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 ASN1Primitive
    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)
    {
        ASN1Primitive o = obj.getObject();

        if (explicit || o instanceof ASN1OctetString)
        {
            return getInstance(o);
        }
        else
        {
            return BEROctetString.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;
        }
        else if (obj instanceof byte[])
        {
            try
            {
                return ASN1OctetString.getInstance(ASN1Primitive.fromByteArray((byte[])obj));
            }
            catch (IOException e)
            {
                throw new IllegalArgumentException("failed to construct OCTET STRING from byte[]: " + e.getMessage());
            }
        }
        else if (obj instanceof ASN1Encodable)
        {
            ASN1Primitive primitive = ((ASN1Encodable)obj).toASN1Primitive();

            if (primitive instanceof ASN1OctetString)
            {
                return (ASN1OctetString)primitive;
            }
        }

        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 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(
        ASN1Primitive o)
    {
        if (!(o instanceof ASN1OctetString))
        {
            return false;
        }

        ASN1OctetString  other = (ASN1OctetString)o;

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

    public ASN1Primitive getLoadedObject()
    {
        return this.toASN1Primitive();
    }

    ASN1Primitive toDERObject()
    {
        return new DEROctetString(string);
    }

    ASN1Primitive toDLObject()
    {
        return new DEROctetString(string);
    }

    abstract void encode(ASN1OutputStream out)
        throws IOException;

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