/* * Base64.java * * Copyright (c) 2003-2004 Digi International * This program and the information contained in it is confidential and * proprietary to Digi International and may not be used, copied, or re- * produced without the prior written permission of Digi International. * */ package com.digi.config.util; /** * Simple base64 encoding and decoding as specified in RFC-2045. * This class is based on public domain code from Robert Harder at * http://iharder.sourceforge.net/base64/. It has been modified * for use by Digi International. */ public class Base64 { /** Maximum line length (76) of Base64 output. */ private final static int MAX_LINE_LENGTH = 76; /** The equals sign (=) as a byte. */ private final static byte EQUALS_SIGN = (byte)'='; /** The new line character (\n) as a byte. */ private final static byte NEW_LINE = (byte)'\n'; /** The 64 valid Base64 values. */ private final static byte[] ALPHABET = { (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N', (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g', (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n', (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z', (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/' }; /** * Translates a Base64 value to either its 6-bit reconstruction value * or a negative number indicating some other meaning. **/ private final static byte[] DECODABET = { -9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 0 - 8 -5,-5, // Whitespace: Tab and Linefeed -9,-9, // Decimal 11 - 12 -5, // Whitespace: Carriage Return -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 14 - 26 -9,-9,-9,-9,-9, // Decimal 27 - 31 -5, // Whitespace: Space -9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 33 - 42 62, // Plus sign at decimal 43 -9,-9,-9, // Decimal 44 - 46 63, // Slash at decimal 47 52,53,54,55,56,57,58,59,60,61, // Numbers zero through nine -9,-9,-9, // Decimal 58 - 60 -1, // Equals sign at decimal 61 -9,-9,-9, // Decimal 62 - 64 0,1,2,3,4,5,6,7,8,9,10,11,12,13, // Letters 'A' through 'N' 14,15,16,17,18,19,20,21,22,23,24,25, // Letters 'O' through 'Z' -9,-9,-9,-9,-9,-9, // Decimal 91 - 96 26,27,28,29,30,31,32,33,34,35,36,37,38, // Letters 'a' through 'm' 39,40,41,42,43,44,45,46,47,48,49,50,51, // Letters 'n' through 'z' -9,-9,-9,-9 // Decimal 123 - 126 /*,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 127 - 139 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255 */ }; private final static byte BAD_ENCODING = -9; // Indicates error in encoding private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding /** Defeats instantiation. */ private Base64(){} /* ******** E N C O D I N G M E T H O D S ******** */ /** * Encodes the first three bytes of array threeBytes * and returns a four-byte array in Base64 notation. * * @param threeBytes the array to convert * @return four byte array in Base64 notation. * @since 1.3 */ private static byte[] encode3to4( byte[] threeBytes ) { return encode3to4( threeBytes, 3 ); } // end encodeToBytes /** * Encodes up to the first three bytes of array threeBytes * and returns a four-byte array in Base64 notation. * The actual number of significant bytes in your array is * given by numSigBytes. * The array threeBytes needs only be as big as * numSigBytes. * * @param threeBytes the array to convert * @param numSigBytes the number of significant bytes in your array * @return four byte array in Base64 notation. * @since 1.3 */ private static byte[] encode3to4( byte[] threeBytes, int numSigBytes ) { byte[] dest = new byte[4]; encode3to4( threeBytes, 0, numSigBytes, dest, 0 ); return dest; } /** * Encodes up to three bytes of the array source * and writes the resulting four Base64 bytes to destination. * The source and destination arrays can be manipulated * anywhere along their length by specifying * srcOffset and destOffset. * This method does not check to make sure your arrays * are large enough to accomodate srcOffset + 3 for * the source array or destOffset + 4 for * the destination array. * The actual number of significant bytes in your array is * given by numSigBytes. * * @param source the array to convert * @param srcOffset the index where conversion begins * @param numSigBytes the number of significant bytes in your array * @param destination the array to hold the conversion * @param destOffset the index where output will be put * @return the destination array * @since 1.3 */ private static byte[] encode3to4( byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset ) { // 1 2 3 // 01234567890123456789012345678901 Bit position // --------000000001111111122222222 Array position from threeBytes // --------| || || || | Six bit groups to index ALPHABET // >>18 >>12 >> 6 >> 0 Right shift necessary // 0x3f 0x3f 0x3f Additional AND // Create buffer with zero-padding if there are only one or two // significant bytes passed in the array. // We have to shift left 24 in order to flush out the 1's that appear // when Java treats a value as negative that is cast from a byte to an int. int inBuff = ( numSigBytes > 0 ? ((source[ srcOffset ] << 24) >>> 8) : 0 ) | ( numSigBytes > 1 ? ((source[ srcOffset + 1 ] << 24) >>> 16) : 0 ) | ( numSigBytes > 2 ? ((source[ srcOffset + 2 ] << 24) >>> 24) : 0 ); switch ( numSigBytes ) { case 3: destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ]; destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ]; destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>> 6) & 0x3f ]; destination[ destOffset + 3 ] = ALPHABET[ (inBuff ) & 0x3f ]; return destination; case 2: destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ]; destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ]; destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>> 6) & 0x3f ]; destination[ destOffset + 3 ] = EQUALS_SIGN; return destination; case 1: destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ]; destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ]; destination[ destOffset + 2 ] = EQUALS_SIGN; destination[ destOffset + 3 ] = EQUALS_SIGN; return destination; default: return destination; } // end switch } // end encode3to4 /** * Encodes a byte array into Base64 notation. * Equivalen to calling * encodeBytes( source, 0, source.length ) * * @param source The data to convert * @since 1.4 */ public static String encodeBytes( byte[] source ) { return encodeBytes( source, true ); } // end encodeBytes /** * Encodes a byte array into Base64 notation. * Equivalen to calling * encodeBytes( source, 0, source.length ) * * @param source The data to convert * @param breakLines Break lines at 80 characters or less. * @since 1.4 */ public static String encodeBytes( byte[] source, boolean breakLines ) { return encodeBytes( source, 0, source.length, breakLines ); } // end encodeBytes /** * Encodes a byte array into Base64 notation. * * @param source The data to convert * @param off Offset in array where conversion should begin * @param len Length of data to convert * @since 1.4 */ public static String encodeBytes( byte[] source, int off, int len ) { return encodeBytes( source, off, len, true ); } // end encodeBytes /** * Encodes a byte array into Base64 notation. * * @param source The data to convert * @param off Offset in array where conversion should begin * @param len Length of data to convert * @param breakLines Break lines at 80 characters or less. * @since 1.4 */ public static String encodeBytes( byte[] source, int off, int len, boolean breakLines ) { int len43 = len * 4 / 3; byte[] outBuff = new byte[ ( len43 ) // Main 4:3 + ( (len % 3) > 0 ? 4 : 0 ) // Account for padding + (breakLines ? ( len43 / MAX_LINE_LENGTH ) : 0) ]; // New lines int d = 0; int e = 0; int len2 = len - 2; int lineLength = 0; for ( ; d < len2; d+=3, e+=4 ) { encode3to4( source, d+off, 3, outBuff, e ); lineLength += 4; if ( breakLines && lineLength == MAX_LINE_LENGTH ) { outBuff[e+4] = NEW_LINE; e++; lineLength = 0; } // end if: end of line } // en dfor: each piece of array if ( d < len ) { encode3to4( source, d+off, len - d, outBuff, e ); e += 4; } // end if: some padding needed return new String( outBuff, 0, e ); } // end encodeBytes /** * Encodes a string in Base64 notation with line breaks * after every 75 Base64 characters. * Of course you probably only need to encode a string * if there are non-ASCII characters in it such as many * non-English languages. * * @param s the string to encode * @return the encoded string * @since 1.3 */ public static String encodeString( String s ) { return encodeString( s, true ); } // end encodeString /** * Encodes a string in Base64 notation with line breaks * after every 75 Base64 characters. * Of course you probably only need to encode a string * if there are non-ASCII characters in it such as many * non-English languages. * * @param s the string to encode * @param breakLines Break lines at 80 characters or less. * @return the encoded string * @since 1.3 */ public static String encodeString( String s, boolean breakLines ) { return encodeBytes( s.getBytes(), breakLines ); } // end encodeString /* ******** D E C O D I N G M E T H O D S ******** */ /** * Decodes the first four bytes of array fourBytes * and returns an array up to three bytes long with the * decoded values. * * @param fourBytes the array with Base64 content * @return array with decoded values * @since 1.3 */ private static byte[] decode4to3( byte[] fourBytes ) { byte[] outBuff1 = new byte[3]; int count = decode4to3( fourBytes, 0, outBuff1, 0 ); byte[] outBuff2 = new byte[ count ]; for ( int i = 0; i < count; i++ ) outBuff2[i] = outBuff1[i]; return outBuff2; } /** * Decodes four bytes from array source * and writes the resulting bytes (up to three of them) * to destination. * The source and destination arrays can be manipulated * anywhere along their length by specifying * srcOffset and destOffset. * This method does not check to make sure your arrays * are large enough to accomodate srcOffset + 4 for * the source array or destOffset + 3 for * the destination array. * This method returns the actual number of bytes that * were converted from the Base64 encoding. * * * @param source the array to convert * @param srcOffset the index where conversion begins * @param destination the array to hold the conversion * @param destOffset the index where output will be put * @return the number of decoded bytes converted * @since 1.3 */ private static int decode4to3( byte[] source, int srcOffset, byte[] destination, int destOffset ) { // Example: Dk== if ( source[ srcOffset + 2] == EQUALS_SIGN ) { // Two ways to do the same thing. Don't know which way I like best. //int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 ) // | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 ); int outBuff = ( ( DECODABET[ source[ srcOffset ] ] & 0xFF ) << 18 ) | ( ( DECODABET[ source[ srcOffset + 1] ] & 0xFF ) << 12 ); destination[ destOffset ] = (byte)( outBuff >>> 16 ); return 1; } // Example: DkL= else if ( source[ srcOffset + 3 ] == EQUALS_SIGN ) { // Two ways to do the same thing. Don't know which way I like best. //int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 ) // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 ) // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 ); int outBuff = ( ( DECODABET[ source[ srcOffset ] ] & 0xFF ) << 18 ) | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 ) | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) << 6 ); destination[ destOffset ] = (byte)( outBuff >>> 16 ); destination[ destOffset + 1 ] = (byte)( outBuff >>> 8 ); return 2; } // Example: DkLE else { try { // Two ways to do the same thing. Don't know which way I like best. //int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 ) // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 ) // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 ) // | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 ); int outBuff = ( ( DECODABET[ source[ srcOffset ] ] & 0xFF ) << 18 ) | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 ) | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) << 6) | ( ( DECODABET[ source[ srcOffset + 3 ] ] & 0xFF ) ); destination[ destOffset ] = (byte)( outBuff >> 16 ); destination[ destOffset + 1 ] = (byte)( outBuff >> 8 ); destination[ destOffset + 2 ] = (byte)( outBuff ); return 3; } catch ( Exception e) { System.out.println(""+source[srcOffset]+ ": " + ( DECODABET[ source[ srcOffset ] ] ) ); System.out.println(""+source[srcOffset+1]+ ": " + ( DECODABET[ source[ srcOffset + 1 ] ] ) ); System.out.println(""+source[srcOffset+2]+ ": " + ( DECODABET[ source[ srcOffset + 2 ] ] ) ); System.out.println(""+source[srcOffset+3]+ ": " + ( DECODABET[ source[ srcOffset + 3 ] ] ) ); return -1; } //e nd catch } } // end decodeToBytes /** * Decodes data from Base64 notation. * * @param s the string to decode * @return the decoded data * @since 1.4 */ public static byte[] decode( String s ) { byte[] bytes = s.getBytes(); return decode( bytes, 0, bytes.length ); } // end decode /** * Decodes data from Base64 notation and * returns it as a string. * Equivlaent to calling * new String( decode( s ) ) * * @param s the strind to decode * @return The data as a string * @since 1.4 */ public static String decodeToString( String s ) { return new String( decode( s ) ); } // end decodeToString /** * Decodes Base64 content in byte array format and returns * the decoded byte array. * * @param source The Base64 encoded data * @param off The offset of where to begin decoding * @param len The length of characters to decode * @return decoded data * @since 1.3 */ public static byte[] decode( byte[] source, int off, int len ) { int len34 = len * 3 / 4; byte[] outBuff = new byte[ len34 ]; // Upper limit on size of output int outBuffPosn = 0; byte[] b4 = new byte[4]; int b4Posn = 0; int i = 0; byte sbiCrop = 0; byte sbiDecode = 0; for ( i = off; i < off+len; i++ ) { sbiCrop = (byte)(source[i] & 0x7f); // Only the low seven bits sbiDecode = DECODABET[ sbiCrop ]; if ( sbiDecode >= WHITE_SPACE_ENC ) { // White space, Equals sign or better if ( sbiDecode >= EQUALS_SIGN_ENC ) { b4[ b4Posn++ ] = sbiCrop; if ( b4Posn > 3 ) { outBuffPosn += decode4to3( b4, 0, outBuff, outBuffPosn ); b4Posn = 0; // If that was the equals sign, break out of 'for' loop if ( sbiCrop == EQUALS_SIGN ) break; } // end if: quartet built } // end if: equals sign or better } // end if: white space, equals sign or better else { System.err.println( "Bad Base64 input character at " + i + ": " + source[i] + "(decimal)" ); return null; } // end else: } // each input character byte[] out = new byte[ outBuffPosn ]; System.arraycopy( outBuff, 0, out, 0, outBuffPosn ); return out; } // end decode } // end class Base64