emons branch

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

src/util/lp/incremental_vector.h

@@ -0,0 +1,76 @@
+/*++
+Copyright (c) 2017 Microsoft Corporation
+
+Module Name:
+
+    <name>
+
+Abstract:
+
+    <abstract>
+
+Author:
+
+    Lev Nachmanson (levnach)
+
+Revision History:
+
+
+--*/
+
+#pragma once
+#include <unordered_map>
+#include <set>
+#include <stack>
+#include "util/vector.h"
+namespace lp {
+template <typename B> class incremental_vector {
+    vector<unsigned> m_stack_of_vector_sizes;
+    vector<B> m_vector;
+public:
+    const B & operator[](unsigned a) const {
+        return m_vector[a];
+    }
+
+    unsigned size() const {
+        return m_vector.size();
+    }
+    
+    void push() {
+        m_stack_of_vector_sizes.push_back(m_vector.size());
+    }
+
+    void pop() {
+        pop(1);
+    }
+
+    template <typename T>  
+    void pop_tail(vector<T> & v, unsigned k) {
+        lp_assert(v.size() >= k);
+        v.shrink(v.size() - k);
+    }
+
+    template <typename T>  
+    void resize(vector<T> & v, unsigned new_size) {
+        v.resize(new_size);
+    }
+
+    void pop(unsigned k) {
+        lp_assert(m_stack_of_vector_sizes.size() >= k);
+        lp_assert(k > 0);
+        m_vector.shrink(peek_size(k));
+        unsigned new_st_size = m_stack_of_vector_sizes.size() - k;
+        m_stack_of_vector_sizes.shrink(k);
+    }
+
+    void push_back(const B & b) {
+        m_vector.push_back(b);
+    }
+
+    unsigned peek_size(unsigned k) const {
+        lp_assert(k > 0 && k <= m_stack_of_vector_sizes.size());
+        return m_stack_of_vector_sizes[m_stack_of_vector_sizes.size() - k];
+    }
+};
+}
+