io.crossbar.autobahn.websocket.utils

Class Utf8Validator

java.lang.Object

io.crossbar.autobahn.websocket.utils.Utf8Validator

public class Utf8Validator
extends java.lang.Object

Incremental UTF-8 validator. The validator runs with constant memory consumption (minimal state). Purpose is to validate UTF-8, not to decode (which could be done easily also, but we rely on Java built in facilities for that).

Implements the algorithm "Flexible and Economical UTF-8 Decoder" by Bjoern Hoehrmann (http://bjoern.hoehrmann.de/utf-8/decoder/dfa/).

Constructor Summary

Constructors

Constructor and Description
Utf8Validator() Create new incremental UTF-8 validator.

Method Summary

Modifier and Type	Method and Description
boolean	isValid() Check if incremental validation (currently) has ended on a complete encoded Unicode codepoint.
int	position() Get end of validated position within stream.
void	reset() Reset validator state to begin validation of new UTF-8 stream.
boolean	validate(byte[] data) Validate a chunk of octets for UTF-8.
boolean	validate(byte[] data, int off, int len) Validate a chunk of octets for UTF-8.

Methods inherited from class java.lang.Object

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

Constructor Detail

Utf8Validator

public Utf8Validator()

Create new incremental UTF-8 validator. The validator is already resetted and thus immediately usable.

Method Detail

reset

public void reset()

Reset validator state to begin validation of new UTF-8 stream.

position

public int position()

Get end of validated position within stream. When validate() returns false, indicating an UTF-8 error, this function can be used to get the exact position within the stream upon which the violation was encountered.

Returns:

Current position with stream validated.

isValid

public boolean isValid()

Check if incremental validation (currently) has ended on a complete encoded Unicode codepoint.

Returns:

True, iff currently ended on codepoint.

validate

public boolean validate(byte[] data,
                        int off,
                        int len)

Validate a chunk of octets for UTF-8.

Parameters:

data - Buffer which contains chunk to validate.

off - Offset within buffer where to continue with validation.

len - Length in octets to validate within buffer.

Returns:

False as soon as UTF-8 violation occurs, true otherwise.

validate

public boolean validate(byte[] data)

Validate a chunk of octets for UTF-8.

Parameters:

data - Buffer which contains chunk to validate.

Returns:

False as soon as UTF-8 violation occurs, true otherwise.