Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/use_list.h

@@ -0,0 +1,120 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    use_list.h
+
+Abstract:
+
+    Use list expression index.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2008-02-04.
+
+Revision History:
+
+--*/
+#ifndef _USE_LIST_H_
+#define _USE_LIST_H_
+
+#include"ast.h"
+#include"vector.h"
+
+/**
+   \brief Generic use-list data-structure.
+*/
+template<typename T>
+class use_list {
+    typedef vector<T> set;
+    vector<set> m_use_list;
+public:
+    typedef typename set::const_iterator iterator;
+    use_list() {}
+    
+    void insert(T const & parent, expr * child) {
+        unsigned id  = child->get_id();
+        if (id >= m_use_list.size())
+            m_use_list.resize(id+1, set());
+        set & s = m_use_list[id];
+        s.push_back(parent);
+    }
+    
+    void erase(T const & parent, expr * child) {
+        unsigned id  = child->get_id();
+        if (id >= m_use_list.size())
+            return;
+        set & s = m_use_list[id];
+        s.erase(parent);
+    }
+
+    void reset() {
+        m_use_list.reset();
+    }
+    
+    iterator begin(expr * e) const {
+        unsigned id = e->get_id();
+        if (id >= m_use_list.size())
+            return 0;
+        return m_use_list[id].begin();
+    }
+    
+    iterator end(expr * e) const {
+        unsigned id = e->get_id();
+        if (id >= m_use_list.size())
+            return 0;
+        return m_use_list[id].end();
+    }
+
+    bool empty(expr * e) const {
+        unsigned id = e->get_id();
+        if (id >= m_use_list.size())
+            return true;
+        return m_use_list[id].empty();
+    }
+};
+
+/**
+   \brief Index for tracking the uses of an expression. It is a
+   mapping from expressions to expressions. For example, consider the
+   term (f a (g a)), the constant a is used by f and g applications.
+   
+   \remark The expressions inserted in this index should not contain
+   quantifiers.
+
+   \warning This index will not increase the reference counter of the
+   indexed expressions.
+*/
+class app_use_list : use_list<app*> {
+    
+    bool m_ignore_vars; //!< when true, variables are not indexed
+    unsigned_vector  m_ref_counter;
+    ptr_vector<app> m_todo;
+
+    void inc_ref(app * n);
+    void dec_ref(app * n);
+
+public:
+    /**
+       \brief If ignore_vars = true, then the index will not track
+       the use of variables.
+    */
+    app_use_list(bool ignore_vars = true):
+        m_ignore_vars(ignore_vars) {
+    }
+
+    /**
+       \brief Update the use list of all direct/indirect children of n.
+    */
+    void insert(expr * n);
+
+    /**
+       \brief Remove n (and its unreachable direct/indirect children) from the index.
+    */
+    void erase(expr * n);
+    
+    void reset();
+};
+
+#endif /* _USE_LIST_H_ */