Z3 sources

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

lib/permutation.cpp

@@ -0,0 +1,76 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    permutation.cpp
+
+Abstract:
+
+    Goodies for managing permutations.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-06-10.
+
+Revision History:
+
+--*/
+#include"permutation.h"
+
+permutation::permutation(unsigned size) {
+    reset(size);
+}
+
+void permutation::reset(unsigned size) {
+    m_p.reset();
+    m_inv_p.reset();
+    for (unsigned i = 0; i < size; i++) {
+        m_p.push_back(i);
+        m_inv_p.push_back(i);
+    }
+}
+
+void permutation::swap(unsigned i, unsigned j) {
+    unsigned i_prime = m_p[i];
+    unsigned j_prime = m_p[j];
+    std::swap(m_p[i], m_p[j]);
+    std::swap(m_inv_p[i_prime], m_inv_p[j_prime]); 
+}
+
+/**
+   \brief Move i after j.
+*/
+void permutation::move_after(unsigned i, unsigned j) {
+    if (i >= j)
+        return;
+    unsigned i_prime = m_p[i];
+    for (unsigned k = i; k < j; k++) {
+        m_p[k] = m_p[k+1];
+        m_inv_p[m_p[k]] = k;
+    }
+    m_p[j] = i_prime;
+    m_inv_p[i_prime] = j;
+    SASSERT(check_invariant());
+}
+
+void permutation::display(std::ostream & out) const {
+    unsigned n = m_p.size();
+    for (unsigned i = 0; i < n; i++) {
+        if (i > 0)
+            out << " ";
+        out << i << ":" << m_p[i];
+    }
+}
+
+bool permutation::check_invariant() const {
+    SASSERT(m_p.size() == m_inv_p.size());
+    unsigned n = m_p.size();
+    for (unsigned i = 0; i < n; i++) {
+        SASSERT(m_p[i] < n);
+        SASSERT(m_inv_p[i] < n);
+        SASSERT(m_p[m_inv_p[i]] == i);
+        SASSERT(m_inv_p[m_p[i]] == i);
+    }
+    return true;
+}