package org.bouncycastle.asn1;

import java.io.IOException;
import java.io.OutputStream;

/**
 * A stream generator for DER SEQUENCEs
 */
public class BERSequenceGenerator
    extends BERGenerator
{
    /**
     * Use the passed in stream as the target for the generator, writing out the header tag
     * for a constructed SEQUENCE.
     *
     * @param out target stream
     * @throws IOException if the target stream cannot be written to.
     */
    public BERSequenceGenerator(
        OutputStream out)
        throws IOException
    {
        super(out);

        writeBERHeader(BERTags.CONSTRUCTED | BERTags.SEQUENCE);
    }

    /**
     * Use the passed in stream as the target for the generator, writing out the header tag
     * for a tagged constructed SEQUENCE (possibly implicit).
     *
     * @param out target stream
     * @param tagNo the tag number to introduce
     * @param isExplicit true if this is an explicitly tagged object, false otherwise.
     * @throws IOException if the target stream cannot be written to.
     */
    public BERSequenceGenerator(
        OutputStream out,
        int tagNo,
        boolean isExplicit)
        throws IOException
    {
        super(out, tagNo, isExplicit);

        writeBERHeader(BERTags.CONSTRUCTED | BERTags.SEQUENCE);
    }

    /**
     * Add an object to the SEQUENCE being generated.
     *
     * @param object an ASN.1 encodable object to add.
     * @throws IOException if the target stream cannot be written to or the object cannot be encoded.
     */
    public void addObject(ASN1Encodable object) throws IOException
    {
        object.toASN1Primitive().encodeTo(_out);
    }

    /**
     * Add an ASN1.1 primitive to the SEQUENCE being generated.
     *
     * @param primitive an ASN.1 primitive to add.
     * @throws IOException if the target stream cannot be written to or the primitive cannot be encoded.
     */
    public void addObject(ASN1Primitive primitive) throws IOException
    {
        primitive.encodeTo(_out);
    }

    /**
     * Close of the generator, writing out the BER end tag.
     *
     * @throws IOException if the target stream cannot be written.
     */
    public void close()
        throws IOException
    {
        writeBEREnd();
    }
}