Module org.jvnet.mimepull
Package org.jvnet.mimepull

Class BASE64DecoderStream

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    final 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.

    • 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  

      • Fields inherited from class java.io.FilterInputStream

        in

    • 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.

    • 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 to len 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.

      • Methods inherited from class java.io.FilterInputStream

        close, mark, read, reset

      • Methods inherited from class java.io.InputStream

        nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • 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_array
        This character array provides the character to value map based on RFC1521.

      • pem_convert_array

        private static final byte[] pem_convert_array

    • Constructor Detail

      • BASE64DecoderStream

        public BASE64DecoderStream​(java.io.InputStream in)
        Create a BASE64 decoder that decodes the specified input stream. The System property mail.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

      • BASE64DecoderStream

        public BASE64DecoderStream​(java.io.InputStream in,
                           boolean ignoreErrors)
        Create a BASE64 decoder that decodes the specified input stream.
        Parameters:
        in - the input stream
        ignoreErrors - ignore errors in encoded data?

    • Method Detail

      • read

        public int read()
         throws java.io.IOException
        Read the next decoded byte from this input stream. The byte is returned as an int in the range 0 to 255. 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 class java.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

      • read

        public int read​(byte[] buf,
                int off,
                int len)
         throws java.io.IOException
        Reads up to len decoded bytes of data from this input stream into an array of bytes. This method blocks until some input is available.
        Overrides:
        read in class java.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.

      • skip

        public long skip​(long n)
          throws java.io.IOException
        Skips over and discards n bytes of data from this stream.
        Overrides:
        skip in class java.io.FilterInputStream
        Throws:
        java.io.IOException

      • markSupported

        public boolean markSupported()
        Tests if this input stream supports marks. Currently this class does not support marks
        Overrides:
        markSupported in class java.io.FilterInputStream

      • 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 class java.io.FilterInputStream
        Throws:
        java.io.IOException

      • 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 bytes
        pos - position in the buffer to start filling
        len - 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

      • 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

      • recentChars

        private java.lang.String 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.