mirror of git://gcc.gnu.org/git/gcc.git
125 lines
3.5 KiB
Java
125 lines
3.5 KiB
Java
/* gnu/regexp/BacktrackStack.java
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Copyright (C) 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 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.java.util.regex;
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/**
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* An instance of this class represents a stack
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* used for backtracking.
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*
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* @author Ito Kazumitsu</A>
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*/
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final class BacktrackStack
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{
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/** A set of data to be used for backtracking. */
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static class Backtrack
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{
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/** REToken to which to go back */
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REToken token;
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/** CharIndexed on which matches are being searched for. */
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CharIndexed input;
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/** REMatch to be used by the REToken token. */
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REMatch match;
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/** Some parameter used by the token's backtrack method. */
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Object param;
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Backtrack (REToken token, CharIndexed input, REMatch match,
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Object param)
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{
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this.token = token;
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this.input = input;
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// REMatch may change before backtracking is needed. So we
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// keep a clone of it.
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this.match = (REMatch) match.clone ();
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this.param = param;
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}
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}
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Backtrack[] stack;
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private int size;
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private int capacity;
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private static final int INITIAL_CAPACITY = 32;
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private static final int CAPACITY_INCREMENT = 16;
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BacktrackStack ()
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{
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stack = new Backtrack[INITIAL_CAPACITY];
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size = 0;
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capacity = INITIAL_CAPACITY;
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}
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boolean empty ()
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{
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return size == 0;
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}
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Backtrack peek ()
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{
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return stack[size - 1];
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}
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Backtrack pop ()
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{
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Backtrack bt = stack[--size];
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stack[size] = null;
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return bt;
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}
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void clear ()
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{
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for (int i = 0; i < size; i++)
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{
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stack[i] = null;
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}
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size = 0;
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}
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void push (Backtrack bt)
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{
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if (size >= capacity)
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{
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capacity += CAPACITY_INCREMENT;
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Backtrack[]newStack = new Backtrack[capacity];
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System.arraycopy (stack, 0, newStack, 0, size);
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stack = newStack;
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}
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stack[size++] = bt;
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}
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}
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