| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| * |
| */ |
| |
| package org.apache.directory.api.util; |
| |
| |
| import org.apache.directory.api.i18n.I18n; |
| |
| |
| /** |
| * Encoding and decoding of Base64 characters to and from raw bytes. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public final class Base64 |
| { |
| |
| /** code characters for values 0..63 */ |
| private static final char[] ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=" |
| .toCharArray(); |
| |
| /** lookup table for converting base64 characters to value in range 0..63 */ |
| private static final byte[] CODES = new byte[256]; |
| |
| static |
| { |
| for ( int ii = 0; ii < 256; ii++ ) |
| { |
| CODES[ii] = -1; |
| } |
| |
| for ( int ii = 'A'; ii <= 'Z'; ii++ ) |
| { |
| CODES[ii] = ( byte ) ( ii - 'A' ); |
| } |
| |
| for ( int ii = 'a'; ii <= 'z'; ii++ ) |
| { |
| CODES[ii] = ( byte ) ( 26 + ii - 'a' ); |
| } |
| |
| for ( int ii = '0'; ii <= '9'; ii++ ) |
| { |
| CODES[ii] = ( byte ) ( 52 + ii - '0' ); |
| } |
| |
| CODES['+'] = 62; |
| CODES['/'] = 63; |
| } |
| |
| /** |
| * Private constructor. |
| */ |
| private Base64() |
| { |
| } |
| |
| |
| /** |
| * Encodes binary data to a Base64 encoded characters. |
| * |
| * @param data |
| * the array of bytes to encode |
| * @return base64-coded character array. |
| */ |
| public static char[] encode( byte[] data ) |
| { |
| char[] out = new char[( ( data.length + 2 ) / 3 ) * 4]; |
| |
| // |
| // 3 bytes encode to 4 chars. Output is always an even |
| // multiple of 4 characters. |
| // |
| for ( int i = 0, index = 0; i < data.length; i += 3, index += 4 ) |
| { |
| boolean isQuadrupel = false; |
| boolean isTripel = false; |
| |
| int val = 0xFF & data[i]; |
| val <<= 8; |
| if ( ( i + 1 ) < data.length ) |
| { |
| val |= ( 0xFF & data[i + 1] ); |
| isTripel = true; |
| } |
| |
| val <<= 8; |
| if ( ( i + 2 ) < data.length ) |
| { |
| val |= ( 0xFF & data[i + 2] ); |
| isQuadrupel = true; |
| } |
| |
| out[index + 3] = ALPHABET[ isQuadrupel ? ( val & 0x3F ) : 64 ]; |
| val >>= 6; |
| out[index + 2] = ALPHABET[ isTripel ? ( val & 0x3F ) : 64 ]; |
| val >>= 6; |
| out[index + 1] = ALPHABET[val & 0x3F]; |
| val >>= 6; |
| out[index + 0] = ALPHABET[val & 0x3F]; |
| } |
| return out; |
| } |
| |
| |
| /** |
| * Decodes a BASE-64 encoded stream to recover the original data. White |
| * space before and after will be trimmed away, but no other manipulation of |
| * the input will be performed. As of version 1.2 this method will properly |
| * handle input containing junk characters (newlines and the like) rather |
| * than throwing an error. It does this by pre-parsing the input and |
| * generating from that a count of VALID input characters. |
| * |
| * @param data |
| * data to decode. |
| * @return the decoded binary data. |
| */ |
| public static byte[] decode( char[] data ) |
| { |
| // as our input could contain non-BASE64 data (newlines, |
| // whitespace of any sort, whatever) we must first adjust |
| // our count of USABLE data so that... |
| // (a) we don't misallocate the output array, and |
| // (b) think that we miscalculated our data length |
| // just because of extraneous throw-away junk |
| |
| int tempLen = data.length; |
| |
| for ( char c : data ) |
| { |
| if ( ( c > 255 ) || CODES[c] < 0 ) |
| { |
| // ignore non-valid chars and padding |
| --tempLen; |
| } |
| } |
| // calculate required length: |
| // -- 3 bytes for every 4 valid base64 chars |
| // -- plus 2 bytes if there are 3 extra base64 chars, |
| // or plus 1 byte if there are 2 extra. |
| |
| int len = ( tempLen / 4 ) * 3; |
| |
| if ( ( tempLen % 4 ) == 3 ) |
| { |
| len += 2; |
| } |
| |
| if ( ( tempLen % 4 ) == 2 ) |
| { |
| len += 1; |
| } |
| |
| byte[] out = new byte[len]; |
| |
| // # of excess bits stored in accum excess bits |
| int shift = 0; |
| int accum = 0; |
| int index = 0; |
| |
| // we now go through the entire array (NOT using the 'tempLen' value) |
| for ( char c : data ) |
| { |
| int value = ( c > 255 ) ? -1 : CODES[c]; |
| |
| // skip over non-code bits |
| if ( value >= 0 ) |
| { |
| // shift up by 6 each time thru |
| // loop, with new bits being put in |
| // at the bottom. whenever there |
| // are 8 or more shifted in, write them |
| // out (from the top, leaving any excess |
| // at the bottom for next iteration. |
| accum <<= 6; |
| shift += 6; |
| accum |= value; |
| |
| if ( shift >= 8 ) |
| { |
| shift -= 8; |
| out[index++] = ( byte ) ( ( accum >> shift ) & 0xff ); |
| } |
| } |
| // we will also have skipped processing a padding null byte ('=') here; |
| // these are used ONLY for padding to an even length and do not legally |
| // occur as encoded data. for this reason we can ignore the fact |
| // that no index++ operation occurs in that special case: the out[] array |
| // is initialized to all-zero bytes to start with and that works to our |
| // advantage in this combination. |
| } |
| |
| // if there is STILL something wrong we just have to throw up now! |
| if ( index != out.length ) |
| { |
| throw new Error( I18n.err( I18n.ERR_17027_WRONG_DATA_LENGTH, index, out.length ) ); |
| } |
| |
| return out; |
| } |
| } |