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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/javax/swing/text/html/parser/support/low/Queue.java | |
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Diffstat (limited to 'libjava/classpath/gnu/javax/swing/text/html/parser/support/low/Queue.java')
-rw-r--r-- | libjava/classpath/gnu/javax/swing/text/html/parser/support/low/Queue.java | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/swing/text/html/parser/support/low/Queue.java b/libjava/classpath/gnu/javax/swing/text/html/parser/support/low/Queue.java new file mode 100644 index 000000000..31cf4bb4d --- /dev/null +++ b/libjava/classpath/gnu/javax/swing/text/html/parser/support/low/Queue.java @@ -0,0 +1,142 @@ +/* Queue.java -- a token queue. + Copyright (C) 2005 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.javax.swing.text.html.parser.support.low; + +import java.util.Arrays; + +/** + * A token queue. + * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org) + */ +public class Queue +{ + Token[] m = new Token[ 64 ]; + int a = 0; + int b = 0; + + /** + * True for the empty queue. + */ + public boolean isEmpty() + { + return size() == 0; + } + + /** + * Add this trace to the end of the queue. + */ + public void add(Token u) + { + if (a < m.length) + { + m [ a ] = u; + a++; + } + else // The end of array has been reached. + { + if (b > 0) // If some elements were deleted from the start of the queue, shift. + { + int d = b; + System.arraycopy(m, b, m, 0, a - b); + b = b - d; + a = a - d; + m [ a ] = u; + a++; + } + else // Enlarge the queue, doubling the size. + { + int n = m.length * 2; + Token[] nm = new Token[ 2 * n ]; + System.arraycopy(m, 0, nm, 0, m.length); + Arrays.fill(m, null); + + nm [ a ] = u; + m = nm; + a++; + } + } + } + + /** + * Clear the queue. + */ + public void clear() + { + a = b = 0; + Arrays.fill(m, null); + } + + /** + * Read the value ahead. 0 is the value that will be returned with + * the following next. This method does not remove values from the + * queue. To test if there is enough tokens in the queue, size() must + * be checked before calling this method. + */ + public Token get(int ahead) + { + int p = b + ahead; + if (p < a) + return m [ p ]; + else + throw new ArrayIndexOutOfBoundsException("Not enough tokens"); + } + + /** + * Read the oldest value from the queue and remove this value from + * the queue. + */ + public Token next() + { + if (a == b) + throw new ArrayIndexOutOfBoundsException("queue empty"); + + Token r = m [ b ]; + m [ b ] = null; + b++; + return r; + } + + /** + * Size of the queue. + */ + public int size() + { + return a - b; + } +} |