java.lang.Object
java.io.InputStream
java.io.FilterInputStream
org.jvnet.mimepull.BASE64DecoderStream
- All Implemented Interfaces:
Closeable
,AutoCloseable
This class implements a BASE64 Decoder. It is implemented as
a FilterInputStream, so one can just wrap this class around
any input stream and read bytes from this filter. The decoding
is done as the bytes are read out.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate byte[]
private int
private boolean
private int
private byte[]
private int
private int
private static final char[]
This character array provides the character to value map based on RFC1521.private static final byte[]
Fields inherited from class java.io.FilterInputStream
in
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Constructor Summary
ConstructorsConstructorDescriptionCreate a BASE64 decoder that decodes the specified input stream.BASE64DecoderStream
(InputStream in, boolean ignoreErrors) Create a BASE64 decoder that decodes the specified input stream. -
Method Summary
Modifier and TypeMethodDescriptionint
Returns the number of bytes that can be read from this input stream without blocking.static byte[]
decode
(byte[] inbuf) Base64 decode a byte array.private int
decode
(byte[] outbuf, int pos, int len) The decoder algorithm.private int
getByte()
Read the next valid byte from the input stream.boolean
Tests if this input stream supports marks.int
read()
Read the next decoded byte from this input stream.int
read
(byte[] buf, int off, int len) Reads up tolen
decoded bytes of data from this input stream into an array of bytes.private String
Return the most recent characters, for use in an error message.long
skip
(long n) Skips over and discards n bytes of data from this stream.Methods inherited from class java.io.FilterInputStream
close, mark, read, reset
Methods inherited from class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
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Field Details
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buffer
private byte[] buffer -
bufsize
private int bufsize -
index
private int index -
input_buffer
private byte[] input_buffer -
input_pos
private int input_pos -
input_len
private int input_len -
ignoreErrors
private boolean ignoreErrors -
pem_array
private static final char[] pem_arrayThis character array provides the character to value map based on RFC1521. -
pem_convert_array
private static final byte[] pem_convert_array
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Constructor Details
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BASE64DecoderStream
Create a BASE64 decoder that decodes the specified input stream. The System propertymail.mime.base64.ignoreerrors
controls whether errors in the encoded data cause an exception or are ignored. The default is false (errors cause exception).- Parameters:
in
- the input stream
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BASE64DecoderStream
Create a BASE64 decoder that decodes the specified input stream.- Parameters:
in
- the input streamignoreErrors
- ignore errors in encoded data?
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Method Details
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read
Read the next decoded byte from this input stream. The byte is returned as anint
in the range0
to255
. If no byte is available because the end of the stream has been reached, the value-1
is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.- Overrides:
read
in classFilterInputStream
- Returns:
- next byte of data, or
-1
if the end of the stream is reached. - Throws:
IOException
- if an I/O error occurs.- See Also:
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read
Reads up tolen
decoded bytes of data from this input stream into an array of bytes. This method blocks until some input is available.- Overrides:
read
in classFilterInputStream
- Parameters:
buf
- the buffer into which the data is read.off
- the start offset of the data.len
- the maximum number of bytes read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the stream has been reached. - Throws:
IOException
- if an I/O error occurs.
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skip
Skips over and discards n bytes of data from this stream.- Overrides:
skip
in classFilterInputStream
- Throws:
IOException
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markSupported
public boolean markSupported()Tests if this input stream supports marks. Currently this class does not support marks- Overrides:
markSupported
in classFilterInputStream
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available
Returns the number of bytes that can be read from this input stream without blocking. However, this figure is only a close approximation in case the original encoded stream contains embedded CRLFs; since the CRLFs are discarded, not decoded- Overrides:
available
in classFilterInputStream
- Throws:
IOException
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decode
The decoder algorithm. Most of the complexity here is dealing with error cases. Returns the number of bytes decoded, which may be zero. Decoding is done by filling an int with 4 6-bit values by shifting them in from the bottom and then extracting 3 8-bit bytes from the int by shifting them out from the bottom.- Parameters:
outbuf
- the buffer into which to put the decoded bytespos
- position in the buffer to start fillinglen
- the number of bytes to fill- Returns:
- the number of bytes filled, always a multiple of three, and may be zero
- Throws:
IOException
- if the data is incorrectly formatted
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getByte
Read the next valid byte from the input stream. Buffer lots of data from underlying stream in input_buffer, for efficiency.- Returns:
- the next byte, -1 on EOF, or -2 if next byte is '=' (padding at end of encoded data)
- Throws:
IOException
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recentChars
Return the most recent characters, for use in an error message. -
decode
public static byte[] decode(byte[] inbuf) Base64 decode a byte array. No line breaks are allowed. This method is suitable for short strings, such as those in the IMAP AUTHENTICATE protocol, but not to decode the entire content of a MIME part. NOTE: inbuf may only contain valid base64 characters. Whitespace is not ignored.
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