Z3 sources

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

lib/approx_nat.cpp

@@ -0,0 +1,61 @@
+/*++
+Copyright (c) 2007 Microsoft Corporation
+
+Module Name:
+
+    approx_nat.cpp
+
+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:
+
+--*/
+#include"approx_nat.h"
+
+approx_nat::approx_nat(unsigned val) {
+    m_value = val > m_limit ? UINT_MAX : val;
+}
+
+approx_nat & approx_nat::operator=(unsigned val) {
+    m_value = val > m_limit ? UINT_MAX : val;
+    return *this;
+}
+
+approx_nat & approx_nat::operator+=(unsigned w) {
+    if (is_huge()) 
+        return *this;
+    if (w > m_limit) {
+        m_value = UINT_MAX;
+        return *this;
+    }
+    m_value += w;
+    if (m_value > m_limit)
+        m_value = UINT_MAX;
+    return *this;
+}
+
+approx_nat & approx_nat::operator*=(unsigned w) {
+    if (is_huge()) 
+        return *this;
+    unsigned long long r = static_cast<unsigned long long>(m_value) * static_cast<unsigned long long>(w);
+    if (r > m_limit)
+        m_value = UINT_MAX;
+    else
+        m_value = static_cast<unsigned>(r);
+    return *this;
+}
+
+std::ostream & operator<<(std::ostream & target, approx_nat const & w) {
+    if (w.is_huge()) 
+        target << "[huge]";
+    else
+        target << w.get_value();
+    return target;
+}