Package com.sun.mail.util
Class BASE64DecoderStream
- java.lang.Object
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- java.io.InputStream
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- java.io.FilterInputStream
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- com.sun.mail.util.BASE64DecoderStream
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public class BASE64DecoderStream extends java.io.FilterInputStream
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
Fields Modifier and Type Field Description private byte[]
buffer
private int
bufsize
private boolean
ignoreErrors
private int
index
private byte[]
input_buffer
private int
input_len
private int
input_pos
private static char[]
pem_array
This character array provides the character to value map based on RFC1521.private static byte[]
pem_convert_array
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Constructor Summary
Constructors Constructor Description BASE64DecoderStream(java.io.InputStream in)
Create a BASE64 decoder that decodes the specified input stream.BASE64DecoderStream(java.io.InputStream in, boolean ignoreErrors)
Create a BASE64 decoder that decodes the specified input stream.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description int
available()
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
markSupported()
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 java.lang.String
recentChars()
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.
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Field Detail
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buffer
private byte[] buffer
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bufsize
private int bufsize
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index
private int index
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input_buffer
private byte[] input_buffer
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input_pos
private int input_pos
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input_len
private int input_len
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ignoreErrors
private boolean ignoreErrors
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pem_array
private static final char[] pem_array
This character array provides the character to value map based on RFC1521.
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pem_convert_array
private static final byte[] pem_convert_array
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Constructor Detail
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BASE64DecoderStream
public BASE64DecoderStream(java.io.InputStream in)
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
public BASE64DecoderStream(java.io.InputStream in, boolean ignoreErrors)
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 Detail
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read
public int read() throws java.io.IOException
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 classjava.io.FilterInputStream
- Returns:
- next byte of data, or
-1
if the end of the stream is reached. - Throws:
java.io.IOException
- if an I/O error occurs.- See Also:
FilterInputStream.in
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read
public int read(byte[] buf, int off, int len) throws java.io.IOException
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 classjava.io.FilterInputStream
- 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:
java.io.IOException
- if an I/O error occurs.
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skip
public long skip(long n) throws java.io.IOException
Skips over and discards n bytes of data from this stream.- Overrides:
skip
in classjava.io.FilterInputStream
- Throws:
java.io.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 classjava.io.FilterInputStream
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available
public int available() throws java.io.IOException
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 classjava.io.FilterInputStream
- Throws:
java.io.IOException
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decode
private int decode(byte[] outbuf, int pos, int len) throws java.io.IOException
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:
java.io.IOException
- if the data is incorrectly formatted
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getByte
private int getByte() throws java.io.IOException
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:
java.io.IOException
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recentChars
private java.lang.String recentChars()
Return the most recent characters, for use in an error message.
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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.- Parameters:
inbuf
- the byte array- Returns:
- the decoded byte array
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