mirror of git://gcc.gnu.org/git/gcc.git
228 lines
6.8 KiB
Java
228 lines
6.8 KiB
Java
/* gnu/regexp/RETokenRepeated.java
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Copyright (C) 1998-2001, 2004 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.regexp;
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import java.util.Vector;
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final class RETokenRepeated extends REToken {
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private REToken token;
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private int min,max;
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private boolean stingy;
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RETokenRepeated(int subIndex, REToken token, int min, int max) {
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super(subIndex);
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this.token = token;
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this.min = min;
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this.max = max;
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}
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/** Sets the minimal matching mode to true. */
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void makeStingy() {
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stingy = true;
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}
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/** Queries if this token has minimal matching enabled. */
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boolean isStingy() {
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return stingy;
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}
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/**
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* The minimum length of a repeated token is the minimum length
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* of the token multiplied by the minimum number of times it must
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* match.
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*/
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int getMinimumLength() {
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return (min * token.getMinimumLength());
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}
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// We do need to save every possible point, but the number of clone()
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// invocations here is really a killer for performance on non-stingy
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// repeat operators. I'm open to suggestions...
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// Hypothetical question: can you have a RE that matches 1 times,
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// 3 times, 5 times, but not 2 times or 4 times? Does having
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// the subexpression back-reference operator allow that?
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boolean match(CharIndexed input, REMatch mymatch) {
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// number of times we've matched so far
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int numRepeats = 0;
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// Possible positions for the next repeat to match at
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REMatch newMatch = mymatch;
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REMatch last = null;
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REMatch current;
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// Add the '0-repeats' index
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// positions.elementAt(z) == position [] in input after <<z>> matches
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Vector positions = new Vector();
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positions.addElement(newMatch);
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// Declare variables used in loop
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REMatch doables;
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REMatch doablesLast;
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REMatch recurrent;
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do {
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// Check for stingy match for each possibility.
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if (stingy && (numRepeats >= min)) {
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REMatch result = matchRest(input, newMatch);
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if (result != null) {
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mymatch.assignFrom(result);
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return true;
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}
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}
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doables = null;
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doablesLast = null;
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// try next repeat at all possible positions
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for (current = newMatch; current != null; current = current.next) {
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recurrent = (REMatch) current.clone();
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if (token.match(input, recurrent)) {
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// add all items in current to doables array
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if (doables == null) {
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doables = recurrent;
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doablesLast = recurrent;
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} else {
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// Order these from longest to shortest
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// Start by assuming longest (more repeats)
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doablesLast.next = recurrent;
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}
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// Find new doablesLast
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while (doablesLast.next != null) {
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doablesLast = doablesLast.next;
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}
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}
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}
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// if none of the possibilities worked out, break out of do/while
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if (doables == null) break;
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// reassign where the next repeat can match
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newMatch = doables;
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// increment how many repeats we've successfully found
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++numRepeats;
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positions.addElement(newMatch);
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} while (numRepeats < max);
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// If there aren't enough repeats, then fail
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if (numRepeats < min) return false;
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// We're greedy, but ease off until a true match is found
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int posIndex = positions.size();
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// At this point we've either got too many or just the right amount.
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// See if this numRepeats works with the rest of the regexp.
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REMatch allResults = null;
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REMatch allResultsLast = null;
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REMatch results = null;
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while (--posIndex >= min) {
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newMatch = (REMatch) positions.elementAt(posIndex);
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results = matchRest(input, newMatch);
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if (results != null) {
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if (allResults == null) {
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allResults = results;
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allResultsLast = results;
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} else {
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// Order these from longest to shortest
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// Start by assuming longest (more repeats)
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allResultsLast.next = results;
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}
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// Find new doablesLast
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while (allResultsLast.next != null) {
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allResultsLast = allResultsLast.next;
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}
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}
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// else did not match rest of the tokens, try again on smaller sample
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}
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if (allResults != null) {
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mymatch.assignFrom(allResults); // does this get all?
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return true;
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}
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// If we fall out, no matches.
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return false;
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}
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private REMatch matchRest(CharIndexed input, final REMatch newMatch) {
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REMatch current, single;
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REMatch doneIndex = null;
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REMatch doneIndexLast = null;
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// Test all possible matches for this number of repeats
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for (current = newMatch; current != null; current = current.next) {
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// clone() separates a single match from the chain
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single = (REMatch) current.clone();
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if (next(input, single)) {
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// chain results to doneIndex
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if (doneIndex == null) {
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doneIndex = single;
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doneIndexLast = single;
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} else {
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doneIndexLast.next = single;
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}
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// Find new doneIndexLast
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while (doneIndexLast.next != null) {
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doneIndexLast = doneIndexLast.next;
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}
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}
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}
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return doneIndex;
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}
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void dump(StringBuffer os) {
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os.append("(?:");
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token.dumpAll(os);
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os.append(')');
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if ((max == Integer.MAX_VALUE) && (min <= 1))
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os.append( (min == 0) ? '*' : '+' );
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else if ((min == 0) && (max == 1))
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os.append('?');
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else {
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os.append('{').append(min);
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if (max > min) {
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os.append(',');
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if (max != Integer.MAX_VALUE) os.append(max);
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}
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os.append('}');
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}
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if (stingy) os.append('?');
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}
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}
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