com.fireflysource.common.string.Utf8Appendable Maven / Gradle / Ivy
package com.fireflysource.common.string;
import com.fireflysource.common.object.TypeUtils;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* Utf8 Appendable abstract base class
*
* This abstract class wraps a standard {@link Appendable} and
* provides methods to append UTF-8 encoded bytes, that are converted into
* characters.
*
* This class is stateful and up to 4 calls to {@link #append(byte)} may be
* needed before state a character is appended to the string buffer.
*
* The UTF-8 decoding is done by this class and no additional buffers or Readers
* are used. The UTF-8 code was inspired by
* http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
*
* License information for Bjoern Hoehrmann's code:
*
* Copyright (c) 2008-2009 Bjoern Hoehrmann <[email protected]>
* 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.
**/
public abstract class Utf8Appendable {
public static final char REPLACEMENT = '\ufffd';
public static final byte[] REPLACEMENT_UTF8 = new byte[]{(byte) 0xEF, (byte) 0xBF, (byte) 0xBD};
private static final int UTF8_ACCEPT = 0;
private static final int UTF8_REJECT = 12;
private static final byte[] BYTE_TABLE =
{
// The first part of the table maps bytes to character classes that
// to reduce the size of the transition table and create bitmasks.
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,
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,
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,
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,
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,
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,
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,
10, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 3, 3, 11, 6, 6, 6, 5, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
};
private static final byte[] TRANS_TABLE =
{
// The second part is a transition table that maps a combination
// of a state of the automaton and a character class to a state.
0, 12, 24, 36, 60, 96, 84, 12, 12, 12, 48, 72, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
12, 0, 12, 12, 12, 12, 12, 0, 12, 0, 12, 12, 12, 24, 12, 12, 12, 12, 12, 24, 12, 24, 12, 12,
12, 12, 12, 12, 12, 12, 12, 24, 12, 12, 12, 12, 12, 24, 12, 12, 12, 12, 12, 12, 12, 24, 12, 12,
12, 12, 12, 12, 12, 12, 12, 36, 12, 36, 12, 12, 12, 36, 12, 12, 12, 12, 12, 36, 12, 36, 12, 12,
12, 36, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12
};
protected final Appendable appendable;
protected int _state = UTF8_ACCEPT;
private int codep;
public Utf8Appendable(Appendable appendable) {
this.appendable = appendable;
}
public abstract int length();
protected void reset() {
_state = UTF8_ACCEPT;
}
private void checkCharAppend() throws IOException {
if (_state != UTF8_ACCEPT) {
appendable.append(REPLACEMENT);
int state = _state;
_state = UTF8_ACCEPT;
throw new NotUtf8Exception("char appended in state " + state);
}
}
public void append(char c) {
try {
checkCharAppend();
appendable.append(c);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public void append(String s) {
try {
checkCharAppend();
appendable.append(s);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public void append(String s, int offset, int length) {
try {
checkCharAppend();
appendable.append(s, offset, offset + length);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public void append(byte b) {
try {
appendByte(b);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public void append(ByteBuffer buf) {
try {
while (buf.remaining() > 0) {
appendByte(buf.get());
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public void append(byte[] b, int offset, int length) {
try {
int end = offset + length;
for (int i = offset; i < end; i++)
appendByte(b[i]);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public boolean append(byte[] b, int offset, int length, int maxChars) {
try {
int end = offset + length;
for (int i = offset; i < end; i++) {
if (length() > maxChars)
return false;
appendByte(b[i]);
}
return true;
} catch (IOException e) {
throw new RuntimeException(e);
}
}
protected void appendByte(byte b) throws IOException {
if (b > 0 && _state == UTF8_ACCEPT) {
appendable.append((char) (b & 0xFF));
} else {
int i = b & 0xFF;
int type = BYTE_TABLE[i];
codep = _state == UTF8_ACCEPT ? (0xFF >> type) & i : (i & 0x3F) | (codep << 6);
int next = TRANS_TABLE[_state + type];
switch (next) {
case UTF8_ACCEPT:
_state = next;
if (codep < Character.MIN_HIGH_SURROGATE) {
appendable.append((char) codep);
} else {
for (char c : Character.toChars(codep))
appendable.append(c);
}
break;
case UTF8_REJECT:
String reason = "byte " + TypeUtils.toHexString(b) + " in state " + (_state / 12);
codep = 0;
_state = UTF8_ACCEPT;
appendable.append(REPLACEMENT);
throw new NotUtf8Exception(reason);
default:
_state = next;
}
}
}
public boolean isUtf8SequenceComplete() {
return _state == UTF8_ACCEPT;
}
protected void checkState() {
if (!isUtf8SequenceComplete()) {
codep = 0;
_state = UTF8_ACCEPT;
try {
appendable.append(REPLACEMENT);
} catch (IOException e) {
throw new RuntimeException(e);
}
throw new NotUtf8Exception("incomplete UTF8 sequence");
}
}
public String toReplacedString() {
if (!isUtf8SequenceComplete()) {
codep = 0;
_state = UTF8_ACCEPT;
try {
appendable.append(REPLACEMENT);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
return appendable.toString();
}
@SuppressWarnings("serial")
public static class NotUtf8Exception extends IllegalArgumentException {
public NotUtf8Exception(String reason) {
super("Not valid UTF8! " + reason);
}
}
}