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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/java/util/regex/BacktrackStack.java | |
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Diffstat (limited to 'libjava/classpath/gnu/java/util/regex/BacktrackStack.java')
-rw-r--r-- | libjava/classpath/gnu/java/util/regex/BacktrackStack.java | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/java/util/regex/BacktrackStack.java b/libjava/classpath/gnu/java/util/regex/BacktrackStack.java new file mode 100644 index 000000000..b03fb8707 --- /dev/null +++ b/libjava/classpath/gnu/java/util/regex/BacktrackStack.java @@ -0,0 +1,124 @@ +/* gnu/regexp/BacktrackStack.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; + +/** + * An instance of this class represents a stack + * used for backtracking. + * + * @author Ito Kazumitsu</A> + */ +final class BacktrackStack +{ + + /** A set of data to be used for backtracking. */ + static class Backtrack + { + /** REToken to which to go back */ + REToken token; + /** CharIndexed on which matches are being searched for. */ + CharIndexed input; + /** REMatch to be used by the REToken token. */ + REMatch match; + /** Some parameter used by the token's backtrack method. */ + Object param; + Backtrack (REToken token, CharIndexed input, REMatch match, + Object param) + { + this.token = token; + this.input = input; + // REMatch may change before backtracking is needed. So we + // keep a clone of it. + this.match = (REMatch) match.clone (); + this.param = param; + } + } + + Backtrack[] stack; + private int size; + private int capacity; + private static final int INITIAL_CAPACITY = 32; + private static final int CAPACITY_INCREMENT = 16; + + BacktrackStack () + { + stack = new Backtrack[INITIAL_CAPACITY]; + size = 0; + capacity = INITIAL_CAPACITY; + } + + boolean empty () + { + return size == 0; + } + + Backtrack peek () + { + return stack[size - 1]; + } + + Backtrack pop () + { + Backtrack bt = stack[--size]; + stack[size] = null; + return bt; + } + + void clear () + { + for (int i = 0; i < size; i++) + { + stack[i] = null; + } + size = 0; + } + + void push (Backtrack bt) + { + if (size >= capacity) + { + capacity += CAPACITY_INCREMENT; + Backtrack[]newStack = new Backtrack[capacity]; + System.arraycopy (stack, 0, newStack, 0, size); + stack = newStack; + } + stack[size++] = bt; + } + +} |