libjava/classpath/tools/gnu/classpath/tools/rmic/Variables.java

   1 /* Variables.java --
   2    Copyright (c) 2004, 2005, 2012 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package gnu.classpath.tools.rmic;
  39
  40 import java.util.HashMap;
  41 import java.util.HashSet;
  42 import java.util.Iterator;
  43
  44 class Variables
  45 {
  46   private final HashSet<Integer> free = new HashSet<Integer>();
  47   private final HashMap<Object,Integer> names = new HashMap<Object,Integer>();
  48   private final HashSet<Object> wides = new HashSet<Object>();
  49   private final HashSet<Object> declared = new HashSet<Object>();
  50   private boolean allocated = false;
  51
  52   public void declare(Object name)
  53   {
  54     declare(name, 1);
  55   }
  56
  57   public void declareWide(Object name)
  58   {
  59     declare(name, 2);
  60   }
  61
  62   public void declare(Object name, int size)
  63   {
  64     if (allocated)
  65       throw new IllegalStateException("cannot declare after allocating");
  66     if (size != 1 && size != 2)
  67       throw new IllegalArgumentException("size must be 1 or 2");
  68     if (names.containsKey(name))
  69       throw new IllegalStateException("already allocated " + name);
  70
  71     allocateNew(name, size);
  72     declared.add(name);
  73   }
  74
  75   private int allocateNew(Object name, int size)
  76   {
  77     // total allocation size is first unallocated slot
  78     int i = free.size() + names.size() + wides.size();
  79     names.put(name, Integer.valueOf(i));
  80     if (size == 2) wides.add(name);
  81     return i;
  82   }
  83
  84   public int allocate(Object name)
  85   {
  86     return allocate(name, 1);
  87   }
  88
  89   public int allocateWide(Object name)
  90   {
  91     return allocate(name, 2);
  92   }
  93
  94   public int allocate(Object name, int size)
  95   {
  96     allocated = true;
  97     if (size != 1 && size != 2)
  98       throw new IllegalArgumentException("size must be 1 or 2");
  99     if (names.containsKey(name))
 100       throw new IllegalStateException("already allocated " + name);
 101
 102     if (size == 2)
 103       {
 104         // look for consecutive free slots
 105         for (Iterator<Integer> it = free.iterator(); it.hasNext(); )
 106           {
 107             Integer i = it.next();
 108             Integer next = Integer.valueOf(i.intValue() + 1);
 109             if (free.contains(next))
 110               {
 111                 free.remove(i);
 112                 free.remove(next);
 113                 wides.add(name);
 114                 names.put(name, i);
 115                 return i.intValue();
 116               }
 117           }
 118       }
 119     else if (free.size() > 0)
 120       {
 121         Integer i = free.iterator().next();
 122         free.remove(i);
 123         names.put(name, i);
 124         return i.intValue();
 125       }
 126
 127     return allocateNew(name, size);
 128   }
 129
 130   public int deallocate(Object name)
 131   {
 132     if (! names.containsKey(name))
 133       throw new IllegalArgumentException("no variable " + name);
 134
 135     if (declared.contains(name))
 136       throw new IllegalStateException(name + " can't be deallocated");
 137
 138     Integer i = names.get(name);
 139     names.remove(name);
 140     free.add(i);
 141     if (wides.remove(name))
 142       free.add(Integer.valueOf(i.intValue() + 1));
 143     return i.intValue();
 144   }
 145
 146   public int get(Object name)
 147   {
 148     if (! names.containsKey(name))
 149       throw new IllegalArgumentException("no variable " + name);
 150
 151     return names.get(name).intValue();
 152   }
 153 }