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  /*
   * 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 com.paypal.base.codec.binary;
 
Provides Base64 encoding and decoding as defined by RFC 2045.

This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein.

The class can be parameterized in the following manner with various constructors:

  • URL-safe mode: Default off.
  • Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
  • Line separator: Default is CRLF ("\r\n")

Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).

This class is not thread-safe. Each thread should use its own instance.

Author(s):
Apache Software Foundation
Version:
$Revision: 1201529 $
Since:
1.0
See also:
RFC 2045
 
 public class Base64 extends BaseNCodec {

    
BASE32 characters are 6 bits in length. They are formed by taking a block of 3 octets to form a 24-bit string, which is converted into 4 BASE64 characters.
 
     private static final int BITS_PER_ENCODED_BYTE = 6;
     private static final int BYTES_PER_UNENCODED_BLOCK = 3;
     private static final int BYTES_PER_ENCODED_BLOCK = 4;

    
Chunk separator per RFC 2045 section 2.1.

N.B. The next major release may break compatibility and make this field private.

See also:
RFC 2045 section 2.1
 
     static final byte[] CHUNK_SEPARATOR = {'\r''\n'};

    
This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet" equivalents as specified in Table 1 of RFC 2045. Thanks to "commons" project in ws.apache.org for this code. http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
 
     private static final byte[] STANDARD_ENCODE_TABLE = {
             'A''B''C''D''E''F''G''H''I''J''K''L''M',
             'N''O''P''Q''R''S''T''U''V''W''X''Y''Z',
             'a''b''c''d''e''f''g''h''i''j''k''l''m',
             'n''o''p''q''r''s''t''u''v''w''x''y''z',
             '0''1''2''3''4''5''6''7''8''9''+''/'
     };

    
This is a copy of the STANDARD_ENCODE_TABLE above, but with + and / changed to - and _ to make the encoded Base64 results more URL-SAFE. This table is only used when the Base64's mode is set to URL-SAFE.
     
     private static final byte[] URL_SAFE_ENCODE_TABLE = {
             'A''B''C''D''E''F''G''H''I''J''K''L''M',
             'N''O''P''Q''R''S''T''U''V''W''X''Y''Z',
             'a''b''c''d''e''f''g''h''i''j''k''l''m',
             'n''o''p''q''r''s''t''u''v''w''x''y''z',
             '0''1''2''3''4''5''6''7''8''9''-''_'
     };

    
This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified in Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64 alphabet but fall within the bounds of the array are translated to -1. Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit). Thanks to "commons" project in ws.apache.org for this code. http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    private static final byte[] DECODE_TABLE = {
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54,
            55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
            5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
            24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
            35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
    };

    
Base64 uses 6-bit fields.

    
Mask used to extract 6 bits, used when encoding
    private static final int MASK_6BITS = 0x3f;
    // The static final fields above are used for the original static byte[] methods on Base64.
    // The private member fields below are used with the new streaming approach, which requires
    // some state be preserved between calls of encode() and decode().

    
Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch between the two modes.
    private final byte[] encodeTable;
    // Only one decode table currently; keep for consistency with Base32 code
    private final byte[] decodeTable = ;

    
Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
    private final byte[] lineSeparator;

    
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. decodeSize = 3 + lineSeparator.length;
    private final int decodeSize;

    
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. encodeSize = 4 + lineSeparator.length;
    private final int encodeSize;

    
Place holder for the bytes we're dealing with for our based logic. Bitwise operations store and extract the encoding or decoding from this variable.
    private int bitWorkArea;

    
Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.

When decoding all variants are supported.

    public Base64() {
        this(0);
    }

    
Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.

When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.

When decoding all variants are supported.

Parameters:
urlSafe if true, URL-safe encoding is used. In most cases this should be set to false.
Since:
1.4
    public Base64(boolean urlSafe) {
        this(urlSafe);
    }

    
Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.

Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

When decoding all variants are supported.

Parameters:
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(int lineLength) {
        this(lineLength);
    }

    
Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

When decoding all variants are supported.

Parameters:
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.
lineSeparator Each line of encoded data will end with this sequence of bytes.
Throws:
java.lang.IllegalArgumentException Thrown when the provided lineSeparator included some base64 characters.
Since:
1.4
    public Base64(int lineLengthbyte[] lineSeparator) {
        this(lineLengthlineSeparatorfalse);
    }

    
Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

When decoding all variants are supported.

Parameters:
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.
lineSeparator Each line of encoded data will end with this sequence of bytes.
urlSafe Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode operations. Decoding seamlessly handles both modes.
Throws:
java.lang.IllegalArgumentException The provided lineSeparator included some base64 characters. That's not going to work!
Since:
1.4
    public Base64(int lineLengthbyte[] lineSeparatorboolean urlSafe) {
                lineLength,
                lineSeparator == null ? 0 : lineSeparator.length);
        // 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)) {
                String sep = StringUtils.newStringUtf8(lineSeparator);
                throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]");
            }            
            if (lineLength > 0){ // null line-sep forces no chunking rather than throwing IAE
                this. =  + lineSeparator.length;
                this. = new byte[lineSeparator.length];
                System.arraycopy(lineSeparator, 0, this., 0, lineSeparator.length);
            } else {
                this. = ;
                this. = null;
            }
        } else {
            this. = ;
            this. = null;
        }
        this. = this. - 1;
        this. = urlSafe ?  : ;
    }

    
Returns our current encode mode. True if we're URL-SAFE, false otherwise.

Returns:
true if we're in URL-SAFE mode, false otherwise.
Since:
1.4
    public boolean isUrlSafe() {
        return this. == ;
    }

    

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, so flush last remaining bytes (if not multiple of 3).

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/

Parameters:
in byte[] array of binary data to base64 encode.
inPos Position to start reading data from.
inAvail Amount of bytes available from input for encoding.
    @Override
    void encode(byte[] inint inPosint inAvail) {
        if () {
            return;
        }
        // inAvail < 0 is how we're informed of EOF in the underlying data we're
        // encoding.
        if (inAvail < 0) {
             = true;
            if (0 ==  &&  == 0) {
                return// no leftovers to process and not using chunking
            }
            ensureBufferSize();
            int savedPos = ;
            switch () { // 0-2
                case 1 : // 8 bits = 6 + 2
                    [++] = [( >> 2) & ]; // top 6 bits
                    [++] = [( << 4) & ]; // remaining 2 
                    // URL-SAFE skips the padding to further reduce size.
                    if ( == ) {
                        [++] = ;
                        [++] = ;
                    }
                    break;
                case 2 : // 16 bits = 6 + 6 + 4
                    [++] = [( >> 10) & ];
                    [++] = [( >> 4) & ];
                    [++] = [( << 2) & ];
                    // URL-SAFE skips the padding to further reduce size.
                    if ( == ) {
                        [++] = ;
                    }
                    break;
            }
             +=  - savedPos// keep track of current line position
            // if currentPos == 0 we are at the start of a line, so don't add CRLF
            if ( > 0 &&  > 0) { 
                System.arraycopy(, 0, .);
                 += .;
            }
        } else {
            for (int i = 0; i < inAvaili++) {
                ensureBufferSize();
                 = (+1) % ;
                int b = in[inPos++];
                if (b < 0) {
                    b += 256;
                }
                 = ( << 8) + b//  BITS_PER_BYTE
                if (0 == ) { // 3 bytes = 24 bits = 4 * 6 bits to extract
                    [++] = [( >> 18) & ];
                    [++] = [( >> 12) & ];
                    [++] = [( >> 6) & ];
                    [++] = [ & ];
                     += ;
                    if ( > 0 &&  <= ) {
                        System.arraycopy(, 0, .);
                         += .;
                         = 0;
                    }
                }
            }
        }
    }

    

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.

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.

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/

Parameters:
in byte[] array of ascii data to base64 decode.
inPos Position to start reading data from.
inAvail Amount of bytes available from input for encoding.
    @Override
    void decode(byte[] inint inPosint inAvail) {
        if () {
            return;
        }
        if (inAvail < 0) {
             = true;
        }
        for (int i = 0; i < inAvaili++) {
            ensureBufferSize();
            byte b = in[inPos++];
            if (b == ) {
                // We're done.
                 = true;
                break;
            } else {
                if (b >= 0 && b < .) {
                    int result = [b];
                    if (result >= 0) {
                         = (+1) % ;
                         = ( << ) + result;
                        if ( == 0) {
                            [++] = (byte) (( >> 16) & );
                            [++] = (byte) (( >> 8) & );
                            [++] = (byte) ( & );
                        }
                    }
                }
            }
        }
        // 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 ( &&  != 0) {
            ensureBufferSize();
            
            // We have some spare bits remaining
            // Output all whole multiples of 8 bits and ignore the rest
            switch () {
           //   case 1: // 6 bits - ignore entirely
           //       break;
                case 2 : // 12 bits = 8 + 4
                     =  >> 4; // dump the extra 4 bits
                    [++] = (byte) (() & );
                    break;
                case 3 : // 18 bits = 8 + 8 + 2
                     =  >> 2; // dump 2 bits
                    [++] = (byte) (( >> 8) & );
                    [++] = (byte) (() & );
                    break;
            }
        }
    }

    
Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.

Deprecated:
1.5 Use isBase64(byte[]), will be removed in 2.0.
Parameters:
arrayOctet byte array to test
Returns:
true 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) {
        return isBase64(arrayOctet);
    }

    
Returns whether or not the octet is in the base 64 alphabet.

Parameters:
octet The value to test
Returns:
true if the value is defined in the the base 64 alphabet, false otherwise.
Since:
1.4
    public static boolean isBase64(byte octet) {
        return octet ==  || (octet >= 0 && octet < . && [octet] != -1);
    }

    
Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.

Parameters:
base64 String to test
Returns:
true if all characters in the String are valid characters in the Base64 alphabet or if the String is empty; false, otherwise
Since:
1.5
    public static boolean isBase64(String base64) {
        return isBase64(StringUtils.getBytesUtf8(base64));
    }
    
    
Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.

Parameters:
arrayOctet byte array to test
Returns:
true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise
Since:
1.5
    
    public static boolean isBase64(byte[] arrayOctet) {
        for (int i = 0; i < arrayOctet.lengthi++) {
            if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
                return false;
            }
        }
        return true;
    }
    
    
Encodes binary data using the base64 algorithm but does not chunk the output.

Parameters:
binaryData binary data to encode
Returns:
byte[] containing Base64 characters in their UTF-8 representation.
    public static byte[] encodeBase64(byte[] binaryData) {
        return encodeBase64(binaryDatafalse);
    }

    
Encodes binary data using the base64 algorithm but does not chunk the output. NOTE: We changed the behaviour of this method from multi-line chunking (commons-codec-1.4) to single-line non-chunking (commons-codec-1.5).

Parameters:
binaryData binary data to encode
Returns:
String containing Base64 characters.
Since:
1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not).
    
    public static String encodeBase64String(byte[] binaryData) {
        return StringUtils.newStringUtf8(encodeBase64(binaryDatafalse));
    }
    
    
Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of + and / characters.

Parameters:
binaryData binary data to encode
Returns:
byte[] containing Base64 characters in their UTF-8 representation.
Since:
1.4
    public static byte[] encodeBase64URLSafe(byte[] binaryData) {
        return encodeBase64(binaryDatafalsetrue);
    }

    
Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of + and / characters.

Parameters:
binaryData binary data to encode
Returns:
String containing Base64 characters
Since:
1.4
    
    public static String encodeBase64URLSafeString(byte[] binaryData) {
        return StringUtils.newStringUtf8(encodeBase64(binaryDatafalsetrue));
    }    

    
Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks

Parameters:
binaryData binary data to encode
Returns:
Base64 characters chunked in 76 character blocks
    public static byte[] encodeBase64Chunked(byte[] binaryData) {
        return encodeBase64(binaryDatatrue);
    }

    
Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.

Parameters:
binaryData Array containing binary data to encode.
isChunked if true this encoder will chunk the base64 output into 76 character blocks
Returns:
Base64-encoded data.
Throws:
java.lang.IllegalArgumentException Thrown when the input array needs an output array bigger than java.lang.Integer.MAX_VALUE
    public static byte[] encodeBase64(byte[] binaryDataboolean isChunked) {
        return encodeBase64(binaryDataisChunkedfalse);
    }

    
Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.

Parameters:
binaryData Array containing binary data to encode.
isChunked if true this encoder will chunk the base64 output into 76 character blocks
urlSafe if true this encoder will emit - and _ instead of the usual + and / characters.
Returns:
Base64-encoded data.
Throws:
java.lang.IllegalArgumentException Thrown when the input array needs an output array bigger than java.lang.Integer.MAX_VALUE
Since:
1.4
    public static byte[] encodeBase64(byte[] binaryDataboolean isChunkedboolean urlSafe) {
        return encodeBase64(binaryDataisChunkedurlSafe.);
    }

    
Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.

Parameters:
binaryData Array containing binary data to encode.
isChunked if true this encoder will chunk the base64 output into 76 character blocks
urlSafe if true this encoder will emit - and _ instead of the usual + and / characters.
maxResultSize The maximum result size to accept.
Returns:
Base64-encoded data.
Throws:
java.lang.IllegalArgumentException Thrown when the input array needs an output array bigger than maxResultSize
Since:
1.4
    public static byte[] encodeBase64(byte[] binaryDataboolean isChunkedboolean urlSafeint maxResultSize) {
        if (binaryData == null || binaryData.length == 0) {
            return binaryData;
        }
        // Create this so can use the super-class method
        // Also ensures that the same roundings are performed by the ctor and the code
        Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, urlSafe);
        long len = b64.getEncodedLength(binaryData);
        if (len > maxResultSize) {
            throw new IllegalArgumentException("Input array too big, the output array would be bigger (" +
                len +
                ") than the specified maximum size of " +
                maxResultSize);
        }
                
        return b64.encode(binaryData);
    }

    
Decodes a Base64 String into octets

Parameters:
base64String String containing Base64 data
Returns:
Array containing decoded data.
Since:
1.4
    public static byte[] decodeBase64(String base64String) {
        return new Base64().decode(base64String);
    }

    
Decodes Base64 data into octets

Parameters:
base64Data Byte array containing Base64 data
Returns:
Array containing decoded data.
    public static byte[] decodeBase64(byte[] base64Data) {
        return new Base64().decode(base64Data);
    }
    // Implementation of the Encoder Interface
    // Implementation of integer encoding used for crypto
    
Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature

Parameters:
pArray a byte array containing base64 character data
Returns:
A BigInteger
Since:
1.4
    public static BigInteger decodeInteger(byte[] pArray) {
        return new BigInteger(1, decodeBase64(pArray));
    }

    
Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature

Parameters:
bigInt a BigInteger
Returns:
A byte array containing base64 character data
Throws:
java.lang.NullPointerException if null is passed in
Since:
1.4
    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 BigInteger without sign bit.

Parameters:
bigInt BigInteger to be converted
Returns:
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(bigBytesstartSrcresizedBytesstartDstlen);
        return resizedBytes;
    }

    
Returns whether or not the octet is in the Base32 alphabet.

Parameters:
octet The value to test
Returns:
true if the value is defined in the the Base32 alphabet false otherwise.
    @Override
    protected boolean isInAlphabet(byte octet) {
        return octet >= 0 && octet < . && [octet] != -1;
    }
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