org.jwat.common.Base32 Maven / Gradle / Ivy
/**
* Java Web Archive Toolkit - Software to read and validate ARC, WARC
* and GZip files. (http://jwat.org/)
* Copyright 2011-2012 Netarkivet.dk (http://netarkivet.dk/)
*
* 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.jwat.common;
import java.io.ByteArrayOutputStream;
import java.util.Arrays;
/**
* Base32 encoder/decoder implementation based on the specifications in
* rfc3548.
*
* @author nicl
*/
public class Base32 {
/** Ascii table used to encode. */
public static String encodeTab = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
/** Table used to decode. */
public static byte[] decodeTab = new byte[ 256 ];
/** Populate decode table. */
static {
Arrays.fill( decodeTab, (byte)0xff );
for ( int i=0; i> 3 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 2 ) & 31;
break;
case 1:
cout |= ( cin >> 6 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin >> 1 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 4 ) & 31;
break;
case 2:
cout |= ( cin >> 4 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 1 ) & 31;
break;
case 3:
cout |= ( cin >> 7 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin >> 2 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 3 ) & 31;
break;
case 4:
cout |= ( cin >> 5 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = cin & 31;
out.append( encodeTab.charAt( cout ) );
break;
}
mod = ( mod + 1 ) % 5;
}
else {
return null;
}
}
else {
b = false;
}
}
/*
* Padding.
*/
switch( mod ) {
case 0:
break;
case 1:
out.append( encodeTab.charAt( cout ) );
out.append( "======" );
break;
case 2:
out.append( encodeTab.charAt( cout ) );
out.append( "====" );
break;
case 3:
out.append( encodeTab.charAt( cout ) );
out.append( "===" );
break;
case 4:
out.append( encodeTab.charAt( cout ) );
out.append( "=" );
break;
}
return out.toString();
}
/**
* Encodes a byte array.
* @param in byte array.
* @return encoded string or null
*/
public static String encodeArray(byte[] in) {
if (in == null) {
return null;
}
if (in.length == 0) {
return "";
}
StringBuffer out = new StringBuffer( 256 );
boolean b = true;
int idx = 0;
int cin;
int cout = 0;
int mod = 0;
/*
* Loop.
*/
while ( b ) {
if ( idx < in.length ) {
cin = in[ idx++ ] & 255;
switch ( mod ) {
case 0:
cout = ( cin >> 3 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 2 ) & 31;
break;
case 1:
cout |= ( cin >> 6 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin >> 1 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 4 ) & 31;
break;
case 2:
cout |= ( cin >> 4 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 1 ) & 31;
break;
case 3:
cout |= ( cin >> 7 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin >> 2 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = ( cin << 3 ) & 31;
break;
case 4:
cout |= ( cin >> 5 ) & 31;
out.append( encodeTab.charAt( cout ) );
cout = cin & 31;
out.append( encodeTab.charAt( cout ) );
break;
}
mod = ( mod + 1 ) % 5;
}
else {
b = false;
}
}
/*
* Padding.
*/
switch( mod ) {
case 0:
break;
case 1:
out.append( encodeTab.charAt( cout ) );
out.append( "======" );
break;
case 2:
out.append( encodeTab.charAt( cout ) );
out.append( "====" );
break;
case 3:
out.append( encodeTab.charAt( cout ) );
out.append( "===" );
break;
case 4:
out.append( encodeTab.charAt( cout ) );
out.append( "=" );
break;
}
return out.toString();
}
}
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