package org.bouncycastle.asn1;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.encoders.Hex;

public abstract class ASN1OctetString
    extends ASN1Object
    implements ASN1OctetStringParser
{
    byte[]  string;

    /**
     * return an Octet String from a tagged object.
     *
     * @param obj the tagged object holding the object we want.
     * @param explicit true if the object is meant to be explicitly
     *              tagged false otherwise.
     * @exception IllegalArgumentException if the tagged object cannot
     *              be converted.
     */
    public static ASN1OctetString getInstance(
        ASN1TaggedObject    obj,
        boolean             explicit)
    {
        DERObject o = obj.getObject();

        if (explicit || o instanceof ASN1OctetString)
        {
            return getInstance(o);
        }
        else
        {
            return BERConstructedOctetString.fromSequence(ASN1Sequence.getInstance(o)); 
        }
    }
    
    /**
     * return an Octet String from the given object.
     *
     * @param obj the object we want converted.
     * @exception IllegalArgumentException if the object cannot be converted.
     */
    public static ASN1OctetString getInstance(
        Object  obj)
    {
        if (obj == null || obj instanceof ASN1OctetString)
        {
            return (ASN1OctetString)obj;
        }

        // TODO: this needs to be deleted in V2
        if (obj instanceof ASN1TaggedObject)
        {
            return getInstance(((ASN1TaggedObject)obj).getObject());
        }

        throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
    }

    /**
     * @param string the octets making up the octet string.
     */
    public ASN1OctetString(
        byte[]  string)
    {
        if (string == null)
        {
            throw new NullPointerException("string cannot be null");
        }
        this.string = string;
    }

    public ASN1OctetString(
        DEREncodable obj)
    {
        try
        {
            this.string = obj.getDERObject().getEncoded(ASN1Encodable.DER);
        }
        catch (IOException e)
        {
            throw new IllegalArgumentException("Error processing object : " + e.toString());
        }
    }

    public InputStream getOctetStream()
    {
        return new ByteArrayInputStream(string);
    }

    public ASN1OctetStringParser parser()
    {
        return this;
    }

    public byte[] getOctets()
    {
        return string;
    }

    public int hashCode()
    {
        return Arrays.hashCode(this.getOctets());
    }

    boolean asn1Equals(
        DERObject  o)
    {
        if (!(o instanceof ASN1OctetString))
        {
            return false;
        }

        ASN1OctetString  other = (ASN1OctetString)o;

        return Arrays.areEqual(string, other.string);
    }

    public DERObject getLoadedObject()
    {
        return this.getDERObject();
    }

    abstract void encode(DEROutputStream out)
        throws IOException;

    public String toString()
    {
      return "#"+new String(Hex.encode(string));
    }
}