Base64.java
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.shiro.codec;
/**
* Provides <a href="http://en.wikipedia.org/wiki/Base64">Base 64</a> encoding and decoding as defined by
* <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.
* <p/>
* This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
* Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
* <p/>
* This class was borrowed from Apache Commons Codec SVN repository (rev. 618419) with modifications
* to enable Base64 conversion without a full dependecny on Commons Codec. We didn't want to reinvent the wheel of
* great work they've done, but also didn't want to force every Shiro user to depend on the commons-codec.jar
* <p/>
* As per the Apache 2.0 license, the original copyright notice and all author and copyright information have
* remained in tact.
*
* @see <a href="http://en.wikipedia.org/wiki/Base64">Wikipedia: Base 64</a>
* @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
* @since 0.9
*/
public class Base64 {
/**
* Chunk size per RFC 2045 section 6.8.
* <p/>
* The character limit does not count the trailing CRLF, but counts all other characters, including any
* equal signs.
*
* @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
*/
static final int CHUNK_SIZE = 76;
/**
* Chunk separator per RFC 2045 section 2.1.
*
* @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
*/
static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
/**
* The base length.
*/
private static final int BASELENGTH = 255;
/**
* Lookup length.
*/
private static final int LOOKUPLENGTH = 64;
/**
* Used to calculate the number of bits in a byte.
*/
private static final int EIGHTBIT = 8;
/**
* Used when encoding something which has fewer than 24 bits.
*/
private static final int SIXTEENBIT = 16;
/**
* Used to determine how many bits data contains.
*/
private static final int TWENTYFOURBITGROUP = 24;
/**
* Used to get the number of Quadruples.
*/
private static final int FOURBYTE = 4;
/**
* Used to test the sign of a byte.
*/
private static final int SIGN = -128;
/**
* Byte used to pad output.
*/
private static final byte PAD = (byte) '=';
/**
* Contains the Base64 values <code>0</code> through <code>63</code> accessed by using character encodings as
* indices.
* <p/>
* <p>For example, <code>base64Alphabet['+']</code> returns <code>62</code>.</p>
* <p/>
* <p>The value of undefined encodings is <code>-1</code>.</p>
*/
private static final byte[] base64Alphabet = new byte[BASELENGTH];
/**
* <p>Contains the Base64 encodings <code>A</code> through <code>Z</code>, followed by <code>a</code> through
* <code>z</code>, followed by <code>0</code> through <code>9</code>, followed by <code>+</code>, and
* <code>/</code>.</p>
* <p/>
* <p>This array is accessed by using character values as indices.</p>
* <p/>
* <p>For example, <code>lookUpBase64Alphabet[62] </code> returns <code>'+'</code>.</p>
*/
private static final byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
// Populating the lookup and character arrays
static {
for (int i = 0; i < BASELENGTH; i++) {
base64Alphabet[i] = (byte) -1;
}
for (int i = 'Z'; i >= 'A'; i--) {
base64Alphabet[i] = (byte) (i - 'A');
}
for (int i = 'z'; i >= 'a'; i--) {
base64Alphabet[i] = (byte) (i - 'a' + 26);
}
for (int i = '9'; i >= '0'; i--) {
base64Alphabet[i] = (byte) (i - '0' + 52);
}
base64Alphabet['+'] = 62;
base64Alphabet['/'] = 63;
for (int i = 0; i <= 25; i++) {
lookUpBase64Alphabet[i] = (byte) ('A' + i);
}
for (int i = 26, j = 0; i <= 51; i++, j++) {
lookUpBase64Alphabet[i] = (byte) ('a' + j);
}
for (int i = 52, j = 0; i <= 61; i++, j++) {
lookUpBase64Alphabet[i] = (byte) ('0' + j);
}
lookUpBase64Alphabet[62] = (byte) '+';
lookUpBase64Alphabet[63] = (byte) '/';
}
/**
* Returns whether or not the <code>octect</code> is in the base 64 alphabet.
*
* @param octect The value to test
* @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
*/
private static boolean isBase64(byte octect) {
if (octect == PAD) {
return true;
} else //noinspection RedundantIfStatement
if (octect < 0 || base64Alphabet[octect] == -1) {
return false;
} else {
return true;
}
}
/**
* Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
*
* @param arrayOctect 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 isBase64(byte[] arrayOctect) {
arrayOctect = discardWhitespace(arrayOctect);
int length = arrayOctect.length;
if (length == 0) {
// shouldn't a 0 length array be valid base64 data?
// return false;
return true;
}
for (int i = 0; i < length; i++) {
if (!isBase64(arrayOctect[i])) {
return false;
}
}
return true;
}
/**
* Discards any whitespace from a base-64 encoded block.
*
* @param data The base-64 encoded data to discard the whitespace from.
* @return The data, less whitespace (see RFC 2045).
*/
static byte[] discardWhitespace(byte[] data) {
byte groomedData[] = new byte[data.length];
int bytesCopied = 0;
for (byte aByte : data) {
switch (aByte) {
case (byte) ' ':
case (byte) '\n':
case (byte) '\r':
case (byte) '\t':
break;
default:
groomedData[bytesCopied++] = aByte;
}
}
byte packedData[] = new byte[bytesCopied];
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
return packedData;
}
/**
* Base64 encodes the specified byte array and then encodes it as a String using Shiro's preferred character
* encoding (UTF-8).
*
* @param bytes the byte array to Base64 encode.
* @return a UTF-8 encoded String of the resulting Base64 encoded byte array.
*/
public static String encodeToString(byte[] bytes) {
byte[] encoded = encode(bytes);
return CodecSupport.toString(encoded);
}
/**
* Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
*
* @param binaryData binary data to encodeToChars
* @return Base64 characters chunked in 76 character blocks
*/
public static byte[] encodeChunked(byte[] binaryData) {
return encode(binaryData, true);
}
/**
* 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 static byte[] encode(byte[] pArray) {
return encode(pArray, false);
}
/**
* Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
*
* @param binaryData Array containing binary data to encodeToChars.
* @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[] encode(byte[] binaryData, boolean isChunked) {
long binaryDataLength = binaryData.length;
long lengthDataBits = binaryDataLength * EIGHTBIT;
long fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
long tripletCount = lengthDataBits / TWENTYFOURBITGROUP;
long encodedDataLengthLong;
int chunckCount = 0;
if (fewerThan24bits != 0) {
// data not divisible by 24 bit
encodedDataLengthLong = (tripletCount + 1) * 4;
} else {
// 16 or 8 bit
encodedDataLengthLong = tripletCount * 4;
}
// If the output is to be "chunked" into 76 character sections,
// for compliance with RFC 2045 MIME, then it is important to
// allow for extra length to account for the separator(s)
if (isChunked) {
chunckCount = (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math
.ceil((float) encodedDataLengthLong / CHUNK_SIZE));
encodedDataLengthLong += chunckCount * CHUNK_SEPARATOR.length;
}
if (encodedDataLengthLong > Integer.MAX_VALUE) {
throw new IllegalArgumentException(
"Input array too big, output array would be bigger than Integer.MAX_VALUE=" + Integer.MAX_VALUE);
}
int encodedDataLength = (int) encodedDataLengthLong;
byte encodedData[] = new byte[encodedDataLength];
byte k, l, b1, b2, b3;
int encodedIndex = 0;
int dataIndex;
int i;
int nextSeparatorIndex = CHUNK_SIZE;
int chunksSoFar = 0;
// log.debug("number of triplets = " + numberTriplets);
for (i = 0; i < tripletCount; i++) {
dataIndex = i * 3;
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
b3 = binaryData[dataIndex + 2];
// log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
// log.debug( "val2 = " + val2 );
// log.debug( "k4 = " + (k<<4) );
// log.debug( "vak = " + (val2 | (k<<4)) );
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3];
encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
encodedIndex += 4;
// If we are chunking, let's put a chunk separator down.
if (isChunked) {
// this assumes that CHUNK_SIZE % 4 == 0
if (encodedIndex == nextSeparatorIndex) {
System.arraycopy(CHUNK_SEPARATOR, 0, encodedData, encodedIndex, CHUNK_SEPARATOR.length);
chunksSoFar++;
nextSeparatorIndex = (CHUNK_SIZE * (chunksSoFar + 1)) + (chunksSoFar * CHUNK_SEPARATOR.length);
encodedIndex += CHUNK_SEPARATOR.length;
}
}
}
// form integral number of 6-bit groups
dataIndex = i * 3;
if (fewerThan24bits == EIGHTBIT) {
b1 = binaryData[dataIndex];
k = (byte) (b1 & 0x03);
// log.debug("b1=" + b1);
// log.debug("b1<<2 = " + (b1>>2) );
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
encodedData[encodedIndex + 2] = PAD;
encodedData[encodedIndex + 3] = PAD;
} else if (fewerThan24bits == SIXTEENBIT) {
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
encodedData[encodedIndex + 3] = PAD;
}
if (isChunked) {
// we also add a separator to the end of the final chunk.
if (chunksSoFar < chunckCount) {
System.arraycopy(CHUNK_SEPARATOR, 0, encodedData, encodedDataLength - CHUNK_SEPARATOR.length,
CHUNK_SEPARATOR.length);
}
}
return encodedData;
}
/**
* Converts the specified UTF-8 Base64 encoded String and decodes it to a resultant UTF-8 encoded string.
*
* @param base64Encoded a UTF-8 Base64 encoded String
* @return the decoded String, UTF-8 encoded.
*/
public static String decodeToString(String base64Encoded) {
byte[] encodedBytes = CodecSupport.toBytes(base64Encoded);
return decodeToString(encodedBytes);
}
/**
* Decodes the specified Base64 encoded byte array and returns the decoded result as a UTF-8 encoded.
*
* @param base64Encoded a Base64 encoded byte array
* @return the decoded String, UTF-8 encoded.
*/
public static String decodeToString(byte[] base64Encoded) {
byte[] decoded = decode(base64Encoded);
return CodecSupport.toString(decoded);
}
/**
* Converts the specified UTF-8 Base64 encoded String and decodes it to a raw Base64 decoded byte array.
*
* @param base64Encoded a UTF-8 Base64 encoded String
* @return the raw Base64 decoded byte array.
*/
public static byte[] decode(String base64Encoded) {
byte[] bytes = CodecSupport.toBytes(base64Encoded);
return decode(bytes);
}
/**
* Decodes Base64 data into octects
*
* @param base64Data Byte array containing Base64 data
* @return Array containing decoded data.
*/
public static byte[] decode(byte[] base64Data) {
// RFC 2045 requires that we discard ALL non-Base64 characters
base64Data = discardNonBase64(base64Data);
// handle the edge case, so we don't have to worry about it later
if (base64Data.length == 0) {
return new byte[0];
}
int numberQuadruple = base64Data.length / FOURBYTE;
byte decodedData[];
byte b1, b2, b3, b4, marker0, marker1;
// Throw away anything not in base64Data
int encodedIndex = 0;
int dataIndex;
{
// this sizes the output array properly - rlw
int lastData = base64Data.length;
// ignore the '=' padding
while (base64Data[lastData - 1] == PAD) {
if (--lastData == 0) {
return new byte[0];
}
}
decodedData = new byte[lastData - numberQuadruple];
}
for (int i = 0; i < numberQuadruple; i++) {
dataIndex = i * 4;
marker0 = base64Data[dataIndex + 2];
marker1 = base64Data[dataIndex + 3];
b1 = base64Alphabet[base64Data[dataIndex]];
b2 = base64Alphabet[base64Data[dataIndex + 1]];
if (marker0 != PAD && marker1 != PAD) {
// No PAD e.g 3cQl
b3 = base64Alphabet[marker0];
b4 = base64Alphabet[marker1];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
} else if (marker0 == PAD) {
// Two PAD e.g. 3c[Pad][Pad]
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
} else {
// One PAD e.g. 3cQ[Pad]
b3 = base64Alphabet[marker0];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
}
encodedIndex += 3;
}
return decodedData;
}
/**
* 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 aByte : data) {
if (isBase64(aByte)) {
groomedData[bytesCopied++] = aByte;
}
}
byte packedData[] = new byte[bytesCopied];
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
return packedData;
}
}