/*
* Copyright 2012-2014 Brian Campbell
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jose4j.keys;
import org.jose4j.base64url.Base64Url;
import org.jose4j.lang.ByteUtil;
import java.math.BigInteger;
/**
*/
public class BigEndianBigInteger
{
public static BigInteger fromBytes(byte[] magnitude)
{
return new BigInteger(1, magnitude);
}
public static BigInteger fromBase64Url(String base64urlEncodedBytes)
{
Base64Url base64Url = new Base64Url();
byte[] magnitude = base64Url.base64UrlDecode(base64urlEncodedBytes);
return fromBytes(magnitude);
}
public static byte[] toByteArray(BigInteger bigInteger, int minArrayLength)
{
byte[] bytes = toByteArray(bigInteger);
if (minArrayLength > bytes.length)
{
bytes = ByteUtil.concat(new byte[minArrayLength - bytes.length], bytes);
}
return bytes;
}
public static byte[] toByteArray(BigInteger bigInteger)
{
if (bigInteger.signum() < 0)
{
String msg = "Cannot convert negative values to an unsigned magnitude byte array: " + bigInteger;
throw new IllegalArgumentException(msg);
}
byte[] twosComplementBytes = bigInteger.toByteArray();
byte[] magnitude;
if ((bigInteger.bitLength() % 8 == 0) && (twosComplementBytes[0] == 0) && twosComplementBytes.length > 1)
{
magnitude = ByteUtil.subArray(twosComplementBytes, 1, twosComplementBytes.length - 1);
}
else
{
magnitude = twosComplementBytes;
}
return magnitude;
}
public static String toBase64Url(BigInteger bigInteger)
{
Base64Url base64Url = new Base64Url();
byte[] bytes = toByteArray(bigInteger);
return base64Url.base64UrlEncode(bytes);
}
public static String toBase64Url(BigInteger bigInteger, int minByteArrayLength)
{
Base64Url base64Url = new Base64Url();
byte[] bytes = toByteArray(bigInteger, minByteArrayLength);
return base64Url.base64UrlEncode(bytes);
}
}