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	/*
	* Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.security.x509;

	import java.io.IOException;
	import java.io.OutputStream;
	import java.util.Enumeration;

	import sun.security.util.*;

	/**
	* Represent the Key Usage Extension.
	*
	* <p>This extension, if present, defines the purpose (e.g., encipherment,
	* signature, certificate signing) of the key contained in the certificate.
	* The usage restriction might be employed when a multipurpose key is to be
	* restricted (e.g., when an RSA key should be used only for signing or only
	* for key encipherment).
	*
	* @author Amit Kapoor
	* @author Hemma Prafullchandra
	* @see Extension
	* @see CertAttrSet
	*/
	public class KeyUsageExtension extends Extension
	implements CertAttrSet<String> {

	/**
	* Identifier for this attribute, to be used with the
	* get, set, delete methods of Certificate, x509 type.
	*/
	public static final String IDENT = "x509.info.extensions.KeyUsage";
	/**
	* Attribute names.
	*/
	public static final String NAME = "KeyUsage";
	public static final String DIGITAL_SIGNATURE = "digital_signature";
	public static final String NON_REPUDIATION = "non_repudiation";
	public static final String KEY_ENCIPHERMENT = "key_encipherment";
	public static final String DATA_ENCIPHERMENT = "data_encipherment";
	public static final String KEY_AGREEMENT = "key_agreement";
	public static final String KEY_CERTSIGN = "key_certsign";
	public static final String CRL_SIGN = "crl_sign";
	public static final String ENCIPHER_ONLY = "encipher_only";
	public static final String DECIPHER_ONLY = "decipher_only";

	// Private data members
	private boolean[] bitString;

	// Encode this extension value
	private void encodeThis() throws IOException {
	DerOutputStream os = new DerOutputStream();
	os.putTruncatedUnalignedBitString(new BitArray(this.bitString));
	this.extensionValue = os.toByteArray();
	}

	/**
	* Check if bit is set.
	*
	* @param position the position in the bit string to check.
	*/
	private boolean isSet(int position) {
	return (position < bitString.length) &&
	bitString[position];
	}

	/**
	* Set the bit at the specified position.
	*/
	private void set(int position, boolean val) {
	// enlarge bitString if necessary
	if (position >= bitString.length) {
	boolean[] tmp = new boolean[position+1];
	System.arraycopy(bitString, 0, tmp, 0, bitString.length);
	bitString = tmp;
	}
	bitString[position] = val;
	}

	/**
	* Create a KeyUsageExtension with the passed bit settings. The criticality
	* is set to true.
	*
	* @param bitString the bits to be set for the extension.
	*/
	public KeyUsageExtension(byte[] bitString) throws IOException {
	this.bitString =
	new BitArray(bitString.length*8,bitString).toBooleanArray();
	this.extensionId = PKIXExtensions.KeyUsage_Id;
	this.critical = true;
	encodeThis();
	}

	/**
	* Create a KeyUsageExtension with the passed bit settings. The criticality
	* is set to true.
	*
	* @param bitString the bits to be set for the extension.
	*/
	public KeyUsageExtension(boolean[] bitString) throws IOException {
	this.bitString = bitString;
	this.extensionId = PKIXExtensions.KeyUsage_Id;
	this.critical = true;
	encodeThis();
	}

	/**
	* Create a KeyUsageExtension with the passed bit settings. The criticality
	* is set to true.
	*
	* @param bitString the bits to be set for the extension.
	*/
	public KeyUsageExtension(BitArray bitString) throws IOException {
	this.bitString = bitString.toBooleanArray();
	this.extensionId = PKIXExtensions.KeyUsage_Id;
	this.critical = true;
	encodeThis();
	}

	/**
	* Create the extension from the passed DER encoded value of the same.
	* The DER encoded value may be wrapped in an OCTET STRING.
	*
	* @param critical true if the extension is to be treated as critical.
	* @param value an array of DER encoded bytes of the actual value (possibly
	* wrapped in an OCTET STRING).
	* @exception ClassCastException if value is not an array of bytes
	* @exception IOException on error.
	*/
	public KeyUsageExtension(Boolean critical, Object value)
	throws IOException {
	this.extensionId = PKIXExtensions.KeyUsage_Id;
	this.critical = critical.booleanValue();
	/*
	* The following check should be activated again after
	* the PKIX profiling work becomes standard and the check
	* is not a barrier to interoperability !
	* if (!this.critical) {
	* throw new IOException("KeyUsageExtension not marked critical,"
	* + " invalid profile.");
	* }
	*/
	byte[] extValue = (byte[]) value;
	if (extValue[0] == DerValue.tag_OctetString) {
	this.extensionValue = new DerValue(extValue).getOctetString();
	} else {
	this.extensionValue = extValue;
	}
	DerValue val = new DerValue(this.extensionValue);
	this.bitString = val.getUnalignedBitString().toBooleanArray();
	}

	/**
	* Create a default key usage.
	*/
	public KeyUsageExtension() {
	extensionId = PKIXExtensions.KeyUsage_Id;
	critical = true;
	bitString = new boolean[0];
	}

	/**
	* Set the attribute value.
	*/
	public void set(String name, Object obj) throws IOException {
	if (!(obj instanceof Boolean)) {
	throw new IOException("Attribute must be of type Boolean.");
	}
	boolean val = ((Boolean)obj).booleanValue();
	if (name.equalsIgnoreCase(DIGITAL_SIGNATURE)) {
	set(0,val);
	} else if (name.equalsIgnoreCase(NON_REPUDIATION)) {
	set(1,val);
	} else if (name.equalsIgnoreCase(KEY_ENCIPHERMENT)) {
	set(2,val);
	} else if (name.equalsIgnoreCase(DATA_ENCIPHERMENT)) {
	set(3,val);
	} else if (name.equalsIgnoreCase(KEY_AGREEMENT)) {
	set(4,val);
	} else if (name.equalsIgnoreCase(KEY_CERTSIGN)) {
	set(5,val);
	} else if (name.equalsIgnoreCase(CRL_SIGN)) {
	set(6,val);
	} else if (name.equalsIgnoreCase(ENCIPHER_ONLY)) {
	set(7,val);
	} else if (name.equalsIgnoreCase(DECIPHER_ONLY)) {
	set(8,val);
	} else {
	throw new IOException("Attribute name not recognized by"
	+ " CertAttrSet:KeyUsage.");
	}
	encodeThis();
	}

	/**
	* Get the attribute value.
	*/
	public Boolean get(String name) throws IOException {
	if (name.equalsIgnoreCase(DIGITAL_SIGNATURE)) {
	return Boolean.valueOf(isSet(0));
	} else if (name.equalsIgnoreCase(NON_REPUDIATION)) {
	return Boolean.valueOf(isSet(1));
	} else if (name.equalsIgnoreCase(KEY_ENCIPHERMENT)) {
	return Boolean.valueOf(isSet(2));
	} else if (name.equalsIgnoreCase(DATA_ENCIPHERMENT)) {
	return Boolean.valueOf(isSet(3));
	} else if (name.equalsIgnoreCase(KEY_AGREEMENT)) {
	return Boolean.valueOf(isSet(4));
	} else if (name.equalsIgnoreCase(KEY_CERTSIGN)) {
	return Boolean.valueOf(isSet(5));
	} else if (name.equalsIgnoreCase(CRL_SIGN)) {
	return Boolean.valueOf(isSet(6));
	} else if (name.equalsIgnoreCase(ENCIPHER_ONLY)) {
	return Boolean.valueOf(isSet(7));
	} else if (name.equalsIgnoreCase(DECIPHER_ONLY)) {
	return Boolean.valueOf(isSet(8));
	} else {
	throw new IOException("Attribute name not recognized by"
	+ " CertAttrSet:KeyUsage.");
	}
	}

	/**
	* Delete the attribute value.
	*/
	public void delete(String name) throws IOException {
	if (name.equalsIgnoreCase(DIGITAL_SIGNATURE)) {
	set(0,false);
	} else if (name.equalsIgnoreCase(NON_REPUDIATION)) {
	set(1,false);
	} else if (name.equalsIgnoreCase(KEY_ENCIPHERMENT)) {
	set(2,false);
	} else if (name.equalsIgnoreCase(DATA_ENCIPHERMENT)) {
	set(3,false);
	} else if (name.equalsIgnoreCase(KEY_AGREEMENT)) {
	set(4,false);
	} else if (name.equalsIgnoreCase(KEY_CERTSIGN)) {
	set(5,false);
	} else if (name.equalsIgnoreCase(CRL_SIGN)) {
	set(6,false);
	} else if (name.equalsIgnoreCase(ENCIPHER_ONLY)) {
	set(7,false);
	} else if (name.equalsIgnoreCase(DECIPHER_ONLY)) {
	set(8,false);
	} else {
	throw new IOException("Attribute name not recognized by"
	+ " CertAttrSet:KeyUsage.");
	}
	encodeThis();
	}

	/**
	* Returns a printable representation of the KeyUsage.
	*/
	public String toString() {
	StringBuilder sb = new StringBuilder();
	sb.append(super.toString());
	sb.append("KeyUsage [\n");

	if (isSet(0)) {
	sb.append(" DigitalSignature\n");
	}
	if (isSet(1)) {
	sb.append(" Non_repudiation\n");
	}
	if (isSet(2)) {
	sb.append(" Key_Encipherment\n");
	}
	if (isSet(3)) {
	sb.append(" Data_Encipherment\n");
	}
	if (isSet(4)) {
	sb.append(" Key_Agreement\n");
	}
	if (isSet(5)) {
	sb.append(" Key_CertSign\n");
	}
	if (isSet(6)) {
	sb.append(" Crl_Sign\n");
	}
	if (isSet(7)) {
	sb.append(" Encipher_Only\n");
	}
	if (isSet(8)) {
	sb.append(" Decipher_Only\n");
	}
	sb.append("]\n");

	return sb.toString();
	}

	/**
	* Write the extension to the DerOutputStream.
	*
	* @param out the DerOutputStream to write the extension to.
	* @exception IOException on encoding errors.
	*/
	public void encode(OutputStream out) throws IOException {
	DerOutputStream tmp = new DerOutputStream();

	if (this.extensionValue == null) {
	this.extensionId = PKIXExtensions.KeyUsage_Id;
	this.critical = true;
	encodeThis();
	}
	super.encode(tmp);
	out.write(tmp.toByteArray());
	}

	/**
	* Return an enumeration of names of attributes existing within this
	* attribute.
	*/
	public Enumeration<String> getElements() {
	AttributeNameEnumeration elements = new AttributeNameEnumeration();
	elements.addElement(DIGITAL_SIGNATURE);
	elements.addElement(NON_REPUDIATION);
	elements.addElement(KEY_ENCIPHERMENT);
	elements.addElement(DATA_ENCIPHERMENT);
	elements.addElement(KEY_AGREEMENT);
	elements.addElement(KEY_CERTSIGN);
	elements.addElement(CRL_SIGN);
	elements.addElement(ENCIPHER_ONLY);
	elements.addElement(DECIPHER_ONLY);

	return (elements.elements());
	}


	public boolean[] getBits() {
	return bitString.clone();
	}

	/**
	* Return the name of this attribute.
	*/
	public String getName() {
	return (NAME);
	}
	}

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