org.codehaus.plexus.util.Base64 Maven / Gradle / Ivy
package org.codehaus.plexus.util;
/*
* Copyright The Codehaus Foundation.
*
* 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.
*/
/**
* Provides Base64 encoding and decoding as defined by RFC 2045.
*
* This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose
* Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein.
*
*
* @see RFC 2045
* @author Apache Software Foundation
* @since 1.0-dev
*
*/
public class Base64
{
//
// Source Id: Base64.java 161350 2005-04-14 20:39:46Z ggregory
//
/**
* Chunk size per RFC 2045 section 6.8.
*
* The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
* equal signs.
*
*
* @see RFC 2045 section 6.8
*/
static final int CHUNK_SIZE = 76;
/**
* Chunk separator per RFC 2045 section 2.1.
*
* @see RFC 2045 section 2.1
*/
static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
/**
* The base length.
*/
static final int BASELENGTH = 255;
/**
* Lookup length.
*/
static final int LOOKUPLENGTH = 64;
/**
* Used to calculate the number of bits in a byte.
*/
static final int EIGHTBIT = 8;
/**
* Used when encoding something which has fewer than 24 bits.
*/
static final int SIXTEENBIT = 16;
/**
* Used to determine how many bits data contains.
*/
static final int TWENTYFOURBITGROUP = 24;
/**
* Used to get the number of Quadruples.
*/
static final int FOURBYTE = 4;
/**
* Used to test the sign of a byte.
*/
static final int SIGN = -128;
/**
* Byte used to pad output.
*/
static final byte PAD = (byte) '=';
/**
* Contains the Base64 values 0 through 63 accessed by using character encodings as
* indices.
*
* For example, base64Alphabet['+'] returns 62.
*
*
* The value of undefined encodings is -1.
*
*/
private static byte[] base64Alphabet = new byte[BASELENGTH];
/**
*
* Contains the Base64 encodings A through Z, followed by a through
* z, followed by 0 through 9, followed by +, and
* /.
*
*
* This array is accessed by using character values as indices.
*
*
* For example, lookUpBase64Alphabet[62] returns '+'.
*
*/
private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
// Populating the lookup and character arrays
static
{
for ( int i = 0; i < BASELENGTH; i++ )
{
base64Alphabet[i] = (byte) -1;
}
for ( int i = 'Z'; i >= 'A'; i-- )
{
base64Alphabet[i] = (byte) ( i - 'A' );
}
for ( int i = 'z'; i >= 'a'; i-- )
{
base64Alphabet[i] = (byte) ( i - 'a' + 26 );
}
for ( int i = '9'; i >= '0'; i-- )
{
base64Alphabet[i] = (byte) ( i - '0' + 52 );
}
base64Alphabet['+'] = 62;
base64Alphabet['/'] = 63;
for ( int i = 0; i <= 25; i++ )
{
lookUpBase64Alphabet[i] = (byte) ( 'A' + i );
}
for ( int i = 26, j = 0; i <= 51; i++, j++ )
{
lookUpBase64Alphabet[i] = (byte) ( 'a' + j );
}
for ( int i = 52, j = 0; i <= 61; i++, j++ )
{
lookUpBase64Alphabet[i] = (byte) ( '0' + j );
}
lookUpBase64Alphabet[62] = (byte) '+';
lookUpBase64Alphabet[63] = (byte) '/';
}
/**
* Returns whether or not the octect is in the base 64 alphabet.
*
* @param octect The value to test
* @return true if the value is defined in the the base 64 alphabet, false otherwise.
*/
private static boolean isBase64( byte octect )
{
if ( octect == PAD )
{
return true;
}
else if ( octect < 0 || base64Alphabet[octect] == -1 )
{
return false;
}
else
{
return true;
}
}
/**
* Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
*
* @param arrayOctect byte array to test
* @return true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
* false, otherwise
*/
public static boolean isArrayByteBase64( byte[] arrayOctect )
{
arrayOctect = discardWhitespace( arrayOctect );
int length = arrayOctect.length;
if ( length == 0 )
{
// shouldn't a 0 length array be valid base64 data?
// return false;
return true;
}
for ( byte anArrayOctect : arrayOctect )
{
if ( !isBase64( anArrayOctect ) )
{
return false;
}
}
return true;
}
/**
* Encodes binary data using the base64 algorithm but does not chunk the output.
*
* @param binaryData binary data to encode
* @return Base64 characters
*/
public static byte[] encodeBase64( byte[] binaryData )
{
return encodeBase64( binaryData, false );
}
/**
* Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
*
* @param binaryData binary data to encode
* @return Base64 characters chunked in 76 character blocks
*/
public static byte[] encodeBase64Chunked( byte[] binaryData )
{
return encodeBase64( binaryData, true );
}
/**
* Decodes a byte[] containing containing characters in the Base64 alphabet.
*
* @param pArray A byte array containing Base64 character data
* @return a byte array containing binary data
*/
public byte[] decode( byte[] pArray )
{
return decodeBase64( pArray );
}
/**
* Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
*
* @param binaryData Array containing binary data to encode.
* @param isChunked if true this encoder will chunk the base64 output into 76 character blocks
* @return Base64-encoded data.
*/
public static byte[] encodeBase64( byte[] binaryData, boolean isChunked )
{
int lengthDataBits = binaryData.length * EIGHTBIT;
int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
byte encodedData[] = null;
int encodedDataLength = 0;
int nbrChunks = 0;
if ( fewerThan24bits != 0 )
{
// data not divisible by 24 bit
encodedDataLength = ( numberTriplets + 1 ) * 4;
}
else
{
// 16 or 8 bit
encodedDataLength = numberTriplets * 4;
}
// If the output is to be "chunked" into 76 character sections,
// for compliance with RFC 2045 MIME, then it is important to
// allow for extra length to account for the separator(s)
if ( isChunked )
{
nbrChunks = ( CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil( (float) encodedDataLength / CHUNK_SIZE ) );
encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
}
encodedData = new byte[encodedDataLength];
byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
int encodedIndex = 0;
int dataIndex = 0;
int i = 0;
int nextSeparatorIndex = CHUNK_SIZE;
int chunksSoFar = 0;
// log.debug("number of triplets = " + numberTriplets);
for ( i = 0; i < numberTriplets; i++ )
{
dataIndex = i * 3;
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
b3 = binaryData[dataIndex + 2];
// log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);
l = (byte) ( b2 & 0x0f );
k = (byte) ( b1 & 0x03 );
byte val1 = ( ( b1 & SIGN ) == 0 ) ? (byte) ( b1 >> 2 ) : (byte) ( ( b1 ) >> 2 ^ 0xc0 );
byte val2 = ( ( b2 & SIGN ) == 0 ) ? (byte) ( b2 >> 4 ) : (byte) ( ( b2 ) >> 4 ^ 0xf0 );
byte val3 = ( ( b3 & SIGN ) == 0 ) ? (byte) ( b3 >> 6 ) : (byte) ( ( b3 ) >> 6 ^ 0xfc );
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
// log.debug( "val2 = " + val2 );
// log.debug( "k4 = " + (k<<4) );
// log.debug( "vak = " + (val2 | (k<<4)) );
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | ( k << 4 )];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[( l << 2 ) | val3];
encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
encodedIndex += 4;
// If we are chunking, let's put a chunk separator down.
if ( isChunked )
{
// this assumes that CHUNK_SIZE % 4 == 0
if ( encodedIndex == nextSeparatorIndex )
{
System.arraycopy( CHUNK_SEPARATOR, 0, encodedData, encodedIndex, CHUNK_SEPARATOR.length );
chunksSoFar++;
nextSeparatorIndex =
( CHUNK_SIZE * ( chunksSoFar + 1 ) ) + ( chunksSoFar * CHUNK_SEPARATOR.length );
encodedIndex += CHUNK_SEPARATOR.length;
}
}
}
// form integral number of 6-bit groups
dataIndex = i * 3;
if ( fewerThan24bits == EIGHTBIT )
{
b1 = binaryData[dataIndex];
k = (byte) ( b1 & 0x03 );
// log.debug("b1=" + b1);
// log.debug("b1<<2 = " + (b1>>2) );
byte val1 = ( ( b1 & SIGN ) == 0 ) ? (byte) ( b1 >> 2 ) : (byte) ( ( b1 ) >> 2 ^ 0xc0 );
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
encodedData[encodedIndex + 2] = PAD;
encodedData[encodedIndex + 3] = PAD;
}
else if ( fewerThan24bits == SIXTEENBIT )
{
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
l = (byte) ( b2 & 0x0f );
k = (byte) ( b1 & 0x03 );
byte val1 = ( ( b1 & SIGN ) == 0 ) ? (byte) ( b1 >> 2 ) : (byte) ( ( b1 ) >> 2 ^ 0xc0 );
byte val2 = ( ( b2 & SIGN ) == 0 ) ? (byte) ( b2 >> 4 ) : (byte) ( ( b2 ) >> 4 ^ 0xf0 );
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | ( k << 4 )];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
encodedData[encodedIndex + 3] = PAD;
}
if ( isChunked )
{
// we also add a separator to the end of the final chunk.
if ( chunksSoFar < nbrChunks )
{
System.arraycopy( CHUNK_SEPARATOR, 0, encodedData, encodedDataLength - CHUNK_SEPARATOR.length,
CHUNK_SEPARATOR.length );
}
}
return encodedData;
}
/**
* Decodes Base64 data into octects
*
* @param base64Data Byte array containing Base64 data
* @return Array containing decoded data.
*/
public static byte[] decodeBase64( byte[] base64Data )
{
// RFC 2045 requires that we discard ALL non-Base64 characters
base64Data = discardNonBase64( base64Data );
// handle the edge case, so we don't have to worry about it later
if ( base64Data.length == 0 )
{
return new byte[0];
}
int numberQuadruple = base64Data.length / FOURBYTE;
byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
// Throw away anything not in base64Data
int encodedIndex = 0;
int dataIndex = 0;
{
// this sizes the output array properly - rlw
int lastData = base64Data.length;
// ignore the '=' padding
while ( base64Data[lastData - 1] == PAD )
{
if ( --lastData == 0 )
{
return new byte[0];
}
}
decodedData = new byte[lastData - numberQuadruple];
}
for ( int i = 0; i < numberQuadruple; i++ )
{
dataIndex = i * 4;
marker0 = base64Data[dataIndex + 2];
marker1 = base64Data[dataIndex + 3];
b1 = base64Alphabet[base64Data[dataIndex]];
b2 = base64Alphabet[base64Data[dataIndex + 1]];
if ( marker0 != PAD && marker1 != PAD )
{
// No PAD e.g 3cQl
b3 = base64Alphabet[marker0];
b4 = base64Alphabet[marker1];
decodedData[encodedIndex] = (byte) ( b1 << 2 | b2 >> 4 );
decodedData[encodedIndex + 1] = (byte) ( ( ( b2 & 0xf ) << 4 ) | ( ( b3 >> 2 ) & 0xf ) );
decodedData[encodedIndex + 2] = (byte) ( b3 << 6 | b4 );
}
else if ( marker0 == PAD )
{
// Two PAD e.g. 3c[Pad][Pad]
decodedData[encodedIndex] = (byte) ( b1 << 2 | b2 >> 4 );
}
else if ( marker1 == PAD )
{
// One PAD e.g. 3cQ[Pad]
b3 = base64Alphabet[marker0];
decodedData[encodedIndex] = (byte) ( b1 << 2 | b2 >> 4 );
decodedData[encodedIndex + 1] = (byte) ( ( ( b2 & 0xf ) << 4 ) | ( ( b3 >> 2 ) & 0xf ) );
}
encodedIndex += 3;
}
return decodedData;
}
/**
* Discards any whitespace from a base-64 encoded block.
*
* @param data The base-64 encoded data to discard the whitespace from.
* @return The data, less whitespace (see RFC 2045).
*/
static byte[] discardWhitespace( byte[] data )
{
byte groomedData[] = new byte[data.length];
int bytesCopied = 0;
for ( byte aData : data )
{
switch ( aData )
{
case (byte) ' ':
case (byte) '\n':
case (byte) '\r':
case (byte) '\t':
break;
default:
groomedData[bytesCopied++] = aData;
}
}
byte packedData[] = new byte[bytesCopied];
System.arraycopy( groomedData, 0, packedData, 0, bytesCopied );
return packedData;
}
/**
* Discards any characters outside of the base64 alphabet, per the requirements on page 25 of RFC 2045 - "Any
* characters outside of the base64 alphabet are to be ignored in base64 encoded data."
*
* @param data The base-64 encoded data to groom
* @return The data, less non-base64 characters (see RFC 2045).
*/
static byte[] discardNonBase64( byte[] data )
{
byte groomedData[] = new byte[data.length];
int bytesCopied = 0;
for ( byte aData : data )
{
if ( isBase64( aData ) )
{
groomedData[bytesCopied++] = aData;
}
}
byte packedData[] = new byte[bytesCopied];
System.arraycopy( groomedData, 0, packedData, 0, bytesCopied );
return packedData;
}
/**
* Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
*
* @param pArray a byte array containing binary data
* @return A byte array containing only Base64 character data
*/
public byte[] encode( byte[] pArray )
{
return encodeBase64( pArray, false );
}
}