Class Base32
- java.lang.Object
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- org.apache.commons.codec.binary.BaseNCodec
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- org.apache.commons.codec.binary.Base32
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- All Implemented Interfaces:
BinaryDecoder
,BinaryEncoder
,Decoder
,Encoder
public class Base32 extends BaseNCodec
Provides Base32 encoding and decoding as defined by RFC 4648.The class can be parameterized in the following manner with various constructors:
- Whether to use the "base32hex" variant instead of the default "base32"
- Line length: Default 76. Line length that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.
- Line separator: Default is CRLF ("\r\n")
This class operates directly on byte streams, and not character streams.
This class is thread-safe.
- Since:
- 1.5
- See Also:
- RFC 4648
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.commons.codec.binary.BaseNCodec
BaseNCodec.Context
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Field Summary
Fields Modifier and Type Field Description private static int
BITS_PER_ENCODED_BYTE
BASE32 characters are 5 bits in length.private static int
BYTES_PER_ENCODED_BLOCK
private static int
BYTES_PER_UNENCODED_BLOCK
private static byte[]
DECODE_TABLE
This array is a lookup table that translates Unicode characters drawn from the "Base32 Alphabet" (as specified in Table 3 of RFC 4648) into their 5-bit positive integer equivalents.private int
decodeSize
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.private byte[]
decodeTable
Decode table to use.private static byte[]
ENCODE_TABLE
This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet" equivalents as specified in Table 3 of RFC 4648.private int
encodeSize
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.private byte[]
encodeTable
Encode table to use.private static byte[]
HEX_DECODE_TABLE
This array is a lookup table that translates Unicode characters drawn from the "Base32 Hex Alphabet" (as specified in Table 4 of RFC 4648) into their 5-bit positive integer equivalents.private static byte[]
HEX_ENCODE_TABLE
This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Hex Alphabet" equivalents as specified in Table 4 of RFC 4648.private byte[]
lineSeparator
Line separator for encoding.private static long
MASK_1BITS
Mask used to extract 1 bits, used when decoding final trailing character.private static long
MASK_2BITS
Mask used to extract 2 bits, used when decoding final trailing character.private static long
MASK_3BITS
Mask used to extract 3 bits, used when decoding final trailing character.private static long
MASK_4BITS
Mask used to extract 4 bits, used when decoding final trailing character.private static int
MASK_5BITS
Mask used to extract 5 bits, used when encoding Base32 bytes-
Fields inherited from class org.apache.commons.codec.binary.BaseNCodec
CHUNK_SEPARATOR, DECODING_POLICY_DEFAULT, EOF, lineLength, MASK_8BITS, MIME_CHUNK_SIZE, pad, PAD, PAD_DEFAULT, PEM_CHUNK_SIZE
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Constructor Summary
Constructors Constructor Description Base32()
Creates a Base32 codec used for decoding and encoding.Base32(boolean useHex)
Creates a Base32 codec used for decoding and encoding.Base32(boolean useHex, byte padding)
Creates a Base32 codec used for decoding and encoding.Base32(byte pad)
Creates a Base32 codec used for decoding and encoding.Base32(int lineLength)
Creates a Base32 codec used for decoding and encoding.Base32(int lineLength, byte[] lineSeparator)
Creates a Base32 codec used for decoding and encoding.Base32(int lineLength, byte[] lineSeparator, boolean useHex)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.Base32(int lineLength, byte[] lineSeparator, boolean useHex, byte padding)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.Base32(int lineLength, byte[] lineSeparator, boolean useHex, byte padding, CodecPolicy decodingPolicy)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description (package private) void
decode(byte[] input, int inPos, int inAvail, BaseNCodec.Context context)
Decodes all of the provided data, starting at inPos, for inAvail bytes.(package private) void
encode(byte[] input, int inPos, int inAvail, BaseNCodec.Context context)
Encodes all of the provided data, starting at inPos, for inAvail bytes.boolean
isInAlphabet(byte octet)
Returns whether or not theoctet
is in the Base32 alphabet.private void
validateCharacter(long emptyBitsMask, BaseNCodec.Context context)
Validates whether decoding the final trailing character is possible in the context of the set of possible base 32 values.private void
validateTrailingCharacters()
Validates whether decoding allows final trailing characters that cannot be created during encoding.-
Methods inherited from class org.apache.commons.codec.binary.BaseNCodec
available, containsAlphabetOrPad, decode, decode, decode, encode, encode, encode, encodeAsString, encodeToString, ensureBufferSize, getChunkSeparator, getCodecPolicy, getDefaultBufferSize, getEncodedLength, hasData, isInAlphabet, isInAlphabet, isStrictDecoding, isWhiteSpace, readResults
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Field Detail
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BITS_PER_ENCODED_BYTE
private static final int BITS_PER_ENCODED_BYTE
BASE32 characters are 5 bits in length. They are formed by taking a block of five octets to form a 40-bit string, which is converted into eight BASE32 characters.- See Also:
- Constant Field Values
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BYTES_PER_ENCODED_BLOCK
private static final int BYTES_PER_ENCODED_BLOCK
- See Also:
- Constant Field Values
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BYTES_PER_UNENCODED_BLOCK
private static final int BYTES_PER_UNENCODED_BLOCK
- See Also:
- Constant Field Values
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DECODE_TABLE
private static final byte[] DECODE_TABLE
This array is a lookup table that translates Unicode characters drawn from the "Base32 Alphabet" (as specified in Table 3 of RFC 4648) into their 5-bit positive integer equivalents. Characters that are not in the Base32 alphabet but fall within the bounds of the array are translated to -1.
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ENCODE_TABLE
private static final byte[] ENCODE_TABLE
This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet" equivalents as specified in Table 3 of RFC 4648.
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HEX_DECODE_TABLE
private static final byte[] HEX_DECODE_TABLE
This array is a lookup table that translates Unicode characters drawn from the "Base32 Hex Alphabet" (as specified in Table 4 of RFC 4648) into their 5-bit positive integer equivalents. Characters that are not in the Base32 Hex alphabet but fall within the bounds of the array are translated to -1.
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HEX_ENCODE_TABLE
private static final byte[] HEX_ENCODE_TABLE
This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Hex Alphabet" equivalents as specified in Table 4 of RFC 4648.
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MASK_5BITS
private static final int MASK_5BITS
Mask used to extract 5 bits, used when encoding Base32 bytes- See Also:
- Constant Field Values
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MASK_4BITS
private static final long MASK_4BITS
Mask used to extract 4 bits, used when decoding final trailing character.- See Also:
- Constant Field Values
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MASK_3BITS
private static final long MASK_3BITS
Mask used to extract 3 bits, used when decoding final trailing character.- See Also:
- Constant Field Values
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MASK_2BITS
private static final long MASK_2BITS
Mask used to extract 2 bits, used when decoding final trailing character.- See Also:
- Constant Field Values
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MASK_1BITS
private static final long MASK_1BITS
Mask used to extract 1 bits, used when decoding final trailing character.- See Also:
- Constant Field Values
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decodeSize
private final int decodeSize
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.decodeSize = {@link #BYTES_PER_ENCODED_BLOCK} - 1 + lineSeparator.length;
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decodeTable
private final byte[] decodeTable
Decode table to use.
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encodeSize
private final int encodeSize
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.encodeSize = {@link #BYTES_PER_ENCODED_BLOCK} + lineSeparator.length;
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encodeTable
private final byte[] encodeTable
Encode table to use.
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lineSeparator
private final byte[] lineSeparator
Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
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Constructor Detail
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Base32
public Base32()
Creates a Base32 codec used for decoding and encoding.When encoding the line length is 0 (no chunking).
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Base32
public Base32(boolean useHex)
Creates a Base32 codec used for decoding and encoding.When encoding the line length is 0 (no chunking).
- Parameters:
useHex
- iftrue
then use Base32 Hex alphabet
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Base32
public Base32(boolean useHex, byte padding)
Creates a Base32 codec used for decoding and encoding.When encoding the line length is 0 (no chunking).
- Parameters:
useHex
- iftrue
then use Base32 Hex alphabetpadding
- byte used as padding byte.
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Base32
public Base32(byte pad)
Creates a Base32 codec used for decoding and encoding.When encoding the line length is 0 (no chunking).
- Parameters:
pad
- byte used as padding byte.
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Base32
public Base32(int lineLength)
Creates a Base32 codec used for decoding and encoding.When encoding the line length is given in the constructor, the line separator is CRLF.
- Parameters:
lineLength
- Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
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Base32
public Base32(int lineLength, byte[] lineSeparator)
Creates a Base32 codec used for decoding and encoding.When encoding the line length and line separator are given in the constructor.
Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.
- Parameters:
lineLength
- Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). 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 thelineSeparator
contains Base32 characters.
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Base32
public Base32(int lineLength, byte[] lineSeparator, boolean useHex)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.When encoding the line length and line separator are given in the constructor.
Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.
- Parameters:
lineLength
- Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). 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.useHex
- iftrue
, then use Base32 Hex alphabet, otherwise use Base32 alphabet- Throws:
java.lang.IllegalArgumentException
- Thrown when thelineSeparator
contains Base32 characters. Or the lineLength > 0 and lineSeparator is null.
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Base32
public Base32(int lineLength, byte[] lineSeparator, boolean useHex, byte padding)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.When encoding the line length and line separator are given in the constructor.
Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.
- Parameters:
lineLength
- Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). 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.useHex
- iftrue
, then use Base32 Hex alphabet, otherwise use Base32 alphabetpadding
- byte used as padding byte.- Throws:
java.lang.IllegalArgumentException
- Thrown when thelineSeparator
contains Base32 characters. Or the lineLength > 0 and lineSeparator is null.
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Base32
public Base32(int lineLength, byte[] lineSeparator, boolean useHex, byte padding, CodecPolicy decodingPolicy)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.When encoding the line length and line separator are given in the constructor.
Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.
- Parameters:
lineLength
- Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). 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.useHex
- iftrue
, then use Base32 Hex alphabet, otherwise use Base32 alphabetpadding
- byte used as padding byte.decodingPolicy
- The decoding policy.- Throws:
java.lang.IllegalArgumentException
- Thrown when thelineSeparator
contains Base32 characters. Or the lineLength > 0 and lineSeparator is null.- Since:
- 1.15
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Method Detail
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decode
void decode(byte[] input, int inPos, int inAvail, BaseNCodec.Context context)
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-Base32 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.
Output is written to
Context#buffer
as 8-bit octets, usingContext#pos
as the buffer position- Specified by:
decode
in classBaseNCodec
- Parameters:
input
- byte[] array of ascii data to Base32 decode.inPos
- Position to start reading data from.inAvail
- Amount of bytes available from input for decoding.context
- the context to be used
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encode
void encode(byte[] input, int inPos, int inAvail, BaseNCodec.Context context)
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 5).
- Specified by:
encode
in classBaseNCodec
- Parameters:
input
- byte[] array of binary data to Base32 encode.inPos
- Position to start reading data from.inAvail
- Amount of bytes available from input for encoding.context
- the context to be used
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isInAlphabet
public boolean isInAlphabet(byte octet)
Returns whether or not theoctet
is in the Base32 alphabet.- Specified by:
isInAlphabet
in classBaseNCodec
- Parameters:
octet
- The value to test- Returns:
true
if the value is defined in the the Base32 alphabetfalse
otherwise.
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validateCharacter
private void validateCharacter(long emptyBitsMask, BaseNCodec.Context context)
Validates whether decoding the final trailing character is possible in the context of the set of possible base 32 values.The character is valid if the lower bits within the provided mask are zero. This is used to test the final trailing base-32 digit is zero in the bits that will be discarded.
- Parameters:
emptyBitsMask
- The mask of the lower bits that should be emptycontext
- the context to be used- Throws:
java.lang.IllegalArgumentException
- if the bits being checked contain any non-zero value
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validateTrailingCharacters
private void validateTrailingCharacters()
Validates whether decoding allows final trailing characters that cannot be created during encoding.- Throws:
java.lang.IllegalArgumentException
- if strict decoding is enabled
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