Z3 sources

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

lib/approx_nat.h

@@ -0,0 +1,45 @@
+/*++
+Copyright (c) 2007 Microsoft Corporation
+
+Module Name:
+
+    approx_nat.h
+
+Abstract:
+
+    Approximated natural numbers. It performs operations on the set [0, ..., 2^{n-2}, huge].
+    Where huge represents all numbers greater than 2^{n-2}. 
+
+Author:
+
+    Leonardo (leonardo) 2008-01-11
+
+Notes:
+
+--*/
+#ifndef _APPROX_NAT_H_
+#define _APPROX_NAT_H_
+
+#include<iostream>
+#include<limits.h>
+
+class approx_nat {
+    unsigned m_value;
+    static const unsigned m_limit = UINT_MAX >> 2;
+public:
+    approx_nat():m_value(0) {}
+    explicit approx_nat(unsigned val);
+    bool is_huge() const { return m_value == UINT_MAX; }
+    unsigned get_value() const { return m_value; }
+    approx_nat & operator=(unsigned w);
+    approx_nat & operator+=(unsigned w);
+    approx_nat & operator+=(approx_nat const & w) { return operator+=(w.m_value); }
+    approx_nat & operator*=(unsigned w);
+    approx_nat & operator*=(approx_nat const & w) { return operator*=(w.m_value); }
+    bool operator<(unsigned w) const { return !is_huge() && m_value < w; }
+    bool operator<(approx_nat const & w) const { return !is_huge() && !w.is_huge() && m_value < w.m_value; }
+};
+
+std::ostream & operator<<(std::ostream & target, approx_nat const & w);
+
+#endif /* _APPROX_NAT_H_ */