| package org.bouncycastle.asn1; |
| |
| import java.io.IOException; |
| |
| /** |
| * A Definite length BIT STRING |
| */ |
| public class DLBitString |
| extends ASN1BitString |
| { |
| /** |
| * return a Bit String that can be definite-length encoded from the passed in object. |
| * |
| * @param obj a DL or DER BitString or an object that can be converted into one. |
| * @exception IllegalArgumentException if the object cannot be converted. |
| * @return an ASN1BitString instance, or null. |
| */ |
| public static ASN1BitString getInstance( |
| Object obj) |
| { |
| if (obj == null || obj instanceof DLBitString) |
| { |
| return (DLBitString)obj; |
| } |
| if (obj instanceof DERBitString) |
| { |
| return (DERBitString)obj; |
| } |
| if (obj instanceof byte[]) |
| { |
| try |
| { |
| return (ASN1BitString)fromByteArray((byte[])obj); |
| } |
| catch (Exception e) |
| { |
| throw new IllegalArgumentException("encoding error in getInstance: " + e.toString()); |
| } |
| } |
| |
| throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName()); |
| } |
| |
| /** |
| * return a Bit 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. |
| * @return an ASN1BitString instance, or null. |
| */ |
| public static ASN1BitString getInstance( |
| ASN1TaggedObject obj, |
| boolean explicit) |
| { |
| ASN1Primitive o = obj.getObject(); |
| |
| if (explicit || o instanceof DLBitString) |
| { |
| return getInstance(o); |
| } |
| else |
| { |
| return fromOctetString(((ASN1OctetString)o).getOctets()); |
| } |
| } |
| |
| protected DLBitString( |
| byte data, |
| int padBits) |
| { |
| this(toByteArray(data), padBits); |
| } |
| |
| private static byte[] toByteArray(byte data) |
| { |
| byte[] rv = new byte[1]; |
| |
| rv[0] = data; |
| |
| return rv; |
| } |
| |
| /** |
| * @param data the octets making up the bit string. |
| * @param padBits the number of extra bits at the end of the string. |
| */ |
| public DLBitString( |
| byte[] data, |
| int padBits) |
| { |
| super(data, padBits); |
| } |
| |
| public DLBitString( |
| byte[] data) |
| { |
| this(data, 0); |
| } |
| |
| public DLBitString( |
| int value) |
| { |
| super(getBytes(value), getPadBits(value)); |
| } |
| |
| public DLBitString( |
| ASN1Encodable obj) |
| throws IOException |
| { |
| super(obj.toASN1Primitive().getEncoded(ASN1Encoding.DER), 0); |
| } |
| |
| boolean isConstructed() |
| { |
| return false; |
| } |
| |
| int encodedLength() |
| { |
| return 1 + StreamUtil.calculateBodyLength(data.length + 1) + data.length + 1; |
| } |
| |
| void encode( |
| ASN1OutputStream out) |
| throws IOException |
| { |
| byte[] string = data; |
| byte[] bytes = new byte[string.length + 1]; |
| |
| bytes[0] = (byte)getPadBits(); |
| System.arraycopy(string, 0, bytes, 1, bytes.length - 1); |
| |
| out.writeEncoded(BERTags.BIT_STRING, bytes); |
| } |
| |
| static DLBitString fromOctetString(byte[] bytes) |
| { |
| if (bytes.length < 1) |
| { |
| throw new IllegalArgumentException("truncated BIT STRING detected"); |
| } |
| |
| int padBits = bytes[0]; |
| byte[] data = new byte[bytes.length - 1]; |
| |
| if (data.length != 0) |
| { |
| System.arraycopy(bytes, 1, data, 0, bytes.length - 1); |
| } |
| |
| return new DLBitString(data, padBits); |
| } |
| } |