1 files changed, 290 insertions, 0 deletions
diff --git a/boost/context/execution_context_v2_void.ipp b/boost/context/execution_context_v2_void.ipp
new file mode 100644
index 0000000000..d0659beafb
--- /dev/null
+++ b/boost/context/execution_context_v2_void.ipp
@@ -0,0 +1,290 @@
+
+//          Copyright Oliver Kowalke 2014.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+namespace detail {
+
+template< typename Ctx, typename Fn >
+transfer_t context_ontop_void( transfer_t t) {
+    auto tpl = static_cast< std::tuple< Fn > * >( t.data);
+    BOOST_ASSERT( nullptr != tpl);
+    typename std::decay< Fn >::type fn = std::forward< Fn >( std::get< 0 >( * tpl) );
+    Ctx ctx{ t.fctx };
+    // execute function
+    ctx = apply(
+            fn,
+            std::forward_as_tuple( std::move( ctx) ) );
+    return { exchange( ctx.fctx_, nullptr), nullptr };
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn, typename ... Params >
+class record_void {
+private:
+    StackAlloc                                          salloc_;
+    stack_context                                       sctx_;
+    typename std::decay< Fn >::type                     fn_;
+    std::tuple< typename std::decay< Params >::type ... > params_;
+
+    static void destroy( record_void * p) noexcept {
+        StackAlloc salloc = p->salloc_;
+        stack_context sctx = p->sctx_;
+        // deallocate record
+        p->~record_void();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    record_void( stack_context sctx, StackAlloc const& salloc,
+            Fn && fn, Params && ... params) noexcept :
+        salloc_( salloc),
+        sctx_( sctx),
+        fn_( std::forward< Fn >( fn) ),
+        params_( std::forward< Params >( params) ... ) {
+    }
+
+    record_void( record_void const&) = delete;
+    record_void & operator=( record_void const&) = delete;
+
+    void deallocate() noexcept {
+        destroy( this);
+    }
+
+    transfer_t run( transfer_t t) {
+        Ctx from{ t.fctx };
+        // invoke context-function
+        Ctx cc = apply(
+                fn_,
+                std::tuple_cat(
+                    params_,
+                    std::forward_as_tuple( std::move( from) ) ) );
+        return { exchange( cc.fctx_, nullptr), nullptr };
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn, typename ... Params >
+fcontext_t context_create_void( StackAlloc salloc, Fn && fn, Params && ... params) {
+    typedef record_void< Ctx, StackAlloc, Fn, Params ... >  record_t;
+
+    auto sctx = salloc.allocate();
+    // reserve space for control structure
+#if defined(BOOST_NO_CXX11_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
+    const std::size_t size = sctx.size - sizeof( record_t);
+    void * sp = static_cast< char * >( sctx.sp) - sizeof( record_t);
+#else
+    constexpr std::size_t func_alignment = 64; // alignof( record_t);
+    constexpr std::size_t func_size = sizeof( record_t);
+    // reserve space on stack
+    void * sp = static_cast< char * >( sctx.sp) - func_size - func_alignment;
+    // align sp pointer
+    std::size_t space = func_size + func_alignment;
+    sp = std::align( func_alignment, func_size, sp, space);
+    BOOST_ASSERT( nullptr != sp);
+    // calculate remaining size
+    const std::size_t size = sctx.size - ( static_cast< char * >( sctx.sp) - static_cast< char * >( sp) );
+#endif
+    // create fast-context
+    const fcontext_t fctx = make_fcontext( sp, size, & context_entry< record_t >);
+    BOOST_ASSERT( nullptr != fctx);
+    // placment new for control structure on context-stack
+    auto rec = ::new ( sp) record_t{
+            sctx, salloc, std::forward< Fn >( fn), std::forward< Params >( params) ... };
+    // transfer control structure to context-stack
+    return jump_fcontext( fctx, rec).fctx;
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn, typename ... Params >
+fcontext_t context_create_void( preallocated palloc, StackAlloc salloc, Fn && fn, Params && ... params) {
+    typedef record_void< Ctx, StackAlloc, Fn, Params ... >  record_t;
+
+    // reserve space for control structure
+#if defined(BOOST_NO_CXX11_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
+    const std::size_t size = palloc.size - sizeof( record_t);
+    void * sp = static_cast< char * >( palloc.sp) - sizeof( record_t);
+#else
+    constexpr std::size_t func_alignment = 64; // alignof( record_t);
+    constexpr std::size_t func_size = sizeof( record_t);
+    // reserve space on stack
+    void * sp = static_cast< char * >( palloc.sp) - func_size - func_alignment;
+    // align sp pointer
+    std::size_t space = func_size + func_alignment;
+    sp = std::align( func_alignment, func_size, sp, space);
+    BOOST_ASSERT( nullptr != sp);
+    // calculate remaining size
+    const std::size_t size = palloc.size - ( static_cast< char * >( palloc.sp) - static_cast< char * >( sp) );
+#endif
+    // create fast-context
+    const fcontext_t fctx = make_fcontext( sp, size, & context_entry< record_t >);
+    BOOST_ASSERT( nullptr != fctx);
+    // placment new for control structure on context-stack
+    auto rec = ::new ( sp) record_t{
+            palloc.sctx, salloc, std::forward< Fn >( fn), std::forward< Params >( params) ... };
+    // transfer control structure to context-stack
+    return jump_fcontext( fctx, rec).fctx;
+}
+
+}
+
+template<>
+class execution_context< void > {
+private:
+    template< typename Ctx, typename StackAlloc, typename Fn, typename ... Params >
+    friend class detail::record_void;
+
+    template< typename Ctx, typename Fn >
+    friend detail::transfer_t detail::context_ontop_void( detail::transfer_t);
+
+    detail::fcontext_t  fctx_{ nullptr };
+
+    execution_context( detail::fcontext_t fctx) noexcept :
+        fctx_( fctx) {
+    }
+
+public:
+    constexpr execution_context() noexcept = default;
+
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+    // segmented-stack requires to preserve the segments of the `current` context
+    // which is not possible (no global pointer to current context)
+    template< typename Fn, typename ... Params >
+    execution_context( std::allocator_arg_t, segmented_stack, Fn &&, Params && ...) = delete;
+
+    template< typename Fn, typename ... Params >
+    execution_context( std::allocator_arg_t, preallocated, segmented_stack, Fn &&, Params && ...) = delete;
+#else
+    template< typename Fn,
+              typename ... Params,
+              typename = detail::disable_overload< execution_context, Fn >
+    >
+    execution_context( Fn && fn, Params && ... params) :
+        // deferred execution of fn and its arguments
+        // arguments are stored in std::tuple<>
+        // non-type template parameter pack via std::index_sequence_for<>
+        // preserves the number of arguments
+        // used to extract the function arguments from std::tuple<>
+        fctx_( detail::context_create_void< execution_context >(
+                    fixedsize_stack(),
+                    std::forward< Fn >( fn),
+                    std::forward< Params >( params) ... ) ) {
+    }
+
+    template< typename StackAlloc,
+              typename Fn,
+              typename ... Params
+    >
+    execution_context( std::allocator_arg_t, StackAlloc salloc, Fn && fn, Params && ... params) :
+        // deferred execution of fn and its arguments
+        // arguments are stored in std::tuple<>
+        // non-type template parameter pack via std::index_sequence_for<>
+        // preserves the number of arguments
+        // used to extract the function arguments from std::tuple<>
+        fctx_( detail::context_create_void< execution_context >(
+                    salloc,
+                    std::forward< Fn >( fn),
+                    std::forward< Params >( params) ... ) ) {
+    }
+
+    template< typename StackAlloc,
+              typename Fn,
+              typename ... Params
+    >
+    execution_context( std::allocator_arg_t, preallocated palloc, StackAlloc salloc, Fn && fn, Params && ... params) :
+        // deferred execution of fn and its arguments
+        // arguments are stored in std::tuple<>
+        // non-type template parameter pack via std::index_sequence_for<>
+        // preserves the number of arguments
+        // used to extract the function arguments from std::tuple<>
+        fctx_( detail::context_create_void< execution_context >(
+                    palloc, salloc,
+                    std::forward< Fn >( fn),
+                    std::forward< Params >( params) ... ) ) {
+    }
+#endif
+
+    ~execution_context() {
+        if ( nullptr != fctx_) {
+            detail::ontop_fcontext( detail::exchange( fctx_, nullptr), nullptr, detail::context_unwind);
+        }
+    }
+
+    execution_context( execution_context && other) noexcept :
+        fctx_( other.fctx_) {
+        other.fctx_ = nullptr;
+    }
+
+    execution_context & operator=( execution_context && other) noexcept {
+        if ( this != & other) {
+            execution_context tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    execution_context( execution_context const& other) noexcept = delete;
+    execution_context & operator=( execution_context const& other) noexcept = delete;
+
+    execution_context operator()() {
+        BOOST_ASSERT( nullptr != fctx_);
+        detail::transfer_t t = detail::jump_fcontext( detail::exchange( fctx_, nullptr), nullptr);
+        return execution_context( t.fctx);
+    }
+
+    template< typename Fn >
+    execution_context operator()( exec_ontop_arg_t, Fn && fn) {
+        BOOST_ASSERT( nullptr != fctx_);
+        std::tuple< Fn > p = std::forward_as_tuple( fn);
+        detail::transfer_t t = detail::ontop_fcontext(
+                detail::exchange( fctx_, nullptr),
+                & p,
+                detail::context_ontop_void< execution_context, Fn >);
+        return execution_context( t.fctx);
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != fctx_;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == fctx_;
+    }
+
+    bool operator==( execution_context const& other) const noexcept {
+        return fctx_ == other.fctx_;
+    }
+
+    bool operator!=( execution_context const& other) const noexcept {
+        return fctx_ != other.fctx_;
+    }
+
+    bool operator<( execution_context const& other) const noexcept {
+        return fctx_ < other.fctx_;
+    }
+
+    bool operator>( execution_context const& other) const noexcept {
+        return other.fctx_ < fctx_;
+    }
+
+    bool operator<=( execution_context const& other) const noexcept {
+        return ! ( * this > other);
+    }
+
+    bool operator>=( execution_context const& other) const noexcept {
+        return ! ( * this < other);
+    }
+
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, execution_context const& other) {
+        if ( nullptr != other.fctx_) {
+            return os << other.fctx_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    void swap( execution_context & other) noexcept {
+        std::swap( fctx_, other.fctx_);
+    }
+};