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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 ); } }




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