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A barebones WebSocket client and server implementation written 100% in Java
/*
* Copyright (c) 2010-2020 Nathan Rajlich
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package org.java_websocket.util;
import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.nio.charset.StandardCharsets;
import org.java_websocket.exceptions.InvalidDataException;
import org.java_websocket.framing.CloseFrame;
public class Charsetfunctions {
/**
* Private constructor for real static class
*/
private Charsetfunctions() {
}
private static final CodingErrorAction codingErrorAction = CodingErrorAction.REPORT;
/*
* @return UTF-8 encoding in bytes
*/
public static byte[] utf8Bytes(String s) {
return s.getBytes(StandardCharsets.UTF_8);
}
/*
* @return ASCII encoding in bytes
*/
public static byte[] asciiBytes(String s) {
return s.getBytes(StandardCharsets.US_ASCII);
}
public static String stringAscii(byte[] bytes) {
return stringAscii(bytes, 0, bytes.length);
}
public static String stringAscii(byte[] bytes, int offset, int length) {
return new String(bytes, offset, length, StandardCharsets.US_ASCII);
}
public static String stringUtf8(byte[] bytes) throws InvalidDataException {
return stringUtf8(ByteBuffer.wrap(bytes));
}
public static String stringUtf8(ByteBuffer bytes) throws InvalidDataException {
CharsetDecoder decode = StandardCharsets.UTF_8.newDecoder();
decode.onMalformedInput(codingErrorAction);
decode.onUnmappableCharacter(codingErrorAction);
String s;
try {
bytes.mark();
s = decode.decode(bytes).toString();
bytes.reset();
} catch (CharacterCodingException e) {
throw new InvalidDataException(CloseFrame.NO_UTF8, e);
}
return s;
}
/**
* Implementation of the "Flexible and Economical UTF-8 Decoder" algorithm by Björn Höhrmann
* (http://bjoern.hoehrmann.de/utf-8/decoder/dfa/)
*/
private static final int[] utf8d = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, // 00..1f
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, // 20..3f
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, // 40..5f
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, // 60..7f
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, // 80..9f
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, // a0..bf
8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, // c0..df
0xa, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // e0..ef
0xb, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // f0..ff
0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1,
1, // s1..s2
1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1,
1, // s3..s4
1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1,
1, // s5..s6
1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
// s7..s8
};
/**
* Check if the provided BytebBuffer contains a valid utf8 encoded string.
*
* Using the algorithm "Flexible and Economical UTF-8 Decoder" by Björn Höhrmann
* (http://bjoern.hoehrmann.de/utf-8/decoder/dfa/)
*
* @param data the ByteBuffer
* @param off offset (for performance reasons)
* @return does the ByteBuffer contain a valid utf8 encoded string
*/
public static boolean isValidUTF8(ByteBuffer data, int off) {
int len = data.remaining();
if (len < off) {
return false;
}
int state = 0;
for (int i = off; i < len; ++i) {
state = utf8d[256 + (state << 4) + utf8d[(0xff & data.get(i))]];
if (state == 1) {
return false;
}
}
return true;
}
/**
* Calling isValidUTF8 with offset 0
*
* @param data the ByteBuffer
* @return does the ByteBuffer contain a valid utf8 encoded string
*/
public static boolean isValidUTF8(ByteBuffer data) {
return isValidUTF8(data, 0);
}
}