857 lines
33 KiB
Java
857 lines
33 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 net.lax1dude.eaglercraft.v1_8;
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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
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* <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.
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*
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* <p>
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* This class implements section <cite>6.8. Base64
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* Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose Internet
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* Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by
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* Freed and Borenstein.
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* </p>
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* <p>
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* The class can be parameterized in the following manner with various
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* constructors:
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* </p>
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* <ul>
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* <li>URL-safe mode: Default off.</li>
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* <li>Line length: Default 76. Line length that aren't multiples of 4 will
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* still essentially end up being multiples of 4 in the encoded data.
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* <li>Line separator: Default is CRLF ("\r\n")</li>
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* </ul>
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* <p>
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* The URL-safe parameter is only applied to encode operations. Decoding
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* seamlessly handles both modes.
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* </p>
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* <p>
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* Since this class operates directly on byte streams, and not character
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* streams, it is hard-coded to only encode/decode character encodings which are
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* compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8,
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* etc).
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* </p>
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* <p>
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* This class is thread-safe.
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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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* @since 1.0
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*/
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public class Base64 extends BaseNCodec {
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/**
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* BASE32 characters are 6 bits in length. They are formed by taking a block of
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* 3 octets to form a 24-bit string, which is converted into 4 BASE64
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* characters.
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*/
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private static final int BITS_PER_ENCODED_BYTE = 6;
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private static final int BYTES_PER_UNENCODED_BLOCK = 3;
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private static final int BYTES_PER_ENCODED_BLOCK = 4;
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/**
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* This array is a lookup table that translates 6-bit positive integer index
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* values into their "Base64 Alphabet" equivalents as specified in Table 1 of
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* 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[] STANDARD_ENCODE_TABLE = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
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'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
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'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1',
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'2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };
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/**
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* This is a copy of the STANDARD_ENCODE_TABLE above, but with + and / changed
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* to - and _ to make the encoded Base64 results more URL-SAFE. This table is
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* only used when the Base64's mode is set to URL-SAFE.
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*/
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private static final byte[] URL_SAFE_ENCODE_TABLE = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
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'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
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'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1',
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'2', '3', '4', '5', '6', '7', '8', '9', '-', '_' };
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/**
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* This array is a lookup table that translates Unicode characters drawn from
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* the "Base64 Alphabet" (as specified in Table 1 of RFC 2045) into their 6-bit
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* positive integer equivalents. Characters that are not in the Base64 alphabet
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* but fall within the bounds of the array are translated to -1.
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*
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* Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This
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* means decoder seamlessly handles both URL_SAFE and STANDARD base64. (The
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* encoder, on the other hand, needs to know ahead of time what to emit).
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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[] DECODE_TABLE = {
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, // 20-2f + - /
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, // 30-3f 0-9
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 40-4f A-O
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, // 50-5f P-Z _
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-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, // 60-6f a-o
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 // 70-7a p-z
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};
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/**
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* Base64 uses 6-bit fields.
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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 4 bits, used when decoding final trailing character. */
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private static final int MASK_4BITS = 0xf;
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/** Mask used to extract 2 bits, used when decoding final trailing character. */
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private static final int MASK_2BITS = 0x3;
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// The static final fields above are used for the original static byte[] methods
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// on Base64.
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// The private member fields below are used with the new streaming approach,
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// which requires
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// some state be preserved between calls of encode() and decode().
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/**
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* Decodes Base64 data into octets.
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* <p>
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* <b>Note:</b> this method seamlessly handles data encoded in URL-safe or
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* normal mode.
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* </p>
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*
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* @param base64Data Byte array containing Base64 data
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* @return Array containing decoded data.
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*/
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public static byte[] decodeBase64(final byte[] base64Data) {
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return new Base64().decode(base64Data);
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}
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/**
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* Decodes a Base64 String into octets.
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* <p>
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* <b>Note:</b> this method seamlessly handles data encoded in URL-safe or
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* normal mode.
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* </p>
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*
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* @param base64String String containing Base64 data
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* @return Array containing decoded data.
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* @since 1.4
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*/
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public static byte[] decodeBase64(final String base64String) {
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return new Base64().decode(base64String);
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}
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// Implementation of integer encoding used for crypto
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/**
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* Decodes a byte64-encoded integer according to crypto standards such as W3C's
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* XML-Signature.
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*
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* @param pArray a byte array containing base64 character data
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* @return A BigInteger
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* @since 1.4
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*/
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public static BigInteger decodeInteger(final byte[] pArray) {
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return new BigInteger(1, decodeBase64(pArray));
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}
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/**
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* Encodes binary data using the base64 algorithm but does not chunk the output.
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*
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* @param binaryData binary data to encode
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* @return byte[] containing Base64 characters in their UTF-8 representation.
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*/
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public static byte[] encodeBase64(final byte[] binaryData) {
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return encodeBase64(binaryData, false);
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}
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/**
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* Encodes binary data using the base64 algorithm, optionally chunking the
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* output into 76 character blocks.
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*
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* @param binaryData Array containing binary data to encode.
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* @param isChunked if {@code true} this encoder will chunk the base64 output
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* into 76 character blocks
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* @return Base64-encoded data.
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* @throws IllegalArgumentException Thrown when the input array needs an output
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* array bigger than {@link Integer#MAX_VALUE}
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*/
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public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked) {
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return encodeBase64(binaryData, isChunked, false);
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}
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/**
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* Encodes binary data using the base64 algorithm, optionally chunking the
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* output into 76 character blocks.
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*
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* @param binaryData Array containing binary data to encode.
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* @param isChunked if {@code true} this encoder will chunk the base64 output
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* into 76 character blocks
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* @param urlSafe if {@code true} this encoder will emit - and _ instead of
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* the usual + and / characters. <b>Note: no padding is added
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* when encoding using the URL-safe alphabet.</b>
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* @return Base64-encoded data.
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* @throws IllegalArgumentException Thrown when the input array needs an output
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* array bigger than {@link Integer#MAX_VALUE}
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* @since 1.4
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*/
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public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) {
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return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
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}
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/**
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* Encodes binary data using the base64 algorithm, optionally chunking the
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* output into 76 character blocks.
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*
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* @param binaryData Array containing binary data to encode.
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* @param isChunked if {@code true} this encoder will chunk the base64
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* output into 76 character blocks
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* @param urlSafe if {@code true} this encoder will emit - and _ instead
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* of the usual + and / characters. <b>Note: no padding is
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* added when encoding using the URL-safe alphabet.</b>
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* @param maxResultSize The maximum result size to accept.
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* @return Base64-encoded data.
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* @throws IllegalArgumentException Thrown when the input array needs an output
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* array bigger than maxResultSize
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* @since 1.4
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*/
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public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe,
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final int maxResultSize) {
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if (binaryData == null || binaryData.length == 0) {
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return binaryData;
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}
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// Create this so can use the super-class method
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// Also ensures that the same roundings are performed by the ctor and the code
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final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
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final long len = b64.getEncodedLength(binaryData);
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if (len > maxResultSize) {
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throw new IllegalArgumentException("Input array too big, the output array would be bigger (" + len
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+ ") than the specified maximum size of " + maxResultSize);
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}
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return b64.encode(binaryData);
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}
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/**
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* Encodes binary data using the base64 algorithm and chunks the encoded output
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* into 76 character blocks
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*
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* @param binaryData binary data to encode
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* @return Base64 characters chunked in 76 character blocks
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*/
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public static byte[] encodeBase64Chunked(final byte[] binaryData) {
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return encodeBase64(binaryData, true);
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}
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/**
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* Encodes binary data using the base64 algorithm but does not chunk the output.
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*
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* NOTE: We changed the behavior of this method from multi-line chunking
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* (commons-codec-1.4) to single-line non-chunking (commons-codec-1.5).
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*
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* @param binaryData binary data to encode
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* @return String containing Base64 characters.
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* @since 1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not).
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*/
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public static String encodeBase64String(final byte[] binaryData) {
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return new String(encodeBase64(binaryData, false), Charset.forName("UTF-8"));
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}
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/**
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* Encodes binary data using a URL-safe variation of the base64 algorithm but
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* does not chunk the output. The url-safe variation emits - and _ instead of +
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* and / characters. <b>Note: no padding is added.</b>
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*
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* @param binaryData binary data to encode
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* @return byte[] containing Base64 characters in their UTF-8 representation.
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* @since 1.4
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*/
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public static byte[] encodeBase64URLSafe(final byte[] binaryData) {
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return encodeBase64(binaryData, false, true);
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}
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/**
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* Encodes binary data using a URL-safe variation of the base64 algorithm but
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* does not chunk the output. The url-safe variation emits - and _ instead of +
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* and / characters. <b>Note: no padding is added.</b>
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*
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* @param binaryData binary data to encode
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* @return String containing Base64 characters
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* @since 1.4
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*/
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public static String encodeBase64URLSafeString(final byte[] binaryData) {
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return new String(encodeBase64(binaryData, false, true), Charset.forName("UTF-8"));
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}
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/**
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* Encodes to a byte64-encoded integer according to crypto standards such as
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* W3C's XML-Signature.
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*
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* @param bigInteger a BigInteger
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* @return A byte array containing base64 character data
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* @throws NullPointerException if null is passed in
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* @since 1.4
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*/
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public static byte[] encodeInteger(final BigInteger bigInteger) {
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return encodeBase64(toIntegerBytes(bigInteger), false);
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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
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* the Base64 alphabet. Currently the method treats whitespace as valid.
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*
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* @param arrayOctet byte array to test
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* @return {@code true} if all bytes are valid characters in the Base64 alphabet
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* or if the byte array is empty; {@code false}, otherwise
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* @deprecated 1.5 Use {@link #isBase64(byte[])}, will be removed in 2.0.
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*/
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@Deprecated
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public static boolean isArrayByteBase64(final byte[] arrayOctet) {
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return isBase64(arrayOctet);
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}
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/**
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* Returns whether or not the {@code octet} is in the base 64 alphabet.
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*
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* @param octet The value to test
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* @return {@code true} if the value is defined in the the base 64 alphabet,
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* {@code false} otherwise.
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* @since 1.4
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*/
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public static boolean isBase64(final byte octet) {
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return octet == PAD_DEFAULT || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
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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
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* the Base64 alphabet. Currently the method treats whitespace as valid.
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*
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* @param arrayOctet byte array to test
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* @return {@code true} if all bytes are valid characters in the Base64 alphabet
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* or if the byte array is empty; {@code false}, otherwise
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* @since 1.5
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*/
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public static boolean isBase64(final byte[] arrayOctet) {
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for (int i = 0; i < arrayOctet.length; i++) {
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if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
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return false;
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}
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}
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return true;
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}
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/**
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* Tests a given String to see if it contains only valid characters within the
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* Base64 alphabet. Currently the method treats whitespace as valid.
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*
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* @param base64 String to test
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* @return {@code true} if all characters in the String are valid characters in
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* the Base64 alphabet or if the String is empty; {@code false},
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* otherwise
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* @since 1.5
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*/
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public static boolean isBase64(final String base64) {
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return isBase64(base64.getBytes(Charset.forName("UTF-8")));
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}
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/**
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* Returns a byte-array representation of a {@code BigInteger} without sign bit.
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*
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* @param bigInt {@code BigInteger} to be converted
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* @return a byte array representation of the BigInteger parameter
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*/
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static byte[] toIntegerBytes(final BigInteger bigInt) {
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int bitlen = bigInt.bitLength();
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// round bitlen
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bitlen = ((bitlen + 7) >> 3) << 3;
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final byte[] bigBytes = bigInt.toByteArray();
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if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
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return bigBytes;
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}
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// set up params for copying everything but sign bit
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int startSrc = 0;
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int len = bigBytes.length;
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// if bigInt is exactly byte-aligned, just skip signbit in copy
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if ((bigInt.bitLength() % 8) == 0) {
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startSrc = 1;
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len--;
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}
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final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
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final byte[] resizedBytes = new byte[bitlen / 8];
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System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
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return resizedBytes;
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}
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/**
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* Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE
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* above remains static because it is able to decode both STANDARD and URL_SAFE
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* streams, but the encodeTable must be a member variable so we can switch
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* between the two modes.
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*/
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private final byte[] encodeTable;
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// Only one decode table currently; keep for consistency with Base32 code
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private final byte[] decodeTable = DECODE_TABLE;
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/**
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* Line separator for encoding. Not used when decoding. Only used if lineLength
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* > 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
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* of room and needs resizing. {@code decodeSize = 3 + lineSeparator.length;}
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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
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* of room and needs resizing. {@code encodeSize = 4 + lineSeparator.length;}
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*/
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private final int encodeSize;
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/**
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* Creates a Base64 codec used for decoding (all modes) and encoding in
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* URL-unsafe mode.
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* <p>
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* When encoding the line length is 0 (no chunking), and the encoding table is
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* STANDARD_ENCODE_TABLE.
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* </p>
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*
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* <p>
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* When decoding all variants are supported.
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* </p>
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*/
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public Base64() {
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this(0);
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}
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/**
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* Creates a Base64 codec used for decoding (all modes) and encoding in the
|
|
* given URL-safe mode.
|
|
* <p>
|
|
* When encoding the line length is 76, the line separator is CRLF, and the
|
|
* encoding table is STANDARD_ENCODE_TABLE.
|
|
* </p>
|
|
*
|
|
* <p>
|
|
* When decoding all variants are supported.
|
|
* </p>
|
|
*
|
|
* @param urlSafe if {@code true}, URL-safe encoding is used. In most cases this
|
|
* should be set to {@code false}.
|
|
* @since 1.4
|
|
*/
|
|
public Base64(final boolean urlSafe) {
|
|
this(MIME_CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
|
|
}
|
|
|
|
/**
|
|
* Creates a Base64 codec used for decoding (all modes) and encoding in
|
|
* URL-unsafe mode.
|
|
* <p>
|
|
* When encoding the line length is given in the constructor, the line separator
|
|
* is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
|
|
* </p>
|
|
* <p>
|
|
* Line lengths that aren't multiples of 4 will still essentially end up being
|
|
* multiples of 4 in the encoded data.
|
|
* </p>
|
|
* <p>
|
|
* When decoding all variants are supported.
|
|
* </p>
|
|
*
|
|
* @param lineLength Each line of encoded data will be at most of the given
|
|
* length (rounded down to nearest multiple of 4). If
|
|
* lineLength <= 0, then the output will not be divided
|
|
* into lines (chunks). Ignored when decoding.
|
|
* @since 1.4
|
|
*/
|
|
public Base64(final int lineLength) {
|
|
this(lineLength, CHUNK_SEPARATOR);
|
|
}
|
|
|
|
/**
|
|
* Creates a Base64 codec used for decoding (all modes) and encoding in
|
|
* URL-unsafe mode.
|
|
* <p>
|
|
* When encoding the line length and line separator are given in the
|
|
* constructor, and the encoding table is STANDARD_ENCODE_TABLE.
|
|
* </p>
|
|
* <p>
|
|
* Line lengths that aren't multiples of 4 will still essentially end up being
|
|
* multiples of 4 in the encoded data.
|
|
* </p>
|
|
* <p>
|
|
* When decoding all variants are supported.
|
|
* </p>
|
|
*
|
|
* @param lineLength Each line of encoded data will be at most of the given
|
|
* length (rounded down to nearest multiple of 4). If
|
|
* lineLength <= 0, then the output will not be divided
|
|
* into lines (chunks). Ignored when decoding.
|
|
* @param lineSeparator Each line of encoded data will end with this sequence of
|
|
* bytes.
|
|
* @throws IllegalArgumentException Thrown when the provided lineSeparator
|
|
* included some base64 characters.
|
|
* @since 1.4
|
|
*/
|
|
public Base64(final int lineLength, final byte[] lineSeparator) {
|
|
this(lineLength, lineSeparator, false);
|
|
}
|
|
|
|
/**
|
|
* Creates a Base64 codec used for decoding (all modes) and encoding in
|
|
* URL-unsafe mode.
|
|
* <p>
|
|
* When encoding the line length and line separator are given in the
|
|
* constructor, and the encoding table is STANDARD_ENCODE_TABLE.
|
|
* </p>
|
|
* <p>
|
|
* Line lengths that aren't multiples of 4 will still essentially end up being
|
|
* multiples of 4 in the encoded data.
|
|
* </p>
|
|
* <p>
|
|
* When decoding all variants are supported.
|
|
* </p>
|
|
*
|
|
* @param lineLength Each line of encoded data will be at most of the given
|
|
* length (rounded down to nearest multiple of 4). If
|
|
* lineLength <= 0, then the output will not be divided
|
|
* into lines (chunks). Ignored when decoding.
|
|
* @param lineSeparator Each line of encoded data will end with this sequence of
|
|
* bytes.
|
|
* @param urlSafe Instead of emitting '+' and '/' we emit '-' and '_'
|
|
* respectively. urlSafe is only applied to encode
|
|
* operations. Decoding seamlessly handles both modes.
|
|
* <b>Note: no padding is added when using the URL-safe
|
|
* alphabet.</b>
|
|
* @throws IllegalArgumentException Thrown when the {@code lineSeparator}
|
|
* contains Base64 characters.
|
|
* @since 1.4
|
|
*/
|
|
public Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe) {
|
|
this(lineLength, lineSeparator, urlSafe, CodecPolicy.LENIANT);
|
|
}
|
|
|
|
/**
|
|
* Creates a Base64 codec used for decoding (all modes) and encoding in
|
|
* URL-unsafe mode.
|
|
* <p>
|
|
* When encoding the line length and line separator are given in the
|
|
* constructor, and the encoding table is STANDARD_ENCODE_TABLE.
|
|
* </p>
|
|
* <p>
|
|
* Line lengths that aren't multiples of 4 will still essentially end up being
|
|
* multiples of 4 in the encoded data.
|
|
* </p>
|
|
* <p>
|
|
* When decoding all variants are supported.
|
|
* </p>
|
|
*
|
|
* @param lineLength Each line of encoded data will be at most of the given
|
|
* length (rounded down to nearest multiple of 4). If
|
|
* lineLength <= 0, then the output will not be divided
|
|
* into lines (chunks). Ignored when decoding.
|
|
* @param lineSeparator Each line of encoded data will end with this sequence
|
|
* of bytes.
|
|
* @param urlSafe Instead of emitting '+' and '/' we emit '-' and '_'
|
|
* respectively. urlSafe is only applied to encode
|
|
* operations. Decoding seamlessly handles both modes.
|
|
* <b>Note: no padding is added when using the URL-safe
|
|
* alphabet.</b>
|
|
* @param decodingPolicy The decoding policy.
|
|
* @throws IllegalArgumentException Thrown when the {@code lineSeparator}
|
|
* contains Base64 characters.
|
|
* @since 1.15
|
|
*/
|
|
public Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe,
|
|
final CodecPolicy decodingPolicy) {
|
|
super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK, lineLength,
|
|
lineSeparator == null ? 0 : lineSeparator.length, PAD_DEFAULT, decodingPolicy);
|
|
// TODO could be simplified if there is no requirement to reject invalid line
|
|
// sep when length <=0
|
|
// @see test case Base64Test.testConstructors()
|
|
if (lineSeparator != null) {
|
|
if (containsAlphabetOrPad(lineSeparator)) {
|
|
final String sep = new String(lineSeparator, Charset.forName("UTF-8"));
|
|
throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]");
|
|
}
|
|
if (lineLength > 0) { // null line-sep forces no chunking rather than throwing IAE
|
|
this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length;
|
|
this.lineSeparator = new byte[lineSeparator.length];
|
|
System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
|
|
} else {
|
|
this.encodeSize = BYTES_PER_ENCODED_BLOCK;
|
|
this.lineSeparator = null;
|
|
}
|
|
} else {
|
|
this.encodeSize = BYTES_PER_ENCODED_BLOCK;
|
|
this.lineSeparator = null;
|
|
}
|
|
this.decodeSize = this.encodeSize - 1;
|
|
this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
|
|
}
|
|
|
|
// Implementation of the Encoder Interface
|
|
|
|
/**
|
|
* <p>
|
|
* Decodes all of the provided data, starting at inPos, for inAvail bytes.
|
|
* Should be called at least twice: once with the data to decode, and once with
|
|
* inAvail set to "-1" to alert decoder that EOF has been reached. The "-1" call
|
|
* is not necessary when decoding, but it doesn't hurt, either.
|
|
* </p>
|
|
* <p>
|
|
* Ignores all non-base64 characters. This is how chunked (e.g. 76 character)
|
|
* data is handled, since CR and LF are silently ignored, but has implications
|
|
* for other bytes, too. This method subscribes to the garbage-in, garbage-out
|
|
* philosophy: it will not check the provided data for validity.
|
|
* </p>
|
|
* <p>
|
|
* Thanks to "commons" project in ws.apache.org for the bitwise operations, and
|
|
* general approach.
|
|
* http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
|
|
* </p>
|
|
*
|
|
* @param in byte[] array of ascii data to base64 decode.
|
|
* @param inPos Position to start reading data from.
|
|
* @param inAvail Amount of bytes available from input for decoding.
|
|
* @param context the context to be used
|
|
*/
|
|
@Override
|
|
void decode(final byte[] in, int inPos, final int inAvail, final Context context) {
|
|
if (context.eof) {
|
|
return;
|
|
}
|
|
if (inAvail < 0) {
|
|
context.eof = true;
|
|
}
|
|
for (int i = 0; i < inAvail; i++) {
|
|
final byte[] buffer = ensureBufferSize(decodeSize, context);
|
|
final byte b = in[inPos++];
|
|
if (b == pad) {
|
|
// We're done.
|
|
context.eof = true;
|
|
break;
|
|
}
|
|
if (b >= 0 && b < DECODE_TABLE.length) {
|
|
final int result = DECODE_TABLE[b];
|
|
if (result >= 0) {
|
|
context.modulus = (context.modulus + 1) % BYTES_PER_ENCODED_BLOCK;
|
|
context.ibitWorkArea = (context.ibitWorkArea << BITS_PER_ENCODED_BYTE) + result;
|
|
if (context.modulus == 0) {
|
|
buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 16) & MASK_8BITS);
|
|
buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
|
|
buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Two forms of EOF as far as base64 decoder is concerned: actual
|
|
// EOF (-1) and first time '=' character is encountered in stream.
|
|
// This approach makes the '=' padding characters completely optional.
|
|
if (context.eof && context.modulus != 0) {
|
|
final byte[] buffer = ensureBufferSize(decodeSize, context);
|
|
|
|
// We have some spare bits remaining
|
|
// Output all whole multiples of 8 bits and ignore the rest
|
|
switch (context.modulus) {
|
|
// case 0 : // impossible, as excluded above
|
|
case 1: // 6 bits - either ignore entirely, or raise an exception
|
|
validateTrailingCharacter();
|
|
break;
|
|
case 2: // 12 bits = 8 + 4
|
|
validateCharacter(MASK_4BITS, context);
|
|
context.ibitWorkArea = context.ibitWorkArea >> 4; // dump the extra 4 bits
|
|
buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
|
|
break;
|
|
case 3: // 18 bits = 8 + 8 + 2
|
|
validateCharacter(MASK_2BITS, context);
|
|
context.ibitWorkArea = context.ibitWorkArea >> 2; // dump 2 bits
|
|
buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
|
|
buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
|
|
break;
|
|
default:
|
|
throw new IllegalStateException("Impossible modulus " + context.modulus);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Encodes all of the provided data, starting at inPos, for inAvail bytes. Must
|
|
* be called at least twice: once with the data to encode, and once with inAvail
|
|
* set to "-1" to alert encoder that EOF has been reached, to flush last
|
|
* remaining bytes (if not multiple of 3).
|
|
* </p>
|
|
* <p>
|
|
* <b>Note: no padding is added when encoding using the URL-safe alphabet.</b>
|
|
* </p>
|
|
* <p>
|
|
* Thanks to "commons" project in ws.apache.org for the bitwise operations, and
|
|
* general approach.
|
|
* http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
|
|
* </p>
|
|
*
|
|
* @param in byte[] array of binary data to base64 encode.
|
|
* @param inPos Position to start reading data from.
|
|
* @param inAvail Amount of bytes available from input for encoding.
|
|
* @param context the context to be used
|
|
*/
|
|
@Override
|
|
void encode(final byte[] in, int inPos, final int inAvail, final Context context) {
|
|
if (context.eof) {
|
|
return;
|
|
}
|
|
// inAvail < 0 is how we're informed of EOF in the underlying data we're
|
|
// encoding.
|
|
if (inAvail < 0) {
|
|
context.eof = true;
|
|
if (0 == context.modulus && lineLength == 0) {
|
|
return; // no leftovers to process and not using chunking
|
|
}
|
|
final byte[] buffer = ensureBufferSize(encodeSize, context);
|
|
final int savedPos = context.pos;
|
|
switch (context.modulus) { // 0-2
|
|
case 0: // nothing to do here
|
|
break;
|
|
case 1: // 8 bits = 6 + 2
|
|
// top 6 bits:
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 2) & MASK_6BITS];
|
|
// remaining 2:
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 4) & MASK_6BITS];
|
|
// URL-SAFE skips the padding to further reduce size.
|
|
if (encodeTable == STANDARD_ENCODE_TABLE) {
|
|
buffer[context.pos++] = pad;
|
|
buffer[context.pos++] = pad;
|
|
}
|
|
break;
|
|
|
|
case 2: // 16 bits = 6 + 6 + 4
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 10) & MASK_6BITS];
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 4) & MASK_6BITS];
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 2) & MASK_6BITS];
|
|
// URL-SAFE skips the padding to further reduce size.
|
|
if (encodeTable == STANDARD_ENCODE_TABLE) {
|
|
buffer[context.pos++] = pad;
|
|
}
|
|
break;
|
|
default:
|
|
throw new IllegalStateException("Impossible modulus " + context.modulus);
|
|
}
|
|
context.currentLinePos += context.pos - savedPos; // keep track of current line position
|
|
// if currentPos == 0 we are at the start of a line, so don't add CRLF
|
|
if (lineLength > 0 && context.currentLinePos > 0) {
|
|
System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);
|
|
context.pos += lineSeparator.length;
|
|
}
|
|
} else {
|
|
for (int i = 0; i < inAvail; i++) {
|
|
final byte[] buffer = ensureBufferSize(encodeSize, context);
|
|
context.modulus = (context.modulus + 1) % BYTES_PER_UNENCODED_BLOCK;
|
|
int b = in[inPos++];
|
|
if (b < 0) {
|
|
b += 256;
|
|
}
|
|
context.ibitWorkArea = (context.ibitWorkArea << 8) + b; // BITS_PER_BYTE
|
|
if (0 == context.modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 18) & MASK_6BITS];
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 12) & MASK_6BITS];
|
|
buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 6) & MASK_6BITS];
|
|
buffer[context.pos++] = encodeTable[context.ibitWorkArea & MASK_6BITS];
|
|
context.currentLinePos += BYTES_PER_ENCODED_BLOCK;
|
|
if (lineLength > 0 && lineLength <= context.currentLinePos) {
|
|
System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);
|
|
context.pos += lineSeparator.length;
|
|
context.currentLinePos = 0;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns whether or not the {@code octet} is in the Base64 alphabet.
|
|
*
|
|
* @param octet The value to test
|
|
* @return {@code true} if the value is defined in the the Base64 alphabet
|
|
* {@code false} otherwise.
|
|
*/
|
|
@Override
|
|
protected boolean isInAlphabet(final byte octet) {
|
|
return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;
|
|
}
|
|
|
|
/**
|
|
* Returns our current encode mode. True if we're URL-SAFE, false otherwise.
|
|
*
|
|
* @return true if we're in URL-SAFE mode, false otherwise.
|
|
* @since 1.4
|
|
*/
|
|
public boolean isUrlSafe() {
|
|
return this.encodeTable == URL_SAFE_ENCODE_TABLE;
|
|
}
|
|
|
|
/**
|
|
* Validates whether decoding the final trailing character is possible in the
|
|
* context of the set of possible base 64 values.
|
|
*
|
|
* <p>
|
|
* The character is valid if the lower bits within the provided mask are zero.
|
|
* This is used to test the final trailing base-64 digit is zero in the bits
|
|
* that will be discarded.
|
|
*
|
|
* @param emptyBitsMask The mask of the lower bits that should be empty
|
|
* @param context the context to be used
|
|
*
|
|
* @throws IllegalArgumentException if the bits being checked contain any
|
|
* non-zero value
|
|
*/
|
|
private void validateCharacter(final int emptyBitsMask, final Context context) {
|
|
if (isStrictDecoding() && (context.ibitWorkArea & emptyBitsMask) != 0) {
|
|
throw new IllegalArgumentException(
|
|
"Strict decoding: Last encoded character (before the paddings if any) is a valid base 64 alphabet but not a possible encoding. "
|
|
+ "Expected the discarded bits from the character to be zero.");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Validates whether decoding allows an entire final trailing character that
|
|
* cannot be used for a complete byte.
|
|
*
|
|
* @throws IllegalArgumentException if strict decoding is enabled
|
|
*/
|
|
private void validateTrailingCharacter() {
|
|
if (isStrictDecoding()) {
|
|
throw new IllegalArgumentException(
|
|
"Strict decoding: Last encoded character (before the paddings if any) is a valid base 64 alphabet but not a possible encoding. "
|
|
+ "Decoding requires at least two trailing 6-bit characters to create bytes.");
|
|
}
|
|
}
|
|
|
|
} |