mirror of https://github.com/moparisthebest/k-9
786 lines
28 KiB
Java
786 lines
28 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.fsck.k9.mail.filter;
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import java.math.BigInteger;
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import java.nio.charset.Charset;
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/**
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* Provides Base64 encoding and decoding as defined by RFC 2045.
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*
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* <p>
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* This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
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* Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
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* </p>
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*
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* @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
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* @author Apache Software Foundation
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* @since 1.0-dev
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* @version $Id$
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*/
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public class Base64 {
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public static String decode(String encoded) {
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if (encoded == null) {
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return null;
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}
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byte[] decoded = new Base64().decode(encoded.getBytes());
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return new String(decoded);
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}
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public static String encode(String s) {
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if (s == null) {
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return null;
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}
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byte[] encoded = new Base64().encode(s.getBytes());
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return new String(encoded);
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}
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/**
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* Chunk size per RFC 2045 section 6.8.
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*
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* <p>
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* The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
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* equal signs.
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* </p>
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*
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* @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
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*/
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static final int CHUNK_SIZE = 76;
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/**
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* Chunk separator per RFC 2045 section 2.1.
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*
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* @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
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*/
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static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};
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/**
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* This array is a lookup table that translates 6-bit positive integer
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* index values into their "Base64 Alphabet" equivalents as specified
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* in Table 1 of RFC 2045.
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*
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* Thanks to "commons" project in ws.apache.org for this code.
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* http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
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*/
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private static final byte[] intToBase64 = {
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
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'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
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'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
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'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
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};
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/**
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* Byte used to pad output.
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*/
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private static final byte PAD = '=';
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/**
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* This array is a lookup table that translates unicode characters
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* drawn from the "Base64 Alphabet" (as specified in Table 1 of RFC 2045)
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* into their 6-bit positive integer equivalents. Characters that
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* are not in the Base64 alphabet but fall within the bounds of the
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* array are translated to -1.
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*
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* Thanks to "commons" project in ws.apache.org for this code.
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* http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
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*/
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private static final byte[] base64ToInt = {
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54,
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55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
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5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
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24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
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35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
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};
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/** Mask used to extract 6 bits, used when encoding */
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private static final int MASK_6BITS = 0x3f;
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/** Mask used to extract 8 bits, used in decoding base64 bytes */
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private static final int MASK_8BITS = 0xff;
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// The static final fields above are used for the original static byte[] methods on Base64.
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// The private member fields below are used with the new streaming approach, which requires
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// some state be preserved between calls of encode() and decode().
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/**
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* Line length for encoding. Not used when decoding. A value of zero or less implies
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* no chunking of the base64 encoded data.
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*/
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private final int lineLength;
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/**
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* Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
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*/
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private final byte[] lineSeparator;
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/**
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* Convenience variable to help us determine when our buffer is going to run out of
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* room and needs resizing. <code>decodeSize = 3 + lineSeparator.length;</code>
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*/
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private final int decodeSize;
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/**
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* Convenience variable to help us determine when our buffer is going to run out of
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* room and needs resizing. <code>encodeSize = 4 + lineSeparator.length;</code>
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*/
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private final int encodeSize;
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/**
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* Buffer for streaming.
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*/
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private byte[] buf;
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/**
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* Position where next character should be written in the buffer.
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*/
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private int pos;
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/**
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* Position where next character should be read from the buffer.
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*/
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private int readPos;
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/**
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* Variable tracks how many characters have been written to the current line.
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* Only used when encoding. We use it to make sure each encoded line never
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* goes beyond lineLength (if lineLength > 0).
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*/
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private int currentLinePos;
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/**
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* Writes to the buffer only occur after every 3 reads when encoding, an
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* every 4 reads when decoding. This variable helps track that.
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*/
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private int modulus;
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/**
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* Boolean flag to indicate the EOF has been reached. Once EOF has been
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* reached, this Base64 object becomes useless, and must be thrown away.
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*/
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private boolean eof;
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/**
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* Place holder for the 3 bytes we're dealing with for our base64 logic.
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* Bitwise operations store and extract the base64 encoding or decoding from
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* this variable.
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*/
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private int x;
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/**
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* Default constructor: lineLength is 76, and the lineSeparator is CRLF
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* when encoding, and all forms can be decoded.
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*/
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public Base64() {
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this(CHUNK_SIZE, CHUNK_SEPARATOR);
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}
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/**
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* <p>
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* Consumer can use this constructor to choose a different lineLength
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* when encoding (lineSeparator is still CRLF). All forms of data can
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* be decoded.
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* </p><p>
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* Note: lineLengths that aren't multiples of 4 will still essentially
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* end up being multiples of 4 in the encoded data.
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* </p>
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*
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* @param lineLength each line of encoded data will be at most this long
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* (rounded up to nearest multiple of 4).
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* If lineLength <= 0, then the output will not be divided into lines (chunks).
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* Ignored when decoding.
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*/
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public Base64(int lineLength) {
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this(lineLength, CHUNK_SEPARATOR);
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}
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/**
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* <p>
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* Consumer can use this constructor to choose a different lineLength
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* and lineSeparator when encoding. All forms of data can
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* be decoded.
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* </p><p>
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* Note: lineLengths that aren't multiples of 4 will still essentially
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* end up being multiples of 4 in the encoded data.
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* </p>
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* @param lineLength Each line of encoded data will be at most this long
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* (rounded up to nearest multiple of 4). Ignored when decoding.
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* If <= 0, then output will not be divided into lines (chunks).
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* @param lineSeparator Each line of encoded data will end with this
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* sequence of bytes.
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* If lineLength <= 0, then the lineSeparator is not used.
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* @throws IllegalArgumentException The provided lineSeparator included
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* some base64 characters. That's not going to work!
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*/
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public Base64(int lineLength, byte[] lineSeparator) {
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this.lineLength = lineLength;
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this.lineSeparator = new byte[lineSeparator.length];
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System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
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if (lineLength > 0) {
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this.encodeSize = 4 + lineSeparator.length;
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} else {
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this.encodeSize = 4;
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}
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this.decodeSize = encodeSize - 1;
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if (containsBase64Byte(lineSeparator)) {
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String sep = new String(lineSeparator, Charset.forName("UTF-8"));
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throw new IllegalArgumentException("lineSeperator must not contain base64 characters: [" + sep + "]");
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}
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}
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/**
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* Returns true if this Base64 object has buffered data for reading.
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*
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* @return true if there is Base64 object still available for reading.
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*/
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boolean hasData() {
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return buf != null;
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}
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/**
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* Returns the amount of buffered data available for reading.
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*
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* @return The amount of buffered data available for reading.
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*/
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int avail() {
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return buf != null ? pos - readPos : 0;
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}
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/** Doubles our buffer. */
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private void resizeBuf() {
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if (buf == null) {
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buf = new byte[8192];
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pos = 0;
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readPos = 0;
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} else {
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byte[] b = new byte[buf.length * 2];
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System.arraycopy(buf, 0, b, 0, buf.length);
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buf = b;
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}
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}
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/**
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* Extracts buffered data into the provided byte[] array, starting
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* at position bPos, up to a maximum of bAvail bytes. Returns how
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* many bytes were actually extracted.
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*
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* @param b byte[] array to extract the buffered data into.
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* @param bPos position in byte[] array to start extraction at.
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* @param bAvail amount of bytes we're allowed to extract. We may extract
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* fewer (if fewer are available).
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* @return The number of bytes successfully extracted into the provided
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* byte[] array.
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*/
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int readResults(byte[] b, int bPos, int bAvail) {
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if (buf != null) {
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int len = Math.min(avail(), bAvail);
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if (buf != b) {
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System.arraycopy(buf, readPos, b, bPos, len);
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readPos += len;
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if (readPos >= pos) {
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buf = null;
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}
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} else {
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// Re-using the original consumer's output array is only
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// allowed for one round.
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buf = null;
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}
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return len;
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} else {
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return eof ? -1 : 0;
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}
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}
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/**
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* Small optimization where we try to buffer directly to the consumer's
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* output array for one round (if consumer calls this method first!) instead
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* of starting our own buffer.
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*
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* @param out byte[] array to buffer directly to.
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* @param outPos Position to start buffering into.
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* @param outAvail Amount of bytes available for direct buffering.
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*/
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void setInitialBuffer(byte[] out, int outPos, int outAvail) {
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// We can re-use consumer's original output array under
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// special circumstances, saving on some System.arraycopy().
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if (out != null && out.length == outAvail) {
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buf = out;
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pos = outPos;
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readPos = outPos;
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}
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}
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/**
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* <p>
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* Encodes all of the provided data, starting at inPos, for inAvail bytes.
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* Must be called at least twice: once with the data to encode, and once
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* with inAvail set to "-1" to alert encoder that EOF has been reached,
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* so flush last remaining bytes (if not multiple of 3).
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* </p><p>
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* Thanks to "commons" project in ws.apache.org for the bitwise operations,
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* and general approach.
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* http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
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* </p>
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*
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* @param in byte[] array of binary data to base64 encode.
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* @param inPos Position to start reading data from.
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* @param inAvail Amount of bytes available from input for encoding.
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*/
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void encode(byte[] in, int inPos, int inAvail) {
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if (eof) {
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return;
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}
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// inAvail < 0 is how we're informed of EOF in the underlying data we're
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// encoding.
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if (inAvail < 0) {
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eof = true;
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if (buf == null || buf.length - pos < encodeSize) {
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resizeBuf();
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}
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switch (modulus) {
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case 1:
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buf[pos++] = intToBase64[(x >> 2) & MASK_6BITS];
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buf[pos++] = intToBase64[(x << 4) & MASK_6BITS];
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buf[pos++] = PAD;
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buf[pos++] = PAD;
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break;
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case 2:
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buf[pos++] = intToBase64[(x >> 10) & MASK_6BITS];
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buf[pos++] = intToBase64[(x >> 4) & MASK_6BITS];
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buf[pos++] = intToBase64[(x << 2) & MASK_6BITS];
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buf[pos++] = PAD;
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break;
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}
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if (lineLength > 0) {
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System.arraycopy(lineSeparator, 0, buf, pos, lineSeparator.length);
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pos += lineSeparator.length;
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}
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} else {
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for (int i = 0; i < inAvail; i++) {
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if (buf == null || buf.length - pos < encodeSize) {
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resizeBuf();
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}
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modulus = (++modulus) % 3;
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int b = in[inPos++];
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if (b < 0) {
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b += 256;
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}
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x = (x << 8) + b;
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if (0 == modulus) {
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buf[pos++] = intToBase64[(x >> 18) & MASK_6BITS];
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buf[pos++] = intToBase64[(x >> 12) & MASK_6BITS];
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buf[pos++] = intToBase64[(x >> 6) & MASK_6BITS];
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buf[pos++] = intToBase64[x & MASK_6BITS];
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currentLinePos += 4;
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if (lineLength > 0 && lineLength <= currentLinePos) {
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System.arraycopy(lineSeparator, 0, buf, pos, lineSeparator.length);
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pos += lineSeparator.length;
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currentLinePos = 0;
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}
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}
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}
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}
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}
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/**
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* <p>
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* Decodes all of the provided data, starting at inPos, for inAvail bytes.
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* Should be called at least twice: once with the data to decode, and once
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* with inAvail set to "-1" to alert decoder that EOF has been reached.
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* The "-1" call is not necessary when decoding, but it doesn't hurt, either.
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* </p><p>
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* Ignores all non-base64 characters. This is how chunked (e.g. 76 character)
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* data is handled, since CR and LF are silently ignored, but has implications
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* for other bytes, too. This method subscribes to the garbage-in, garbage-out
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* philosophy: it will not check the provided data for validity.
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* </p><p>
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* Thanks to "commons" project in ws.apache.org for the bitwise operations,
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|
* and general approach.
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|
* http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
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* </p>
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* @param in byte[] array of ascii data to base64 decode.
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* @param inPos Position to start reading data from.
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* @param inAvail Amount of bytes available from input for encoding.
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*/
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void decode(byte[] in, int inPos, int inAvail) {
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if (eof) {
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return;
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}
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if (inAvail < 0) {
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eof = true;
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}
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for (int i = 0; i < inAvail; i++) {
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if (buf == null || buf.length - pos < decodeSize) {
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resizeBuf();
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}
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byte b = in[inPos++];
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if (b == PAD) {
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x = x << 6;
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switch (modulus) {
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case 2:
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x = x << 6;
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buf[pos++] = (byte)((x >> 16) & MASK_8BITS);
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break;
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case 3:
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buf[pos++] = (byte)((x >> 16) & MASK_8BITS);
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buf[pos++] = (byte)((x >> 8) & MASK_8BITS);
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break;
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}
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// WE'RE DONE!!!!
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eof = true;
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return;
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} else {
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if (b >= 0 && b < base64ToInt.length) {
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int result = base64ToInt[b];
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if (result >= 0) {
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modulus = (++modulus) % 4;
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x = (x << 6) + result;
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if (modulus == 0) {
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buf[pos++] = (byte)((x >> 16) & MASK_8BITS);
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buf[pos++] = (byte)((x >> 8) & MASK_8BITS);
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buf[pos++] = (byte)(x & MASK_8BITS);
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}
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}
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}
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}
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}
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}
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|
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/**
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* Returns whether or not the <code>octet</code> is in the base 64 alphabet.
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|
*
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* @param octet
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* The value to test
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* @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
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*/
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public static boolean isBase64(byte octet) {
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return octet == PAD || (octet >= 0 && octet < base64ToInt.length && base64ToInt[octet] != -1);
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}
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|
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/**
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|
* Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
|
|
* Currently the method treats whitespace as valid.
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|
*
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|
* @param arrayOctet
|
|
* byte array to test
|
|
* @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is
|
|
* empty; false, otherwise
|
|
*/
|
|
public static boolean isArrayByteBase64(byte[] arrayOctet) {
|
|
for (byte anArrayOctet : arrayOctet) {
|
|
if (!isBase64(anArrayOctet) && !isWhiteSpace(anArrayOctet)) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
|
|
*
|
|
* @param arrayOctet
|
|
* byte array to test
|
|
* @return <code>true</code> if any byte is a valid character in the Base64 alphabet; false herwise
|
|
*/
|
|
private static boolean containsBase64Byte(byte[] arrayOctet) {
|
|
for (byte element : arrayOctet) {
|
|
if (isBase64(element)) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* 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 an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the
|
|
* Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[].
|
|
*
|
|
* @param pObject
|
|
* Object to decode
|
|
* @return An object (of type byte[]) containing the binary data which corresponds to the byte[] supplied.
|
|
* @throws DecoderException
|
|
* if the parameter supplied is not of type byte[]
|
|
*/
|
|
public Object decode(Object pObject) throws DecoderException {
|
|
if (!(pObject instanceof byte[])) {
|
|
throw new DecoderException("Parameter supplied to Base64 decode is not a byte[]");
|
|
}
|
|
return decode((byte[]) pObject);
|
|
}
|
|
|
|
/**
|
|
* 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 <code>true</code> this encoder will chunk the base64 output into 76 character blocks
|
|
* @return Base64-encoded data.
|
|
* @throws IllegalArgumentException
|
|
* Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
|
|
*/
|
|
public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
|
|
if (binaryData == null || binaryData.length == 0) {
|
|
return binaryData;
|
|
}
|
|
Base64 b64 = isChunked ? new Base64() : new Base64(0);
|
|
|
|
long len = (binaryData.length * 4) / 3;
|
|
long mod = len % 4;
|
|
if (mod != 0) {
|
|
len += 4 - mod;
|
|
}
|
|
if (isChunked) {
|
|
len += (1 + (len / CHUNK_SIZE)) * CHUNK_SEPARATOR.length;
|
|
}
|
|
|
|
if (len > Integer.MAX_VALUE) {
|
|
throw new IllegalArgumentException(
|
|
"Input array too big, output array would be bigger than Integer.MAX_VALUE=" + Integer.MAX_VALUE);
|
|
}
|
|
byte[] buf = new byte[(int) len];
|
|
b64.setInitialBuffer(buf, 0, buf.length);
|
|
b64.encode(binaryData, 0, binaryData.length);
|
|
b64.encode(binaryData, 0, -1); // Notify encoder of EOF.
|
|
|
|
// Encoder might have resized, even though it was unnecessary.
|
|
if (b64.buf != buf) {
|
|
b64.readResults(buf, 0, buf.length);
|
|
}
|
|
return buf;
|
|
}
|
|
|
|
/**
|
|
* Decodes Base64 data into octets
|
|
*
|
|
* @param base64Data Byte array containing Base64 data
|
|
* @return Array containing decoded data.
|
|
*/
|
|
public static byte[] decodeBase64(byte[] base64Data) {
|
|
if (base64Data == null || base64Data.length == 0) {
|
|
return base64Data;
|
|
}
|
|
Base64 b64 = new Base64();
|
|
|
|
long len = (base64Data.length * 3) / 4;
|
|
byte[] buf = new byte[(int) len];
|
|
b64.setInitialBuffer(buf, 0, buf.length);
|
|
b64.decode(base64Data, 0, base64Data.length);
|
|
b64.decode(base64Data, 0, -1); // Notify decoder of EOF.
|
|
|
|
// We have no idea what the line-length was, so we
|
|
// cannot know how much of our array wasn't used.
|
|
byte[] result = new byte[b64.pos];
|
|
b64.readResults(result, 0, result.length);
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Check if a byte value is whitespace or not.
|
|
*
|
|
* @param byteToCheck the byte to check
|
|
* @return true if byte is whitespace, false otherwise
|
|
*/
|
|
private static boolean isWhiteSpace(byte byteToCheck) {
|
|
switch (byteToCheck) {
|
|
case ' ' :
|
|
case '\n' :
|
|
case '\r' :
|
|
case '\t' :
|
|
return true;
|
|
default :
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 element : data) {
|
|
if (isBase64(element)) {
|
|
groomedData[bytesCopied++] = element;
|
|
}
|
|
}
|
|
|
|
byte packedData[] = new byte[bytesCopied];
|
|
|
|
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
|
|
|
|
return packedData;
|
|
}
|
|
|
|
// Implementation of the Encoder Interface
|
|
|
|
/**
|
|
* Encodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the
|
|
* Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].
|
|
*
|
|
* @param pObject
|
|
* Object to encode
|
|
* @return An object (of type byte[]) containing the base64 encoded data which corresponds to the byte[] supplied.
|
|
* @throws EncoderException
|
|
* if the parameter supplied is not of type byte[]
|
|
*/
|
|
public Object encode(Object pObject) throws EncoderException {
|
|
if (!(pObject instanceof byte[])) {
|
|
throw new EncoderException("Parameter supplied to Base64 encode is not a byte[]");
|
|
}
|
|
return encode((byte[]) pObject);
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
|
|
// Implementation of integer encoding used for crypto
|
|
/**
|
|
* Decode a byte64-encoded integer according to crypto
|
|
* standards such as W3C's XML-Signature
|
|
*
|
|
* @param pArray a byte array containing base64 character data
|
|
* @return A BigInteger
|
|
*/
|
|
public static BigInteger decodeInteger(byte[] pArray) {
|
|
return new BigInteger(1, decodeBase64(pArray));
|
|
}
|
|
|
|
/**
|
|
* Encode to a byte64-encoded integer according to crypto
|
|
* standards such as W3C's XML-Signature
|
|
*
|
|
* @param bigInt a BigInteger
|
|
* @return A byte array containing base64 character data
|
|
* @throws NullPointerException if null is passed in
|
|
*/
|
|
public static byte[] encodeInteger(BigInteger bigInt) {
|
|
if (bigInt == null) {
|
|
throw new NullPointerException("encodeInteger called with null parameter");
|
|
}
|
|
|
|
return encodeBase64(toIntegerBytes(bigInt), false);
|
|
}
|
|
|
|
/**
|
|
* Returns a byte-array representation of a <code>BigInteger</code>
|
|
* without sign bit.
|
|
*
|
|
* @param bigInt <code>BigInteger</code> to be converted
|
|
* @return a byte array representation of the BigInteger parameter
|
|
*/
|
|
static byte[] toIntegerBytes(BigInteger bigInt) {
|
|
int bitlen = bigInt.bitLength();
|
|
// round bitlen
|
|
bitlen = ((bitlen + 7) >> 3) << 3;
|
|
byte[] bigBytes = bigInt.toByteArray();
|
|
|
|
if (((bigInt.bitLength() % 8) != 0) &&
|
|
(((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
|
|
return bigBytes;
|
|
}
|
|
|
|
// set up params for copying everything but sign bit
|
|
int startSrc = 0;
|
|
int len = bigBytes.length;
|
|
|
|
// if bigInt is exactly byte-aligned, just skip signbit in copy
|
|
if ((bigInt.bitLength() % 8) == 0) {
|
|
startSrc = 1;
|
|
len--;
|
|
}
|
|
|
|
int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
|
|
byte[] resizedBytes = new byte[bitlen / 8];
|
|
|
|
System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
|
|
|
|
return resizedBytes;
|
|
}
|
|
|
|
static class DecoderException extends Exception {
|
|
private static final long serialVersionUID = -3786485780312120437L;
|
|
|
|
DecoderException(String error) {
|
|
super(error);
|
|
}
|
|
}
|
|
|
|
static class EncoderException extends Exception {
|
|
private static final long serialVersionUID = -5204809025392124652L;
|
|
|
|
EncoderException(String error) {
|
|
super(error);
|
|
}
|
|
}
|
|
}
|