Move the free_list management into a separate class for reuse.

* src/misc/freelist.hh, src/misc/freelist.cc: New files.
* src/misc/Makefile.am (misc_HEADERS, libmisc_la_SOURCES): Add them.
* src/misc/bddalloc.hh (bdd_allocator): Inherit from free_list and
make dump_free_list visible.
* src/misc/bddalloc.cc (bdd_allocator::allocate_variables): Move
all the code into free_list::register_n() and
bdd_allocator::extend(), and call the former.
(bdd_allocator::release_variables): Move all the code into
free_list::release_n() and call it.
(bdd_allocator::extend): New method.
* src/tgba/bdddict.cc (bdd_dict::dump): Call dump_free_list;

ChangeLog

@@ -1,3 +1,19 @@
+2004-03-18  Alexandre Duret-Lutz  <adl@src.lip6.fr>
+
+	Move the free_list management into a separate class for reuse.
+
+	* src/misc/freelist.hh, src/misc/freelist.cc: New files.
+	* src/misc/Makefile.am (misc_HEADERS, libmisc_la_SOURCES): Add them.
+	* src/misc/bddalloc.hh (bdd_allocator): Inherit from free_list and
+	make dump_free_list visible.
+	* src/misc/bddalloc.cc (bdd_allocator::allocate_variables): Move
+	all the code into free_list::register_n() and
+	bdd_allocator::extend(), and call the former.
+	(bdd_allocator::release_variables): Move all the code into
+	free_list::release_n() and call it.
+	(bdd_allocator::extend): New method.
+	* src/tgba/bdddict.cc (bdd_dict::dump): Call dump_free_list;
+
 2004-03-09  Alexandre Duret-Lutz  <adl@src.lip6.fr>
 
 	* configure.ac, NEWS: Bump version to 0.0s.

src/misc/Makefile.am

@@ -28,6 +28,7 @@ misc_HEADERS = \
   bddalloc.hh \
   bddlt.hh \
   escape.hh \
+  freelist.hh \
   hash.hh \
   minato.hh \
   version.hh
@@ -36,5 +37,6 @@ noinst_LTLIBRARIES = libmisc.la
 libmisc_la_SOURCES = \
   bddalloc.cc \
   escape.cc \
+  freelist.cc \
   minato.cc \
   version.cc

src/misc/bddalloc.cc

@@ -1,4 +1,4 @@
-// Copyright (C) 2003  Laboratoire d'Informatique de Paris 6 (LIP6),
+// Copyright (C) 2003, 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
 // et Marie Curie.
 //
@@ -32,7 +32,7 @@ namespace spot
     : lvarnum(varnum)
   {
     initialize();
-    free_list.push_front(pos_lenght_pair(0, lvarnum));
+    fl.push_front(pos_lenght_pair(0, lvarnum));
   }
 
   void
@@ -71,52 +71,27 @@ namespace spot
   int
   bdd_allocator::allocate_variables(int n)
   {
-    // Browse the free list until we find N consecutive variables.  We
+    return register_n(n);
-    // try not to fragment the list my allocating the variables in the
+  }
-    // smallest free range we find.
-    free_list_type::iterator best = free_list.end();
-    free_list_type::iterator cur;
-    for (cur = free_list.begin(); cur != free_list.end(); ++cur)
-      {
-	if (cur->second < n)
-	  continue;
-	if (n == cur->second)
-	  {
-	    best = cur;
-	    break;
-	  }
-	if (best == free_list.end()
-	    || cur->second < best->second)
-	  best = cur;
-      }
 
-    // We have found enough free variables.
+  void
-    if (best != free_list.end())
+  bdd_allocator::release_variables(int base, int n)
-      {
+  {
-	int result = best->first;
+    release_n(base, n);
-	best->second -= n;
+  }
-	assert(best->second >= 0);
-	// Erase the range if it's now empty.
-	if (best->second == 0)
-	  free_list.erase(best);
-	else
-	  best->first += n;
-	return result;
-      }
-
-    // We haven't found enough adjacent free variables;
-    // ask BuDDy for some more.
 
+  int
+  bdd_allocator::extend(int n)
+  {
     // If we already have some free variable at the end
     // of the variable space, allocate just the difference.
-    if (free_list.size() > 0
+    if (fl.size() > 0 && fl.back().first + fl.back().second == lvarnum)
-	&& free_list.back().first + free_list.back().second == lvarnum)
       {
-	int res = free_list.back().first;
+	int res = fl.back().first;
-	int endvar = free_list.back().second;
+	int endvar = fl.back().second;
 	assert(n > endvar);
 	extvarnum(n - endvar);
-	free_list.pop_back();
+	fl.pop_back();
 	return res;
       }
     else
@@ -127,40 +102,4 @@ namespace spot
 	return res;
       }
   }
-
-  void
-  bdd_allocator::release_variables(int base, int n)
-  {
-    free_list_type::iterator cur;
-    int end = base + n;
-    for (cur = free_list.begin(); cur != free_list.end(); ++cur)
-      {
-	// Append to a range ...
-	if (cur->first + cur->second == base)
-	  {
-	    cur->second += n;
-	    // Maybe the next item on the list can be merged.
-	    free_list_type::iterator next = cur;
-	    ++next;
-	    if (next != free_list.end()
-		&& next->first == end)
-	      {
-		cur->second += next->second;
-		free_list.erase(next);
-	      }
-	    return;
-	  }
-	// ... or prepend to a range ...
-	if (cur->first == end)
-	  {
-	    cur->first -= n;
-	    cur->second += n;
-	    return;
-	  }
-	// ... or insert a new range.
-	if (cur->first > end)
-	  break;
-      }
-    free_list.insert(cur, pos_lenght_pair(base, n));
-  }
 }

src/misc/bddalloc.hh

@@ -22,14 +22,14 @@
 #ifndef SPOT_MISC_BDDALLOC_HH
 # define SPOT_MISC_BDDALLOC_HH
 
+#include "freelist.hh"
 #include <list>
 #include <utility>
 
 namespace spot
 {
-
   /// Manage ranges of variables.
-  class bdd_allocator
+  class bdd_allocator: private free_list
   {
   public:
     /// Default constructor.
@@ -40,16 +40,16 @@ namespace spot
     int allocate_variables(int n);
     /// Release \a n BDD variables starting at \a base.
     void release_variables(int base, int n);
+
+    using free_list::dump_free_list;
   protected:
     static bool initialized; ///< Whether the BDD library has been initialized.
     static int varnum; ///< number of variables in use in the BDD library.
     int lvarnum; ///< number of variables in use in this allocator.
-    typedef std::pair<int, int> pos_lenght_pair;
-    typedef std::list<pos_lenght_pair> free_list_type;
-    free_list_type free_list; ///< Tracks unused BDD variables.
   private:
     /// Require more variables.
     void extvarnum(int more);
+    virtual int extend(int n);
   };
 
 }

src/misc/freelist.cc

@@ -0,0 +1,118 @@
+// Copyright (C) 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
+// département Systèmes Répartis Coopératifs (SRC), Université Pierre
+// et Marie Curie.
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot 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.
+//
+// Spot 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 Spot; see the file COPYING.  If not, write to the Free
+// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+
+#include "freelist.hh"
+#include <cassert>
+#include <iostream>
+
+namespace spot
+{
+
+  free_list::~free_list()
+  {
+  }
+
+  int
+  free_list::register_n(int n)
+  {
+    // Browse the free list until we find N consecutive variables.  We
+    // try not to fragment the list my allocating the variables in the
+    // smallest free range we find.
+    free_list_type::iterator best = fl.end();
+    free_list_type::iterator cur;
+    for (cur = fl.begin(); cur != fl.end(); ++cur)
+      {
+	if (cur->second < n)
+	  continue;
+	if (n == cur->second)
+	  {
+	    best = cur;
+	    break;
+	  }
+	if (best == fl.end()
+	    || cur->second < best->second)
+	  best = cur;
+      }
+
+    // We have found enough free variables.
+    if (best != fl.end())
+      {
+	int result = best->first;
+	best->second -= n;
+	assert(best->second >= 0);
+	// Erase the range if it's now empty.
+	if (best->second == 0)
+	  fl.erase(best);
+	else
+	  best->first += n;
+	return result;
+      }
+
+    // We haven't found enough adjacent free variables;
+    // ask for some more.
+    return extend(n);
+  }
+
+  void
+  free_list::release_n(int base, int n)
+  {
+    free_list_type::iterator cur;
+    int end = base + n;
+    for (cur = fl.begin(); cur != fl.end(); ++cur)
+      {
+	// Append to a range ...
+	if (cur->first + cur->second == base)
+	  {
+	    cur->second += n;
+	    // Maybe the next item on the list can be merged.
+	    free_list_type::iterator next = cur;
+	    ++next;
+	    if (next != fl.end() && next->first == end)
+	      {
+		cur->second += next->second;
+		fl.erase(next);
+	      }
+	    return;
+	  }
+	// ... or prepend to a range ...
+	if (cur->first == end)
+	  {
+	    cur->first -= n;
+	    cur->second += n;
+	    return;
+	  }
+	// ... or insert a new range.
+	if (cur->first > end)
+	  break;
+      }
+    fl.insert(cur, pos_lenght_pair(base, n));
+  }
+
+  std::ostream&
+  free_list::dump_free_list(std::ostream& os) const
+  {
+    free_list_type::const_iterator i;
+    for (i = fl.begin(); i != fl.end(); ++i)
+      os << "  (" << i->first << ", " << i->second << ")";
+    return os;
+  }
+
+}

src/misc/freelist.hh

@@ -0,0 +1,69 @@
+// Copyright (C) 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
+// département Systèmes Répartis Coopératifs (SRC), Université Pierre
+// et Marie Curie.
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot 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.
+//
+// Spot 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 Spot; see the file COPYING.  If not, write to the Free
+// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+
+
+#ifndef SPOT_MISC_FREELIST_HH
+# define SPOT_MISC_FREELIST_HH
+
+#include <list>
+#include <utility>
+
+namespace spot
+{
+
+  /// Manage list of free integers.
+  class free_list
+  {
+  public:
+    virtual ~free_list();
+
+    /// \brief Find \a n consecutive integers.
+    ///
+    /// Browse the list of free integers until \a n consecutive
+    /// integers are found.  Extend the list (using extend()) otherwise.
+    /// \return the first integer of the range
+    int register_n(int n);
+
+    /// Release \a n consecutive integers starting at \a base.
+    void release_n(int base, int n);
+
+    /// Dump the list to \a os for debugging.
+    std::ostream& dump_free_list(std::ostream& os) const;
+  protected:
+
+    /// Allocate \a n integer.
+    ///
+    /// This function is called by register_n() when the free list is
+    /// empty or if \a n consecutive integers could not be found.  It
+    /// should allocate more integers, possibly changing the list, and
+    /// return the first integer on a range of n consecutive integer
+    /// requested by the user.
+    virtual int extend(int n) = 0;
+
+    /// Such pairs describe \c second free integer starting at \first.
+    typedef std::pair<int, int> pos_lenght_pair;
+    typedef std::list<pos_lenght_pair> free_list_type;
+    free_list_type fl; ///< Tracks unused BDD variables.
+  };
+
+}
+
+#endif // SPOT_MISC_FREELIST_HH

src/tgba/bdddict.cc

@@ -1,4 +1,4 @@
-// Copyright (C) 2003  Laboratoire d'Informatique de Paris 6 (LIP6),
+// Copyright (C) 2003, 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
 // et Marie Curie.
 //
@@ -269,9 +269,7 @@ namespace spot
 	to_string(fi->first, os) << "]" << std::endl;
       }
     os << "Free list:" << std::endl;
-    free_list_type::const_iterator i;
+    dump_free_list(os);
-    for (i = free_list.begin(); i != free_list.end(); ++i)
-      os << "  (" << i->first << ", " << i->second << ")";
     os << std::endl;
     return os;
   }