Merge branch 'value-init' into develop

boostorg · Jun 25, 2016 · da9ad91 · da9ad91
2 parents bbdd63b + f9cd490
commit da9ad91
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Showing 3 changed files with 129 additions and 5 deletions.
diff --git a/.travis.yml b/.travis.yml
@@ -168,7 +168,7 @@ script:
 
     - |
       for build_type in debug minsizerel release; do
-        for asan_type in ASANVARIANT; do
+        for asan_type in $ASANVARIANT; do
           build_dir="build-$build_type-asan-$asan_type"
           mkdir $build_dir
           cd $build_dir

diff --git a/include/fit/construct.hpp b/include/fit/construct.hpp
@@ -85,8 +85,75 @@ struct by_adaptor;
 
 namespace detail {
 
-template<class T>
+template<class T, class=void>
 struct construct_f
+{
+    typedef typename std::aligned_storage<sizeof(T)>::type storage;
+
+    struct storage_holder
+    {
+        storage * s;
+        storage_holder(storage* x) : s(x)
+        {}
+
+        T& data()
+        {
+            return *reinterpret_cast<T*>(s);
+        }
+
+        ~storage_holder()
+        {
+            this->data().~T();
+        }
+    };
+
+    constexpr construct_f()
+    {}
+    template<class... Ts, FIT_ENABLE_IF_CONSTRUCTIBLE(T, Ts...)>
+    T operator()(Ts&&... xs) const
+    {
+        storage buffer{};
+        new(&buffer) T(FIT_FORWARD(Ts)(xs)...);
+        storage_holder h(&buffer);
+        return h.data();
+    }
+
+    template<class X, FIT_ENABLE_IF_CONSTRUCTIBLE(T, std::initializer_list<X>&&)>
+    T operator()(std::initializer_list<X>&& x) const
+    {
+        storage buffer{};
+        new(&buffer) T(static_cast<std::initializer_list<X>&&>(x));
+        storage_holder h(&buffer);
+        return h.data();
+    }
+
+    template<class X, FIT_ENABLE_IF_CONSTRUCTIBLE(T, std::initializer_list<X>&)>
+    T operator()(std::initializer_list<X>& x) const
+    {
+        storage buffer{};
+        new(&buffer) T(x);
+        storage_holder h(&buffer);
+        return h.data();
+    }
+
+    template<class X, FIT_ENABLE_IF_CONSTRUCTIBLE(T, const std::initializer_list<X>&)>
+    T operator()(const std::initializer_list<X>& x) const
+    {
+        storage buffer{};
+        new(&buffer) T(x);
+        storage_holder h(&buffer);
+        return h.data();
+    }
+
+    template<class F>
+    constexpr by_adaptor<F, construct_f> by(F f) const
+    {
+        return by_adaptor<F, construct_f>(static_cast<F&&>(f), *this);
+    }
+};
+
+template<class T>
+struct construct_f<T, typename std::enable_if<FIT_IS_LITERAL(T)>::type>
 {
     constexpr construct_f()
     {}
@@ -130,7 +197,7 @@ struct construct_template_f
         FIT_ENABLE_IF_CONSTRUCTIBLE(Result, Ts...)>
     constexpr Result operator()(Ts&&... xs) const
     {
-        return Result(FIT_FORWARD(Ts)(xs)...);
+        return construct_f<Result>()(FIT_FORWARD(Ts)(xs)...);
     }
 
     template<class F>
@@ -157,7 +224,7 @@ struct construct_meta_f
         FIT_ENABLE_IF_CONSTRUCTIBLE(Result, Ts...)>
     constexpr Result operator()(Ts&&... xs) const
     {
-        return Result(FIT_FORWARD(Ts)(xs)...);
+        return construct_f<Result>()(FIT_FORWARD(Ts)(xs)...);
     }
 
     template<class F>
@@ -178,7 +245,7 @@ struct construct_meta_template_f
         FIT_ENABLE_IF_CONSTRUCTIBLE(Result, Ts...)>
     constexpr Result operator()(Ts&&... xs) const
     {
-        return Result(FIT_FORWARD(Ts)(xs)...);
+        return construct_f<Result>()(FIT_FORWARD(Ts)(xs)...);
     }
 
     template<class F>

diff --git a/test/construct.cpp b/test/construct.cpp
@@ -32,13 +32,70 @@ struct tuple_meta_class
     };
 };
 
+struct implicit_default
+{
+    int mem1;
+    std::string mem2;
+};
+
+struct user_default
+{
+    int mem1;
+    std::string mem2;
+    user_default() { }
+};
+
+struct user_construct
+{
+    int mem1;
+    std::string mem2;
+    user_construct(int) { }
+};
+
+template<class T>
+struct template_user_construct
+{
+    int mem1;
+    std::string mem2;
+    template_user_construct(T) { }
+};
+
+
 FIT_TEST_CASE()
 {
     auto v = fit::construct<std::vector<int>>()(5, 5);
     FIT_TEST_CHECK(v.size() == 5);
     FIT_TEST_CHECK(v == std::vector<int>{5, 5, 5, 5, 5});
 }
 
+FIT_TEST_CASE()
+{
+    auto x = fit::construct<implicit_default>()();
+    FIT_TEST_CHECK(x.mem1 == 0);
+    FIT_TEST_CHECK(x.mem2 == "");
+}
+
+FIT_TEST_CASE()
+{
+    auto x = fit::construct<user_default>()();
+    FIT_TEST_CHECK(x.mem1 == 0);
+    FIT_TEST_CHECK(x.mem2 == "");
+}
+
+FIT_TEST_CASE()
+{
+    auto x = fit::construct<user_construct>()(3);
+    FIT_TEST_CHECK(x.mem1 == 0);
+    FIT_TEST_CHECK(x.mem2 == "");
+}
+
+FIT_TEST_CASE()
+{
+    auto x = fit::construct<template_user_construct>()(3);
+    FIT_TEST_CHECK(x.mem1 == 0);
+    FIT_TEST_CHECK(x.mem2 == "");
+}
+
 FIT_TEST_CASE()
 {
     auto make = fit::construct<std::vector<int>>().by(fit::_1 * fit::_1);