| // Copyright 2002 Google Inc. |
| // |
| // 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. |
| |
| // This code was converted from code at http://iharder.sourceforge.net/base64/ |
| // Lots of extraneous features were removed. |
| /* The original code said: |
| * <p> |
| * 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 |
| * <a href="http://iharder.net/xmlizable">http://iharder.net/xmlizable</a> |
| * periodically to check for updates or to contribute improvements. |
| * </p> |
| * |
| * @author Robert Harder |
| * @author rharder@usa.net |
| * @version 1.3 |
| */ |
| |
| package com.google.enterprise.secmgr.common; |
| |
| /** |
| * Base64 converter class. This code is not a full-blown MIME encoder; |
| * it simply converts binary data to base64 data and back. |
| */ |
| public class Base64 { |
| /** Specify encoding (value is {@code true}). */ |
| public static final boolean ENCODE = true; |
| |
| /** Specify decoding (value is {@code false}). */ |
| public static final boolean DECODE = false; |
| |
| /** The equals sign (=) as a byte. */ |
| private static final byte EQUALS_SIGN = (byte) '='; |
| |
| /** The new line character (\n) as a byte. */ |
| private static final byte NEW_LINE = (byte) '\n'; |
| |
| /** The 64 valid Base64 values. */ |
| public static final byte[] ALPHABET = |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" |
| .getBytes(); |
| |
| /** The 64 valid web safe Base64 values. */ |
| public static final byte[] WEBSAFE_ALPHABET = |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_" |
| .getBytes(); |
| |
| /** |
| * Translates a Base64 value to either its 6-bit reconstruction value |
| * or a negative number indicating some other meaning. This can decode |
| * content that was endoded with either the standard ALPHABET or the |
| * WEBSAFE_ALPHABET. |
| */ |
| private static final 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, // Decimal 44 |
| 62, // Dash '-' sign at decimal 45 (from WebSafe encoding) |
| -9, // Decimal 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, // Decimal 91-94 |
| 63, // Underscore '_' at decimal 95 (from WebSafe encoding) |
| -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 |
| }; |
| |
| // Indicates white space in encoding. |
| private static final byte WHITE_SPACE_ENC = -5; |
| |
| // Indicates equals sign in encoding. |
| private static final byte EQUALS_SIGN_ENC = -1; |
| |
| private Base64() { |
| // Defeats instantiation. |
| } |
| |
| /* ******** E N C O D I N G M E T H O D S ******** */ |
| |
| /** |
| * Encodes up to three bytes of the array <var>source</var> |
| * and writes the resulting four Base64 bytes to <var>destination</var>. |
| * The source and destination arrays can be manipulated |
| * anywhere along their length by specifying |
| * <var>srcOffset</var> and <var>destOffset</var>. |
| * This method does not check to make sure your arrays |
| * are large enough to accommodate <var>srcOffset</var> + 3 for |
| * the <var>source</var> array or <var>destOffset</var> + 4 for |
| * the <var>destination</var> array. |
| * The actual number of significant bytes in your array is |
| * given by <var>numSigBytes</var>. |
| * |
| * @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 <var>destination</var> array |
| * @since 1.3 |
| */ |
| 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 len43 = ((len + 2) / 3) * 4; |
| byte[] outBuff = new byte[len43 + (len43 / maxLineLength)]; |
| |
| encode(source, off, len, outBuff, 0, alphabet, maxLineLength); |
| return outBuff; |
| } |
| |
| /** |
| * Encodes a byte array into Base64 notation into a destination byte array. |
| * Warning: No check is made to make sure the destination is big enough |
| * to hold the conversion. |
| * This was optimally constructed for use by Base64FilterInputStream. |
| * |
| * @param source The data to convert |
| * @param sourceOffset Offset in source array where conversion should begin |
| * @param sourceLength Length of data to convert |
| * @param dest The destination array for converted data |
| * @param destOffset Offset in destination array to write |
| * @param alphabet is the encoding alphabet |
| * @param maxLineLength maximum length of one line. |
| * @return the number of bytes written to destination. |
| */ |
| static int encode(byte[] source, int sourceOffset, int sourceLength, |
| byte[] dest, int destOffset, byte[] alphabet, int maxLineLength) { |
| int s = 0; |
| int d = destOffset; |
| int len = sourceLength - 2; |
| int lineLength = 0; |
| |
| for (; s < len; s += 3, d += 4) { |
| // The following block of code is the same as |
| // encode3to4( source, s + off, 3, dest, d, alphabet ); |
| // but inlined for faster encoding (~20% improvement) |
| int inBuff = |
| ((source[s + sourceOffset] << 24) >>> 8) |
| | ((source[s + 1 + sourceOffset] << 24) >>> 16) |
| | ((source[s + 2 + sourceOffset] << 24) >>> 24); |
| dest[d] = alphabet[(inBuff >>> 18)]; |
| dest[d + 1] = alphabet[(inBuff >>> 12) & 0x3f]; |
| dest[d + 2] = alphabet[(inBuff >>> 6) & 0x3f]; |
| dest[d + 3] = alphabet[(inBuff) & 0x3f]; |
| |
| if ((lineLength += 4) >= maxLineLength) { |
| dest[d + 4] = NEW_LINE; |
| d++; |
| lineLength = 0; |
| } // end if: end of line |
| } // end for: each piece of array |
| |
| if (s < sourceLength) { |
| encode3to4(source, s + sourceOffset, sourceLength - s, dest, d, alphabet); |
| d += 4; |
| if ((lineLength += 4) >= maxLineLength) { |
| dest[d++] = NEW_LINE; |
| } |
| } |
| |
| return d - destOffset; |
| } |
| |
| /* ******** D E C O D I N G M E T H O D S ******** */ |
| |
| /** |
| * Decodes four bytes from array <var>source</var> |
| * and writes the resulting bytes (up to three of them) |
| * to <var>destination</var>. |
| * The source and destination arrays can be manipulated |
| * anywhere along their length by specifying |
| * <var>srcOffset</var> and <var>destOffset</var>. |
| * This method does not check to make sure your arrays |
| * are large enough to accommodate <var>srcOffset</var> + 4 for |
| * the <var>source</var> array or <var>destOffset</var> + 3 for |
| * the <var>destination</var> 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. |
| * Understands either standard or web-safe encoding. |
| * |
| * @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, DECODABET); |
| } |
| |
| /** |
| * Decodes Base64 content in byte array format and returns |
| * the decoded byte array. |
| * Understands either standard or web-safe encoding. |
| * |
| * @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, DECODABET); |
| } |
| |
| /** |
| * Decodes Base64 content in byte array format and returns |
| * the decoded byte array. |
| * Understands either standard or web-safe encoding. |
| * |
| * @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 Base64 content using the supplied decodabet and returns |
| * the decoded byte array. |
| * Understands either standard or web-safe encoding. |
| * |
| * @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; |
| } |
| } |