Parse an octal integer from a header buffer.
*
* @param header The header buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The number of header bytes to parse.
* @return The integer value of the octal bytes.
*/
public static int
getOctalBytes( long value, byte[] buf, int offset, int length )
{
byte[] result = new byte[ length ];
int idx = length - 1;
buf[ offset + idx ] = 0;
--idx;
buf[ offset + idx ] = (byte) ' ';
--idx;
if ( value == 0 )
{
buf[ offset + idx ] = (byte) '0';
--idx;
}
else
{
for ( long val = value ; idx >= 0 && val > 0 ; --idx )
{
buf[ offset + idx ] = (byte)
( (byte) '0' + (byte) (val & 7) );
val = val >> 3;
}
}
for ( ; idx >= 0 ; --idx )
{
buf[ offset + idx ] = (byte) ' ';
}
return offset + length;
}
/**
* Parse an octal long integer from a header buffer.
*
* @param header The header buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The number of header bytes to parse.
* @return The long value of the octal bytes.
*/
public static int
getLongOctalBytes( long value, byte[] buf, int offset, int length )
{
byte[] temp = new byte[ length + 1 ];
TarHeader.getOctalBytes( value, temp, 0, length + 1 );
System.arraycopy( temp, 0, buf, offset, length );
return offset + length;
}
/**
* Parse the checksum octal integer from a header buffer.
*
* @param header The header buffer from which to parse.
* @param offset The offset into the buffer from which to parse.
* @param length The number of header bytes to parse.
* @return The integer value of the entry's checksum.
*/
public static int
getCheckSumOctalBytes( long value, byte[] buf, int offset, int length )
{
TarHeader.getOctalBytes( value, buf, offset, length );
buf[ offset + length - 1 ] = (byte) ' ';
buf[ offset + length - 2 ] = 0;
return offset + length;
}
}
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