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+/* gnu/regexp/RETokenWordBoundary.java
+ Copyright (C) 2006 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package gnu.java.util.regex;
+
+/**
+ * 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;
+ }
+
+ int getMaximumLength() {
+ return 0;
+ }
+
+
+ REMatch matchThis(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 ? mymatch : null);
+ }
+
+ boolean returnsFixedLengthMatches() { return true; }
+
+ int findFixedLengthMatches(CharIndexed input, REMatch mymatch, int max) {
+ if(matchThis(input, mymatch) != null) return max;
+ else return 0;
+ }
+
+ void dump(StringBuffer os) {
+ if (where == (BEGIN | END)) {
+ os.append( negated ? "\\B" : "\\b" );
+ } else if (where == BEGIN) {
+ os.append("\\<");
+ } else {
+ os.append("\\>");
+ }
+ }
+}