/* BitString.java -- Java representation of the BIT STRING type. Copyright (C) 2003, 2014 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ package gnu.java.security.der; import gnu.java.lang.CPStringBuilder; import java.math.BigInteger; import java.util.Arrays; /** * Immutable representation of a bit string, which is equivalent to a * byte array except some number of the rightmost bits are ignored. For * example, this could be the bit string: * *
00010101 11101101 11010xxx* *
Where the "xxx" represents three bits that should be ignored, and
* can have any value.
*
* @author Casey Marshall (csm@gnu.org)
*/
public class BitString implements Cloneable, Comparabletrue
value
* corresponding to each "1" in this bit string. The boolean array is
* cloned before it is returned.
*
* @return The boolean array.
*/
public boolean[] toBooleanArray()
{
if (boolVal == null)
{
boolVal = new boolean[size()];
for (int i = 0, j = 7, k = 0; i < boolVal.length; i++)
{
boolVal[i] = (bytes[k] & 1 << j--) != 0;
if (j < 0)
{
j = 7;
k++;
}
}
}
return (boolean[]) boolVal.clone();
}
public Object clone()
{
try
{
return super.clone();
}
catch (CloneNotSupportedException cce)
{
throw new InternalError(cce.getMessage());
}
}
@Override
public int compareTo(BitString that)
{
if (this.equals(that))
return 0;
if (this.bytes.length != that.bytes.length)
return (this.bytes.length < that.bytes.length) ? -1 : 1;
if (this.ignoredBits != that.ignoredBits)
return (this.ignoredBits < that.ignoredBits) ? -1 : 1;
for (int i = 0; i < this.bytes.length; i++)
if (this.bytes[i] != that.bytes[i])
return (this.bytes[i] < that.bytes[i]) ? -1 : 1;
return 0; // not reached.
}
public int hashCode()
{
int result = 0;
for (int i = 0; i < bytes.length - 1; ++i)
result = result * 31 + bytes[i];
if (bytes.length > 0)
{
int lastByte = bytes[bytes.length - 1] & ~ ((1 << ignoredBits) - 1);
result = result * 31 + lastByte;
}
return result;
}
public boolean equals(Object o)
{
if (!(o instanceof BitString))
return false;
BitString that = (BitString) o;
// True for cloned instances.
if (this.bytes == that.bytes && this.ignoredBits == that.ignoredBits)
return true;
if (this.ignoredBits == that.ignoredBits)
return Arrays.equals(this.bytes, that.bytes);
return false;
}
public String toString()
{
CPStringBuilder sb = new CPStringBuilder();
for (int i = 0, j = 7, k = 0; i < size(); i++)
{
sb.append((bytes[k] & 1 << j) != 0 ? "1" : "0");
j--;
if (j < 0)
{
j = 7;
k++;
}
}
return sb.toString();
}
}