Class Base64Util.Base64
- Enclosing class:
- Base64Util
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final byte[]
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.private byte[]
Buffer for streaming.(package private) static final byte[]
Chunk separator per RFC 2045 section 2.1.(package private) static final int
Chunk size per RFC 2045 section 6.8.private int
Variable tracks how many characters have been written to the current line.private final int
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.private final int
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.private boolean
Boolean flag to indicate the EOF has been reached.private static final byte[]
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.private final int
Line length for encoding.private final byte[]
Line separator for encoding.private static final int
Mask used to extract 6 bits, used when encodingprivate static final int
Mask used to extract 8 bits, used in decoding base64 bytesprivate int
Writes to the buffer only occur after every 3 reads when encoding, an every 4 reads when decoding.private static final byte
Byte used to pad output.private int
Position where next character should be written in the buffer.private int
Position where next character should be read from the buffer.private int
Place holder for the 3 bytes we're dealing with for our base64 logic. -
Constructor Summary
ConstructorsConstructorDescriptionBase64()
Default constructor: lineLength is 76, and the lineSeparator is CRLF when encoding, and all forms can be decoded.Base64
(int lineLength) Consumer can use this constructor to choose a different lineLength when encoding (lineSeparator is still CRLF).Base64
(int lineLength, byte[] lineSeparator) Consumer can use this constructor to choose a different lineLength and lineSeparator when encoding. -
Method Summary
Modifier and TypeMethodDescription(package private) int
avail()
Returns the amount of buffered data available for reading.private static boolean
containsBase64Byte
(byte[] arrayOctet) byte[]
decode
(byte[] pArray) Decodes a byte[] containing containing characters in the Base64 alphabet.(package private) void
decode
(byte[] in, int inPos, int inAvail) Decodes all of the provided data, starting at inPos, for inAvail bytes.Decodes an Object using the base64 algorithm.static byte[]
decodeBase64
(byte[] base64Data) Decodes Base64 data into octetsstatic BigInteger
decodeInteger
(byte[] pArray) Decode a byte64-encoded integer according to crypto standards such as W3C's XML-Signature(package private) static byte[]
discardNonBase64
(byte[] data) 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."(package private) static byte[]
discardWhitespace
(byte[] data) Deprecated.This method is no longer neededbyte[]
encode
(byte[] pArray) Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.(package private) void
encode
(byte[] in, int inPos, int inAvail) Encodes all of the provided data, starting at inPos, for inAvail bytes.Encodes an Object using the base64 algorithm.static byte[]
encodeBase64
(byte[] binaryData) Encodes binary data using the base64 algorithm but does not chunk the output.static byte[]
encodeBase64
(byte[] binaryData, boolean isChunked) Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.static byte[]
encodeBase64Chunked
(byte[] binaryData) Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocksstatic byte[]
encodeInteger
(BigInteger bigInt) Encode to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature(package private) boolean
hasData()
Returns true if this Base64 object has buffered data for reading.static boolean
isArrayByteBase64
(byte[] arrayOctet) Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.static boolean
isBase64
(byte octet) Returns whether or not theoctet
is in the base 64 alphabet.private static boolean
isWhiteSpace
(byte byteToCheck) Check if a byte value is whitespace or not.(package private) int
readResults
(byte[] b, int bPos, int bAvail) Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail bytes.private void
Doubles our buffer.(package private) void
setInitialBuffer
(byte[] out, int outPos, int outAvail) Small optimization where we try to buffer directly to the consumer's output array for one round (if consumer calls this method first!) instead of starting our own buffer.(package private) static byte[]
toIntegerBytes
(BigInteger bigInt) Returns a byte-array representation of aBigInteger
without sign bit.
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Field Details
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CHUNK_SIZE
static final int CHUNK_SIZEChunk size per RFC 2045 section 6.8.The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
- See Also:
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CHUNK_SEPARATOR
static final byte[] CHUNK_SEPARATORChunk separator per RFC 2045 section 2.1.- See Also:
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intToBase64
private static final byte[] intToBase64This 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/ -
PAD
private static final byte PADByte used to pad output.- See Also:
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base64ToInt
private static final byte[] base64ToIntThis 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. Thanks to "commons" project in ws.apache.org for this code. http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ -
MASK_6BITS
private static final int MASK_6BITSMask used to extract 6 bits, used when encoding- See Also:
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MASK_8BITS
private static final int MASK_8BITSMask used to extract 8 bits, used in decoding base64 bytes- See Also:
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lineLength
private final int lineLengthLine length for encoding. Not used when decoding. A value of zero or less implies no chunking of the base64 encoded data. -
lineSeparator
private final byte[] lineSeparatorLine separator for encoding. Not used when decoding. Only used if lineLength > 0. -
decodeSize
private final int decodeSizeConvenience variable to help us determine when our buffer is going to run out of room and needs resizing.decodeSize = 3 + lineSeparator.length;
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encodeSize
private final int encodeSizeConvenience variable to help us determine when our buffer is going to run out of room and needs resizing.encodeSize = 4 + lineSeparator.length;
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buf
private byte[] bufBuffer for streaming. -
pos
private int posPosition where next character should be written in the buffer. -
readPos
private int readPosPosition where next character should be read from the buffer. -
currentLinePos
private int currentLinePosVariable tracks how many characters have been written to the current line. Only used when encoding. We use it to make sure each encoded line never goes beyond lineLength (if lineLength > 0). -
modulus
private int modulusWrites to the buffer only occur after every 3 reads when encoding, an every 4 reads when decoding. This variable helps track that. -
eof
private boolean eofBoolean flag to indicate the EOF has been reached. Once EOF has been reached, this Base64 object becomes useless, and must be thrown away. -
x
private int xPlace holder for the 3 bytes we're dealing with for our base64 logic. Bitwise operations store and extract the base64 encoding or decoding from this variable.
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Constructor Details
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Base64
public Base64()Default constructor: lineLength is 76, and the lineSeparator is CRLF when encoding, and all forms can be decoded. -
Base64
public Base64(int lineLength) Consumer can use this constructor to choose a different lineLength when encoding (lineSeparator is still CRLF). All forms of data can be decoded.
Note: lineLengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
- Parameters:
lineLength
- each line of encoded data will be at most this long (rounded up to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
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Base64
public Base64(int lineLength, byte[] lineSeparator) Consumer can use this constructor to choose a different lineLength and lineSeparator when encoding. All forms of data can be decoded.
Note: lineLengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
- Parameters:
lineLength
- Each line of encoded data will be at most this long (rounded up to nearest multiple of 4). Ignored when decoding. If <= 0, then output will not be divided into lines (chunks).lineSeparator
- Each line of encoded data will end with this sequence of bytes. If lineLength <= 0, then the lineSeparator is not used.- Throws:
IllegalArgumentException
- The provided lineSeparator included some base64 characters. That's not going to work!
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Method Details
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hasData
boolean hasData()Returns true if this Base64 object has buffered data for reading.- Returns:
- true if there is Base64 object still available for reading.
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avail
int avail()Returns the amount of buffered data available for reading.- Returns:
- The amount of buffered data available for reading.
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resizeBuf
private void resizeBuf()Doubles our buffer. -
readResults
int readResults(byte[] b, int bPos, int bAvail) Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail bytes. Returns how many bytes were actually extracted.- Parameters:
b
- byte[] array to extract the buffered data into.bPos
- position in byte[] array to start extraction at.bAvail
- amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).- Returns:
- The number of bytes successfully extracted into the provided byte[] array.
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setInitialBuffer
void setInitialBuffer(byte[] out, int outPos, int outAvail) Small optimization where we try to buffer directly to the consumer's output array for one round (if consumer calls this method first!) instead of starting our own buffer.- Parameters:
out
- byte[] array to buffer directly to.outPos
- Position to start buffering into.outAvail
- Amount of bytes available for direct buffering.
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encode
void encode(byte[] in, int inPos, int inAvail) 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.
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decode
void decode(byte[] in, int inPos, int inAvail) 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.
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isBase64
public static boolean isBase64(byte octet) Returns whether or not theoctet
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.
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isArrayByteBase64
public static boolean isArrayByteBase64(byte[] arrayOctet) 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
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containsBase64Byte
private static boolean containsBase64Byte(byte[] arrayOctet) -
encodeBase64
public static byte[] encodeBase64(byte[] binaryData) Encodes binary data using the base64 algorithm but does not chunk the output.- Parameters:
binaryData
- binary data to encode- Returns:
- Base64 characters
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encodeBase64Chunked
public static byte[] encodeBase64Chunked(byte[] binaryData) 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
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decode
Decodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[].- Parameters:
pObject
- Object to decode- Returns:
- An object (of type byte[]) containing the binary data which corresponds to the byte[] supplied.
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decode
public byte[] decode(byte[] pArray) Decodes a byte[] containing containing characters in the Base64 alphabet.- Parameters:
pArray
- A byte array containing Base64 character data- Returns:
- a byte array containing binary data
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encodeBase64
public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.- Parameters:
binaryData
- Array containing binary data to encode.isChunked
- iftrue
this encoder will chunk the base64 output into 76 character blocks- Returns:
- Base64-encoded data.
- Throws:
IllegalArgumentException
- Thrown when the input array needs an output array bigger thanInteger.MAX_VALUE
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decodeBase64
public static byte[] decodeBase64(byte[] base64Data) Decodes Base64 data into octets- Parameters:
base64Data
- Byte array containing Base64 data- Returns:
- Array containing decoded data.
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discardWhitespace
static byte[] discardWhitespace(byte[] data) Deprecated.This method is no longer neededDiscards any whitespace from a base-64 encoded block.- Parameters:
data
- The base-64 encoded data to discard the whitespace from.- Returns:
- The data, less whitespace (see RFC 2045).
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isWhiteSpace
private static boolean isWhiteSpace(byte byteToCheck) Check if a byte value is whitespace or not.- Parameters:
byteToCheck
- the byte to check- Returns:
- true if byte is whitespace, false otherwise
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discardNonBase64
static byte[] discardNonBase64(byte[] data) 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."- Parameters:
data
- The base-64 encoded data to groom- Returns:
- The data, less non-base64 characters (see RFC 2045).
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encode
Encodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].- Parameters:
pObject
- Object to encode- Returns:
- An object (of type byte[]) containing the base64 encoded data which corresponds to the byte[] supplied.
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encode
public byte[] encode(byte[] pArray) Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.- Parameters:
pArray
- a byte array containing binary data- Returns:
- A byte array containing only Base64 character data
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decodeInteger
Decode 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
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encodeInteger
Encode 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:
NullPointerException
- if null is passed in
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toIntegerBytes
Returns a byte-array representation of aBigInteger
without sign bit.- Parameters:
bigInt
-BigInteger
to be converted- Returns:
- a byte array representation of the BigInteger parameter
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