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A GWT cryptography library ported from Legion of the Bouncy Castle.
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package org.bouncycastle.asn1;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;
import org.bouncycastle.util.Arrays;
/**
* ASN.1 SEQUENCE and SEQUENCE OF constructs.
*
* DER form is always definite form length fields, while
* BER support uses indefinite form.
*
* X.690
* 8: Basic encoding rules
* 8.9 Encoding of a sequence value
* 8.9.1 The encoding of a sequence value shall be constructed.
*
* 8.9.2 The contents octets shall consist of the complete
* encoding of one data value from each of the types listed in
* the ASN.1 definition of the sequence type, in the order of
* their appearance in the definition, unless the type was referenced
* with the keyword OPTIONAL or the keyword DEFAULT.
*
* 8.9.3 The encoding of a data value may, but need not,
* be present for a type which was referenced with the keyword
* OPTIONAL or the keyword DEFAULT.
* If present, it shall appear in the encoding at the point
* corresponding to the appearance of the type in the ASN.1 definition.
*
* 8.10 Encoding of a sequence-of value
*
* 8.10.1 The encoding of a sequence-of value shall be constructed.
*
* 8.10.2 The contents octets shall consist of zero,
* one or more complete encodings of data values from the type listed in
* the ASN.1 definition.
*
* 8.10.3 The order of the encodings of the data values shall be
* the same as the order of the data values in the sequence-of value to
* be encoded.
*
* 9: Canonical encoding rules
* 9.1 Length forms
* If the encoding is constructed, it shall employ the indefinite-length form.
* If the encoding is primitive, it shall include the fewest length octets necessary.
* [Contrast with 8.1.3.2 b).]
*
* 11: Restrictions on BER employed by both CER and DER
* 11.5 Set and sequence components with default value
* The encoding of a set value or sequence value shall not include
* an encoding for any component value which is equal to
* its default value.
*/
public abstract class ASN1Sequence
extends ASN1Primitive
implements org.bouncycastle.util.Iterable
{
protected Vector seq = new Vector();
/**
* Return an ASN1Sequence from the given object.
*
* @param obj the object we want converted.
* @exception IllegalArgumentException if the object cannot be converted.
* @return an ASN1Sequence instance, or null.
*/
public static ASN1Sequence getInstance(
Object obj)
{
if (obj == null || obj instanceof ASN1Sequence)
{
return (ASN1Sequence)obj;
}
else if (obj instanceof ASN1SequenceParser)
{
return ASN1Sequence.getInstance(((ASN1SequenceParser)obj).toASN1Primitive());
}
else if (obj instanceof byte[])
{
try
{
return ASN1Sequence.getInstance(fromByteArray((byte[])obj));
}
catch (IOException e)
{
throw new IllegalArgumentException("failed to construct sequence from byte[]: " + e.getMessage());
}
}
else if (obj instanceof ASN1Encodable)
{
ASN1Primitive primitive = ((ASN1Encodable)obj).toASN1Primitive();
if (primitive instanceof ASN1Sequence)
{
return (ASN1Sequence)primitive;
}
}
throw new IllegalArgumentException("unknown object in getInstance: " + obj.getClass().getName());
}
/**
* Return an ASN1 sequence from a tagged object. There is a special
* case here, if an object appears to have been explicitly tagged on
* reading but we were expecting it to be implicitly tagged in the
* normal course of events it indicates that we lost the surrounding
* sequence - so we need to add it back (this will happen if the tagged
* object is a sequence that contains other sequences). If you are
* dealing with implicitly tagged sequences you really should
* be using this method.
*
* @param obj the tagged object.
* @param explicit true if the object is meant to be explicitly tagged,
* false otherwise.
* @exception IllegalArgumentException if the tagged object cannot
* be converted.
* @return an ASN1Sequence instance.
*/
public static ASN1Sequence getInstance(
ASN1TaggedObject obj,
boolean explicit)
{
if (explicit)
{
if (!obj.isExplicit())
{
throw new IllegalArgumentException("object implicit - explicit expected.");
}
return ASN1Sequence.getInstance(obj.getObject().toASN1Primitive());
}
else
{
//
// constructed object which appears to be explicitly tagged
// when it should be implicit means we have to add the
// surrounding sequence.
//
if (obj.isExplicit())
{
if (obj instanceof BERTaggedObject)
{
return new BERSequence(obj.getObject());
}
else
{
return new DLSequence(obj.getObject());
}
}
else
{
if (obj.getObject() instanceof ASN1Sequence)
{
return (ASN1Sequence)obj.getObject();
}
}
}
throw new IllegalArgumentException("unknown object in getInstance: " + obj.getClass().getName());
}
/**
* Create an empty sequence
*/
protected ASN1Sequence()
{
}
/**
* Create a sequence containing one object
* @param obj the object to be put in the SEQUENCE.
*/
protected ASN1Sequence(
ASN1Encodable obj)
{
seq.addElement(obj);
}
/**
* Create a sequence containing a vector of objects.
* @param v the vector of objects to be put in the SEQUENCE
*/
protected ASN1Sequence(
ASN1EncodableVector v)
{
for (int i = 0; i != v.size(); i++)
{
seq.addElement(v.get(i));
}
}
/*
* Create a sequence containing a vector of objects.
*/
protected ASN1Sequence(
ASN1Encodable[] array)
{
for (int i = 0; i != array.length; i++)
{
seq.addElement(array[i]);
}
}
public ASN1Encodable[] toArray()
{
ASN1Encodable[] values = new ASN1Encodable[this.size()];
for (int i = 0; i != this.size(); i++)
{
values[i] = this.getObjectAt(i);
}
return values;
}
public Enumeration getObjects()
{
return seq.elements();
}
public ASN1SequenceParser parser()
{
final ASN1Sequence outer = this;
return new ASN1SequenceParser()
{
private final int max = size();
private int index;
public ASN1Encodable readObject() throws IOException
{
if (index == max)
{
return null;
}
ASN1Encodable obj = getObjectAt(index++);
if (obj instanceof ASN1Sequence)
{
return ((ASN1Sequence)obj).parser();
}
if (obj instanceof ASN1Set)
{
return ((ASN1Set)obj).parser();
}
return obj;
}
public ASN1Primitive getLoadedObject()
{
return outer;
}
public ASN1Primitive toASN1Primitive()
{
return outer;
}
};
}
/**
* Return the object at the sequence position indicated by index.
*
* @param index the sequence number (starting at zero) of the object
* @return the object at the sequence position indicated by index.
*/
public ASN1Encodable getObjectAt(
int index)
{
return (ASN1Encodable)seq.elementAt(index);
}
/**
* Return the number of objects in this sequence.
*
* @return the number of objects in this sequence.
*/
public int size()
{
return seq.size();
}
public int hashCode()
{
Enumeration e = this.getObjects();
int hashCode = size();
while (e.hasMoreElements())
{
Object o = getNext(e);
hashCode *= 17;
hashCode ^= o.hashCode();
}
return hashCode;
}
boolean asn1Equals(
ASN1Primitive o)
{
if (!(o instanceof ASN1Sequence))
{
return false;
}
ASN1Sequence other = (ASN1Sequence)o;
if (this.size() != other.size())
{
return false;
}
Enumeration s1 = this.getObjects();
Enumeration s2 = other.getObjects();
while (s1.hasMoreElements())
{
ASN1Encodable obj1 = getNext(s1);
ASN1Encodable obj2 = getNext(s2);
ASN1Primitive o1 = obj1.toASN1Primitive();
ASN1Primitive o2 = obj2.toASN1Primitive();
if (o1 == o2 || o1.equals(o2))
{
continue;
}
return false;
}
return true;
}
private ASN1Encodable getNext(Enumeration e)
{
ASN1Encodable encObj = (ASN1Encodable)e.nextElement();
return encObj;
}
/**
* Change current SEQUENCE object to be encoded as {@link DERSequence}.
* This is part of Distinguished Encoding Rules form serialization.
*/
ASN1Primitive toDERObject()
{
ASN1Sequence derSeq = new DERSequence();
derSeq.seq = this.seq;
return derSeq;
}
/**
* Change current SEQUENCE object to be encoded as {@link DLSequence}.
* This is part of Direct Length form serialization.
*/
ASN1Primitive toDLObject()
{
ASN1Sequence dlSeq = new DLSequence();
dlSeq.seq = this.seq;
return dlSeq;
}
boolean isConstructed()
{
return true;
}
abstract void encode(ASN1OutputStream out)
throws IOException;
public String toString()
{
return seq.toString();
}
public Iterator iterator()
{
return new Arrays.Iterator(toArray());
}
}