package org.bouncycastle.asn1.x509;
import java.io.IOException;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.DERPrintableString;
import org.bouncycastle.util.Strings;
/**
* It turns out that the number of standard ways the fields in a DN should be
* encoded into their ASN.1 counterparts is rapidly approaching the
* number of machines on the internet. By default the X509Name class
* will produce UTF8Strings in line with the current recommendations (RFC 3280).
* <p>
* An example of an encoder look like below:
* <pre>
* public class X509DirEntryConverter
* extends X509NameEntryConverter
* {
* public ASN1Primitive getConvertedValue(
* ASN1ObjectIdentifier oid,
* String value)
* {
* if (str.length() != 0 && str.charAt(0) == '#')
* {
* return convertHexEncoded(str, 1);
* }
* if (oid.equals(EmailAddress))
* {
* return new DERIA5String(str);
* }
* else if (canBePrintable(str))
* {
* return new DERPrintableString(str);
* }
* else if (canBeUTF8(str))
* {
* return new DERUTF8String(str);
* }
* else
* {
* return new DERBMPString(str);
* }
* }
* }
*/
public abstract class X509NameEntryConverter
{
/**
* Convert an inline encoded hex string rendition of an ASN.1
* object back into its corresponding ASN.1 object.
*
* @param str the hex encoded object
* @param off the index at which the encoding starts
* @return the decoded object
*/
protected ASN1Primitive convertHexEncoded(
String str,
int off)
throws IOException
{
str = Strings.toLowerCase(str);
byte[] data = new byte[(str.length() - off) / 2];
for (int index = 0; index != data.length; index++)
{
char left = str.charAt((index * 2) + off);
char right = str.charAt((index * 2) + off + 1);
if (left < 'a')
{
data[index] = (byte)((left - '0') << 4);
}
else
{
data[index] = (byte)((left - 'a' + 10) << 4);
}
if (right < 'a')
{
data[index] |= (byte)(right - '0');
}
else
{
data[index] |= (byte)(right - 'a' + 10);
}
}
ASN1InputStream aIn = new ASN1InputStream(data);
return aIn.readObject();
}
/**
* return true if the passed in String can be represented without
* loss as a PrintableString, false otherwise.
*/
protected boolean canBePrintable(
String str)
{
return DERPrintableString.isPrintableString(str);
}
/**
* Convert the passed in String value into the appropriate ASN.1
* encoded object.
*
* @param oid the oid associated with the value in the DN.
* @param value the value of the particular DN component.
* @return the ASN.1 equivalent for the value.
*/
public abstract ASN1Primitive getConvertedValue(ASN1ObjectIdentifier oid, String value);
}