/*******************************************************************************
* Copyright 2015 See AUTHORS file.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
/*******************************************************************************
* Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
*
* 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
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* 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
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*
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******************************************************************************/
package com.badlogic.gdx.utils;
/** Utf8Decoder converts UTF-8 encoded bytes into characters properly handling buffer boundaries.
*
* This class is stateful and up to 4 calls to {@link #decode(byte)} may be needed before a character is appended to the char
* buffer.
*
* The UTF-8 decoding is done by this class and no additional buffers are created. The UTF-8 code was inspired by
* http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
*
* @author davebaol */
public class Utf8Decoder {
private static final char REPLACEMENT = '\ufffd';
private static final int UTF8_ACCEPT = 0;
private static final int UTF8_REJECT = 12;
// This table maps bytes to character classes to reduce
// the size of the transition table and create bitmasks.
private static final byte[] BYTE_TABLE = {
// @off - disable libgdx formatter
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
// @on - enable libgdx formatter
};
// This is a transition table that maps a combination of a
// state of the automaton and a character class to a state.
private static final byte[] TRANSITION_TABLE = {
// @off - disable libgdx formatter
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
// @on - enable libgdx formatter
};
private int codePoint;
private int state;
private final char[] utf16Char = new char[2];
private char[] charBuffer;
private int charOffset;
public Utf8Decoder () {
this.state = UTF8_ACCEPT;
}
protected void reset () {
state = UTF8_ACCEPT;
}
public int decode (byte[] b, int offset, int length, char[] charBuffer, int charOffset) {
this.charBuffer = charBuffer;
this.charOffset = charOffset;
int end = offset + length;
for (int i = offset; i < end; i++)
decode(b[i]);
return this.charOffset - charOffset;
}
private void decode (byte b) {
if (b > 0 && state == UTF8_ACCEPT) {
charBuffer[charOffset++] = (char)(b & 0xFF);
} else {
int i = b & 0xFF;
int type = BYTE_TABLE[i];
codePoint = state == UTF8_ACCEPT ? (0xFF >> type) & i : (i & 0x3F) | (codePoint << 6);
int next = TRANSITION_TABLE[state + type];
switch (next) {
case UTF8_ACCEPT:
state = next;
if (codePoint < Character.MIN_HIGH_SURROGATE) {
charBuffer[charOffset++] = (char)codePoint;
} else {
// The code below is equivalent to
// for (char c : Character.toChars(codePoint)) charBuffer[charOffset++] = c;
// but does not allocate a char array.
int codePointLength = Character.toChars(codePoint, utf16Char, 0);
charBuffer[charOffset++] = utf16Char[0];
if (codePointLength == 2) charBuffer[charOffset++] = utf16Char[1];
}
break;
case UTF8_REJECT:
codePoint = 0;
state = UTF8_ACCEPT;
charBuffer[charOffset++] = REPLACEMENT;
break;
default:
state = next;
break;
}
}
}
}