Z3 sources

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

lib/backtrackable_set.h

@@ -0,0 +1,114 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    backtrackable_set.h
+
+Abstract:
+
+    Quick hack for support backtrackable sets.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-01-08.
+
+Revision History:
+
+--*/
+#ifndef _BACKTRACKABLE_SET_H_
+#define _BACKTRACKABLE_SET_H_
+
+#include"vector.h"
+
+template<typename T>
+struct default_eh {
+    void operator()(T const & e, bool ins) {}
+};
+
+// quick hack for having backtrackable sets.
+//
+// EV is a big hack, it should be used with care.
+// 
+template<typename Set, typename T, typename EV=default_eh<T> >
+class backtrackable_set : private EV {
+    enum trail_kind { DEL, INS };
+    typedef std::pair<trail_kind, T> trail_obj;
+    Set                m_set;
+    svector<trail_obj> m_trail;
+    svector<unsigned>  m_scopes;
+
+public:
+    typedef typename Set::iterator iterator;
+    
+    backtrackable_set(EV const & ev = EV()):
+        EV(ev) {
+    }
+
+    void insert(T const & e) {
+        if (m_scopes.empty()) {
+            m_set.insert(e);
+        }
+        else if (!m_set.contains(e)) {
+            m_set.insert(e);
+            m_trail.push_back(std::make_pair(INS, e));
+        }
+    }
+                
+    void erase(T const & e) {
+        if (m_scopes.empty()) {
+            m_set.insert(e); 
+        }
+        else if (m_set.contains(e)) {
+            m_set.erase(e);
+            m_trail.push_back(std::make_pair(DEL, e));
+        }
+    }
+
+    bool contains(T const & e) const {
+        return m_set.contains(e);
+    }
+
+    bool empty() const {
+        return m_set.empty();
+    }
+
+    void push_scope() {
+        m_scopes.push_back(m_trail.size());
+    }
+
+    void pop_scope() {
+        unsigned old_sz  = m_scopes.back();
+        m_scopes.pop_back();
+        SASSERT(old_sz <= m_trail.size());
+        while (m_trail.size() > old_sz) {
+            trail_obj & t = m_trail.back();
+            if (t.first == INS) {
+                this->operator()(t.second, true);
+                m_set.erase(t.second);
+            }
+            else {
+                SASSERT(t.first == DEL);
+                this->operator()(t.second, false);
+                m_set.insert(t.second);
+            }
+            m_trail.pop_back();
+        }
+    }
+    
+    void reset() {
+        m_scopes.reset();
+        m_trail.reset();
+        m_set.reset();
+    }
+    
+    iterator begin() const {
+        return m_set.begin();
+    }
+    
+    iterator end() const {
+        return m_set.end();
+    }
+};
+
+#endif