- * I am placing this code in the Public Domain. Do with it as you will. - * This software comes with no guarantees or warranties but with - * plenty of well-wishing instead! - * Please visit - * http://iharder.net/xmlizable - * periodically to check for updates or to contribute improvements. - *
- * - * @author Robert Harder - * @author rharder@usa.net - * @version 1.3 - */ - -/** - * Base64 converter class. This code is not a full-blown MIME encoder; - * it simply converts binary data to base64 data and back. - * - *Note {@link CharBase64} is a GWT-compatible implementation of this - * class. - */ -public class Base64 { - /** Specify encoding (value is {@code true}). */ - public final static boolean ENCODE = true; - - /** Specify decoding (value is {@code false}). */ - public final static boolean DECODE = false; - - /** 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) '/'}; - - /** - * The 64 valid web safe Base64 values. - */ - private final static byte[] WEBSAFE_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, -9 // Decimal 123 - 127 - /* ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 128 - 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 */ - }; - - /** The web safe decodabet */ - private final static byte[] WEBSAFE_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, -9, -9, // Decimal 33 - 44 - 62, // Dash '-' sign at decimal 45 - -9, -9, // Decimal 46-47 - 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, // Decimal 91-94 - 63, // Underscore '_' at decimal 95 - -9, // Decimal 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, -9 // Decimal 123 - 127 - /* ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 128 - 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 */ - }; - - // Indicates white space in encoding - private final static byte WHITE_SPACE_ENC = -5; - // Indicates equals sign in encoding - private final static byte EQUALS_SIGN_ENC = -1; - - /** Defeats instantiation. */ - private Base64() { - } - - /* ******** E N C O D I N G M E T H O D S ******** */ - - /** - * 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 accommodate 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 - * @param alphabet is the encoding alphabet - * @return the destination array - * @since 1.3 - */ - private static byte[] encode3to4(byte[] source, int srcOffset, - int numSigBytes, byte[] destination, int destOffset, byte[] alphabet) { - // 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. - * Equivalent to calling - * {@code encodeBytes(source, 0, source.length)} - * - * @param source The data to convert - * @since 1.4 - */ - public static String encode(byte[] source) { - return encode(source, 0, source.length, ALPHABET, true); - } - - /** - * Encodes a byte array into web safe Base64 notation. - * - * @param source The data to convert - * @param doPadding is {@code true} to pad result with '=' chars - * if it does not fall on 3 byte boundaries - */ - public static String encodeWebSafe(byte[] source, boolean doPadding) { - return encode(source, 0, source.length, WEBSAFE_ALPHABET, doPadding); - } - - /** - * 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 alphabet is the encoding alphabet - * @param doPadding is {@code true} to pad result with '=' chars - * if it does not fall on 3 byte boundaries - * @since 1.4 - */ - public static String encode(byte[] source, int off, int len, byte[] alphabet, - boolean doPadding) { - byte[] outBuff = encode(source, off, len, alphabet, Integer.MAX_VALUE); - int outLen = outBuff.length; - - // If doPadding is false, set length to truncate '=' - // padding characters - while (doPadding == false && outLen > 0) { - if (outBuff[outLen - 1] != '=') { - break; - } - outLen -= 1; - } - - return new String(outBuff, 0, outLen); - } - - /** - * 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 alphabet is the encoding alphabet - * @param maxLineLength maximum length of one line. - * @return the BASE64-encoded byte array - */ - public static byte[] encode(byte[] source, int off, int len, byte[] alphabet, - int maxLineLength) { - int lenDiv3 = (len + 2) / 3; // ceil(len / 3) - int len43 = lenDiv3 * 4; - byte[] outBuff = new byte[len43 // Main 4:3 - + (len43 / maxLineLength)]; // New lines - - int d = 0; - int e = 0; - int len2 = len - 2; - int lineLength = 0; - for (; d < len2; d += 3, e += 4) { - - // The following block of code is the same as - // encode3to4( source, d + off, 3, outBuff, e, alphabet ); - // but inlined for faster encoding (~20% improvement) - int inBuff = - ((source[d + off] << 24) >>> 8) - | ((source[d + 1 + off] << 24) >>> 16) - | ((source[d + 2 + off] << 24) >>> 24); - outBuff[e] = alphabet[(inBuff >>> 18)]; - outBuff[e + 1] = alphabet[(inBuff >>> 12) & 0x3f]; - outBuff[e + 2] = alphabet[(inBuff >>> 6) & 0x3f]; - outBuff[e + 3] = alphabet[(inBuff) & 0x3f]; - - lineLength += 4; - if (lineLength == maxLineLength) { - outBuff[e + 4] = NEW_LINE; - e++; - lineLength = 0; - } // end if: end of line - } // end for: each piece of array - - if (d < len) { - encode3to4(source, d + off, len - d, outBuff, e, alphabet); - - lineLength += 4; - if (lineLength == maxLineLength) { - // Add a last newline - outBuff[e + 4] = NEW_LINE; - e++; - } - e += 4; - } - - assert (e == outBuff.length); - return outBuff; - } - - - /* ******** D E C O D I N G M E T H O D S ******** */ - - - /** - * 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 accommodate 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 - * @param decodabet the decodabet for decoding Base64 content - * @return the number of decoded bytes converted - * @since 1.3 - */ - private static int decode4to3(byte[] source, int srcOffset, - byte[] destination, int destOffset, byte[] decodabet) { - // Example: Dk== - if (source[srcOffset + 2] == EQUALS_SIGN) { - int outBuff = - ((decodabet[source[srcOffset]] << 24) >>> 6) - | ((decodabet[source[srcOffset + 1]] << 24) >>> 12); - - destination[destOffset] = (byte) (outBuff >>> 16); - return 1; - } else if (source[srcOffset + 3] == EQUALS_SIGN) { - // Example: DkL= - int outBuff = - ((decodabet[source[srcOffset]] << 24) >>> 6) - | ((decodabet[source[srcOffset + 1]] << 24) >>> 12) - | ((decodabet[source[srcOffset + 2]] << 24) >>> 18); - - destination[destOffset] = (byte) (outBuff >>> 16); - destination[destOffset + 1] = (byte) (outBuff >>> 8); - return 2; - } else { - // Example: DkLE - 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); - - destination[destOffset] = (byte) (outBuff >> 16); - destination[destOffset + 1] = (byte) (outBuff >> 8); - destination[destOffset + 2] = (byte) (outBuff); - return 3; - } - } // end decodeToBytes - - - /** - * Decodes data from Base64 notation. - * - * @param s the string to decode (decoded in default encoding) - * @return the decoded data - * @since 1.4 - */ - public static byte[] decode(String s) throws Base64DecoderException { - byte[] bytes = s.getBytes(); - return decode(bytes, 0, bytes.length); - } - - /** - * Decodes data from web safe Base64 notation. - * Web safe encoding uses '-' instead of '+', '_' instead of '/' - * - * @param s the string to decode (decoded in default encoding) - * @return the decoded data - */ - public static byte[] decodeWebSafe(String s) throws Base64DecoderException { - byte[] bytes = s.getBytes(); - return decodeWebSafe(bytes, 0, bytes.length); - } - - /** - * Decodes Base64 content in byte array format and returns - * the decoded byte array. - * - * @param source The Base64 encoded data - * @return decoded data - * @since 1.3 - * @throws Base64DecoderException - */ - public static byte[] decode(byte[] source) throws Base64DecoderException { - return decode(source, 0, source.length); - } - - /** - * Decodes web safe Base64 content in byte array format and returns - * the decoded data. - * Web safe encoding uses '-' instead of '+', '_' instead of '/' - * - * @param source the string to decode (decoded in default encoding) - * @return the decoded data - */ - public static byte[] decodeWebSafe(byte[] source) - throws Base64DecoderException { - return decodeWebSafe(source, 0, source.length); - } - - /** - * 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 - * @throws Base64DecoderException - */ - public static byte[] decode(byte[] source, int off, int len) - throws Base64DecoderException { - return decode(source, off, len, DECODABET); - } - - /** - * Decodes web safe Base64 content in byte array format and returns - * the decoded byte array. - * Web safe encoding uses '-' instead of '+', '_' instead of '/' - * - * @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 - */ - public static byte[] decodeWebSafe(byte[] source, int off, int len) - throws Base64DecoderException { - return decode(source, off, len, WEBSAFE_DECODABET); - } - - /** - * Decodes Base64 content using the supplied decodabet 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 - * @param decodabet the decodabet for decoding Base64 content - * @return decoded data - */ - public static byte[] decode(byte[] source, int off, int len, byte[] decodabet) - throws Base64DecoderException { - int len34 = len * 3 / 4; - byte[] outBuff = new byte[2 + 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 = 0; i < len; i++) { - sbiCrop = (byte) (source[i + off] & 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) { - // An equals sign (for padding) must not occur at position 0 or 1 - // and must be the last byte[s] in the encoded value - if (sbiCrop == EQUALS_SIGN) { - int bytesLeft = len - i; - byte lastByte = (byte) (source[len - 1 + off] & 0x7f); - if (b4Posn == 0 || b4Posn == 1) { - throw new Base64DecoderException( - "invalid padding byte '=' at byte offset " + i); - } else if ((b4Posn == 3 && bytesLeft > 2) - || (b4Posn == 4 && bytesLeft > 1)) { - throw new Base64DecoderException( - "padding byte '=' falsely signals end of encoded value " - + "at offset " + i); - } else if (lastByte != EQUALS_SIGN && lastByte != NEW_LINE) { - throw new Base64DecoderException( - "encoded value has invalid trailing byte"); - } - break; - } - - b4[b4Posn++] = sbiCrop; - if (b4Posn == 4) { - outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, decodabet); - b4Posn = 0; - } - } - } else { - throw new Base64DecoderException("Bad Base64 input character at " + i - + ": " + source[i + off] + "(decimal)"); - } - } - - // Because web safe encoding allows non padding base64 encodes, we - // need to pad the rest of the b4 buffer with equal signs when - // b4Posn != 0. There can be at most 2 equal signs at the end of - // four characters, so the b4 buffer must have two or three - // characters. This also catches the case where the input is - // padded with EQUALS_SIGN - if (b4Posn != 0) { - if (b4Posn == 1) { - throw new Base64DecoderException("single trailing character at offset " - + (len - 1)); - } - b4[b4Posn++] = EQUALS_SIGN; - outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, decodabet); - } - - byte[] out = new byte[outBuffPosn]; - System.arraycopy(outBuff, 0, out, 0, outBuffPosn); - return out; - } -} \ No newline at end of file -- cgit v1.2.3