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org.keycloak.models.utils.Base32 Maven / Gradle / Ivy
/*
* Copyright 2016 Red Hat, Inc. and/or its affiliates
* and other contributors as indicated by the @author tags.
*
* 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.keycloak.models.utils;
/* (PD) 2006 The Bitzi Corporation
* Please see http://bitzi.com/publicdomain for more info.
*
* $Id: Base32.java,v 1.2 2006/07/14 04:58:39 gojomo Exp $
*/
/**
* Base32 - encodes and decodes RFC3548 Base32 (see http://www.faqs.org/rfcs/rfc3548.html )
*
* @author Robert Kaye
* @author Gordon Mohr
*/
public class Base32 {
private static final String base32Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
private static final int[] base32Lookup = { 0xFF, 0xFF, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14,
0x15, 0x16, 0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
/**
* Encodes byte array to Base32 String.
*
* @param bytes Bytes to encode.
* @return Encoded byte array bytes as a String.
*
*/
public static String encode(final byte[] bytes) {
int i = 0, index = 0, digit = 0;
int currByte, nextByte;
StringBuffer base32 = new StringBuffer((bytes.length + 7) * 8 / 5);
while (i < bytes.length) {
currByte = (bytes[i] >= 0) ? bytes[i] : (bytes[i] + 256);
/* Is the current digit going to span a byte boundary? */
if (index > 3) {
if ((i + 1) < bytes.length) {
nextByte = (bytes[i + 1] >= 0) ? bytes[i + 1] : (bytes[i + 1] + 256);
} else {
nextByte = 0;
}
digit = currByte & (0xFF >> index);
index = (index + 5) % 8;
digit <<= index;
digit |= nextByte >> (8 - index);
i++;
} else {
digit = (currByte >> (8 - (index + 5))) & 0x1F;
index = (index + 5) % 8;
if (index == 0)
i++;
}
base32.append(base32Chars.charAt(digit));
}
return base32.toString();
}
/**
* Decodes the given Base32 String to a raw byte array.
*
* @param base32
* @return Decoded base32 String as a raw byte array.
*/
public static byte[] decode(final String base32) {
int i, index, lookup, offset, digit;
byte[] bytes = new byte[base32.length() * 5 / 8];
for (i = 0, index = 0, offset = 0; i < base32.length(); i++) {
lookup = base32.charAt(i) - '0';
/* Skip chars outside the lookup table */
if (lookup < 0 || lookup >= base32Lookup.length) {
continue;
}
digit = base32Lookup[lookup];
/* If this digit is not in the table, ignore it */
if (digit == 0xFF) {
continue;
}
if (index <= 3) {
index = (index + 5) % 8;
if (index == 0) {
bytes[offset] |= digit;
offset++;
if (offset >= bytes.length)
break;
} else {
bytes[offset] |= digit << (8 - index);
}
} else {
index = (index + 5) % 8;
bytes[offset] |= (digit >>> index);
offset++;
if (offset >= bytes.length) {
break;
}
bytes[offset] |= digit << (8 - index);
}
}
return bytes;
}
}
