org.apache.fontbox.cff.Type1FontUtil Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.fontbox.cff;
import java.util.Locale;
/**
* This class contains some helper methods handling Type1-Fonts.
*
* @author Villu Ruusmann
*/
public final class Type1FontUtil
{
private Type1FontUtil()
{
}
/**
* Converts a byte-array into a string with the corresponding hex value.
* @param bytes the byte array
* @return the string with the hex value
*/
public static String hexEncode(byte[] bytes)
{
StringBuilder sb = new StringBuilder();
for (byte aByte : bytes)
{
String string = Integer.toHexString(aByte & 0xff);
if (string.length() == 1)
{
sb.append("0");
}
sb.append(string.toUpperCase(Locale.US));
}
return sb.toString();
}
/**
* Converts a string representing a hex value into a byte array.
* @param string the string representing the hex value
* @return the hex value as byte array
*/
public static byte[] hexDecode(String string)
{
if (string.length() % 2 != 0)
{
throw new IllegalArgumentException();
}
byte[] bytes = new byte[string.length() / 2];
for (int i = 0; i < string.length(); i += 2)
{
bytes[i / 2] = (byte) Integer.parseInt(string.substring(i, i + 2), 16);
}
return bytes;
}
/**
* Encrypt eexec.
* @param buffer the given data
* @return the encrypted data
*/
public static byte[] eexecEncrypt(byte[] buffer)
{
return encrypt(buffer, 55665, 4);
}
/**
* Encrypt charstring.
* @param buffer the given data
* @param n blocksize?
* @return the encrypted data
*/
public static byte[] charstringEncrypt(byte[] buffer, int n)
{
return encrypt(buffer, 4330, n);
}
private static byte[] encrypt(byte[] plaintextBytes, int r, int n)
{
byte[] buffer = new byte[plaintextBytes.length + n];
for (int i = 0; i < n; i++)
{
buffer[i] = 0;
}
System.arraycopy(plaintextBytes, 0, buffer, n, buffer.length - n);
int c1 = 52845;
int c2 = 22719;
byte[] ciphertextBytes = new byte[buffer.length];
for (int i = 0; i < buffer.length; i++)
{
int plain = buffer[i] & 0xff;
int cipher = plain ^ r >> 8;
ciphertextBytes[i] = (byte) cipher;
r = (cipher + r) * c1 + c2 & 0xffff;
}
return ciphertextBytes;
}
/**
* Decrypt eexec.
* @param buffer the given encrypted data
* @return the decrypted data
*/
public static byte[] eexecDecrypt(byte[] buffer)
{
return decrypt(buffer, 55665, 4);
}
/**
* Decrypt charstring.
* @param buffer the given encrypted data
* @param n blocksize?
* @return the decrypted data
*/
public static byte[] charstringDecrypt(byte[] buffer, int n)
{
return decrypt(buffer, 4330, n);
}
private static byte[] decrypt(byte[] ciphertextBytes, int r, int n)
{
byte[] buffer = new byte[ciphertextBytes.length];
int c1 = 52845;
int c2 = 22719;
for (int i = 0; i < ciphertextBytes.length; i++)
{
int cipher = ciphertextBytes[i] & 0xff;
int plain = cipher ^ r >> 8;
buffer[i] = (byte) plain;
r = (cipher + r) * c1 + c2 & 0xffff;
}
byte[] plaintextBytes = new byte[ciphertextBytes.length - n];
System.arraycopy(buffer, n, plaintextBytes, 0, plaintextBytes.length);
return plaintextBytes;
}
}