io.undertow.util

Class FlexBase64.Encoder

java.lang.Object

io.undertow.util.FlexBase64.Encoder

Enclosing class:

FlexBase64

public static final class FlexBase64.Encoder
extends Object

Controls the encoding process.

Method Summary

Modifier and Type	Method and Description
int	complete(byte[] target, int pos) Completes an encoding session by writing out the necessary padding.
void	complete(ByteBuffer target) Completes an encoding session by writing out the necessary padding.
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.
void	encode(ByteBuffer source, ByteBuffer target) Encodes bytes read from source and writes them in base64 format to target.
int	getLastInputPosition() Gets the last position where encoding left off in the last byte array that was used.

Methods inherited from class java.lang.Object

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

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