package org.bouncycastle.asn1;

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

The DLSet encodes ASN.1 SET value without element ordering,
and always using definite length form.

X.690
8: Basic encoding rules
8.11 Encoding of a set value 
8.11.1 The encoding of a set value shall be constructed

8.11.2 The contents octets shall consist of the complete
encoding of a data value from each of the types listed in the
ASN.1 definition of the set type, in an order chosen by the sender,
unless the type was referenced with the keyword
OPTIONAL or the keyword DEFAULT.

8.11.3 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.

NOTE — The order of data values in a set value is not significant,
and places no constraints on the order during transfer

9: Canonical encoding rules
9.3 Set components
The encodings of the component values of a set value shall
appear in an order determined by their tags as specified
in 8.6 of ITU-T Rec. X.680 | ISO/IEC 8824-1.
Additionally, for the purposes of determining the order in which
components are encoded when one or more component is an untagged
choice type, each untagged choice type is ordered as though it
has a tag equal to that of the smallest tag in that choice type
or any untagged choice types nested within.
10: Distinguished encoding rules
10.3 Set components
The encodings of the component values of a set value shall appear
in an order determined by their tags as specified
in 8.6 of ITU-T Rec. X.680 | ISO/IEC 8824-1.

NOTE — Where a component of the set is an untagged choice type,
the location of that component in the ordering will depend on
the tag of the choice component being encoded.

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.
/**
 * The DLSet encodes ASN.1 SET value without element ordering,
 * and always using definite length form.
 * <hr>
 * <h2>X.690</h2>
 * <h3>8: Basic encoding rules</h3>
 * <h4>8.11 Encoding of a set value </h4>
 * <b>8.11.1</b> The encoding of a set value shall be constructed
 * <p>
 * <b>8.11.2</b> The contents octets shall consist of the complete
 * encoding of a data value from each of the types listed in the
 * ASN.1 definition of the set type, in an order chosen by the sender,
 * unless the type was referenced with the keyword
 * <b>OPTIONAL</b> or the keyword <b>DEFAULT</b>.
 * <p>
 * <b>8.11.3</b> The encoding of a data value may, but need not,
 * be present for a type which was referenced with the keyword
 * <b>OPTIONAL</b> or the keyword <b>DEFAULT</b>.
 * <blockquote>
 * NOTE &mdash; The order of data values in a set value is not significant,
 * and places no constraints on the order during transfer
 * </blockquote>
 * <h3>9: Canonical encoding rules</h3>
 * <h4>9.3 Set components</h4>
 * The encodings of the component values of a set value shall
 * appear in an order determined by their tags as specified
 * in 8.6 of ITU-T Rec. X.680 | ISO/IEC 8824-1.
 * Additionally, for the purposes of determining the order in which
 * components are encoded when one or more component is an untagged
 * choice type, each untagged choice type is ordered as though it
 * has a tag equal to that of the smallest tag in that choice type
 * or any untagged choice types nested within.
 * <h3>10: Distinguished encoding rules</h3>
 * <h4>10.3 Set components</h4>
 * The encodings of the component values of a set value shall appear
 * in an order determined by their tags as specified
 * in 8.6 of ITU-T Rec. X.680 | ISO/IEC 8824-1.
 * <blockquote>
 * NOTE &mdash; Where a component of the set is an untagged choice type,
 * the location of that component in the ordering will depend on
 * the tag of the choice component being encoded.
 * </blockquote>
 * <h3>11: Restrictions on BER employed by both CER and DER</h3>
 * <h4>11.5 Set and sequence components with default value </h4>
 * 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 class DLSet
    extends ASN1Set
{
    private int bodyLength = -1;

    
create an empty set
/**
     * create an empty set
     */
    public DLSet()
    {
    }

    
Params:
obj – - a single object that makes up the set./**
     * @param obj - a single object that makes up the set.
     */
    public DLSet(
        ASN1Encodable obj)
    {
        super(obj);
    }

    
Params:
v – - a vector of objects making up the set./**
     * @param v - a vector of objects making up the set.
     */
    public DLSet(
        ASN1EncodableVector v)
    {
        super(v, false);
    }

    
create a set from an array of objects.
/**
     * create a set from an array of objects.
     */
    public DLSet(
        ASN1Encodable[] a)
    {
        super(a, false);
    }

    private int getBodyLength()
        throws IOException
    {
        if (bodyLength < 0)
        {
            int length = 0;

            for (Enumeration e = this.getObjects(); e.hasMoreElements();)
            {
                Object obj = e.nextElement();

                length += ((ASN1Encodable)obj).toASN1Primitive().toDLObject().encodedLength();
            }

            bodyLength = length;
        }

        return bodyLength;
    }

    int encodedLength()
        throws IOException
    {
        int length = getBodyLength();

        return 1 + StreamUtil.calculateBodyLength(length) + length;
    }

    
A note on the implementation:

As DL requires the constructed, definite-length model to
be used for structured types, this varies slightly from the
ASN.1 descriptions given. Rather than just outputting SET,
we also have to specify CONSTRUCTED, and the objects length.
/**
     * A note on the implementation:
     * <p>
     * As DL requires the constructed, definite-length model to
     * be used for structured types, this varies slightly from the
     * ASN.1 descriptions given. Rather than just outputting SET,
     * we also have to specify CONSTRUCTED, and the objects length.
     */
    void encode(
        ASN1OutputStream out)
        throws IOException
    {
        ASN1OutputStream dOut = out.getDLSubStream();
        int length = getBodyLength();

        out.write(BERTags.SET | BERTags.CONSTRUCTED);
        out.writeLength(length);

        for (Enumeration e = this.getObjects(); e.hasMoreElements();)
        {
            Object obj = e.nextElement();

            dOut.writeObject((ASN1Encodable)obj);
        }
    }
}