Package io.undertow.util

Class FlexBase64.Encoder

  • Enclosing class:
    FlexBase64
    public static final class FlexBase64.Encoder
extends Object
    Controls the encoding process.

    • Method Detail

      • encode

        public void encode​(ByteBuffer source,
                   ByteBuffer target)
        Encodes bytes read from source and writes them in base64 format to target. If the source limit is hit, this method will return and save the current state, such that future calls can resume the encoding process. In addition, if the target does not have the capacity to fit an entire quad of bytes, this method will also return and save state for subsequent calls to this method. Once all bytes have been encoded to the target, complete(java.nio.ByteBuffer) should be called to add the necessary padding characters.
        Parameters:
        source - the byte buffer to read from
        target - the byte buffer to write to

      • encode

        public int encode​(byte[] source,
                  int pos,
                  int limit,
                  byte[] target,
                  int opos,
                  int olimit)
        Encodes bytes read from source and writes them in base64 format to target. If the source limit is hit, this method will return and save the current state, such that future calls can resume the encoding process. In addition, if the target does not have the capacity to fit an entire quad of bytes, this method will also return and save state for subsequent calls to this method. Once all bytes have been encoded to the target, complete(byte[], int) should be called to add the necessary padding characters. In order to determine the last read position, the getLastInputPosition() can be used.

        Note that the limit values are not lengths, they are positions similar to Buffer.limit(). To calculate a length simply subtract position from limit.

        
  Encoder encoder = FlexBase64.createEncoder(false);
  byte[] outBuffer = new byte[10];
  // Encode "ell"
  int outPosition = encoder.encode("hello".getBytes("US-ASCII"), 1, 4, outBuffer, 5, 10);
  // Prints "9 : ZWxs"
  System.out.println(outPosition + " : " + new String(outBuffer, 0, 5, outPosition - 5));
        Parameters:
        source - the byte array to read from
        pos - ths position in the byte array to start reading from
        limit - the position in the byte array that is after the end of the source data
        target - the byte array to write base64 bytes to
        opos - the position to start writing to the target array at
        olimit - the position in the target byte array that makes the end of the writable area (exclusive)
        Returns:
        the position in the target array immediately following the last byte written

      • getLastInputPosition

        public int getLastInputPosition()
        Gets the last position where encoding left off in the last byte array that was used. If the target for encoded content does not have the necessary capacity, this method should be used to determine where to start from on subsequent reads.
        Returns:
        the last known read position

      • complete

        public int complete​(byte[] target,
                    int pos)
        Completes an encoding session by writing out the necessary padding. This is essential to complying with the Base64 format. This method will write at most 4 or 2 bytes starting at pos,depending on whether or not wrapping is enabled. 
        
  Encoder encoder = FlexBase64.createEncoder(false);
  byte[] outBuffer = new byte[13];

  // Encodes "ello"
  int outPosition = encoder.encode("hello".getBytes("US-ASCII"), 0, 4, outBuffer, 5, 13);
  outPosition = encoder.complete(outBuffer, outPosition);

  // Prints "13 : aGVsbA=="
  System.out.println(outPosition + " : " + new String(outBuffer, 0, 5, outPosition - 5));
        Parameters:
        target - the byte array to write to
        pos - the position to start writing at
        Returns:
        the position after the last byte written

      • complete

        public void complete​(ByteBuffer target)
        Completes an encoding session by writing out the necessary padding. This is essential to complying with the Base64 format. This method will write at most 4 or 2 bytes, depending on whether or not wrapping is enabled.
        Parameters:
        target - the byte buffer to write to