/*
* Copyright (c) 1998-2009 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source 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 of the License, or
* (at your option) any later version.
*
* Resin Open Source 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, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
*
* Free Software Foundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Nam Nguyen
*/
package com.caucho.quercus.lib.regexp;
import com.caucho.quercus.env.Env;
import com.caucho.quercus.env.StringValue;
/**
* FIFO cache of line-item regular expressions.
*/
public class RegexpCache
{
private final Regexp []_cache;
private int _head;
private static final int MAX_SIZE = 4;
public RegexpCache()
{
_cache = new Regexp[MAX_SIZE];
}
public Regexp get(Env env, StringValue str)
{
int head = _head;
for (int i = 0; i < MAX_SIZE; i++) {
Regexp regexp = _cache[(head + i) % MAX_SIZE];
if (regexp == null)
break;
else {
StringValue rawRegexp = regexp.getRawRegexp();
if (rawRegexp == str || rawRegexp.equals(str))
return regexp;
}
}
Regexp regexp = RegexpModule.createRegexp(env, str);
head = head - 1;
if (head < 0)
head = MAX_SIZE - 1;
_cache[head] = regexp;
_head = head;
return regexp;
}
}