Source code

001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.directory.shared.util;
021
022
023/**
024 * Various Character methods are kept here.
025 *
026 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
027 */
028public final class Chars
029{
030    /** &lt;alpha> ::= [0x41-0x5A] | [0x61-0x7A] */
031    public static final boolean[] ALPHA =
032        {
033            false, false, false, false, false, false, false, false,
034            false, false, false, false, false, false, false, false,
035            false, false, false, false, false, false, false, false,
036            false, false, false, false, false, false, false, false,
037            false, false, false, false, false, false, false, false,
038            false, false, false, false, false, false, false, false,
039            false, false, false, false, false, false, false, false,
040            false, false, false, false, false, false, false, false,
041            false, true,  true,  true,  true,  true,  true,  true,
042            true,  true,  true,  true,  true,  true,  true,  true,
043            true,  true,  true,  true,  true,  true,  true,  true,
044            true,  true,  true,  false, false, false, false, false,
045            false, true,  true,  true,  true,  true,  true,  true,
046            true,  true,  true,  true,  true,  true,  true,  true,
047            true,  true,  true,  true,  true,  true,  true,  true,
048            true,  true,  true,  false, false, false, false, false
049        };
050    /** &lt;alpha-lower-case> ::= [0x61-0x7A] */
051    public static final boolean[] ALPHA_LOWER_CASE =
052        {
053            false, false, false, false, false, false, false, false,
054            false, false, false, false, false, false, false, false,
055            false, false, false, false, false, false, false, false,
056            false, false, false, false, false, false, false, false,
057            false, false, false, false, false, false, false, false,
058            false, false, false, false, false, false, false, false,
059            false, false, false, false, false, false, false, false,
060            false, false, false, false, false, false, false, false,
061            false, false, false, false, false, false, false, false,
062            false, false, false, false, false, false, false, false,
063            false, false, false, false, false, false, false, false,
064            false, false, false, false, false, false, false, false,
065            false, true,  true,  true,  true,  true,  true,  true,
066            true,  true,  true,  true,  true,  true,  true,  true,
067            true,  true,  true,  true,  true,  true,  true,  true,
068            true,  true,  true,  false, false, false, false, false
069        };
070    /** &lt;alpha-upper-case> ::= [0x41-0x5A] */
071    public static final boolean[] ALPHA_UPPER_CASE =
072        {
073            false, false, false, false, false, false, false, false,
074            false, false, false, false, false, false, false, false,
075            false, false, false, false, false, false, false, false,
076            false, false, false, false, false, false, false, false,
077            false, false, false, false, false, false, false, false,
078            false, false, false, false, false, false, false, false,
079            false, false, false, false, false, false, false, false,
080            false, false, false, false, false, false, false, false,
081            false, true,  true,  true,  true,  true,  true,  true,
082            true,  true,  true,  true,  true,  true,  true,  true,
083            true,  true,  true,  true,  true,  true,  true,  true,
084            true,  true,  true,  false, false, false, false, false,
085            false, false, false, false, false, false, false, false,
086            false, false, false, false, false, false, false, false,
087            false, false, false, false, false, false, false, false,
088            false, false, false, false, false, false, false, false,
089        };
090    /** &lt;alpha-digit> | &lt;digit> */
091    public static final boolean[] ALPHA_DIGIT =
092        {
093            false, false, false, false, false, false, false, false,
094            false, false, false, false, false, false, false, false,
095            false, false, false, false, false, false, false, false,
096            false, false, false, false, false, false, false, false,
097            false, false, false, false, false, false, false, false,
098            false, false, false, false, false, false, false, false,
099            true,  true,  true,  true,  true,  true,  true,  true,
100            true,  true,  false, false, false, false, false, false,
101            false, true,  true,  true,  true,  true,  true,  true,
102            true,  true,  true,  true,  true,  true,  true,  true,
103            true,  true,  true,  true,  true,  true,  true,  true,
104            true,  true,  true,  false, false, false, false, false,
105            false, true,  true,  true,  true,  true,  true,  true,
106            true,  true,  true,  true,  true,  true,  true,  true,
107            true,  true,  true,  true,  true,  true,  true,  true,
108            true,  true,  true,  false, false, false, false, false
109        };
110    /** &lt;alpha> | &lt;digit> | '-' */
111    public static final boolean[] CHAR =
112        {
113            false, false, false, false, false, false, false, false,
114            false, false, false, false, false, false, false, false,
115            false, false, false, false, false, false, false, false,
116            false, false, false, false, false, false, false, false,
117            false, false, false, false, false, false, false, false,
118            false, false, false, false, false, true,  false, false,
119            true,  true,  true,  true,  true,  true,  true,  true,
120            true,  true,  false, false, false, false, false, false,
121            false, true,  true,  true,  true,  true,  true,  true,
122            true,  true,  true,  true,  true,  true,  true,  true,
123            true,  true,  true,  true,  true,  true,  true,  true,
124            true,  true,  true,  false, false, false, false, false,
125            false, true,  true,  true,  true,  true,  true,  true,
126            true,  true,  true,  true,  true,  true,  true,  true,
127            true,  true,  true,  true,  true,  true,  true,  true,
128            true,  true,  true,  false, false, false, false, false
129        };
130    /** '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' */
131    public static final boolean[] DIGIT =
132        {
133            false, false, false, false, false, false, false, false,
134            false, false, false, false, false, false, false, false,
135            false, false, false, false, false, false, false, false,
136            false, false, false, false, false, false, false, false,
137            false, false, false, false, false, false, false, false,
138            false, false, false, false, false, false, false, false,
139            true,  true,  true,  true,  true,  true,  true,  true,
140            true,  true,  false, false, false, false, false, false,
141            false, false, false, false, false, false, false, false,
142            false, false, false, false, false, false, false, false,
143            false, false, false, false, false, false, false, false,
144            false, false, false, false, false, false, false, false,
145            false, false, false, false, false, false, false, false,
146            false, false, false, false, false, false, false, false,
147            false, false, false, false, false, false, false, false,
148            false, false, false, false, false, false, false, false
149        };
150    /** &lt;hex> ::= [0x30-0x39] | [0x41-0x46] | [0x61-0x66] */
151    public static final boolean[] HEX =
152        {
153            false, false, false, false, false, false, false, false,
154            false, false, false, false, false, false, false, false,
155            false, false, false, false, false, false, false, false,
156            false, false, false, false, false, false, false, false,
157            false, false, false, false, false, false, false, false,
158            false, false, false, false, false, false, false, false,
159            true,  true,  true,  true,  true,  true,  true,  true,
160            true,  true,  false, false, false, false, false, false,
161            false, true,  true,  true,  true,  true,  true,  false,
162            false, false, false, false, false, false, false, false,
163            false, false, false, false, false, false, false, false,
164            false, false, false, false, false, false, false, false,
165            false, true,  true,  true,  true,  true,  true,  false,
166            false, false, false, false, false, false, false, false,
167            false, false, false, false, false, false, false, false,
168            false, false, false, false, false, false, false, false };
169
170    /* *
171    * Test if the current character is equal to a specific character.
172    *
173    * @param chars The buffer which contains the data
174    * @param index
175    *            Current position in the buffer
176    * @param car The character we want to compare with the current buffer position
177    * @return <code>true</code> if the current character equals the given character.
178    */
179    public static boolean isCharASCII( char[] chars, int index, char car )
180    {
181        if ( ( chars == null ) || ( chars.length == 0 ) || ( index < 0 ) || ( index >= chars.length ) )
182        {
183            return false;
184        }
185        else
186        {
187            return ( ( chars[index] == car ) ? true : false );
188        }
189    }
190
191    /**
192     * Test if the current character is equal to a specific character.
193     *
194     * @param string The String which contains the data
195     * @param index Current position in the string
196     * @param car The character we want to compare with the current string
197     *            position
198     * @return <code>true</code> if the current character equals the given
199     *         character.
200     */
201    public static boolean isCharASCII( String string, int index, char car )
202    {
203        if ( string == null )
204        {
205            return false;
206        }
207
208        int length = string.length();
209
210        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
211        {
212            return false;
213        }
214        else
215        {
216            return string.charAt( index ) == car;
217        }
218    }
219
220    /**
221     * Test if the current character is equal to a specific character.
222     *
223     * @param string The String which contains the data
224     * @param index Current position in the string
225     * @param car The character we want to compare with the current string
226     *            position
227     * @return <code>true</code> if the current character equals the given
228     *         character.
229     */
230    public static boolean isICharASCII( String string, int index, char car )
231    {
232        if ( string == null )
233        {
234            return false;
235        }
236
237        int length = string.length();
238
239        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
240        {
241            return false;
242        }
243        else
244        {
245            return ( ( string.charAt( index ) | 0x20 ) & car ) == car;
246        }
247    }
248
249    /**
250     * Test if the current character is equal to a specific character.
251     *
252     * @param bytes The String which contains the data
253     * @param index Current position in the string
254     * @param car The character we want to compare with the current string
255     *            position
256     * @return <code>true</code> if the current character equals the given
257     *         character.
258     */
259    public static boolean isICharASCII( byte[] bytes, int index, char car )
260    {
261        if ( bytes == null )
262        {
263            return false;
264        }
265
266        int length = bytes.length;
267
268        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
269        {
270            return false;
271        }
272        else
273        {
274            return ( ( bytes[ index ] | 0x20 ) & car ) == car;
275        }
276    }
277
278    /**
279     * Test if the current byte is an Alpha character :
280     * &lt;alpha> ::= [0x41-0x5A] | [0x61-0x7A]
281     *
282     * @param c The byte to test
283     *
284     * @return <code>true</code> if the byte is an Alpha
285     *         character
286     */
287    public static boolean isAlpha( byte c )
288    {
289        return ( ( c > 0 ) && ( c <= 127 ) && ALPHA[c] );
290    }
291
292    /**
293     * Test if the current character is an Alpha character :
294     * &lt;alpha> ::= [0x41-0x5A] | [0x61-0x7A]
295     *
296     * @param c The char to test
297     *
298     * @return <code>true</code> if the character is an Alpha
299     *         character
300     */
301    public static boolean isAlpha( char c )
302    {
303        return ( ( c > 0 ) && ( c <= 127 ) && ALPHA[c] );
304    }
305
306    /**
307     * Test if the current character is an Alpha character : &lt;alpha> ::=
308     * [0x41-0x5A] | [0x61-0x7A]
309     *
310     * @param bytes The buffer which contains the data
311     * @param index Current position in the buffer
312     * @return <code>true</code> if the current character is an Alpha
313     *         character
314     */
315    public static boolean isAlphaASCII( byte[] bytes, int index )
316    {
317        if ( ( bytes == null ) || ( bytes.length == 0 ) || ( index < 0 ) || ( index >= bytes.length ) )
318        {
319            return false;
320        }
321        else
322        {
323            byte c = bytes[index];
324
325            if ( ( ( c | 0x7F ) != 0x7F ) || !ALPHA[c] )
326            {
327                return false;
328            }
329            else
330            {
331                return true;
332            }
333        }
334    }
335
336    /**
337     * Test if the current character is an Alpha character : &lt;alpha> ::=
338     * [0x41-0x5A] | [0x61-0x7A]
339     *
340     * @param chars The buffer which contains the data
341     * @param index Current position in the buffer
342     * @return <code>true</code> if the current character is an Alpha
343     *         character
344     */
345    public static boolean isAlphaASCII( char[] chars, int index )
346    {
347        if ( ( chars == null ) || ( chars.length == 0 ) || ( index < 0 ) || ( index >= chars.length ) )
348        {
349            return false;
350        }
351        else
352        {
353            char c = chars[index];
354
355            if ( ( c > 127 ) || !ALPHA[c] )
356            {
357                return false;
358            }
359            else
360            {
361                return true;
362            }
363        }
364    }
365
366    /**
367     * Test if the current character is an Alpha character : &lt;alpha> ::=
368     * [0x41-0x5A] | [0x61-0x7A]
369     *
370     * @param string The string which contains the data
371     * @param index Current position in the string
372     * @return <code>true</code> if the current character is an Alpha
373     *         character
374     */
375    public static boolean isAlphaASCII( String string, int index )
376    {
377        if ( string == null )
378        {
379            return false;
380        }
381
382        int length = string.length();
383
384        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
385        {
386            return false;
387        }
388        else
389        {
390            char c = string.charAt( index );
391
392            if ( ( c > 127 ) || !ALPHA[c] )
393            {
394                return false;
395            }
396            else
397            {
398                return true;
399            }
400        }
401    }
402
403    /**
404     * Test if the current character is a lowercased Alpha character : <br/>
405     * &lt;alpha> ::= [0x61-0x7A]
406     *
407     * @param string The string which contains the data
408     * @param index Current position in the string
409     * @return <code>true</code> if the current character is a lower Alpha
410     *         character
411     */
412    public static boolean isAlphaLowercaseASCII( String string, int index )
413    {
414        if ( string == null )
415        {
416            return false;
417        }
418
419        int length = string.length();
420
421        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
422        {
423            return false;
424        }
425        else
426        {
427            char c = string.charAt( index );
428
429            if ( ( c > 127 ) || !ALPHA_LOWER_CASE[c] )
430            {
431                return false;
432            }
433            else
434            {
435                return true;
436            }
437        }
438    }
439
440    /**
441     * Test if the current character is a uppercased Alpha character : <br/>
442     * &lt;alpha> ::= [0x61-0x7A]
443     *
444     * @param string The string which contains the data
445     * @param index Current position in the string
446     * @return <code>true</code> if the current character is a lower Alpha
447     *         character
448     */
449    public static boolean isAlphaUppercaseASCII( String string, int index )
450    {
451        if ( string == null )
452        {
453            return false;
454        }
455
456        int length = string.length();
457
458        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
459        {
460            return false;
461        }
462        else
463        {
464            char c = string.charAt( index );
465
466            if ( ( c > 127 ) || !ALPHA_UPPER_CASE[c] )
467            {
468                return false;
469            }
470            else
471            {
472                return true;
473            }
474        }
475    }
476
477    /**
478     * Check if the current character is an 7 bits ASCII CHAR (between 0 and
479     * 127).
480     * &lt;char> ::= &lt;alpha> | &lt;digit>
481     *
482     * @param string The string which contains the data
483     * @param index Current position in the string
484     * @return The position of the next character, if the current one is a CHAR.
485     */
486    public static boolean isAlphaDigit( String string, int index )
487    {
488        if ( string == null )
489        {
490            return false;
491        }
492
493        int length = string.length();
494
495        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
496        {
497            return false;
498        }
499        else
500        {
501            char c = string.charAt( index );
502
503            if ( ( c > 127 ) || !ALPHA_DIGIT[c] )
504            {
505                return false;
506            }
507            else
508            {
509                return true;
510            }
511        }
512    }
513
514    /**
515     * Check if the current character is an 7 bits ASCII CHAR (between 0 and
516     * 127). &lt;char> ::= &lt;alpha> | &lt;digit> | '-'
517     *
518     * @param bytes The buffer which contains the data
519     * @param index Current position in the buffer
520     * @return The position of the next character, if the current one is a CHAR.
521     */
522    public static boolean isAlphaDigitMinus( byte[] bytes, int index )
523    {
524        if ( ( bytes == null ) || ( bytes.length == 0 ) || ( index < 0 ) || ( index >= bytes.length ) )
525        {
526            return false;
527        }
528        else
529        {
530            byte c = bytes[index];
531
532            if ( ( ( c | 0x7F ) != 0x7F ) || !CHAR[c] )
533            {
534                return false;
535            }
536            else
537            {
538                return true;
539            }
540        }
541    }
542
543    /**
544     * Check if the current character is an 7 bits ASCII CHAR (between 0 and
545     * 127). &lt;char> ::= &lt;alpha> | &lt;digit> | '-'
546     *
547     * @param chars The buffer which contains the data
548     * @param index Current position in the buffer
549     * @return The position of the next character, if the current one is a CHAR.
550     */
551    public static boolean isAlphaDigitMinus( char[] chars, int index )
552    {
553        if ( ( chars == null ) || ( chars.length == 0 ) || ( index < 0 ) || ( index >= chars.length ) )
554        {
555            return false;
556        }
557        else
558        {
559            char c = chars[index];
560
561            if ( ( c > 127 ) || !CHAR[c] )
562            {
563                return false;
564            }
565            else
566            {
567                return true;
568            }
569        }
570    }
571
572    /**
573     * Check if the current character is an 7 bits ASCII CHAR (between 0 and
574     * 127). &lt;char> ::= &lt;alpha> | &lt;digit> | '-'
575     *
576     * @param string The string which contains the data
577     * @param index Current position in the string
578     * @return The position of the next character, if the current one is a CHAR.
579     */
580    public static boolean isAlphaDigitMinus( String string, int index )
581    {
582        if ( string == null )
583        {
584            return false;
585        }
586
587        int length = string.length();
588
589        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
590        {
591            return false;
592        }
593        else
594        {
595            char c = string.charAt( index );
596
597            if ( ( c > 127 ) || !CHAR[c] )
598            {
599                return false;
600            }
601            else
602            {
603                return true;
604            }
605        }
606    }
607
608    /**
609     * Test if the current character is a bit, ie 0 or 1.
610     *
611     * @param string
612     *            The String which contains the data
613     * @param index
614     *            Current position in the string
615     * @return <code>true</code> if the current character is a bit (0 or 1)
616     */
617    public static boolean isBit( String string, int index )
618    {
619        if ( string == null )
620        {
621            return false;
622        }
623
624        int length = string.length();
625
626        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
627        {
628            return false;
629        }
630        else
631        {
632            char c =  string.charAt(  index );
633            return ( ( c == '0' ) || ( c == '1' ) );
634        }
635    }
636
637    /**
638     * Test if the current character is a digit &lt;digit> ::= '0' | '1' | '2' |
639     * '3' | '4' | '5' | '6' | '7' | '8' | '9'
640     *
641     * @param bytes The buffer which contains the data
642     * @return <code>true</code> if the current character is a Digit
643     */
644    public static boolean isDigit( byte[] bytes )
645    {
646        if ( ( bytes == null ) || ( bytes.length == 0 ) )
647        {
648            return false;
649        }
650        else
651        {
652            return ( ( ( ( bytes[0] | 0x7F ) != 0x7F ) || !DIGIT[bytes[0]] ) ? false : true );
653        }
654    }
655
656    /**
657     * Test if the current character is a digit &lt;digit> ::= '0' | '1' | '2' |
658     * '3' | '4' | '5' | '6' | '7' | '8' | '9'
659     *
660     * @param car the character to test
661     *
662     * @return <code>true</code> if the character is a Digit
663     */
664    public static boolean isDigit( char car )
665    {
666        return ( car >= '0' ) && ( car <= '9' );
667    }
668
669    /**
670     * Test if the current character is a digit &lt;digit> ::= '0' | '1' | '2' |
671     * '3' | '4' | '5' | '6' | '7' | '8' | '9'
672     *
673     * @param bytes The buffer which contains the data
674     * @param index Current position in the buffer
675     * @return <code>true</code> if the current character is a Digit
676     */
677    public static boolean isDigit( byte[] bytes, int index )
678    {
679        if ( ( bytes == null ) || ( bytes.length == 0 ) || ( index < 0 ) || ( index >= bytes.length ) )
680        {
681            return false;
682        }
683        else
684        {
685            return ( ( ( ( bytes[index] | 0x7F ) !=  0x7F ) || !DIGIT[bytes[index]] ) ? false : true );
686        }
687    }
688
689    /**
690     * Test if the current character is a digit &lt;digit> ::= '0' | '1' | '2' |
691     * '3' | '4' | '5' | '6' | '7' | '8' | '9'
692     *
693     * @param chars The buffer which contains the data
694     * @param index Current position in the buffer
695     * @return <code>true</code> if the current character is a Digit
696     */
697    public static boolean isDigit( char[] chars, int index )
698    {
699        if ( ( chars == null ) || ( chars.length == 0 ) || ( index < 0 ) || ( index >= chars.length ) )
700        {
701            return false;
702        }
703        else
704        {
705            return ( ( ( chars[index] > 127 ) || !DIGIT[chars[index]] ) ? false : true );
706        }
707    }
708
709    /**
710     * Test if the current character is a digit &lt;digit> ::= '0' | '1' | '2' |
711     * '3' | '4' | '5' | '6' | '7' | '8' | '9'
712     *
713     * @param string The string which contains the data
714     * @param index Current position in the string
715     * @return <code>true</code> if the current character is a Digit
716     */
717    public static boolean isDigit( String string, int index )
718    {
719        if ( string == null )
720        {
721            return false;
722        }
723
724        int length = string.length();
725
726        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
727        {
728            return false;
729        }
730        else
731        {
732            char c = string.charAt(  index  );
733            return ( ( ( c > 127 ) || !DIGIT[c] ) ? false : true );
734        }
735    }
736
737    /**
738     * Test if the current character is a digit &lt;digit> ::= '0' | '1' | '2' |
739     * '3' | '4' | '5' | '6' | '7' | '8' | '9'
740     *
741     * @param chars The buffer which contains the data
742     * @return <code>true</code> if the current character is a Digit
743     */
744    public static boolean isDigit( char[] chars )
745    {
746        if ( ( chars == null ) || ( chars.length == 0 ) )
747        {
748            return false;
749        }
750        else
751        {
752            return ( ( ( chars[0] > 127 ) || !DIGIT[chars[0]] ) ? false : true );
753        }
754    }
755
756    /**
757     * Check if the current byte is an Hex Char
758     * &lt;hex> ::= [0x30-0x39] | [0x41-0x46] | [0x61-0x66]
759     *
760     * @param b The byte we want to check
761     * @return <code>true</code> if the current byte is a Hex byte
762     */
763    public static boolean isHex( byte b )
764    {
765        return ( ( b | 0x7F ) == 0x7F ) || HEX[b];
766    }
767
768    /**
769     * Check if the current character is an Hex Char &lt;hex> ::= [0x30-0x39] |
770     * [0x41-0x46] | [0x61-0x66]
771     *
772     * @param bytes The buffer which contains the data
773     * @param index Current position in the buffer
774     * @return <code>true</code> if the current character is a Hex Char
775     */
776    public static boolean isHex( byte[] bytes, int index )
777    {
778        if ( ( bytes == null ) || ( bytes.length == 0 ) || ( index < 0 ) || ( index >= bytes.length ) )
779        {
780            return false;
781        }
782        else
783        {
784            byte c = bytes[index];
785
786            if ( ( ( c | 0x7F ) != 0x7F ) || !HEX[c] )
787            {
788                return false;
789            }
790            else
791            {
792                return true;
793            }
794        }
795    }
796
797    /**
798     * Check if the current character is an Hex Char &lt;hex> ::= [0x30-0x39] |
799     * [0x41-0x46] | [0x61-0x66]
800     *
801     * @param chars The buffer which contains the data
802     * @param index Current position in the buffer
803     * @return <code>true</code> if the current character is a Hex Char
804     */
805    public static boolean isHex( char[] chars, int index )
806    {
807        if ( ( chars == null ) || ( chars.length == 0 ) || ( index < 0 ) || ( index >= chars.length ) )
808        {
809            return false;
810        }
811        else
812        {
813            char c = chars[index];
814
815            if ( ( c > 127 ) || !HEX[c] )
816            {
817                return false;
818            }
819            else
820            {
821                return true;
822            }
823        }
824    }
825
826    /**
827     * Check if the current character is an Hex Char &lt;hex> ::= [0x30-0x39] |
828     * [0x41-0x46] | [0x61-0x66]
829     *
830     * @param string The string which contains the data
831     * @param index Current position in the string
832     * @return <code>true</code> if the current character is a Hex Char
833     */
834    public static boolean isHex( String string, int index )
835    {
836        if ( string == null )
837        {
838            return false;
839        }
840
841        int length = string.length();
842
843        if ( ( length == 0 ) || ( index < 0 ) || ( index >= length ) )
844        {
845            return false;
846        }
847        else
848        {
849            char c = string.charAt( index );
850
851            if ( ( c > 127 ) || !HEX[c] )
852            {
853                return false;
854            }
855            else
856            {
857                return true;
858            }
859        }
860    }
861}