Subversion Repositories openrisc

/* Variables.java --

   Copyright (c) 2004, 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., 59 Temple Place, Suite 330, Boston, MA

02111-1307 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.classpath.tools.rmic;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

class Variables

{

  private final HashSet free = new HashSet();

  private final HashMap names = new HashMap();

  private final HashSet wides = new HashSet();

  private final HashSet declared = new HashSet();

  private boolean allocated = false;

  public void declare(Object name)

  {

    declare(name, 1);

  }

  public void declareWide(Object name)

  {

    declare(name, 2);

  }

  public void declare(Object name, int size)

  {

    if (allocated)

      throw new IllegalStateException("cannot declare after allocating");

    if (size != 1 && size != 2)

      throw new IllegalArgumentException("size must be 1 or 2");

    if (names.containsKey(name))

      throw new IllegalStateException("already allocated " + name);

    allocateNew(name, size);

    declared.add(name);

  }

  private int allocateNew(Object name, int size)

  {

    // total allocation size is first unallocated slot

    int i = free.size() + names.size() + wides.size();

    names.put(name, new Integer(i));

    if (size == 2) wides.add(name);

    return i;

  }

  public int allocate(Object name)

  {

    return allocate(name, 1);

  }

  public int allocateWide(Object name)

  {

    return allocate(name, 2);

  }

  public int allocate(Object name, int size)

  {

    allocated = true;

    if (size != 1 && size != 2)

      throw new IllegalArgumentException("size must be 1 or 2");

    if (names.containsKey(name))

      throw new IllegalStateException("already allocated " + name);

    if (size == 2)

      {

        // look for consecutive free slots

        for (Iterator it = free.iterator(); it.hasNext(); )

          {

            Integer i = (Integer) it.next();

            Integer next = new Integer(i.intValue() + 1);

            if (free.contains(next))

              {

                free.remove(i);

                free.remove(next);

                wides.add(name);

                names.put(name, i);

                return i.intValue();

              }

          }

      }

    else if (free.size() > 0)

      {

        Integer i = (Integer) free.iterator().next();

        free.remove(i);

        names.put(name, i);

        return i.intValue();

      }

    return allocateNew(name, size);

  }

  public int deallocate(Object name)

  {

    if (! names.containsKey(name))

      throw new IllegalArgumentException("no variable " + name);

    if (declared.contains(name))

      throw new IllegalStateException(name + " can't be deallocated");

    Integer i = (Integer) names.get(name);

    names.remove(name);

    free.add(i);

    if (wides.remove(name))

      free.add(new Integer(i.intValue() + 1));

    return i.intValue();

  }

  public int get(Object name)

  {

    if (! names.containsKey(name))

      throw new IllegalArgumentException("no variable " + name);

    return ((Integer) names.get(name)).intValue();

  }

}