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	/*
	* Copyright (c) 1996, 2010, 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.util;

	import java.io.ByteArrayOutputStream;
	import java.io.OutputStream;
	import java.io.IOException;
	import java.text.SimpleDateFormat;
	import java.util.Date;
	import java.util.TimeZone;
	import java.util.Comparator;
	import java.util.Arrays;
	import java.math.BigInteger;
	import java.util.Locale;


	/**
	* Output stream marshaling DER-encoded data. This is eventually provided
	* in the form of a byte array; there is no advance limit on the size of
	* that byte array.
	*
	* <P>At this time, this class supports only a subset of the types of
	* DER data encodings which are defined. That subset is sufficient for
	* generating most X.509 certificates.
	*
	*
	* @author David Brownell
	* @author Amit Kapoor
	* @author Hemma Prafullchandra
	*/
	public class DerOutputStream
	extends ByteArrayOutputStream implements DerEncoder {
	/**
	* Construct an DER output stream.
	*
	* @param size how large a buffer to preallocate.
	*/
	public DerOutputStream(int size) { super(size); }

	/**
	* Construct an DER output stream.
	*/
	public DerOutputStream() { }

	/**
	* Writes tagged, pre-marshaled data. This calcuates and encodes
	* the length, so that the output data is the standard triple of
	* { tag, length, data } used by all DER values.
	*
	* @param tag the DER value tag for the data, such as
	* <em>DerValue.tag_Sequence</em>
	* @param buf buffered data, which must be DER-encoded
	*/
	public void write(byte tag, byte[] buf) throws IOException {
	write(tag);
	putLength(buf.length);
	write(buf, 0, buf.length);
	}

	/**
	* Writes tagged data using buffer-to-buffer copy. As above,
	* this writes a standard DER record. This is often used when
	* efficiently encapsulating values in sequences.
	*
	* @param tag the DER value tag for the data, such as
	* <em>DerValue.tag_Sequence</em>
	* @param out buffered data
	*/
	public void write(byte tag, DerOutputStream out) throws IOException {
	write(tag);
	putLength(out.count);
	write(out.buf, 0, out.count);
	}

	/**
	* Writes implicitly tagged data using buffer-to-buffer copy. As above,
	* this writes a standard DER record. This is often used when
	* efficiently encapsulating implicitly tagged values.
	*
	* @param tag the DER value of the context-specific tag that replaces
	* original tag of the value in the output, such as in
	* <pre>
	* <em> <field> [N] IMPLICIT <type></em>
	* </pre>
	* For example, <em>FooLength [1] IMPLICIT INTEGER</em>, with value=4;
	* would be encoded as "81 01 04" whereas in explicit
	* tagging it would be encoded as "A1 03 02 01 04".
	* Notice that the tag is A1 and not 81, this is because with
	* explicit tagging the form is always constructed.
	* @param value original value being implicitly tagged
	*/
	public void writeImplicit(byte tag, DerOutputStream value)
	throws IOException {
	write(tag);
	write(value.buf, 1, value.count-1);
	}

	/**
	* Marshals pre-encoded DER value onto the output stream.
	*/
	public void putDerValue(DerValue val) throws IOException {
	val.encode(this);
	}

	/*
	* PRIMITIVES -- these are "universal" ASN.1 simple types.
	*
	* BOOLEAN, INTEGER, BIT STRING, OCTET STRING, NULL
	* OBJECT IDENTIFIER, SEQUENCE(OF), SET(OF)
	* PrintableString, T61String, IA5String, UTCTime
	*/

	/**
	* Marshals a DER boolean on the output stream.
	*/
	public void putBoolean(boolean val) throws IOException {
	write(DerValue.tag_Boolean);
	putLength(1);
	if (val) {
	write(0xff);
	} else {
	write(0);
	}
	}

	/**
	* Marshals a DER enumerated on the output stream.
	* @param i the enumerated value.
	*/
	public void putEnumerated(int i) throws IOException {
	write(DerValue.tag_Enumerated);
	putIntegerContents(i);
	}

	/**
	* Marshals a DER integer on the output stream.
	*
	* @param i the integer in the form of a BigInteger.
	*/
	public void putInteger(BigInteger i) throws IOException {
	write(DerValue.tag_Integer);
	byte[] buf = i.toByteArray(); // least number of bytes
	putLength(buf.length);
	write(buf, 0, buf.length);
	}

	/**
	* Marshals a DER integer on the output stream.
	* @param i the integer in the form of an Integer.
	*/
	public void putInteger(Integer i) throws IOException {
	putInteger(i.intValue());
	}

	/**
	* Marshals a DER integer on the output stream.
	* @param i the integer.
	*/
	public void putInteger(int i) throws IOException {
	write(DerValue.tag_Integer);
	putIntegerContents(i);
	}

	private void putIntegerContents(int i) throws IOException {

	byte[] bytes = new byte[4];
	int start = 0;

	// Obtain the four bytes of the int

	bytes[3] = (byte) (i & 0xff);
	bytes[2] = (byte)((i & 0xff00) >>> 8);
	bytes[1] = (byte)((i & 0xff0000) >>> 16);
	bytes[0] = (byte)((i & 0xff000000) >>> 24);

	// Reduce them to the least number of bytes needed to
	// represent this int

	if (bytes[0] == (byte)0xff) {

	// Eliminate redundant 0xff

	for (int j = 0; j < 3; j++) {
	if ((bytes[j] == (byte)0xff) &&
	((bytes[j+1] & 0x80) == 0x80))
	start++;
	else
	break;
	}
	} else if (bytes[0] == 0x00) {

	// Eliminate redundant 0x00

	for (int j = 0; j < 3; j++) {
	if ((bytes[j] == 0x00) &&
	((bytes[j+1] & 0x80) == 0))
	start++;
	else
	break;
	}
	}

	putLength(4 - start);
	for (int k = start; k < 4; k++)
	write(bytes[k]);
	}

	/**
	* Marshals a DER bit string on the output stream. The bit
	* string must be byte-aligned.
	*
	* @param bits the bit string, MSB first
	*/
	public void putBitString(byte[] bits) throws IOException {
	write(DerValue.tag_BitString);
	putLength(bits.length + 1);
	write(0); // all of last octet is used
	write(bits);
	}

	/**
	* Marshals a DER bit string on the output stream.
	* The bit strings need not be byte-aligned.
	*
	* @param bits the bit string, MSB first
	*/
	public void putUnalignedBitString(BitArray ba) throws IOException {
	byte[] bits = ba.toByteArray();

	write(DerValue.tag_BitString);
	putLength(bits.length + 1);
	write(bits.length*8 - ba.length()); // excess bits in last octet
	write(bits);
	}

	/**
	* Marshals a truncated DER bit string on the output stream.
	* The bit strings need not be byte-aligned.
	*
	* @param bits the bit string, MSB first
	*/
	public void putTruncatedUnalignedBitString(BitArray ba) throws IOException {
	putUnalignedBitString(ba.truncate());
	}

	/**
	* DER-encodes an ASN.1 OCTET STRING value on the output stream.
	*
	* @param octets the octet string
	*/
	public void putOctetString(byte[] octets) throws IOException {
	write(DerValue.tag_OctetString, octets);
	}

	/**
	* Marshals a DER "null" value on the output stream. These are
	* often used to indicate optional values which have been omitted.
	*/
	public void putNull() throws IOException {
	write(DerValue.tag_Null);
	putLength(0);
	}

	/**
	* Marshals an object identifier (OID) on the output stream.
	* Corresponds to the ASN.1 "OBJECT IDENTIFIER" construct.
	*/
	public void putOID(ObjectIdentifier oid) throws IOException {
	oid.encode(this);
	}

	/**
	* Marshals a sequence on the output stream. This supports both
	* the ASN.1 "SEQUENCE" (zero to N values) and "SEQUENCE OF"
	* (one to N values) constructs.
	*/
	public void putSequence(DerValue[] seq) throws IOException {
	DerOutputStream bytes = new DerOutputStream();
	int i;

	for (i = 0; i < seq.length; i++)
	seq[i].encode(bytes);

	write(DerValue.tag_Sequence, bytes);
	}

	/**
	* Marshals the contents of a set on the output stream without
	* ordering the elements. Ok for BER encoding, but not for DER
	* encoding.
	*
	* For DER encoding, use orderedPutSet() or orderedPutSetOf().
	*/
	public void putSet(DerValue[] set) throws IOException {
	DerOutputStream bytes = new DerOutputStream();
	int i;

	for (i = 0; i < set.length; i++)
	set[i].encode(bytes);

	write(DerValue.tag_Set, bytes);
	}

	/**
	* Marshals the contents of a set on the output stream. Sets
	* are semantically unordered, but DER requires that encodings of
	* set elements be sorted into ascending lexicographical order
	* before being output. Hence sets with the same tags and
	* elements have the same DER encoding.
	*
	* This method supports the ASN.1 "SET OF" construct, but not
	* "SET", which uses a different order.
	*/
	public void putOrderedSetOf(byte tag, DerEncoder[] set) throws IOException {
	putOrderedSet(tag, set, lexOrder);
	}

	/**
	* Marshals the contents of a set on the output stream. Sets
	* are semantically unordered, but DER requires that encodings of
	* set elements be sorted into ascending tag order
	* before being output. Hence sets with the same tags and
	* elements have the same DER encoding.
	*
	* This method supports the ASN.1 "SET" construct, but not
	* "SET OF", which uses a different order.
	*/
	public void putOrderedSet(byte tag, DerEncoder[] set) throws IOException {
	putOrderedSet(tag, set, tagOrder);
	}

	/**
	* Lexicographical order comparison on byte arrays, for ordering
	* elements of a SET OF objects in DER encoding.
	*/
	private static ByteArrayLexOrder lexOrder = new ByteArrayLexOrder();

	/**
	* Tag order comparison on byte arrays, for ordering elements of
	* SET objects in DER encoding.
	*/
	private static ByteArrayTagOrder tagOrder = new ByteArrayTagOrder();

	/**
	* Marshals a the contents of a set on the output stream with the
	* encodings of its sorted in increasing order.
	*
	* @param order the order to use when sorting encodings of components.
	*/
	private void putOrderedSet(byte tag, DerEncoder[] set,
	Comparator<byte[]> order) throws IOException {
	DerOutputStream[] streams = new DerOutputStream[set.length];

	for (int i = 0; i < set.length; i++) {
	streams[i] = new DerOutputStream();
	set[i].derEncode(streams[i]);
	}

	// order the element encodings
	byte[][] bufs = new byte[streams.length][];
	for (int i = 0; i < streams.length; i++) {
	bufs[i] = streams[i].toByteArray();
	}
	Arrays.<byte[]>sort(bufs, order);

	DerOutputStream bytes = new DerOutputStream();
	for (int i = 0; i < streams.length; i++) {
	bytes.write(bufs[i]);
	}
	write(tag, bytes);

	}

	/**
	* Marshals a string as a DER encoded UTF8String.
	*/
	public void putUTF8String(String s) throws IOException {
	writeString(s, DerValue.tag_UTF8String, "UTF8");
	}

	/**
	* Marshals a string as a DER encoded PrintableString.
	*/
	public void putPrintableString(String s) throws IOException {
	writeString(s, DerValue.tag_PrintableString, "ASCII");
	}

	/**
	* Marshals a string as a DER encoded T61String.
	*/
	public void putT61String(String s) throws IOException {
	/*
	* Works for characters that are defined in both ASCII and
	* T61.
	*/
	writeString(s, DerValue.tag_T61String, "ISO-8859-1");
	}

	/**
	* Marshals a string as a DER encoded IA5String.
	*/
	public void putIA5String(String s) throws IOException {
	writeString(s, DerValue.tag_IA5String, "ASCII");
	}

	/**
	* Marshals a string as a DER encoded BMPString.
	*/
	public void putBMPString(String s) throws IOException {
	writeString(s, DerValue.tag_BMPString, "UnicodeBigUnmarked");
	}

	/**
	* Marshals a string as a DER encoded GeneralString.
	*/
	public void putGeneralString(String s) throws IOException {
	writeString(s, DerValue.tag_GeneralString, "ASCII");
	}

	/**
	* Private helper routine for writing DER encoded string values.
	* @param s the string to write
	* @param stringTag one of the DER string tags that indicate which
	* encoding should be used to write the string out.
	* @param enc the name of the encoder that should be used corresponding
	* to the above tag.
	*/
	private void writeString(String s, byte stringTag, String enc)
	throws IOException {

	byte[] data = s.getBytes(enc);
	write(stringTag);
	putLength(data.length);
	write(data);
	}

	/**
	* Marshals a DER UTC time/date value.
	*
	* <P>YYMMDDhhmmss{Z\|+hhmm\|-hhmm} ... emits only using Zulu time
	* and with seconds (even if seconds=0) as per RFC 5280.
	*/
	public void putUTCTime(Date d) throws IOException {
	putTime(d, DerValue.tag_UtcTime);
	}

	/**
	* Marshals a DER Generalized Time/date value.
	*
	* <P>YYYYMMDDhhmmss{Z\|+hhmm\|-hhmm} ... emits only using Zulu time
	* and with seconds (even if seconds=0) as per RFC 5280.
	*/
	public void putGeneralizedTime(Date d) throws IOException {
	putTime(d, DerValue.tag_GeneralizedTime);
	}

	/**
	* Private helper routine for marshalling a DER UTC/Generalized
	* time/date value. If the tag specified is not that for UTC Time
	* then it defaults to Generalized Time.
	* @param d the date to be marshalled
	* @param tag the tag for UTC Time or Generalized Time
	*/
	private void putTime(Date d, byte tag) throws IOException {

	/*
	* Format the date.
	*/

	TimeZone tz = TimeZone.getTimeZone("GMT");
	String pattern = null;

	if (tag == DerValue.tag_UtcTime) {
	pattern = "yyMMddHHmmss'Z'";
	} else {
	tag = DerValue.tag_GeneralizedTime;
	pattern = "yyyyMMddHHmmss'Z'";
	}

	SimpleDateFormat sdf = new SimpleDateFormat(pattern, Locale.US);
	sdf.setTimeZone(tz);
	byte[] time = (sdf.format(d)).getBytes("ISO-8859-1");

	/*
	* Write the formatted date.
	*/

	write(tag);
	putLength(time.length);
	write(time);
	}

	/**
	* Put the encoding of the length in the stream.
	*
	* @params len the length of the attribute.
	* @exception IOException on writing errors.
	*/
	public void putLength(int len) throws IOException {
	if (len < 128) {
	write((byte)len);

	} else if (len < (1 << 8)) {
	write((byte)0x081);
	write((byte)len);

	} else if (len < (1 << 16)) {
	write((byte)0x082);
	write((byte)(len >> 8));
	write((byte)len);

	} else if (len < (1 << 24)) {
	write((byte)0x083);
	write((byte)(len >> 16));
	write((byte)(len >> 8));
	write((byte)len);

	} else {
	write((byte)0x084);
	write((byte)(len >> 24));
	write((byte)(len >> 16));
	write((byte)(len >> 8));
	write((byte)len);
	}
	}

	/**
	* Put the tag of the attribute in the stream.
	*
	* @params class the tag class type, one of UNIVERSAL, CONTEXT,
	* APPLICATION or PRIVATE
	* @params form if true, the value is constructed, otherwise it is
	* primitive.
	* @params val the tag value
	*/
	public void putTag(byte tagClass, boolean form, byte val) {
	byte tag = (byte)(tagClass \| val);
	if (form) {
	tag \|= (byte)0x20;
	}
	write(tag);
	}

	/**
	* Write the current contents of this <code>DerOutputStream</code>
	* to an <code>OutputStream</code>.
	*
	* @exception IOException on output error.
	*/
	public void derEncode(OutputStream out) throws IOException {
	out.write(toByteArray());
	}
	}

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