package org.apache.commons.ssl.asn1;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
public class DERBitString
extends ASN1Object
implements DERString {
private static final char[] table = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
protected byte[] data;
protected int padBits;
/**
* return the correct number of pad bits for a bit string defined in
* a 32 bit constant
*/
static protected int getPadBits(
int bitString) {
int val = 0;
for (int i = 3; i >= 0; i--) {
//
// this may look a little odd, but if it isn't done like this pre jdk1.2
// JVM's break!
//
if (i != 0) {
if ((bitString >> (i * 8)) != 0) {
val = (bitString >> (i * 8)) & 0xFF;
break;
}
} else {
if (bitString != 0) {
val = bitString & 0xFF;
break;
}
}
}
if (val == 0) {
return 7;
}
int bits = 1;
while (((val <<= 1) & 0xFF) != 0) {
bits++;
}
return 8 - bits;
}
/**
* return the correct number of bytes for a bit string defined in
* a 32 bit constant
*/
static protected byte[] getBytes(int bitString) {
int bytes = 4;
for (int i = 3; i >= 1; i--) {
if ((bitString & (0xFF << (i * 8))) != 0) {
break;
}
bytes--;
}
byte[] result = new byte[bytes];
for (int i = 0; i < bytes; i++) {
result[i] = (byte) ((bitString >> (i * 8)) & 0xFF);
}
return result;
}
/**
* return a Bit String from the passed in object
*
* @throws IllegalArgumentException if the object cannot be converted.
*/
public static DERBitString getInstance(
Object obj) {
if (obj == null || obj instanceof DERBitString) {
return (DERBitString) obj;
}
if (obj instanceof ASN1OctetString) {
byte[] bytes = ((ASN1OctetString) obj).getOctets();
int padBits = bytes[0];
byte[] data = new byte[bytes.length - 1];
System.arraycopy(bytes, 1, data, 0, bytes.length - 1);
return new DERBitString(data, padBits);
}
if (obj instanceof ASN1TaggedObject) {
return getInstance(((ASN1TaggedObject) obj).getObject());
}
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.
* @throws IllegalArgumentException if the tagged object cannot
* be converted.
*/
public static DERBitString getInstance(
ASN1TaggedObject obj,
boolean explicit) {
return getInstance(obj.getObject());
}
protected DERBitString(
byte data,
int padBits) {
this.data = new byte[1];
this.data[0] = data;
this.padBits = padBits;
}
/**
* @param data the octets making up the bit string.
* @param padBits the number of extra bits at the end of the string.
*/
public DERBitString(
byte[] data,
int padBits) {
this.data = data;
this.padBits = padBits;
}
public DERBitString(
byte[] data) {
this(data, 0);
}
public DERBitString(
DEREncodable obj) {
try {
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
DEROutputStream dOut = new DEROutputStream(bOut);
dOut.writeObject(obj);
dOut.close();
this.data = bOut.toByteArray();
this.padBits = 0;
}
catch (IOException e) {
throw new IllegalArgumentException("Error processing object : " + e.toString());
}
}
public byte[] getBytes() {
return data;
}
public int getPadBits() {
return padBits;
}
/** @return the value of the bit string as an int (truncating if necessary) */
public int intValue() {
int value = 0;
for (int i = 0; i != data.length && i != 4; i++) {
value |= (data[i] & 0xff) << (8 * i);
}
return value;
}
void encode(
DEROutputStream out)
throws IOException {
byte[] bytes = new byte[getBytes().length + 1];
bytes[0] = (byte) getPadBits();
System.arraycopy(getBytes(), 0, bytes, 1, bytes.length - 1);
out.writeEncoded(BIT_STRING, bytes);
}
public int hashCode() {
int value = 0;
for (int i = 0; i != data.length; i++) {
value ^= (data[i] & 0xff) << (i % 4);
}
return value;
}
protected boolean asn1Equals(
DERObject o) {
if (!(o instanceof DERBitString)) {
return false;
}
DERBitString other = (DERBitString) o;
if (data.length != other.data.length) {
return false;
}
for (int i = 0; i != data.length; i++) {
if (data[i] != other.data[i]) {
return false;
}
}
return (padBits == other.padBits);
}
public String getString() {
StringBuffer buf = new StringBuffer("#");
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
ASN1OutputStream aOut = new ASN1OutputStream(bOut);
try {
aOut.writeObject(this);
}
catch (IOException e) {
throw new RuntimeException("internal error encoding BitString");
}
byte[] string = bOut.toByteArray();
for (int i = 0; i != string.length; i++) {
buf.append(table[(string[i] >>> 4) & 0xf]);
buf.append(table[string[i] & 0xf]);
}
return buf.toString();
}
public String toString() {
return getString();
}
}