Implement noinit_allocator_adaptor

test/noinit_adaptor_test.cpp

@@ -0,0 +1,107 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/default_allocator.hpp>
+#include <boost/core/noinit_adaptor.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <vector>
+
+template<class T>
+class creator
+    : public boost::default_allocator<T> {
+public:
+    template<class U>
+    struct rebind {
+        typedef creator<U> other;
+    };
+
+    creator(int* count)
+        : count_(count) { }
+
+    template<class U>
+    creator(const creator<U>& other)
+        : count_(other.count()) { }
+
+    template<class U, class V>
+    void construct(U*, const V&) {
+        ++(*count_);
+    }
+
+    template<class U>
+    void destroy(U*) {
+        --(*count_);
+    }
+
+    int* count() const {
+        return count_;
+    }
+
+private:
+    int* count_;
+};
+
+template<class T, class U>
+inline bool
+operator==(const creator<T>& lhs, const creator<U>& rhs)
+{
+    return lhs.count() == rhs.count();
+}
+
+template<class T, class U>
+inline bool
+operator!=(const creator<T>& lhs, const creator<U>& rhs)
+{
+    return !(lhs == rhs);
+}
+
+class type {
+public:
+    type() { }
+
+    type(int value)
+        : value_(value) { }
+
+    int value() const {
+        return value_;
+    }
+
+private:
+    int value_;
+};
+
+int main()
+{
+    {
+        int c = 0;
+        std::vector<int, boost::noinit_adaptor<creator<int> > > v(&c);
+        BOOST_TEST(c == 0);
+        v.push_back(1);
+        BOOST_TEST(v.front() == 1);
+        v.push_back(2);
+        BOOST_TEST(c == 0);
+        v.clear();
+        BOOST_TEST(c == 0);
+        v.resize(5);
+        BOOST_TEST(c == 0);
+        v.front() = 1;
+    }
+    {
+        int c = 0;
+        std::vector<type, boost::noinit_adaptor<creator<type> > > v(&c);
+        BOOST_TEST(c == 0);
+        v.push_back(1);
+        BOOST_TEST(v.front().value() == 1);
+        v.push_back(2);
+        BOOST_TEST(c == 0);
+        v.clear();
+        BOOST_TEST(c == 0);
+        v.resize(5);
+        BOOST_TEST(c == 0);
+        v.front() = 1;
+    }
+    return boost::report_errors();
+}