/* *  gnu/regexp/RETokenWordBoundary.java *  Copyright (C) 2001 Wes Biggs * *  This library is free software; you can redistribute it and/or modify *  it under the terms of the GNU Lesser General Public License as published *  by the Free Software Foundation; either version 2.1 of the License, or *  (at your option) any later version. * *  This library is distributed in the hope that it will be useful, *  but WITHOUT ANY WARRANTY; without even the implied warranty of *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *  GNU Lesser General Public License for more details. * *  You should have received a copy of the GNU Lesser General Public License *  along with this program; if not, write to the Free Software *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */package gnu.regexp;/** * Represents a combination lookahead/lookbehind for POSIX [:alnum:]. */final class RETokenWordBoundary extends REToken {    private boolean negated;    private int where;    static final int BEGIN = 1;    static final int END = 2;    RETokenWordBoundary(int subIndex, int where, boolean negated) {	super(subIndex);	this.where = where;	this.negated = negated;    }        boolean match(CharIndexed input, REMatch mymatch) {	// Word boundary means input[index-1] was a word character	// and input[index] is not, or input[index] is a word character	// and input[index-1] was not	//  In the string "one two three", these positions match:	//  |o|n|e| |t|w|o| |t|h|r|e|e|	//  ^     ^ ^     ^ ^         ^	boolean after = false;  // is current character a letter or digit?	boolean before = false; // is previous character a letter or digit?	char ch;	// TODO: Also check REG_ANCHORINDEX vs. anchor	if (((mymatch.eflags & RE.REG_ANCHORINDEX) != RE.REG_ANCHORINDEX) 	    || (mymatch.offset + mymatch.index > mymatch.anchor)) {	    if ((ch = input.charAt(mymatch.index - 1)) != CharIndexed.OUT_OF_BOUNDS) {		before = Character.isLetterOrDigit(ch) || (ch == '_');	    }	}	if ((ch = input.charAt(mymatch.index)) != CharIndexed.OUT_OF_BOUNDS) {	    after = Character.isLetterOrDigit(ch) || (ch == '_');	}	// if (before) and (!after), we're at end (\>)	// if (after) and (!before), we're at beginning (\<)	boolean doNext = false;	if ((where & BEGIN) == BEGIN) {	    doNext = after && !before;	}	if ((where & END) == END) {	    doNext ^= before && !after;	}	if (negated) doNext = !doNext;	return (doNext ? next(input, mymatch) : false);    }        void dump(StringBuffer os) {	if (where == (BEGIN | END)) {	    os.append( negated ? "\\B" : "\\b" );	} else if (where == BEGIN) {	    os.append("\\<");	} else {	    os.append("\\>");	}    }}