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// This file is part of the AspectC++ compiler 'ac++'.
// Copyright (C) 1999-2003 The 'ac++' developers (see aspectc.org)
//
// This program 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.
//
// This program 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 this program; if not, write to the Free
// Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
// MA 02111-1307 USA
#ifndef __OrderPlanner_h__
#define __OrderPlanner_h__
#include <set>
#include <map>
#include <vector>
using namespace std;
template <typename Item, typename Compare = less<Item*> >
class OrderPlanner {
struct Links;
typedef map<Item*,Links,Compare> NodeMap;
typedef typename NodeMap::value_type Node;
struct Links {
set<Node*> _in;
set<Node*> _out;
};
NodeMap _node_map;
vector<Item*> _total_order;
public:
// consider an order relation of two nodes
void precedence (Item &first, Item &later);
// calculate the total order => false if there is a cycle
bool plan ();
// get the result
int items () const { return _total_order.size (); }
Item &item (int i) const { return *_total_order[i]; }
};
template <typename Item, typename Compare>
bool OrderPlanner<Item, Compare>::plan () {
// loop until all node have been moved to the total order vector
while (_node_map.size () > 0) {
// loop over all remaining nodes and count number of shifted nodes
int moved = 0;
typename NodeMap::iterator curr = _node_map.begin ();
while (curr != _node_map.end ()) {
// shift the current node if it has no incoming edge
// (no left node has a higher precedence)
if ((*curr).second._in.size () == 0) {
moved++;
// add this node to the total order
_total_order.push_back ((*curr).first);
// remove the edges of this node to other nodes with lower precedence
for (typename set<Node*>::iterator edge = (*curr).second._out.begin ();
edge != (*curr).second._out.end (); ++edge)
(*edge)->second._in.erase (&*curr);
// remove the node
typename NodeMap::iterator rem = curr;
++curr;
_node_map.erase (rem);
}
else {
++curr;
}
}
// if no node was moved there must be a cycle in the graph!
if (moved == 0)
return false;
}
return true;
}
template <typename Item, typename Compare>
void OrderPlanner<Item, Compare>::precedence (Item &first, Item &later) {
// find/insert the 'first' node
typename NodeMap::iterator f = _node_map.find (&first);
if (f == _node_map.end ()) {
_node_map.insert (Node (&first, Links ()));
f = _node_map.find (&first);
}
// find/insert the 'later' node
typename NodeMap::iterator l = _node_map.find (&later);
if (l == _node_map.end ()) {
_node_map.insert (Node (&later, Links ()));
l = _node_map.find (&later);
}
// insert the incoming and outgoing edges
(*f).second._out.insert (&*l);
(*l).second._in.insert (&*f);
}
#endif // __OrderPlanner_h__
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