整理

include/boost/smart_ptr/allocate_shared_array.hpp

@@ -0,0 +1,346 @@
+/*
+Copyright 2012-2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_SMART_PTR_ALLOCATE_SHARED_ARRAY_HPP
+#define BOOST_SMART_PTR_ALLOCATE_SHARED_ARRAY_HPP
+
+#include <boost/core/allocator_access.hpp>
+#include <boost/core/alloc_construct.hpp>
+#include <boost/core/first_scalar.hpp>
+#include <boost/smart_ptr/shared_ptr.hpp>
+#include <boost/smart_ptr/detail/sp_type_traits.hpp>
+#include <type_traits>
+
+namespace boost {
+namespace detail {
+
+template<class T>
+struct sp_array_element {
+    typedef typename std::remove_cv<typename
+        std::remove_extent<T>::type>::type type;
+};
+
+template<class T>
+struct sp_array_count {
+    enum {
+        value = 1
+    };
+};
+
+template<class T, std::size_t N>
+struct sp_array_count<T[N]> {
+    enum {
+        value = N * sp_array_count<T>::value
+    };
+};
+
+template<std::size_t N, std::size_t M>
+struct sp_max_size {
+    enum {
+        value = N < M ? M : N
+    };
+};
+
+template<std::size_t N, std::size_t M>
+struct sp_align_up {
+    enum {
+        value = (N + M - 1) & ~(M - 1)
+    };
+};
+
+template<class T>
+constexpr inline std::size_t
+sp_objects(std::size_t size) noexcept
+{
+    return (size + sizeof(T) - 1) / sizeof(T);
+}
+
+template<class A>
+class sp_array_state {
+public:
+    typedef A type;
+
+    template<class U>
+    sp_array_state(const U& _allocator, std::size_t _size) noexcept
+        : allocator_(_allocator),
+          size_(_size) { }
+
+    A& allocator() noexcept {
+        return allocator_;
+    }
+
+    std::size_t size() const noexcept {
+        return size_;
+    }
+
+private:
+    A allocator_;
+    std::size_t size_;
+};
+
+template<class A, std::size_t N>
+class sp_size_array_state {
+public:
+    typedef A type;
+
+    template<class U>
+    sp_size_array_state(const U& _allocator, std::size_t) noexcept
+        : allocator_(_allocator) { }
+
+    A& allocator() noexcept {
+        return allocator_;
+    }
+
+    constexpr std::size_t size() const noexcept {
+        return N;
+    }
+
+private:
+    A allocator_;
+};
+
+template<class T, class U>
+struct sp_array_alignment {
+    enum {
+        value = sp_max_size<std::alignment_of<T>::value,
+            std::alignment_of<U>::value>::value
+    };
+};
+
+template<class T, class U>
+struct sp_array_offset {
+    enum {
+        value = sp_align_up<sizeof(T), sp_array_alignment<T, U>::value>::value
+    };
+};
+
+template<class U, class T>
+inline U*
+sp_array_start(T* base) noexcept
+{
+    enum {
+        size = sp_array_offset<T, U>::value
+    };
+    return reinterpret_cast<U*>(reinterpret_cast<char*>(base) + size);
+}
+
+template<class A, class T>
+class sp_array_creator {
+    typedef typename A::value_type element;
+
+    enum {
+        offset = sp_array_offset<T, element>::value
+    };
+
+    typedef typename sp_type_with_alignment<sp_array_alignment<T,
+        element>::value>::type type;
+
+public:
+    template<class U>
+    sp_array_creator(const U& other, std::size_t size) noexcept
+        : other_(other),
+          size_(sp_objects<type>(offset + sizeof(element) * size)) { }
+
+    T* create() {
+        return reinterpret_cast<T*>(other_.allocate(size_));
+    }
+
+    void destroy(T* base) {
+        other_.deallocate(reinterpret_cast<type*>(base), size_);
+    }
+
+private:
+    typename boost::allocator_rebind<A, type>::type other_;
+    std::size_t size_;
+};
+
+template<class T>
+class BOOST_SYMBOL_VISIBLE sp_array_base
+    : public sp_counted_base {
+    typedef typename T::type allocator;
+
+public:
+    typedef typename allocator::value_type type;
+
+    template<class A>
+    sp_array_base(const A& other, type* start, std::size_t size)
+        : state_(other, size) {
+        boost::alloc_construct_n(state_.allocator(),
+            boost::first_scalar(start),
+            state_.size() * sp_array_count<type>::value);
+    }
+
+    template<class A, class U>
+    sp_array_base(const A& other, type* start, std::size_t size, const U& list)
+        : state_(other, size) {
+        enum {
+            count = sp_array_count<type>::value
+        };
+        boost::alloc_construct_n(state_.allocator(),
+            boost::first_scalar(start), state_.size() * count,
+            boost::first_scalar(&list), count);
+    }
+
+    T& state() noexcept {
+        return state_;
+    }
+
+    void dispose() noexcept override {
+        boost::alloc_destroy_n(state_.allocator(),
+            boost::first_scalar(sp_array_start<type>(this)),
+            state_.size() * sp_array_count<type>::value);
+    }
+
+    void destroy() noexcept override {
+        sp_array_creator<allocator, sp_array_base> other(state_.allocator(),
+            state_.size());
+        this->~sp_array_base();
+        other.destroy(this);
+    }
+
+    void* get_deleter(const sp_typeinfo_&) noexcept override {
+        return 0;
+    }
+
+    void* get_local_deleter(const sp_typeinfo_&)
+        noexcept override {
+        return 0;
+    }
+
+    void* get_untyped_deleter() noexcept override {
+        return 0;
+    }
+
+private:
+    T state_;
+};
+
+template<class A, class T>
+struct sp_array_result {
+public:
+    template<class U>
+    sp_array_result(const U& other, std::size_t size)
+        : creator_(other, size),
+          result_(creator_.create()) { }
+
+    ~sp_array_result() {
+        if (result_) {
+            creator_.destroy(result_);
+        }
+    }
+
+    T* get() const noexcept {
+        return result_;
+    }
+
+    void release() noexcept {
+        result_ = 0;
+    }
+
+private:
+    sp_array_result(const sp_array_result&);
+    sp_array_result& operator=(const sp_array_result&);
+
+    sp_array_creator<A, T> creator_;
+    T* result_;
+};
+
+} /* detail */
+
+template<class T, class A>
+inline typename std::enable_if<detail::sp_is_unbounded_array<T>::value, shared_ptr<T> >::type
+allocate_shared(const A& allocator, std::size_t count)
+{
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename allocator_rebind<A, element>::type other;
+    typedef detail::sp_array_state<other> state;
+    typedef detail::sp_array_base<state> base;
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count);
+    result.release();
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
+}
+
+template<class T, class A>
+inline typename std::enable_if<detail::sp_is_bounded_array<T>::value, shared_ptr<T> >::type
+allocate_shared(const A& allocator)
+{
+    enum {
+        count = std::extent<T>::value
+    };
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename allocator_rebind<A, element>::type other;
+    typedef detail::sp_size_array_state<other, std::extent<T>::value> state;
+    typedef detail::sp_array_base<state> base;
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count);
+    result.release();
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
+}
+
+template<class T, class A>
+inline typename std::enable_if<detail::sp_is_unbounded_array<T>::value, shared_ptr<T> >::type
+allocate_shared(const A& allocator, std::size_t count,
+    const typename std::remove_extent<T>::type& value)
+{
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename allocator_rebind<A, element>::type other;
+    typedef detail::sp_array_state<other> state;
+    typedef detail::sp_array_base<state> base;
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count, value);
+    result.release();
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
+}
+
+template<class T, class A>
+inline typename std::enable_if<detail::sp_is_bounded_array<T>::value, shared_ptr<T> >::type
+allocate_shared(const A& allocator,
+    const typename std::remove_extent<T>::type& value)
+{
+    enum {
+        count = std::extent<T>::value
+    };
+    typedef typename detail::sp_array_element<T>::type element;
+    typedef typename allocator_rebind<A, element>::type other;
+    typedef detail::sp_size_array_state<other, std::extent<T>::value> state;
+    typedef detail::sp_array_base<state> base;
+    detail::sp_array_result<other, base> result(allocator, count);
+    base* node = result.get();
+    element* start = detail::sp_array_start<element>(node);
+    ::new(static_cast<void*>(node)) base(allocator, start, count, value);
+    result.release();
+    return shared_ptr<T>(detail::sp_internal_constructor_tag(), start,
+        detail::shared_count(static_cast<detail::sp_counted_base*>(node)));
+}
+
+template<class T, class A>
+inline typename std::enable_if<detail::sp_is_unbounded_array<T>::value, shared_ptr<T> >::type
+allocate_shared_noinit(const A& allocator, std::size_t count)
+{
+    return boost::allocate_shared<T>(boost::noinit_adapt(allocator), count);
+}
+
+template<class T, class A>
+inline typename std::enable_if<detail::sp_is_bounded_array<T>::value, shared_ptr<T> >::type
+allocate_shared_noinit(const A& allocator)
+{
+    return boost::allocate_shared<T>(boost::noinit_adapt(allocator));
+}
+
+} /* boost */
+
+#endif