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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package sun.security.x509;
import java.io.IOException;
import java.util.Arrays;
import sun.security.util.*;
/**
* Represent a X509 Extension Attribute.
*
* <p>Extensions are additional attributes which can be inserted in a X509
* v3 certificate. For example a "Driving License Certificate" could have
* the driving license number as a extension.
*
* <p>Extensions are represented as a sequence of the extension identifier
* (Object Identifier), a boolean flag stating whether the extension is to
* be treated as being critical and the extension value itself (this is again
* a DER encoding of the extension value).
* <pre>
* ASN.1 definition of Extension:
* Extension ::= SEQUENCE {
* ExtensionId OBJECT IDENTIFIER,
* critical BOOLEAN DEFAULT FALSE,
* extensionValue OCTET STRING
* }
* </pre>
* All subclasses need to implement a constructor of the form
* <pre>
* <subclass> (Boolean, Object)
* </pre>
* where the Object is typically an array of DER encoded bytes.
* <p>
* @author Amit Kapoor
* @author Hemma Prafullchandra
*/
public class Extension {
protected ObjectIdentifier extensionId = null;
protected boolean critical = false;
protected byte[] extensionValue = null;
/**
* Default constructor. Used only by sub-classes.
*/
public Extension() { }
/**
* Constructs an extension from a DER encoded array of bytes.
*/
public Extension(DerValue derVal) throws IOException {
DerInputStream in = derVal.toDerInputStream();
// Object identifier
extensionId = in.getOID();
// If the criticality flag was false, it will not have been encoded.
DerValue val = in.getDerValue();
if (val.tag == DerValue.tag_Boolean) {
critical = val.getBoolean();
// Extension value (DER encoded)
val = in.getDerValue();
extensionValue = val.getOctetString();
} else {
critical = false;
extensionValue = val.getOctetString();
}
}
/**
* Constructs an Extension from individual components of ObjectIdentifier,
* criticality and the DER encoded OctetString.
*
* @param extensionId the ObjectIdentifier of the extension
* @param critical the boolean indicating if the extension is critical
* @param extensionValue the DER encoded octet string of the value.
*/
public Extension(ObjectIdentifier extensionId, boolean critical,
byte[] extensionValue) throws IOException {
this.extensionId = extensionId;
this.critical = critical;
// passed in a DER encoded octet string, strip off the tag
// and length
DerValue inDerVal = new DerValue(extensionValue);
this.extensionValue = inDerVal.getOctetString();
}
/**
* Constructs an Extension from another extension. To be used for
* creating decoded subclasses.
*
* @param ext the extension to create from.
*/
public Extension(Extension ext) {
this.extensionId = ext.extensionId;
this.critical = ext.critical;
this.extensionValue = ext.extensionValue;
}
/**
* Write the extension to the DerOutputStream.
*
* @param out the DerOutputStream to write the extension to.
* @exception IOException on encoding errors
*/
public void encode(DerOutputStream out) throws IOException {
if (extensionId == null)
throw new IOException("Null OID to encode for the extension!");
if (extensionValue == null)
throw new IOException("No value to encode for the extension!");
DerOutputStream dos = new DerOutputStream();
dos.putOID(extensionId);
if (critical)
dos.putBoolean(critical);
dos.putOctetString(extensionValue);
out.write(DerValue.tag_Sequence, dos);
}
/**
* Returns true if extension is critical.
*/
public boolean isCritical() {
return critical;
}
/**
* Returns the ObjectIdentifier of the extension.
*/
public ObjectIdentifier getExtensionId() {
return extensionId;
}
/**
* Returns the extension value as an byte array for further processing.
* Note, this is the raw DER value of the extension, not the DER
* encoded octet string which is in the certificate.
* This method does not return a clone; it is the responsibility of the
* caller to clone the array if necessary.
*/
public byte[] getExtensionValue() {
return extensionValue;
}
/**
* Returns the Extension in user readable form.
*/
public String toString() {
String s = "ObjectId: " + extensionId.toString();
if (critical) {
s += " Criticality=true\n";
} else {
s += " Criticality=false\n";
}
return (s);
}
// Value to mix up the hash
private static final int hashMagic = 31;
/**
* Returns a hashcode value for this Extension.
*
* @return the hashcode value.
*/
public int hashCode() {
int h = 0;
if (extensionValue != null) {
byte[] val = extensionValue;
int len = val.length;
while (len > 0)
h += len * val[--len];
}
h = h * hashMagic + extensionId.hashCode();
h = h * hashMagic + (critical?1231:1237);
return h;
}
/**
* Compares this Extension for equality with the specified
* object. If the <code>other</code> object is an
* <code>instanceof</code> <code>Extension</code>, then
* its encoded form is retrieved and compared with the
* encoded form of this Extension.
*
* @param other the object to test for equality with this Extension.
* @return true iff the other object is of type Extension, and the
* criticality flag, object identifier and encoded extension value of
* the two Extensions match, false otherwise.
*/
public boolean equals(Object other) {
if (this == other)
return true;
if (!(other instanceof Extension))
return false;
Extension otherExt = (Extension) other;
if (critical != otherExt.critical)
return false;
if (!extensionId.equals(otherExt.extensionId))
return false;
return Arrays.equals(extensionValue, otherExt.extensionValue);
}
}