early-access version 3088

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/continuation.hpp

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+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#if defined(BOOST_USE_UCONTEXT)
+#include <boost/context/continuation_ucontext.hpp>
+#elif defined(BOOST_USE_WINFIB)
+#include <boost/context/continuation_winfib.hpp>
+#else
+#include <boost/context/continuation_fcontext.hpp>
+#endif

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/continuation_fcontext.hpp

@@ -0,0 +1,370 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_CONTINUATION_H
+#define BOOST_CONTEXT_CONTINUATION_H
+
+#include <boost/context/detail/config.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <exception>
+#include <functional>
+#include <memory>
+#include <ostream>
+#include <tuple>
+#include <utility>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/intrusive_ptr.hpp>
+
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+#include <boost/context/detail/exchange.hpp>
+#endif
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/detail/disable_overload.hpp>
+#include <boost/context/detail/exception.hpp>
+#include <boost/context/detail/fcontext.hpp>
+#include <boost/context/detail/tuple.hpp>
+#include <boost/context/fixedsize_stack.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/preallocated.hpp>
+#include <boost/context/segmented_stack.hpp>
+#include <boost/context/stack_context.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+#if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable: 4702)
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+inline
+transfer_t context_unwind( transfer_t t) {
+    throw forced_unwind( t.fctx);
+    return { nullptr, nullptr };
+}
+
+template< typename Rec >
+transfer_t context_exit( transfer_t t) noexcept {
+    Rec * rec = static_cast< Rec * >( t.data);
+    // destroy context stack
+    rec->deallocate();
+    return { nullptr, nullptr };
+}
+
+template< typename Rec >
+void context_entry( transfer_t t) noexcept {
+    // transfer control structure to the context-stack
+    Rec * rec = static_cast< Rec * >( t.data);
+    BOOST_ASSERT( nullptr != t.fctx);
+    BOOST_ASSERT( nullptr != rec);
+    try {
+        // jump back to `create_context()`
+        t = jump_fcontext( t.fctx, nullptr);
+        // start executing
+        t.fctx = rec->run( t.fctx);
+    } catch ( forced_unwind const& ex) {
+        t = { ex.fctx, nullptr };
+    }
+    BOOST_ASSERT( nullptr != t.fctx);
+    // destroy context-stack of `this`context on next context
+    ontop_fcontext( t.fctx, rec, context_exit< Rec >);
+    BOOST_ASSERT_MSG( false, "context already terminated");
+}
+
+template< typename Ctx, typename Fn >
+transfer_t context_ontop( transfer_t t) {
+    auto p = static_cast< std::tuple< Fn > * >( t.data);
+    BOOST_ASSERT( nullptr != p);
+    typename std::decay< Fn >::type fn = std::get< 0 >( * p);
+    t.data = nullptr;
+    Ctx c{ t.fctx };
+    // execute function, pass continuation via reference
+    c = fn( std::move( c) );
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+    return { exchange( c.fctx_, nullptr), nullptr };
+#else
+    return { std::exchange( c.fctx_, nullptr), nullptr };
+#endif
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+class record {
+private:
+    stack_context                                       sctx_;
+    typename std::decay< StackAlloc >::type             salloc_;
+    typename std::decay< Fn >::type                     fn_;
+
+    static void destroy( record * p) noexcept {
+        typename std::decay< StackAlloc >::type salloc = std::move( p->salloc_);
+        stack_context sctx = p->sctx_;
+        // deallocate record
+        p->~record();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    record( stack_context sctx, StackAlloc && salloc,
+            Fn && fn) noexcept :
+        sctx_( sctx),
+        salloc_( std::forward< StackAlloc >( salloc)),
+        fn_( std::forward< Fn >( fn) ) {
+    }
+
+    record( record const&) = delete;
+    record & operator=( record const&) = delete;
+
+    void deallocate() noexcept {
+        destroy( this);
+    }
+
+    fcontext_t run( fcontext_t fctx) {
+        Ctx c{ fctx };
+        // invoke context-function
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+        c = boost::context::detail::invoke( fn_, std::move( c) );
+#else
+        c = std::invoke( fn_, std::move( c) );
+#endif
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return exchange( c.fctx_, nullptr);
+#else
+        return std::exchange( c.fctx_, nullptr);
+#endif
+    }
+};
+
+template< typename Record, typename StackAlloc, typename Fn >
+fcontext_t create_context1( StackAlloc && salloc, Fn && fn) {
+    auto sctx = salloc.allocate();
+    // reserve space for control structure
+	void * storage = reinterpret_cast< void * >(
+			( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( Record) ) )
+            & ~static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    Record * record = new ( storage) Record{
+            sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // 64byte gab between control structure and stack top
+    // should be 16byte aligned
+    void * stack_top = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( storage) - static_cast< uintptr_t >( 64) );
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sctx.size) );
+    // create fast-context
+    const std::size_t size = reinterpret_cast< uintptr_t >( stack_top) - reinterpret_cast< uintptr_t >( stack_bottom);
+    const fcontext_t fctx = make_fcontext( stack_top, size, & context_entry< Record >);
+    BOOST_ASSERT( nullptr != fctx);
+    // transfer control structure to context-stack
+    return jump_fcontext( fctx, record).fctx;
+}
+
+template< typename Record, typename StackAlloc, typename Fn >
+fcontext_t create_context2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( palloc.sp) - static_cast< uintptr_t >( sizeof( Record) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context-stack
+    Record * record = new ( storage) Record{
+            palloc.sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // 64byte gab between control structure and stack top
+    void * stack_top = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( storage) - static_cast< uintptr_t >( 64) );
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( palloc.sctx.sp) - static_cast< uintptr_t >( palloc.sctx.size) );
+    // create fast-context
+    const std::size_t size = reinterpret_cast< uintptr_t >( stack_top) - reinterpret_cast< uintptr_t >( stack_bottom);
+    const fcontext_t fctx = make_fcontext( stack_top, size, & context_entry< Record >);
+    BOOST_ASSERT( nullptr != fctx);
+    // transfer control structure to context-stack
+    return jump_fcontext( fctx, record).fctx;
+}
+
+}
+
+class continuation {
+private:
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend class detail::record;
+
+    template< typename Ctx, typename Fn >
+    friend detail::transfer_t
+    detail::context_ontop( detail::transfer_t);
+
+    template< typename StackAlloc, typename Fn >
+    friend continuation
+    callcc( std::allocator_arg_t, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend continuation
+    callcc( std::allocator_arg_t, preallocated, StackAlloc &&, Fn &&);
+
+    detail::fcontext_t  fctx_{ nullptr };
+
+    continuation( detail::fcontext_t fctx) noexcept :
+        fctx_{ fctx } {
+    }
+
+public:
+    continuation() noexcept = default;
+
+    ~continuation() {
+        if ( BOOST_UNLIKELY( nullptr != fctx_) ) {
+            detail::ontop_fcontext(
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    detail::exchange( fctx_, nullptr),
+#else
+                    std::exchange( fctx_, nullptr),
+#endif
+                   nullptr,
+                   detail::context_unwind);
+        }
+    }
+
+    continuation( continuation && other) noexcept {
+        swap( other);
+    }
+
+    continuation & operator=( continuation && other) noexcept {
+        if ( BOOST_LIKELY( this != & other) ) {
+            continuation tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    continuation( continuation const& other) noexcept = delete;
+    continuation & operator=( continuation const& other) noexcept = delete;
+
+    continuation resume() & {
+        return std::move( * this).resume();
+    }
+
+    continuation resume() && {
+        BOOST_ASSERT( nullptr != fctx_);
+        return { detail::jump_fcontext(
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    detail::exchange( fctx_, nullptr),
+#else
+                    std::exchange( fctx_, nullptr),
+#endif
+                    nullptr).fctx };
+    }
+
+    template< typename Fn >
+    continuation resume_with( Fn && fn) & {
+        return std::move( * this).resume_with( std::forward< Fn >( fn) );
+    }
+
+    template< typename Fn >
+    continuation resume_with( Fn && fn) && {
+        BOOST_ASSERT( nullptr != fctx_);
+        auto p = std::make_tuple( std::forward< Fn >( fn) );
+        return { detail::ontop_fcontext(
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    detail::exchange( fctx_, nullptr),
+#else
+                    std::exchange( fctx_, nullptr),
+#endif
+                    & p,
+                    detail::context_ontop< continuation, Fn >).fctx };
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != fctx_;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == fctx_;
+    }
+
+    bool operator<( continuation const& other) const noexcept {
+        return fctx_ < other.fctx_;
+    }
+
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other) {
+        if ( nullptr != other.fctx_) {
+            return os << other.fctx_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    void swap( continuation & other) noexcept {
+        std::swap( fctx_, other.fctx_);
+    }
+};
+
+template<
+    typename Fn,
+    typename = detail::disable_overload< continuation, Fn >
+>
+continuation
+callcc( Fn && fn) {
+    return callcc(
+            std::allocator_arg, fixedsize_stack(),
+            std::forward< Fn >( fn) );
+}
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, StackAlloc && salloc, Fn && fn) {
+    using Record = detail::record< continuation, StackAlloc, Fn >;
+    return continuation{
+                detail::create_context1< Record >(
+                        std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) }.resume();
+}
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    using Record = detail::record< continuation, StackAlloc, Fn >;
+    return continuation{
+                detail::create_context2< Record >(
+                        palloc, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) }.resume();
+}
+
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+template< typename Fn >
+continuation
+callcc( std::allocator_arg_t, segmented_stack, Fn &&);
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, preallocated, segmented_stack, Fn &&);
+#endif
+
+inline
+void swap( continuation & l, continuation & r) noexcept {
+    l.swap( r);
+}
+
+}}
+
+#if defined(BOOST_MSVC)
+# pragma warning(pop)
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_CONTINUATION_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/continuation_ucontext.hpp

@@ -0,0 +1,538 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_CONTINUATION_H
+#define BOOST_CONTEXT_CONTINUATION_H
+
+#include <boost/predef.h>
+#if BOOST_OS_MACOS
+#define _XOPEN_SOURCE 600
+#endif
+
+extern "C" {
+#include <ucontext.h>
+}
+
+#include <boost/context/detail/config.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <functional>
+#include <memory>
+#include <ostream>
+#include <system_error>
+#include <tuple>
+#include <utility>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+
+#include <boost/context/detail/disable_overload.hpp>
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+#include <boost/context/detail/exchange.hpp>
+#endif
+#include <boost/context/detail/externc.hpp>
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/fixedsize_stack.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/preallocated.hpp>
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+#include <boost/context/segmented_stack.hpp>
+#endif
+#include <boost/context/stack_context.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+// tampoline function
+// entered if the execution context
+// is resumed for the first time
+template< typename Record >
+static void entry_func( void * data) noexcept {
+    Record * record = static_cast< Record * >( data);
+    BOOST_ASSERT( nullptr != record);
+    // start execution of toplevel context-function
+    record->run();
+}
+
+struct BOOST_CONTEXT_DECL activation_record {
+    ucontext_t                                                  uctx{};
+    stack_context                                               sctx{};
+    bool                                                        main_ctx{ true };
+	activation_record                                       *	from{ nullptr };
+    std::function< activation_record*(activation_record*&) >    ontop{};
+    bool                                                        terminated{ false };
+    bool                                                        force_unwind{ false };
+#if defined(BOOST_USE_ASAN)
+    void                                                    *   fake_stack{ nullptr };
+    void                                                    *   stack_bottom{ nullptr };
+    std::size_t                                                 stack_size{ 0 };
+#endif
+
+    static activation_record *& current() noexcept;
+
+    // used for toplevel-context
+    // (e.g. main context, thread-entry context)
+    activation_record() {
+        if ( BOOST_UNLIKELY( 0 != ::getcontext( & uctx) ) ) {
+            throw std::system_error(
+                    std::error_code( errno, std::system_category() ),
+                    "getcontext() failed");
+        }
+    }
+
+    activation_record( stack_context sctx_) noexcept :
+        sctx( sctx_ ),
+        main_ctx( false ) {
+    } 
+
+    virtual ~activation_record() {
+	}
+
+    activation_record( activation_record const&) = delete;
+    activation_record & operator=( activation_record const&) = delete;
+
+    bool is_main_context() const noexcept {
+        return main_ctx;
+    }
+
+    activation_record * resume() {
+		from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        current() = this;
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+        // adjust segmented stack properties
+        __splitstack_getcontext( from->sctx.segments_ctx);
+        __splitstack_setcontext( sctx.segments_ctx);
+#endif
+#if defined(BOOST_USE_ASAN)
+        if ( terminated) {
+            __sanitizer_start_switch_fiber( nullptr, stack_bottom, stack_size);
+        } else {
+            __sanitizer_start_switch_fiber( & from->fake_stack, stack_bottom, stack_size);
+        }
+#endif
+        // context switch from parent context to `this`-context
+        ::swapcontext( & from->uctx, & uctx);
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_finish_switch_fiber( current()->fake_stack,
+                                         (const void **) & current()->from->stack_bottom,
+                                         & current()->from->stack_size);
+#endif
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    template< typename Ctx, typename Fn >
+    activation_record * resume_with( Fn && fn) {
+		from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        // returned by continuation::current()
+        current() = this;
+#if defined(BOOST_NO_CXX14_GENERIC_LAMBDAS)
+        current()->ontop = std::bind(
+                [](typename std::decay< Fn >::type & fn, activation_record *& ptr){
+                    Ctx c{ ptr };
+                    c = fn( std::move( c) );
+                    if ( ! c) {
+                        ptr = nullptr;
+                    }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    return exchange( c.ptr_, nullptr);
+#else
+                    return std::exchange( c.ptr_, nullptr);
+#endif
+                },
+                std::forward< Fn >( fn),
+                std::placeholders::_1);
+#else
+        current()->ontop = [fn=std::forward<Fn>(fn)](activation_record *& ptr){
+            Ctx c{ ptr };
+            c = fn( std::move( c) );
+            if ( ! c) {
+                ptr = nullptr;
+            }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+            return exchange( c.ptr_, nullptr);
+#else
+            return std::exchange( c.ptr_, nullptr);
+#endif
+        };
+#endif
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+        // adjust segmented stack properties
+        __splitstack_getcontext( from->sctx.segments_ctx);
+        __splitstack_setcontext( sctx.segments_ctx);
+#endif
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_start_switch_fiber( & from->fake_stack, stack_bottom, stack_size);
+#endif
+        // context switch from parent context to `this`-context
+        ::swapcontext( & from->uctx, & uctx);
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_finish_switch_fiber( current()->fake_stack,
+                                         (const void **) & current()->from->stack_bottom,
+                                         & current()->from->stack_size);
+#endif
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    virtual void deallocate() noexcept {
+    }
+};
+
+struct BOOST_CONTEXT_DECL activation_record_initializer {
+    activation_record_initializer() noexcept;
+    ~activation_record_initializer();
+};
+
+struct forced_unwind {
+    activation_record   *   from{ nullptr };
+
+    forced_unwind( activation_record * from_) noexcept :
+        from{ from_ } {
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+class capture_record : public activation_record {
+private:
+    typename std::decay< StackAlloc >::type             salloc_;
+    typename std::decay< Fn >::type                     fn_;
+
+    static void destroy( capture_record * p) noexcept {
+        typename std::decay< StackAlloc >::type salloc = std::move( p->salloc_);
+        stack_context sctx = p->sctx;
+        // deallocate activation record
+        p->~capture_record();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    capture_record( stack_context sctx, StackAlloc && salloc, Fn && fn) noexcept :
+        activation_record{ sctx },
+        salloc_{ std::forward< StackAlloc >( salloc) },
+        fn_( std::forward< Fn >( fn) ) {
+    }
+
+    void deallocate() noexcept override final {
+        BOOST_ASSERT( main_ctx || ( ! main_ctx && terminated) );
+        destroy( this);
+    }
+
+    void run() {
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_finish_switch_fiber( fake_stack,
+                                         (const void **) & from->stack_bottom,
+                                         & from->stack_size);
+#endif
+        Ctx c{ from };
+        try {
+            // invoke context-function
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+            c = boost::context::detail::invoke( fn_, std::move( c) );
+#else
+            c = std::invoke( fn_, std::move( c) );
+#endif  
+        } catch ( forced_unwind const& ex) {
+            c = Ctx{ ex.from };
+        }
+        // this context has finished its task
+		from = nullptr;
+        ontop = nullptr;
+        terminated = true;
+        force_unwind = false;
+        c.resume();
+        BOOST_ASSERT_MSG( false, "continuation already terminated");
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static activation_record * create_context1( StackAlloc && salloc, Fn && fn) {
+    typedef capture_record< Ctx, StackAlloc, Fn >  capture_t;
+
+    auto sctx = salloc.allocate();
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // stack bottom
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sctx.size) );
+    // create user-context
+    if ( BOOST_UNLIKELY( 0 != ::getcontext( & record->uctx) ) ) {
+        record->~capture_t();
+        salloc.deallocate( sctx);
+        throw std::system_error(
+                std::error_code( errno, std::system_category() ),
+                "getcontext() failed");
+    }
+    record->uctx.uc_stack.ss_sp = stack_bottom;
+    // 64byte gap between control structure and stack top
+    record->uctx.uc_stack.ss_size = reinterpret_cast< uintptr_t >( storage) -
+            reinterpret_cast< uintptr_t >( stack_bottom) - static_cast< uintptr_t >( 64);
+    record->uctx.uc_link = nullptr;
+    ::makecontext( & record->uctx, ( void (*)() ) & entry_func< capture_t >, 1, record);
+#if defined(BOOST_USE_ASAN)
+    record->stack_bottom = record->uctx.uc_stack.ss_sp;
+    record->stack_size = record->uctx.uc_stack.ss_size;
+#endif
+    return record;
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static activation_record * create_context2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    typedef capture_record< Ctx, StackAlloc, Fn >  capture_t; 
+
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( palloc.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            palloc.sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // stack bottom
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( palloc.sctx.sp) - static_cast< uintptr_t >( palloc.sctx.size) );
+    // create user-context
+    if ( BOOST_UNLIKELY( 0 != ::getcontext( & record->uctx) ) ) {
+        record->~capture_t();
+        salloc.deallocate( palloc.sctx);
+        throw std::system_error(
+                std::error_code( errno, std::system_category() ),
+                "getcontext() failed");
+    }
+    record->uctx.uc_stack.ss_sp = stack_bottom;
+    // 64byte gap between control structure and stack top
+    record->uctx.uc_stack.ss_size = reinterpret_cast< uintptr_t >( storage) -
+            reinterpret_cast< uintptr_t >( stack_bottom) - static_cast< uintptr_t >( 64);
+    record->uctx.uc_link = nullptr;
+    ::makecontext( & record->uctx,  ( void (*)() ) & entry_func< capture_t >, 1, record);
+#if defined(BOOST_USE_ASAN)
+    record->stack_bottom = record->uctx.uc_stack.ss_sp;
+    record->stack_size = record->uctx.uc_stack.ss_size;
+#endif
+    return record;
+}
+
+}
+
+class BOOST_CONTEXT_DECL continuation {
+private:
+    friend struct detail::activation_record;
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend class detail::capture_record;
+
+	template< typename Ctx, typename StackAlloc, typename Fn >
+	friend detail::activation_record * detail::create_context1( StackAlloc &&, Fn &&);
+
+	template< typename Ctx, typename StackAlloc, typename Fn >
+	friend detail::activation_record * detail::create_context2( preallocated, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend continuation
+    callcc( std::allocator_arg_t, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend continuation
+    callcc( std::allocator_arg_t, preallocated, StackAlloc &&, Fn &&);
+
+    detail::activation_record   *   ptr_{ nullptr };
+
+    continuation( detail::activation_record * ptr) noexcept :
+        ptr_{ ptr } {
+    }
+
+public:
+    continuation() = default;
+
+    ~continuation() {
+        if ( BOOST_UNLIKELY( nullptr != ptr_) && ! ptr_->main_ctx) {
+            if ( BOOST_LIKELY( ! ptr_->terminated) ) {
+                ptr_->force_unwind = true;
+                ptr_->resume();
+                BOOST_ASSERT( ptr_->terminated);
+            }
+            ptr_->deallocate();
+        }
+    }
+
+    continuation( continuation const&) = delete;
+    continuation & operator=( continuation const&) = delete;
+
+    continuation( continuation && other) noexcept {
+        swap( other);
+    }
+
+    continuation & operator=( continuation && other) noexcept {
+        if ( BOOST_LIKELY( this != & other) ) {
+            continuation tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    continuation resume() & {
+        return std::move( * this).resume();
+    }
+
+    continuation resume() && {
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::activation_record * ptr = detail::exchange( ptr_, nullptr)->resume();
+#else
+        detail::activation_record * ptr = std::exchange( ptr_, nullptr)->resume();
+#endif
+        if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
+            ptr = detail::activation_record::current()->ontop( ptr);
+            detail::activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    template< typename Fn >
+    continuation resume_with( Fn && fn) & {
+        return std::move( * this).resume_with( std::forward< Fn >( fn) );
+    }
+
+    template< typename Fn >
+    continuation resume_with( Fn && fn) && {
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::activation_record * ptr =
+            detail::exchange( ptr_, nullptr)->resume_with< continuation >( std::forward< Fn >( fn) );
+#else
+        detail::activation_record * ptr =
+            std::exchange( ptr_, nullptr)->resume_with< continuation >( std::forward< Fn >( fn) );
+#endif
+        if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
+            ptr = detail::activation_record::current()->ontop( ptr);
+            detail::activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != ptr_ && ! ptr_->terminated;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == ptr_ || ptr_->terminated;
+    }
+
+    bool operator<( continuation const& other) const noexcept {
+        return ptr_ < other.ptr_;
+    }
+
+    #if !defined(BOOST_EMBTC)
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    #else
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other);
+
+    #endif
+
+    void swap( continuation & other) noexcept {
+        std::swap( ptr_, other.ptr_);
+    }
+};
+
+#if defined(BOOST_EMBTC)
+
+    template< typename charT, class traitsT >
+    inline std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+#endif
+    
+template<
+    typename Fn,
+    typename = detail::disable_overload< continuation, Fn >
+>
+continuation
+callcc( Fn && fn) {
+	return callcc(
+			std::allocator_arg,
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+			segmented_stack(),
+#else
+			fixedsize_stack(),
+#endif
+			std::forward< Fn >( fn) );
+}
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, StackAlloc && salloc, Fn && fn) {
+	return continuation{
+		detail::create_context1< continuation >(
+				std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) }.resume();
+}
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, preallocated palloc, StackAlloc && salloc, Fn && fn) {
+	return continuation{
+		detail::create_context2< continuation >(
+				palloc, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) }.resume();
+}
+
+inline
+void swap( continuation & l, continuation & r) noexcept {
+    l.swap( r);
+}
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_CONTINUATION_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/continuation_winfib.hpp

@@ -0,0 +1,473 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_CONTINUATION_H
+#define BOOST_CONTEXT_CONTINUATION_H
+
+#include <windows.h>
+
+#include <boost/context/detail/config.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <functional>
+#include <memory>
+#include <ostream>
+#include <system_error>
+#include <tuple>
+#include <utility>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+
+#include <boost/context/detail/disable_overload.hpp>
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+#include <boost/context/detail/exchange.hpp>
+#endif
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/fixedsize_stack.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/preallocated.hpp>
+#include <boost/context/stack_context.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+#if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable: 4702)
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+// tampoline function
+// entered if the execution context
+// is resumed for the first time
+template< typename Record >
+static VOID WINAPI entry_func( LPVOID data) noexcept {
+    Record * record = static_cast< Record * >( data);
+    BOOST_ASSERT( nullptr != record);
+    // start execution of toplevel context-function
+    record->run();
+}
+
+struct BOOST_CONTEXT_DECL activation_record {
+    LPVOID                                                      fiber{ nullptr };
+    stack_context                                               sctx{};
+    bool                                                        main_ctx{ true };
+    activation_record                                       *   from{ nullptr };
+    std::function< activation_record*(activation_record*&) >    ontop{};
+    bool                                                        terminated{ false };
+    bool                                                        force_unwind{ false };
+
+    static activation_record *& current() noexcept;
+
+    // used for toplevel-context
+    // (e.g. main context, thread-entry context)
+    activation_record() noexcept {
+#if ( _WIN32_WINNT > 0x0600)
+        if ( ::IsThreadAFiber() ) {
+            fiber = ::GetCurrentFiber();
+        } else {
+            fiber = ::ConvertThreadToFiber( nullptr);
+        }
+#else
+        fiber = ::ConvertThreadToFiber( nullptr);
+        if ( BOOST_UNLIKELY( nullptr == fiber) ) {
+            DWORD err = ::GetLastError();
+            BOOST_ASSERT( ERROR_ALREADY_FIBER == err);
+            fiber = ::GetCurrentFiber(); 
+            BOOST_ASSERT( nullptr != fiber);
+            BOOST_ASSERT( reinterpret_cast< LPVOID >( 0x1E00) != fiber);
+        }
+#endif
+    }
+
+    activation_record( stack_context sctx_) noexcept :
+        sctx{ sctx_ },
+        main_ctx{ false } {
+    } 
+
+    virtual ~activation_record() {
+        if ( BOOST_UNLIKELY( main_ctx) ) {
+            ::ConvertFiberToThread();
+        } else {
+            ::DeleteFiber( fiber);
+        }
+    }
+
+    activation_record( activation_record const&) = delete;
+    activation_record & operator=( activation_record const&) = delete;
+
+    bool is_main_context() const noexcept {
+        return main_ctx;
+    }
+
+    activation_record * resume() {
+        from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        current() = this;
+        // context switch from parent context to `this`-context
+        // context switch
+        ::SwitchToFiber( fiber);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return detail::exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    template< typename Ctx, typename Fn >
+    activation_record * resume_with( Fn && fn) {
+        from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        // returned by continuation::current()
+        current() = this;
+#if defined(BOOST_NO_CXX14_GENERIC_LAMBDAS)
+        current()->ontop = std::bind(
+                [](typename std::decay< Fn >::type & fn, activation_record *& ptr){
+                    Ctx c{ ptr };
+                    c = fn( std::move( c) );
+                    if ( ! c) {
+                        ptr = nullptr;
+                    }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    return exchange( c.ptr_, nullptr);
+#else
+                    return std::exchange( c.ptr_, nullptr);
+#endif
+                },
+                std::forward< Fn >( fn),
+                std::placeholders::_1);
+#else
+        current()->ontop = [fn=std::forward<Fn>(fn)](activation_record *& ptr){
+            Ctx c{ ptr };
+            c = fn( std::move( c) );
+            if ( ! c) {
+                ptr = nullptr;
+            }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+            return exchange( c.ptr_, nullptr);
+#else
+            return std::exchange( c.ptr_, nullptr);
+#endif
+        };
+#endif
+        // context switch
+        ::SwitchToFiber( fiber);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return detail::exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    virtual void deallocate() noexcept {
+    }
+};
+
+struct BOOST_CONTEXT_DECL activation_record_initializer {
+    activation_record_initializer() noexcept;
+    ~activation_record_initializer();
+};
+
+struct forced_unwind {
+    activation_record   *   from{ nullptr };
+
+    explicit forced_unwind( activation_record * from_) :
+        from{ from_ } {
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+class capture_record : public activation_record {
+private:
+    typename std::decay< StackAlloc >::type             salloc_;
+    typename std::decay< Fn >::type                     fn_;
+
+    static void destroy( capture_record * p) noexcept {
+        typename std::decay< StackAlloc >::type salloc = std::move( p->salloc_);
+        stack_context sctx = p->sctx;
+        // deallocate activation record
+        p->~capture_record();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    capture_record( stack_context sctx, StackAlloc && salloc, Fn && fn) noexcept :
+        activation_record( sctx),
+        salloc_( std::forward< StackAlloc >( salloc)),
+        fn_( std::forward< Fn >( fn) ) {
+    }
+
+    void deallocate() noexcept override final {
+        BOOST_ASSERT( main_ctx || ( ! main_ctx && terminated) );
+        destroy( this);
+    }
+
+    void run() {
+        Ctx c{ from };
+        try {
+            // invoke context-function
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+            c = boost::context::detail::invoke( fn_, std::move( c) );
+#else
+            c = std::invoke( fn_, std::move( c) );
+#endif  
+        } catch ( forced_unwind const& ex) {
+            c = Ctx{ ex.from };
+        }
+        // this context has finished its task
+        from = nullptr;
+        ontop = nullptr;
+        terminated = true;
+        force_unwind = false;
+        c.resume();
+        BOOST_ASSERT_MSG( false, "continuation already terminated");
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static activation_record * create_context1( StackAlloc && salloc, Fn && fn) {
+    typedef capture_record< Ctx, StackAlloc, Fn >  capture_t;
+
+    auto sctx = salloc.allocate();
+    BOOST_ASSERT( ( sizeof( capture_t) ) < sctx.size);
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // create user-context
+    record->fiber = ::CreateFiber( sctx.size, & detail::entry_func< capture_t >, record);
+    return record;
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static activation_record * create_context2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    typedef capture_record< Ctx, StackAlloc, Fn >  capture_t; 
+
+    BOOST_ASSERT( ( sizeof( capture_t) ) < palloc.size);
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( palloc.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            palloc.sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // create user-context
+    record->fiber = ::CreateFiber( palloc.sctx.size, & detail::entry_func< capture_t >, record);
+    return record;
+}
+
+}
+
+class BOOST_CONTEXT_DECL continuation {
+private:
+    friend struct detail::activation_record;
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend class detail::capture_record;
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend detail::activation_record * detail::create_context1( StackAlloc &&, Fn &&);
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend detail::activation_record * detail::create_context2( preallocated, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend continuation
+    callcc( std::allocator_arg_t, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend continuation
+    callcc( std::allocator_arg_t, preallocated, StackAlloc &&, Fn &&);
+
+    detail::activation_record   *   ptr_{ nullptr };
+
+    continuation( detail::activation_record * ptr) noexcept :
+        ptr_{ ptr } {
+    }
+
+public:
+    continuation() = default;
+
+    ~continuation() {
+        if ( BOOST_UNLIKELY( nullptr != ptr_) && ! ptr_->main_ctx) {
+            if ( BOOST_LIKELY( ! ptr_->terminated) ) {
+                ptr_->force_unwind = true;
+                ptr_->resume();
+                BOOST_ASSERT( ptr_->terminated);
+            }
+            ptr_->deallocate();
+        }
+    }
+
+    continuation( continuation const&) = delete;
+    continuation & operator=( continuation const&) = delete;
+
+    continuation( continuation && other) noexcept {
+        swap( other);
+    }
+
+    continuation & operator=( continuation && other) noexcept {
+        if ( BOOST_LIKELY( this != & other) ) {
+            continuation tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    continuation resume() & {
+        return std::move( * this).resume();
+    }
+
+    continuation resume() && {
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::activation_record * ptr = detail::exchange( ptr_, nullptr)->resume();
+#else
+        detail::activation_record * ptr = std::exchange( ptr_, nullptr)->resume();
+#endif
+        if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
+            ptr = detail::activation_record::current()->ontop( ptr);
+            detail::activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    template< typename Fn >
+    continuation resume_with( Fn && fn) & {
+        return std::move( * this).resume_with( std::forward< Fn >( fn) );
+    }
+
+    template< typename Fn >
+    continuation resume_with( Fn && fn) && {
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::activation_record * ptr =
+            detail::exchange( ptr_, nullptr)->resume_with< continuation >( std::forward< Fn >( fn) );
+#else
+        detail::activation_record * ptr =
+            std::exchange( ptr_, nullptr)->resume_with< continuation >( std::forward< Fn >( fn) );
+#endif
+        if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
+            ptr = detail::activation_record::current()->ontop( ptr);
+            detail::activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != ptr_ && ! ptr_->terminated;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == ptr_ || ptr_->terminated;
+    }
+
+    bool operator<( continuation const& other) const noexcept {
+        return ptr_ < other.ptr_;
+    }
+    
+    #if !defined(BOOST_EMBTC)
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    #else
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other);
+
+    #endif
+
+    void swap( continuation & other) noexcept {
+        std::swap( ptr_, other.ptr_);
+    }
+};
+
+#if defined(BOOST_EMBTC)
+
+    template< typename charT, class traitsT >
+    inline std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, continuation const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+#endif
+    
+template<
+    typename Fn,
+    typename = detail::disable_overload< continuation, Fn >
+>
+continuation
+callcc( Fn && fn) {
+    return callcc(
+            std::allocator_arg,
+            fixedsize_stack(),
+            std::forward< Fn >( fn) );
+}
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, StackAlloc && salloc, Fn && fn) {
+    return continuation{
+        detail::create_context1< continuation >(
+                std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) }.resume();
+}
+
+template< typename StackAlloc, typename Fn >
+continuation
+callcc( std::allocator_arg_t, preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    return continuation{
+        detail::create_context2< continuation >(
+                palloc, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) }.resume();
+}
+
+inline
+void swap( continuation & l, continuation & r) noexcept {
+    l.swap( r);
+}
+
+}}
+
+#if defined(BOOST_MSVC)
+# pragma warning(pop)
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_CONTINUATION_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/apply.hpp

@@ -0,0 +1,74 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_APPLY_H
+#define BOOST_CONTEXT_DETAIL_APPLY_H
+
+#include <functional>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/detail/index_sequence.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+#if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable: 4100)
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+template< typename Fn, typename Tpl, std::size_t ... I >
+auto
+apply_impl( Fn && fn, Tpl && tpl, index_sequence< I ... >) 
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+    -> decltype( boost::context::detail::invoke( std::forward< Fn >( fn), std::get< I >( std::forward< Tpl >( tpl) ) ... ) )
+#else
+    -> decltype( std::invoke( std::forward< Fn >( fn), std::get< I >( std::forward< Tpl >( tpl) ) ... ) )
+#endif
+{
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+    return boost::context::detail::invoke( std::forward< Fn >( fn), std::get< I >( std::forward< Tpl >( tpl) ) ... );
+#else
+    return std::invoke( std::forward< Fn >( fn), std::get< I >( std::forward< Tpl >( tpl) ) ... );
+#endif
+}
+
+template< typename Fn, typename Tpl >
+auto
+apply( Fn && fn, Tpl && tpl) 
+    -> decltype( apply_impl( std::forward< Fn >( fn),
+                 std::forward< Tpl >( tpl),
+                 make_index_sequence< std::tuple_size< typename std::decay< Tpl >::type >::value >{}) )
+{
+    return apply_impl( std::forward< Fn >( fn),
+                       std::forward< Tpl >( tpl),
+                       make_index_sequence< std::tuple_size< typename std::decay< Tpl >::type >::value >{});
+}
+
+}}}
+
+#if defined(BOOST_MSVC)
+# pragma warning(pop)
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_APPLY_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/config.hpp

@@ -0,0 +1,136 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_CONFIG_H
+#define BOOST_CONTEXT_DETAIL_CONFIG_H
+
+// required for SD-6 compile-time integer sequences
+#include <utility>
+
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+
+#ifdef BOOST_CONTEXT_DECL
+# undef BOOST_CONTEXT_DECL
+#endif
+
+#if (defined(BOOST_ALL_DYN_LINK) || defined(BOOST_CONTEXT_DYN_LINK) ) && ! defined(BOOST_CONTEXT_STATIC_LINK)
+# if defined(BOOST_CONTEXT_SOURCE)
+#  define BOOST_CONTEXT_DECL BOOST_SYMBOL_EXPORT
+#  define BOOST_CONTEXT_BUILD_DLL
+# else
+#  define BOOST_CONTEXT_DECL BOOST_SYMBOL_IMPORT
+# endif
+#endif
+
+#if ! defined(BOOST_CONTEXT_DECL)
+# define BOOST_CONTEXT_DECL
+#endif
+
+#if ! defined(BOOST_USE_UCONTEXT) && defined(__CYGWIN__)
+# define BOOST_USE_UCONTEXT
+#endif
+
+#if ! defined(BOOST_CONTEXT_SOURCE) && ! defined(BOOST_ALL_NO_LIB) && ! defined(BOOST_CONTEXT_NO_LIB)
+# define BOOST_LIB_NAME boost_context
+# if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_CONTEXT_DYN_LINK)
+#  define BOOST_DYN_LINK
+# endif
+# include <boost/config/auto_link.hpp>
+#endif
+
+#undef BOOST_CONTEXT_CALLDECL
+#if (defined(i386) || defined(__i386__) || defined(__i386) \
+     || defined(__i486__) || defined(__i586__) || defined(__i686__) \
+     || defined(__X86__) || defined(_X86_) || defined(__THW_INTEL__) \
+     || defined(__I86__) || defined(__INTEL__) || defined(__IA32__) \
+     || defined(_M_IX86) || defined(_I86_)) && defined(BOOST_WINDOWS)
+# define BOOST_CONTEXT_CALLDECL __cdecl
+#else
+# define BOOST_CONTEXT_CALLDECL
+#endif
+
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+# if ! ( (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6) ) ) || \
+         (defined(__clang__) && (__clang_major__ > 2 || ( __clang_major__ == 2 && __clang_minor__ > 3) ) ) )
+#  error "compiler does not support segmented_stack stacks"
+# endif
+# define BOOST_CONTEXT_SEGMENTS 10
+#endif
+
+
+#define BOOST_CONTEXT_NO_CXX14_INTEGER_SEQUENCE
+// use rd6 macros for std::integer_sequence
+#if defined(__cpp_lib_integer_sequence) && __cpp_lib_integer_sequence >= 201304
+# undef BOOST_CONTEXT_NO_CXX14_INTEGER_SEQUENCE
+#endif
+// workaroud: MSVC 14 does not provide macros to test for compile-time integer sequence
+#if _MSC_VER > 1800 // _MSC_VER == 1800 -> MS Visual Studio 2013
+# undef BOOST_CONTEXT_NO_INDEX_SEQUENCE
+#endif
+// workaround: Xcode clang feature detection
+#if ! defined(__cpp_lib_integer_sequence) && __cpp_lib_integer_sequence >= 201304
+# if _LIBCPP_STD_VER > 11
+#  undef BOOST_CONTEXT_NO_CXX14_INTEGER_SEQUENCE
+# endif
+#endif
+
+// workaroud: MSVC 14 does support constexpr
+#if _MSC_VER > 1800 // _MSC_VER == 1800 -> MS Visual Studio 2013
+# undef BOOST_NO_CXX11_CONSTEXPR
+#endif
+
+#undef BOOST_CONTEXT_NO_CXX11
+#if defined(BOOST_NO_CXX11_AUTO_DECLARATIONS) || \
+    defined(BOOST_NO_CXX11_CONSTEXPR) || \
+    defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) || \
+    defined(BOOST_NO_CXX11_FINAL) || \
+    defined(BOOST_NO_CXX11_HDR_TUPLE) || \
+    defined(BOOST_NO_CXX11_NOEXCEPT) || \
+    defined(BOOST_NO_CXX11_NULLPTR) || \
+    defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || \
+    defined(BOOST_NO_CXX11_TEMPLATE_ALIASES) || \
+    defined(BOOST_NO_CXX11_UNIFIED_INITIALISATION_SYNTAX) || \
+    defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) || \
+    defined(BOOST_NO_HDR_ATOMIC) || \
+    defined(BOOST_NO_HDR_TUPLE) 
+# define BOOST_CONTEXT_NO_CXX11
+#endif
+
+#if ! defined(BOOST_EXECUTION_CONTEXT)
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+#  define BOOST_EXECUTION_CONTEXT 1
+# else
+#  define BOOST_EXECUTION_CONTEXT 2
+# endif
+#endif
+
+#if ! defined(BOOST_NO_CXX11_CONSTEXPR)
+// modern architectures have cachelines with 64byte length
+// ARM Cortex-A15 32/64byte, Cortex-A9 16/32/64bytes
+// MIPS 74K: 32byte, 4KEc: 16byte
+// ist should be safe to use 64byte for all
+static constexpr std::size_t cache_alignment{ 64 };
+static constexpr std::size_t cacheline_length{ 64 };
+// lookahead size for prefetching
+static constexpr std::size_t prefetch_stride{ 4 * cacheline_length };
+#endif
+
+#if defined(__GLIBCPP__) || defined(__GLIBCXX__)
+// GNU libstdc++ 3
+#  define BOOST_CONTEXT_HAS_CXXABI_H
+#endif
+
+#if defined( BOOST_CONTEXT_HAS_CXXABI_H )
+# include <cxxabi.h>
+#endif
+
+#if defined(__OpenBSD__)
+// stacks need mmap(2) with MAP_STACK
+# define BOOST_CONTEXT_USE_MAP_STACK
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_CONFIG_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/disable_overload.hpp

@@ -0,0 +1,40 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_DISABLE_OVERLOAD_H
+#define BOOST_CONTEXT_DETAIL_DISABLE_OVERLOAD_H
+
+#include <type_traits>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+// http://ericniebler.com/2013/08/07/universal-references-and-the-copy-constructo/
+template< typename X, typename Y >
+using disable_overload =
+    typename std::enable_if<
+        ! std::is_base_of<
+            X,
+            typename std::decay< Y >::type
+        >::value
+    >::type;
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_DISABLE_OVERLOAD_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/exception.hpp

@@ -0,0 +1,39 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_EXCEPTION_H
+#define BOOST_CONTEXT_DETAIL_EXCEPTION_H
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+
+#include <boost/context/detail/fcontext.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+struct forced_unwind {
+    fcontext_t  fctx{ nullptr };
+
+    forced_unwind() = default;
+
+    forced_unwind( fcontext_t fctx_) :
+        fctx( fctx_) {
+    }
+};
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_EXCEPTION_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/exchange.hpp

@@ -0,0 +1,36 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_EXCHANGE_H
+#define BOOST_CONTEXT_DETAIL_EXCHANGE_H
+
+#include <algorithm>
+#include <utility>
+
+#include <boost/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+template< typename T, typename U = T >
+T exchange( T & t, U && nv) {
+    T ov = std::move( t);
+    t = std::forward< U >( nv);
+    return ov;
+}
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_EXCHANGE_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/externc.hpp

@@ -0,0 +1,23 @@
+
+//          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)
+//
+
+#include <boost/config.hpp>
+#include <boost/context/detail/config.hpp>
+
+#if defined(BOOST_USE_ASAN)
+extern "C" {
+void __sanitizer_start_switch_fiber( void **, const void *, size_t);
+void __sanitizer_finish_switch_fiber( void *, const void **, size_t *);
+}
+#endif
+
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+extern "C" {
+void __splitstack_getcontext( void * [BOOST_CONTEXT_SEGMENTS]);
+void __splitstack_setcontext( void * [BOOST_CONTEXT_SEGMENTS]);
+}
+#endif

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/fcontext.hpp

@@ -0,0 +1,46 @@
+
+//          Copyright Oliver Kowalke 2009.
+// 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)
+
+#ifndef BOOST_CONTEXT_DETAIL_FCONTEXT_H
+#define BOOST_CONTEXT_DETAIL_FCONTEXT_H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+typedef void*   fcontext_t;
+
+struct transfer_t {
+    fcontext_t  fctx;
+    void    *   data;
+};
+
+extern "C" BOOST_CONTEXT_DECL
+transfer_t BOOST_CONTEXT_CALLDECL jump_fcontext( fcontext_t const to, void * vp);
+extern "C" BOOST_CONTEXT_DECL
+fcontext_t BOOST_CONTEXT_CALLDECL make_fcontext( void * sp, std::size_t size, void (* fn)( transfer_t) );
+
+// based on an idea of Giovanni Derreta
+extern "C" BOOST_CONTEXT_DECL
+transfer_t BOOST_CONTEXT_CALLDECL ontop_fcontext( fcontext_t const to, void * vp, transfer_t (* fn)( transfer_t) );
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_FCONTEXT_H
+

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/index_sequence.hpp

@@ -0,0 +1,50 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_INDEX_SEQUENCE_H
+#define BOOST_CONTEXT_DETAIL_INDEX_SEQUENCE_H
+
+#include <cstddef>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#if defined(BOOST_CONTEXT_NO_CXX14_INTEGER_SEQUENCE)
+#include <boost/mp11/integer_sequence.hpp>
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+#if ! defined(BOOST_CONTEXT_NO_CXX14_INTEGER_SEQUENCE)
+template< std::size_t ... I >
+using index_sequence = std::index_sequence< I ... >;
+template< std::size_t I >
+using make_index_sequence = std::make_index_sequence< I >;
+template< typename ... T >
+using index_sequence_for = std::index_sequence_for< T ... >;
+#else
+template< std::size_t ... I >
+using index_sequence = mp11::index_sequence< I ... >;
+template< std::size_t I >
+using make_index_sequence = mp11::make_index_sequence< I >;
+template< typename ... T >
+using index_sequence_for = mp11::index_sequence_for< T ... >;
+#endif
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_INDEX_SEQUENCE_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/invoke.hpp

@@ -0,0 +1,50 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_INVOKE_H
+#define BOOST_CONTEXT_DETAIL_INVOKE_H
+
+#include <functional>
+#include <type_traits>
+#include <utility>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+template< typename Fn, typename ... Args >
+typename std::enable_if<
+    std::is_member_pointer< typename std::decay< Fn >::type >::value,
+    typename std::result_of< Fn &&( Args && ... ) >::type
+>::type
+invoke( Fn && fn, Args && ... args) {
+    return std::mem_fn( fn)( std::forward< Args >( args) ... );   
+}
+
+template< typename Fn, typename ... Args >
+typename std::enable_if<
+    ! std::is_member_pointer< typename std::decay< Fn >::type >::value,
+    typename std::result_of< Fn &&( Args && ... ) >::type
+>::type
+invoke( Fn && fn, Args && ... args) {
+    return std::forward< Fn >( fn)( std::forward< Args >( args) ... );
+}
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_INVOKE_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/prefetch.hpp

@@ -0,0 +1,78 @@
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_DETAIL_PREFETCH_H
+#define BOOST_CONTEXT_DETAIL_PREFETCH_H
+
+#include <cstddef>
+#include <cstdint>
+
+#include <boost/config.hpp>
+#include <boost/predef.h>
+
+#include <boost/context/detail/config.hpp>
+
+#if BOOST_COMP_INTEL || BOOST_COMP_INTEL_EMULATED
+#include <immintrin.h>
+#endif
+
+#if BOOST_COMP_MSVC && !defined(_M_ARM) && !defined(_M_ARM64)
+#include <mmintrin.h>
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+#if BOOST_COMP_GNUC || BOOST_COMP_CLANG
+#define BOOST_HAS_PREFETCH 1
+BOOST_FORCEINLINE
+void prefetch( void * addr) {
+    // L1 cache : hint == 1
+    __builtin_prefetch( addr, 1, 1);
+}
+#elif BOOST_COMP_INTEL || BOOST_COMP_INTEL_EMULATED
+#define BOOST_HAS_PREFETCH 1
+BOOST_FORCEINLINE
+void prefetch( void * addr) {
+    // L1 cache : hint == _MM_HINT_T0
+    _mm_prefetch( (const char *)addr, _MM_HINT_T0);
+}
+#elif BOOST_COMP_MSVC && !defined(_M_ARM) && !defined(_M_ARM64)
+#define BOOST_HAS_PREFETCH 1
+BOOST_FORCEINLINE
+void prefetch( void * addr) {
+    // L1 cache : hint == _MM_HINT_T0
+    _mm_prefetch( (const char *)addr, _MM_HINT_T0);
+}
+#endif
+
+inline
+void prefetch_range( void * addr, std::size_t len) {
+#if defined(BOOST_HAS_PREFETCH)
+    void * vp = addr;
+    void * end = reinterpret_cast< void * >(
+        reinterpret_cast< uintptr_t >( addr) + static_cast< uintptr_t >( len) );
+    while ( vp < end) {
+        prefetch( vp);
+        vp = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( vp) + static_cast< uintptr_t >( prefetch_stride) );
+    }
+#endif
+}
+
+#undef BOOST_HAS_PREFETCH
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_PREFETCH_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/detail/tuple.hpp

@@ -0,0 +1,129 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_DETAIL_TUPLE_H
+#define BOOST_CONTEXT_DETAIL_TUPLE_H
+
+#include <tuple>
+#include <utility>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/detail/index_sequence.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+template< typename ... S, typename ... T, std::size_t ... I >
+void
+head_impl( std::tuple< S ... > & s,
+           std::tuple< T ... > & t, index_sequence< I ... >) {
+    t = std::tuple< T ... >{ std::get< I >( s) ... };
+}
+
+template< typename ... S, typename ... T, std::size_t ... I >
+void
+head_impl( std::tuple< S ... > && s,
+           std::tuple< T ... > & t, index_sequence< I ... >) {
+    t = std::tuple< T ... >{ std::get< I >( std::move( s) ) ... };
+}
+
+template< typename ... S, std::size_t ... I1, typename ... T, std::size_t ... I2 >
+void
+tail_impl( std::tuple< S ... > & s, index_sequence< I1 ... >,
+           std::tuple< T ... > & t, index_sequence< I2 ... >) {
+    constexpr std::size_t Idx = (sizeof...(I1)) - (sizeof...(I2));
+    t = std::tuple< T ... >{ std::get< (Idx + I2) >( s) ... };
+}
+
+template< typename ... S, std::size_t ... I1, typename ... T, std::size_t ... I2 >
+void
+tail_impl( std::tuple< S ... > && s, index_sequence< I1 ... >,
+           std::tuple< T ... > & t, index_sequence< I2 ... >) {
+    constexpr std::size_t Idx = (sizeof...(I1)) - (sizeof...(I2));
+    t = std::tuple< T ... >{ std::get< (Idx + I2) >( std::move( s) ) ... };
+}
+
+template< typename ... T >
+class tuple_head;
+
+template< typename ... T >
+class tuple_head< std::tuple< T ... > > {
+private:
+    std::tuple< T ... > &   t_;
+
+public:
+    tuple_head( std::tuple< T ... > & t) noexcept :
+        t_( t) {
+    }
+
+    template< typename ... S >
+    void operator=( std::tuple< S ... > & s) {
+        static_assert((sizeof...(T)) <= (sizeof...(S)), "invalid tuple size");
+        head_impl( s,
+                   t_, index_sequence_for< T ... >{} );
+    }
+    template< typename ... S >
+    void operator=( std::tuple< S ... > && s) {
+        static_assert((sizeof...(T)) <= (sizeof...(S)), "invalid tuple size");
+        head_impl( std::move( s),
+                   t_, index_sequence_for< T ... >{} );
+    }
+};
+
+template< typename ... T >
+class tuple_tail;
+
+template< typename ... T >
+class tuple_tail< std::tuple< T ... > > {
+private:
+    std::tuple< T ... > &   t_;
+
+public:
+    tuple_tail( std::tuple< T ... > & t) noexcept :
+        t_( t) {
+    }
+
+    template< typename ... S >
+    void operator=( std::tuple< S ... > & s) {
+        static_assert((sizeof...(T)) <= (sizeof...(S)), "invalid tuple size");
+        tail_impl( s, index_sequence_for< S ... >{},
+                   t_, index_sequence_for< T ... >{} );
+    }
+
+    template< typename ... S >
+    void operator=( std::tuple< S ... > && s) {
+        static_assert((sizeof...(T)) <= (sizeof...(S)), "invalid tuple size");
+        tail_impl( std::move( s), index_sequence_for< S ... >{},
+                   t_, index_sequence_for< T ... >{} );
+    }
+};
+
+template< typename ... T >
+detail::tuple_head< std::tuple< T ... > >
+head( std::tuple< T ... > & tpl) {
+    return tuple_head< std::tuple< T ... > >{ tpl };
+}
+
+template< typename ... T >
+detail::tuple_tail< std::tuple< T ... > >
+tail( std::tuple< T ... > & tpl) {
+    return tuple_tail< std::tuple< T ... > >{ tpl };
+}
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_DETAIL_TUPLE_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/fiber.hpp

@@ -0,0 +1,13 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#if defined(BOOST_USE_UCONTEXT)
+#include <boost/context/fiber_ucontext.hpp>
+#elif defined(BOOST_USE_WINFIB)
+#include <boost/context/fiber_winfib.hpp>
+#else
+#include <boost/context/fiber_fcontext.hpp>
+#endif

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/fiber_fcontext.hpp

@@ -0,0 +1,370 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_FIBER_H
+#define BOOST_CONTEXT_FIBER_H
+
+#include <boost/context/detail/config.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <exception>
+#include <functional>
+#include <memory>
+#include <ostream>
+#include <tuple>
+#include <utility>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/intrusive_ptr.hpp>
+
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+#include <boost/context/detail/exchange.hpp>
+#endif
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/detail/disable_overload.hpp>
+#include <boost/context/detail/exception.hpp>
+#include <boost/context/detail/fcontext.hpp>
+#include <boost/context/detail/tuple.hpp>
+#include <boost/context/fixedsize_stack.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/preallocated.hpp>
+#include <boost/context/segmented_stack.hpp>
+#include <boost/context/stack_context.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+#if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable: 4702)
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+inline
+transfer_t fiber_unwind( transfer_t t) {
+    throw forced_unwind( t.fctx);
+    return { nullptr, nullptr };
+}
+
+template< typename Rec >
+transfer_t fiber_exit( transfer_t t) noexcept {
+    Rec * rec = static_cast< Rec * >( t.data);
+    // destroy context stack
+    rec->deallocate();
+    return { nullptr, nullptr };
+}
+
+template< typename Rec >
+void fiber_entry( transfer_t t) noexcept {
+    // transfer control structure to the context-stack
+    Rec * rec = static_cast< Rec * >( t.data);
+    BOOST_ASSERT( nullptr != t.fctx);
+    BOOST_ASSERT( nullptr != rec);
+    try {
+        // jump back to `create_context()`
+        t = jump_fcontext( t.fctx, nullptr);
+        // start executing
+        t.fctx = rec->run( t.fctx);
+    } catch ( forced_unwind const& ex) {
+        t = { ex.fctx, nullptr };
+    }
+    BOOST_ASSERT( nullptr != t.fctx);
+    // destroy context-stack of `this`context on next context
+    ontop_fcontext( t.fctx, rec, fiber_exit< Rec >);
+    BOOST_ASSERT_MSG( false, "context already terminated");
+}
+
+template< typename Ctx, typename Fn >
+transfer_t fiber_ontop( transfer_t t) {
+    BOOST_ASSERT( nullptr != t.data);
+    auto p = *static_cast< Fn * >( t.data);
+    t.data = nullptr;
+    // execute function, pass fiber via reference
+    Ctx c = p( Ctx{ t.fctx } );
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+    return { exchange( c.fctx_, nullptr), nullptr };
+#else
+    return { std::exchange( c.fctx_, nullptr), nullptr };
+#endif
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+class fiber_record {
+private:
+    stack_context                                       sctx_;
+    typename std::decay< StackAlloc >::type             salloc_;
+    typename std::decay< Fn >::type                     fn_;
+
+    static void destroy( fiber_record * p) noexcept {
+        typename std::decay< StackAlloc >::type salloc = std::move( p->salloc_);
+        stack_context sctx = p->sctx_;
+        // deallocate fiber_record
+        p->~fiber_record();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    fiber_record( stack_context sctx, StackAlloc && salloc,
+            Fn && fn) noexcept :
+        sctx_( sctx),
+        salloc_( std::forward< StackAlloc >( salloc)),
+        fn_( std::forward< Fn >( fn) ) {
+    }
+
+    fiber_record( fiber_record const&) = delete;
+    fiber_record & operator=( fiber_record const&) = delete;
+
+    void deallocate() noexcept {
+        destroy( this);
+    }
+
+    fcontext_t run( fcontext_t fctx) {
+        // invoke context-function
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+        Ctx c = boost::context::detail::invoke( fn_, Ctx{ fctx } );
+#else
+        Ctx c = std::invoke( fn_, Ctx{ fctx } );
+#endif
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return exchange( c.fctx_, nullptr);
+#else
+        return std::exchange( c.fctx_, nullptr);
+#endif
+    }
+};
+
+template< typename Record, typename StackAlloc, typename Fn >
+fcontext_t create_fiber1( StackAlloc && salloc, Fn && fn) {
+    auto sctx = salloc.allocate();
+    // reserve space for control structure
+	void * storage = reinterpret_cast< void * >(
+			( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( Record) ) )
+            & ~static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    Record * record = new ( storage) Record{
+            sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // 64byte gab between control structure and stack top
+    // should be 16byte aligned
+    void * stack_top = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( storage) - static_cast< uintptr_t >( 64) );
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sctx.size) );
+    // create fast-context
+    const std::size_t size = reinterpret_cast< uintptr_t >( stack_top) - reinterpret_cast< uintptr_t >( stack_bottom);
+    const fcontext_t fctx = make_fcontext( stack_top, size, & fiber_entry< Record >);
+    BOOST_ASSERT( nullptr != fctx);
+    // transfer control structure to context-stack
+    return jump_fcontext( fctx, record).fctx;
+}
+
+template< typename Record, typename StackAlloc, typename Fn >
+fcontext_t create_fiber2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( palloc.sp) - static_cast< uintptr_t >( sizeof( Record) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context-stack
+    Record * record = new ( storage) Record{
+            palloc.sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // 64byte gab between control structure and stack top
+    void * stack_top = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( storage) - static_cast< uintptr_t >( 64) );
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( palloc.sctx.sp) - static_cast< uintptr_t >( palloc.sctx.size) );
+    // create fast-context
+    const std::size_t size = reinterpret_cast< uintptr_t >( stack_top) - reinterpret_cast< uintptr_t >( stack_bottom);
+    const fcontext_t fctx = make_fcontext( stack_top, size, & fiber_entry< Record >);
+    BOOST_ASSERT( nullptr != fctx);
+    // transfer control structure to context-stack
+    return jump_fcontext( fctx, record).fctx;
+}
+
+}
+
+class fiber {
+private:
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend class detail::fiber_record;
+
+    template< typename Ctx, typename Fn >
+    friend detail::transfer_t
+    detail::fiber_ontop( detail::transfer_t);
+
+    template< typename StackAlloc, typename Fn >
+    friend fiber
+    callcc( std::allocator_arg_t, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend fiber
+    callcc( std::allocator_arg_t, preallocated, StackAlloc &&, Fn &&);
+
+    detail::fcontext_t  fctx_{ nullptr };
+
+    fiber( detail::fcontext_t fctx) noexcept :
+        fctx_{ fctx } {
+    }
+
+public:
+    fiber() noexcept = default;
+
+    template< typename Fn, typename = detail::disable_overload< fiber, Fn > >
+    fiber( Fn && fn) :
+        fiber{ std::allocator_arg, fixedsize_stack(), std::forward< Fn >( fn) } {
+    }
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, StackAlloc && salloc, Fn && fn) :
+        fctx_{ detail::create_fiber1< detail::fiber_record< fiber, StackAlloc, Fn > >(
+                std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) } {
+    }
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, preallocated palloc, StackAlloc && salloc, Fn && fn) :
+        fctx_{ detail::create_fiber2< detail::fiber_record< fiber, StackAlloc, Fn > >(
+                palloc, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) } {
+    }
+
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+    template< typename Fn >
+    fiber( std::allocator_arg_t, segmented_stack, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, preallocated, segmented_stack, Fn &&);
+#endif
+
+    ~fiber() {
+        if ( BOOST_UNLIKELY( nullptr != fctx_) ) {
+            detail::ontop_fcontext(
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    detail::exchange( fctx_, nullptr),
+#else
+                    std::exchange( fctx_, nullptr),
+#endif
+                   nullptr,
+                   detail::fiber_unwind);
+        }
+    }
+
+    fiber( fiber && other) noexcept {
+        swap( other);
+    }
+
+    fiber & operator=( fiber && other) noexcept {
+        if ( BOOST_LIKELY( this != & other) ) {
+            fiber tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    fiber( fiber const& other) noexcept = delete;
+    fiber & operator=( fiber const& other) noexcept = delete;
+
+    fiber resume() && {
+        BOOST_ASSERT( nullptr != fctx_);
+        return { detail::jump_fcontext(
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    detail::exchange( fctx_, nullptr),
+#else
+                    std::exchange( fctx_, nullptr),
+#endif
+                    nullptr).fctx };
+    }
+
+    template< typename Fn >
+    fiber resume_with( Fn && fn) && {
+        BOOST_ASSERT( nullptr != fctx_);
+        auto p = std::forward< Fn >( fn);
+        return { detail::ontop_fcontext(
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    detail::exchange( fctx_, nullptr),
+#else
+                    std::exchange( fctx_, nullptr),
+#endif
+                    & p,
+                    detail::fiber_ontop< fiber, decltype(p) >).fctx };
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != fctx_;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == fctx_;
+    }
+
+    bool operator<( fiber const& other) const noexcept {
+        return fctx_ < other.fctx_;
+    }
+
+    #if !defined(BOOST_EMBTC)
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
+        if ( nullptr != other.fctx_) {
+            return os << other.fctx_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    #else
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other);
+
+    #endif
+
+    void swap( fiber & other) noexcept {
+        std::swap( fctx_, other.fctx_);
+    }
+};
+
+#if defined(BOOST_EMBTC)
+
+    template< typename charT, class traitsT >
+    inline std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
+        if ( nullptr != other.fctx_) {
+            return os << other.fctx_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+#endif
+    
+inline
+void swap( fiber & l, fiber & r) noexcept {
+    l.swap( r);
+}
+
+typedef fiber fiber_context;
+
+}}
+
+#if defined(BOOST_MSVC)
+# pragma warning(pop)
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_FIBER_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/fiber_ucontext.hpp

@@ -0,0 +1,566 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_FIBER_H
+#define BOOST_CONTEXT_FIBER_H
+
+#include <boost/predef.h>
+#if BOOST_OS_MACOS
+#define _XOPEN_SOURCE 600
+#endif
+
+extern "C" {
+#include <ucontext.h>
+}
+
+#include <boost/context/detail/config.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <functional>
+#include <memory>
+#include <ostream>
+#include <system_error>
+#include <tuple>
+#include <utility>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/predef.h>
+
+#include <boost/context/detail/disable_overload.hpp>
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+#include <boost/context/detail/exchange.hpp>
+#endif
+#include <boost/context/detail/externc.hpp>
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/fixedsize_stack.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/preallocated.hpp>
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+#include <boost/context/segmented_stack.hpp>
+#endif
+#include <boost/context/stack_context.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+#ifdef BOOST_USE_TSAN
+#include <sanitizer/tsan_interface.h>
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+// tampoline function
+// entered if the execution context
+// is resumed for the first time
+template< typename Record >
+static void fiber_entry_func( void * data) noexcept {
+    Record * record = static_cast< Record * >( data);
+    BOOST_ASSERT( nullptr != record);
+    // start execution of toplevel context-function
+    record->run();
+}
+
+struct BOOST_CONTEXT_DECL fiber_activation_record {
+    ucontext_t                                                  uctx{};
+    stack_context                                               sctx{};
+    bool                                                        main_ctx{ true };
+	fiber_activation_record                                       *	from{ nullptr };
+    std::function< fiber_activation_record*(fiber_activation_record*&) >    ontop{};
+    bool                                                        terminated{ false };
+    bool                                                        force_unwind{ false };
+#if defined(BOOST_USE_ASAN)
+    void                                                    *   fake_stack{ nullptr };
+    void                                                    *   stack_bottom{ nullptr };
+    std::size_t                                                 stack_size{ 0 };
+#endif
+
+#if defined(BOOST_USE_TSAN)
+    void * tsan_fiber{ nullptr };
+    bool destroy_tsan_fiber{ true };
+#endif
+
+    static fiber_activation_record *& current() noexcept;
+
+    // used for toplevel-context
+    // (e.g. main context, thread-entry context)
+    fiber_activation_record() {
+        if ( BOOST_UNLIKELY( 0 != ::getcontext( & uctx) ) ) {
+            throw std::system_error(
+                    std::error_code( errno, std::system_category() ),
+                    "getcontext() failed");
+        }
+
+#if defined(BOOST_USE_TSAN)
+        tsan_fiber = __tsan_get_current_fiber();
+        destroy_tsan_fiber = false;
+#endif
+    }
+
+    fiber_activation_record( stack_context sctx_) noexcept :
+        sctx( sctx_ ),
+        main_ctx( false ) {
+    } 
+
+    virtual ~fiber_activation_record() {
+#if defined(BOOST_USE_TSAN)
+        if (destroy_tsan_fiber)
+            __tsan_destroy_fiber(tsan_fiber);
+#endif
+	}
+
+    fiber_activation_record( fiber_activation_record const&) = delete;
+    fiber_activation_record & operator=( fiber_activation_record const&) = delete;
+
+    bool is_main_context() const noexcept {
+        return main_ctx;
+    }
+
+    fiber_activation_record * resume() {
+		from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        current() = this;
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+        // adjust segmented stack properties
+        __splitstack_getcontext( from->sctx.segments_ctx);
+        __splitstack_setcontext( sctx.segments_ctx);
+#endif
+#if defined(BOOST_USE_ASAN)
+        if ( terminated) {
+            __sanitizer_start_switch_fiber( nullptr, stack_bottom, stack_size);
+        } else {
+            __sanitizer_start_switch_fiber( & from->fake_stack, stack_bottom, stack_size);
+        }
+#endif
+#if defined (BOOST_USE_TSAN)
+        __tsan_switch_to_fiber(tsan_fiber, 0);
+#endif
+        // context switch from parent context to `this`-context
+        ::swapcontext( & from->uctx, & uctx);
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_finish_switch_fiber( current()->fake_stack,
+                                         (const void **) & current()->from->stack_bottom,
+                                         & current()->from->stack_size);
+#endif
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    template< typename Ctx, typename Fn >
+    fiber_activation_record * resume_with( Fn && fn) {
+		from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        // returned by fiber::current()
+        current() = this;
+#if defined(BOOST_NO_CXX14_GENERIC_LAMBDAS)
+        current()->ontop = std::bind(
+                [](typename std::decay< Fn >::type & fn, fiber_activation_record *& ptr){
+                    Ctx c{ ptr };
+                    c = fn( std::move( c) );
+                    if ( ! c) {
+                        ptr = nullptr;
+                    }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    return exchange( c.ptr_, nullptr);
+#else
+                    return std::exchange( c.ptr_, nullptr);
+#endif
+                },
+                std::forward< Fn >( fn),
+                std::placeholders::_1);
+#else
+        current()->ontop = [fn=std::forward<Fn>(fn)](fiber_activation_record *& ptr){
+            Ctx c{ ptr };
+            c = fn( std::move( c) );
+            if ( ! c) {
+                ptr = nullptr;
+            }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+            return exchange( c.ptr_, nullptr);
+#else
+            return std::exchange( c.ptr_, nullptr);
+#endif
+        };
+#endif
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+        // adjust segmented stack properties
+        __splitstack_getcontext( from->sctx.segments_ctx);
+        __splitstack_setcontext( sctx.segments_ctx);
+#endif
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_start_switch_fiber( & from->fake_stack, stack_bottom, stack_size);
+#endif
+#if defined (BOOST_USE_TSAN)
+        __tsan_switch_to_fiber(tsan_fiber, 0);
+#endif
+        // context switch from parent context to `this`-context
+        ::swapcontext( & from->uctx, & uctx);
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_finish_switch_fiber( current()->fake_stack,
+                                         (const void **) & current()->from->stack_bottom,
+                                         & current()->from->stack_size);
+#endif
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    virtual void deallocate() noexcept {
+    }
+};
+
+struct BOOST_CONTEXT_DECL fiber_activation_record_initializer {
+    fiber_activation_record_initializer() noexcept;
+    ~fiber_activation_record_initializer();
+};
+
+struct forced_unwind {
+    fiber_activation_record  *  from{ nullptr };
+
+    forced_unwind( fiber_activation_record * from_) noexcept :
+        from{ from_ } {
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+class fiber_capture_record : public fiber_activation_record {
+private:
+    typename std::decay< StackAlloc >::type             salloc_;
+    typename std::decay< Fn >::type                     fn_;
+
+    static void destroy( fiber_capture_record * p) noexcept {
+        typename std::decay< StackAlloc >::type salloc = std::move( p->salloc_);
+        stack_context sctx = p->sctx;
+        // deallocate activation record
+        p->~fiber_capture_record();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    fiber_capture_record( stack_context sctx, StackAlloc && salloc, Fn && fn) noexcept :
+        fiber_activation_record{ sctx },
+        salloc_{ std::forward< StackAlloc >( salloc) },
+        fn_( std::forward< Fn >( fn) ) {
+    }
+
+    void deallocate() noexcept override final {
+        BOOST_ASSERT( main_ctx || ( ! main_ctx && terminated) );
+        destroy( this);
+    }
+
+    void run() {
+#if defined(BOOST_USE_ASAN)
+        __sanitizer_finish_switch_fiber( fake_stack,
+                                         (const void **) & from->stack_bottom,
+                                         & from->stack_size);
+#endif
+        Ctx c{ from };
+        try {
+            // invoke context-function
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+            c = boost::context::detail::invoke( fn_, std::move( c) );
+#else
+            c = std::invoke( fn_, std::move( c) );
+#endif  
+        } catch ( forced_unwind const& ex) {
+            c = Ctx{ ex.from };
+        }
+        // this context has finished its task
+		from = nullptr;
+        ontop = nullptr;
+        terminated = true;
+        force_unwind = false;
+        std::move( c).resume();
+        BOOST_ASSERT_MSG( false, "fiber already terminated");
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static fiber_activation_record * create_fiber1( StackAlloc && salloc, Fn && fn) {
+    typedef fiber_capture_record< Ctx, StackAlloc, Fn >  capture_t;
+
+    auto sctx = salloc.allocate();
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // stack bottom
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sctx.size) );
+    // create user-context
+    if ( BOOST_UNLIKELY( 0 != ::getcontext( & record->uctx) ) ) {
+        record->~capture_t();
+        salloc.deallocate( sctx);
+        throw std::system_error(
+                std::error_code( errno, std::system_category() ),
+                "getcontext() failed");
+    }
+#if BOOST_OS_BSD_FREE
+    // because FreeBSD defines stack_t::ss_sp as char *
+    record->uctx.uc_stack.ss_sp = static_cast< char * >( stack_bottom);
+#else
+    record->uctx.uc_stack.ss_sp = stack_bottom;
+#endif
+    // 64byte gap between control structure and stack top
+    record->uctx.uc_stack.ss_size = reinterpret_cast< uintptr_t >( storage) -
+            reinterpret_cast< uintptr_t >( stack_bottom) - static_cast< uintptr_t >( 64);
+    record->uctx.uc_link = nullptr;
+    ::makecontext( & record->uctx, ( void (*)() ) & fiber_entry_func< capture_t >, 1, record);
+#if defined(BOOST_USE_ASAN)
+    record->stack_bottom = record->uctx.uc_stack.ss_sp;
+    record->stack_size = record->uctx.uc_stack.ss_size;
+#endif
+#if defined (BOOST_USE_TSAN)
+    record->tsan_fiber = __tsan_create_fiber(0);
+#endif
+    return record;
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static fiber_activation_record * create_fiber2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    typedef fiber_capture_record< Ctx, StackAlloc, Fn >  capture_t; 
+
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( palloc.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            palloc.sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // stack bottom
+    void * stack_bottom = reinterpret_cast< void * >(
+            reinterpret_cast< uintptr_t >( palloc.sctx.sp) - static_cast< uintptr_t >( palloc.sctx.size) );
+    // create user-context
+    if ( BOOST_UNLIKELY( 0 != ::getcontext( & record->uctx) ) ) {
+        record->~capture_t();
+        salloc.deallocate( palloc.sctx);
+        throw std::system_error(
+                std::error_code( errno, std::system_category() ),
+                "getcontext() failed");
+    }
+#if BOOST_OS_BSD_FREE
+    // because FreeBSD defines stack_t::ss_sp as char *
+    record->uctx.uc_stack.ss_sp = static_cast< char * >( stack_bottom);
+#else
+    record->uctx.uc_stack.ss_sp = stack_bottom;
+#endif
+    // 64byte gap between control structure and stack top
+    record->uctx.uc_stack.ss_size = reinterpret_cast< uintptr_t >( storage) -
+            reinterpret_cast< uintptr_t >( stack_bottom) - static_cast< uintptr_t >( 64);
+    record->uctx.uc_link = nullptr;
+    ::makecontext( & record->uctx,  ( void (*)() ) & fiber_entry_func< capture_t >, 1, record);
+#if defined(BOOST_USE_ASAN)
+    record->stack_bottom = record->uctx.uc_stack.ss_sp;
+    record->stack_size = record->uctx.uc_stack.ss_size;
+#endif
+#if defined (BOOST_USE_TSAN)
+    record->tsan_fiber = __tsan_create_fiber(0);
+#endif
+    return record;
+}
+
+}
+
+class BOOST_CONTEXT_DECL fiber {
+private:
+    friend struct detail::fiber_activation_record;
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend class detail::fiber_capture_record;
+
+	template< typename Ctx, typename StackAlloc, typename Fn >
+	friend detail::fiber_activation_record * detail::create_fiber1( StackAlloc &&, Fn &&);
+
+	template< typename Ctx, typename StackAlloc, typename Fn >
+	friend detail::fiber_activation_record * detail::create_fiber2( preallocated, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend fiber
+    callcc( std::allocator_arg_t, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend fiber
+    callcc( std::allocator_arg_t, preallocated, StackAlloc &&, Fn &&);
+
+    detail::fiber_activation_record   *   ptr_{ nullptr };
+
+    fiber( detail::fiber_activation_record * ptr) noexcept :
+        ptr_{ ptr } {
+    }
+
+public:
+    fiber() = default;
+
+    template< typename Fn, typename = detail::disable_overload< fiber, Fn > >
+    fiber( Fn && fn) :
+        fiber{
+                std::allocator_arg,
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+                segmented_stack(),
+#else
+                fixedsize_stack(),
+#endif
+                std::forward< Fn >( fn) } {
+    }
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, StackAlloc && salloc, Fn && fn) :
+        ptr_{ detail::create_fiber1< fiber >(
+                std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) } {
+    }
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, preallocated palloc, StackAlloc && salloc, Fn && fn) :
+        ptr_{ detail::create_fiber2< fiber >(
+                palloc, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) } {
+    }
+
+    ~fiber() {
+        if ( BOOST_UNLIKELY( nullptr != ptr_) && ! ptr_->main_ctx) {
+            if ( BOOST_LIKELY( ! ptr_->terminated) ) {
+                ptr_->force_unwind = true;
+                ptr_->resume();
+                BOOST_ASSERT( ptr_->terminated);
+            }
+            ptr_->deallocate();
+        }
+    }
+
+    fiber( fiber const&) = delete;
+    fiber & operator=( fiber const&) = delete;
+
+    fiber( fiber && other) noexcept {
+        swap( other);
+    }
+
+    fiber & operator=( fiber && other) noexcept {
+        if ( BOOST_LIKELY( this != & other) ) {
+            fiber tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    fiber resume() && {
+        BOOST_ASSERT( nullptr != ptr_);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::fiber_activation_record * ptr = detail::exchange( ptr_, nullptr)->resume();
+#else
+        detail::fiber_activation_record * ptr = std::exchange( ptr_, nullptr)->resume();
+#endif
+        if ( BOOST_UNLIKELY( detail::fiber_activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::fiber_activation_record::current()->ontop) ) {
+            ptr = detail::fiber_activation_record::current()->ontop( ptr);
+            detail::fiber_activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    template< typename Fn >
+    fiber resume_with( Fn && fn) && {
+        BOOST_ASSERT( nullptr != ptr_);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::fiber_activation_record * ptr =
+            detail::exchange( ptr_, nullptr)->resume_with< fiber >( std::forward< Fn >( fn) );
+#else
+        detail::fiber_activation_record * ptr =
+            std::exchange( ptr_, nullptr)->resume_with< fiber >( std::forward< Fn >( fn) );
+#endif
+        if ( BOOST_UNLIKELY( detail::fiber_activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::fiber_activation_record::current()->ontop) ) {
+            ptr = detail::fiber_activation_record::current()->ontop( ptr);
+            detail::fiber_activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != ptr_ && ! ptr_->terminated;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == ptr_ || ptr_->terminated;
+    }
+
+    bool operator<( fiber const& other) const noexcept {
+        return ptr_ < other.ptr_;
+    }
+
+    #if !defined(BOOST_EMBTC)
+
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    #else
+
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other);
+
+    #endif
+
+    void swap( fiber & other) noexcept {
+        std::swap( ptr_, other.ptr_);
+    }
+};
+
+#if defined(BOOST_EMBTC)
+
+    template< typename charT, class traitsT >
+    inline std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+#endif
+
+inline
+void swap( fiber & l, fiber & r) noexcept {
+    l.swap( r);
+}
+
+typedef fiber fiber_context;
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_FIBER_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/fiber_winfib.hpp

@@ -0,0 +1,458 @@
+
+//          Copyright Oliver Kowalke 2017.
+// 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)
+
+#ifndef BOOST_CONTEXT_FIBER_H
+#define BOOST_CONTEXT_FIBER_H
+
+#include <windows.h>
+
+#include <boost/context/detail/config.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <functional>
+#include <memory>
+#include <ostream>
+#include <system_error>
+#include <tuple>
+#include <utility>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+
+#include <boost/context/detail/disable_overload.hpp>
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+#include <boost/context/detail/exchange.hpp>
+#endif
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+#include <boost/context/detail/invoke.hpp>
+#endif
+#include <boost/context/fixedsize_stack.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/preallocated.hpp>
+#include <boost/context/stack_context.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+#if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable: 4702)
+#endif
+
+namespace boost {
+namespace context {
+namespace detail {
+
+// tampoline function
+// entered if the execution context
+// is resumed for the first time
+template< typename Record >
+static VOID WINAPI fiber_entry_func( LPVOID data) noexcept {
+    Record * record = static_cast< Record * >( data);
+    BOOST_ASSERT( nullptr != record);
+    // start execution of toplevel context-function
+    record->run();
+}
+
+struct BOOST_CONTEXT_DECL fiber_activation_record {
+    LPVOID                                                      fiber{ nullptr };
+    stack_context                                               sctx{};
+    bool                                                        main_ctx{ true };
+    fiber_activation_record                                       *   from{ nullptr };
+    std::function< fiber_activation_record*(fiber_activation_record*&) >    ontop{};
+    bool                                                        terminated{ false };
+    bool                                                        force_unwind{ false };
+
+    static fiber_activation_record *& current() noexcept;
+
+    // used for toplevel-context
+    // (e.g. main context, thread-entry context)
+    fiber_activation_record() noexcept {
+#if ( _WIN32_WINNT > 0x0600)
+        if ( ::IsThreadAFiber() ) {
+            fiber = ::GetCurrentFiber();
+        } else {
+            fiber = ::ConvertThreadToFiber( nullptr);
+        }
+#else
+        fiber = ::ConvertThreadToFiber( nullptr);
+        if ( BOOST_UNLIKELY( nullptr == fiber) ) {
+            BOOST_ASSERT( ERROR_ALREADY_FIBER == ::GetLastError());
+            fiber = ::GetCurrentFiber(); 
+            BOOST_ASSERT( nullptr != fiber);
+            BOOST_ASSERT( reinterpret_cast< LPVOID >( 0x1E00) != fiber);
+        }
+#endif
+    }
+
+    fiber_activation_record( stack_context sctx_) noexcept :
+        sctx{ sctx_ },
+        main_ctx{ false } {
+    } 
+
+    virtual ~fiber_activation_record() {
+        if ( BOOST_UNLIKELY( main_ctx) ) {
+            ::ConvertFiberToThread();
+        } else {
+            ::DeleteFiber( fiber);
+        }
+    }
+
+    fiber_activation_record( fiber_activation_record const&) = delete;
+    fiber_activation_record & operator=( fiber_activation_record const&) = delete;
+
+    bool is_main_context() const noexcept {
+        return main_ctx;
+    }
+
+    fiber_activation_record * resume() {
+        from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        current() = this;
+        // context switch from parent context to `this`-context
+        // context switch
+        ::SwitchToFiber( fiber);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return detail::exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    template< typename Ctx, typename Fn >
+    fiber_activation_record * resume_with( Fn && fn) {
+        from = current();
+        // store `this` in static, thread local pointer
+        // `this` will become the active (running) context
+        // returned by fiber::current()
+        current() = this;
+#if defined(BOOST_NO_CXX14_GENERIC_LAMBDAS)
+        current()->ontop = std::bind(
+                [](typename std::decay< Fn >::type & fn, fiber_activation_record *& ptr){
+                    Ctx c{ ptr };
+                    c = fn( std::move( c) );
+                    if ( ! c) {
+                        ptr = nullptr;
+                    }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+                    return exchange( c.ptr_, nullptr);
+#else
+                    return std::exchange( c.ptr_, nullptr);
+#endif
+                },
+                std::forward< Fn >( fn),
+                std::placeholders::_1);
+#else
+        current()->ontop = [fn=std::forward<Fn>(fn)](fiber_activation_record *& ptr){
+            Ctx c{ ptr };
+            c = fn( std::move( c) );
+            if ( ! c) {
+                ptr = nullptr;
+            }
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+            return exchange( c.ptr_, nullptr);
+#else
+            return std::exchange( c.ptr_, nullptr);
+#endif
+        };
+#endif
+        // context switch
+        ::SwitchToFiber( fiber);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        return detail::exchange( current()->from, nullptr);
+#else
+        return std::exchange( current()->from, nullptr);
+#endif
+    }
+
+    virtual void deallocate() noexcept {
+    }
+};
+
+struct BOOST_CONTEXT_DECL fiber_activation_record_initializer {
+    fiber_activation_record_initializer() noexcept;
+    ~fiber_activation_record_initializer();
+};
+
+struct forced_unwind {
+    fiber_activation_record  *  from{ nullptr };
+
+    explicit forced_unwind( fiber_activation_record * from_) :
+        from{ from_ } {
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+class fiber_capture_record : public fiber_activation_record {
+private:
+    typename std::decay< StackAlloc >::type             salloc_;
+    typename std::decay< Fn >::type                     fn_;
+
+    static void destroy( fiber_capture_record * p) noexcept {
+        typename std::decay< StackAlloc >::type salloc = std::move( p->salloc_);
+        stack_context sctx = p->sctx;
+        // deallocate activation record
+        p->~fiber_capture_record();
+        // destroy stack with stack allocator
+        salloc.deallocate( sctx);
+    }
+
+public:
+    fiber_capture_record( stack_context sctx, StackAlloc && salloc, Fn && fn) noexcept :
+        fiber_activation_record( sctx),
+        salloc_( std::forward< StackAlloc >( salloc)),
+        fn_( std::forward< Fn >( fn) ) {
+    }
+
+    void deallocate() noexcept override final {
+        BOOST_ASSERT( main_ctx || ( ! main_ctx && terminated) );
+        destroy( this);
+    }
+
+    void run() {
+        Ctx c{ from };
+        try {
+            // invoke context-function
+#if defined(BOOST_NO_CXX17_STD_INVOKE)
+            c = boost::context::detail::invoke( fn_, std::move( c) );
+#else
+            c = std::invoke( fn_, std::move( c) );
+#endif  
+        } catch ( forced_unwind const& ex) {
+            c = Ctx{ ex.from };
+        }
+        // this context has finished its task
+        from = nullptr;
+        ontop = nullptr;
+        terminated = true;
+        force_unwind = false;
+        std::move( c).resume();
+        BOOST_ASSERT_MSG( false, "fiber already terminated");
+    }
+};
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static fiber_activation_record * create_fiber1( StackAlloc && salloc, Fn && fn) {
+    typedef fiber_capture_record< Ctx, StackAlloc, Fn >  capture_t;
+
+    auto sctx = salloc.allocate();
+    BOOST_ASSERT( ( sizeof( capture_t) ) < sctx.size);
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( sctx.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // create user-context
+    record->fiber = ::CreateFiber( sctx.size, & detail::fiber_entry_func< capture_t >, record);
+    return record;
+}
+
+template< typename Ctx, typename StackAlloc, typename Fn >
+static fiber_activation_record * create_fiber2( preallocated palloc, StackAlloc && salloc, Fn && fn) {
+    typedef fiber_capture_record< Ctx, StackAlloc, Fn >  capture_t; 
+
+    BOOST_ASSERT( ( sizeof( capture_t) ) < palloc.size);
+    // reserve space for control structure
+    void * storage = reinterpret_cast< void * >(
+            ( reinterpret_cast< uintptr_t >( palloc.sp) - static_cast< uintptr_t >( sizeof( capture_t) ) )
+            & ~ static_cast< uintptr_t >( 0xff) );
+    // placment new for control structure on context stack
+    capture_t * record = new ( storage) capture_t{
+            palloc.sctx, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) };
+    // create user-context
+    record->fiber = ::CreateFiber( palloc.sctx.size, & detail::fiber_entry_func< capture_t >, record);
+    return record;
+}
+
+}
+
+class BOOST_CONTEXT_DECL fiber {
+private:
+    friend struct detail::fiber_activation_record;
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend class detail::fiber_capture_record;
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend detail::fiber_activation_record * detail::create_fiber1( StackAlloc &&, Fn &&);
+
+    template< typename Ctx, typename StackAlloc, typename Fn >
+    friend detail::fiber_activation_record * detail::create_fiber2( preallocated, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend fiber
+    callcc( std::allocator_arg_t, StackAlloc &&, Fn &&);
+
+    template< typename StackAlloc, typename Fn >
+    friend fiber
+    callcc( std::allocator_arg_t, preallocated, StackAlloc &&, Fn &&);
+
+    detail::fiber_activation_record   *   ptr_{ nullptr };
+
+    fiber( detail::fiber_activation_record * ptr) noexcept :
+        ptr_{ ptr } {
+    }
+
+public:
+    fiber() = default;
+
+    template< typename Fn, typename = detail::disable_overload< fiber, Fn > >
+    fiber( Fn && fn) :
+        fiber{ std::allocator_arg,
+               fixedsize_stack(),
+               std::forward< Fn >( fn) } {
+    }
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, StackAlloc && salloc, Fn && fn) :
+        ptr_{ detail::create_fiber1< fiber >(
+                std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) } {;
+    }
+
+    template< typename StackAlloc, typename Fn >
+    fiber( std::allocator_arg_t, preallocated palloc, StackAlloc && salloc, Fn && fn) :
+        ptr_{ detail::create_fiber2< fiber >(
+                palloc, std::forward< StackAlloc >( salloc), std::forward< Fn >( fn) ) } {
+    }
+
+    ~fiber() {
+        if ( BOOST_UNLIKELY( nullptr != ptr_) && ! ptr_->main_ctx) {
+            if ( BOOST_LIKELY( ! ptr_->terminated) ) {
+                ptr_->force_unwind = true;
+                ptr_->resume();
+                BOOST_ASSERT( ptr_->terminated);
+            }
+            ptr_->deallocate();
+        }
+    }
+
+    fiber( fiber const&) = delete;
+    fiber & operator=( fiber const&) = delete;
+
+    fiber( fiber && other) noexcept {
+        swap( other);
+    }
+
+    fiber & operator=( fiber && other) noexcept {
+        if ( BOOST_LIKELY( this != & other) ) {
+            fiber tmp = std::move( other);
+            swap( tmp);
+        }
+        return * this;
+    }
+
+    fiber resume() && {
+        BOOST_ASSERT( nullptr != ptr_);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::fiber_activation_record * ptr = detail::exchange( ptr_, nullptr)->resume();
+#else
+        detail::fiber_activation_record * ptr = std::exchange( ptr_, nullptr)->resume();
+#endif
+        if ( BOOST_UNLIKELY( detail::fiber_activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::fiber_activation_record::current()->ontop) ) {
+            ptr = detail::fiber_activation_record::current()->ontop( ptr);
+            detail::fiber_activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    template< typename Fn >
+    fiber resume_with( Fn && fn) && {
+        BOOST_ASSERT( nullptr != ptr_);
+#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
+        detail::fiber_activation_record * ptr =
+            detail::exchange( ptr_, nullptr)->resume_with< fiber >( std::forward< Fn >( fn) );
+#else
+        detail::fiber_activation_record * ptr =
+            std::exchange( ptr_, nullptr)->resume_with< fiber >( std::forward< Fn >( fn) );
+#endif
+        if ( BOOST_UNLIKELY( detail::fiber_activation_record::current()->force_unwind) ) {
+            throw detail::forced_unwind{ ptr};
+        } else if ( BOOST_UNLIKELY( nullptr != detail::fiber_activation_record::current()->ontop) ) {
+            ptr = detail::fiber_activation_record::current()->ontop( ptr);
+            detail::fiber_activation_record::current()->ontop = nullptr;
+        }
+        return { ptr };
+    }
+
+    explicit operator bool() const noexcept {
+        return nullptr != ptr_ && ! ptr_->terminated;
+    }
+
+    bool operator!() const noexcept {
+        return nullptr == ptr_ || ptr_->terminated;
+    }
+
+    bool operator<( fiber const& other) const noexcept {
+        return ptr_ < other.ptr_;
+    }
+    
+    #if !defined(BOOST_EMBTC)
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+    #else
+    
+    template< typename charT, class traitsT >
+    friend std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other);
+
+    #endif
+
+    void swap( fiber & other) noexcept {
+        std::swap( ptr_, other.ptr_);
+    }
+};
+
+#if defined(BOOST_EMBTC)
+
+    template< typename charT, class traitsT >
+    inline std::basic_ostream< charT, traitsT > &
+    operator<<( std::basic_ostream< charT, traitsT > & os, fiber const& other) {
+        if ( nullptr != other.ptr_) {
+            return os << other.ptr_;
+        } else {
+            return os << "{not-a-context}";
+        }
+    }
+
+#endif
+
+inline
+void swap( fiber & l, fiber & r) noexcept {
+    l.swap( r);
+}
+
+typedef fiber fiber_context;
+
+}}
+
+#if defined(BOOST_MSVC)
+# pragma warning(pop)
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_FIBER_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/fixedsize_stack.hpp

@@ -0,0 +1,97 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_FIXEDSIZE_H
+#define BOOST_CONTEXT_FIXEDSIZE_H
+
+#include <cstddef>
+#include <cstdlib>
+#include <new>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/stack_context.hpp>
+#include <boost/context/stack_traits.hpp>
+
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+extern "C" {
+#include <sys/mman.h>
+}
+#endif
+
+#if defined(BOOST_USE_VALGRIND)
+#include <valgrind/valgrind.h>
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+template< typename traitsT >
+class basic_fixedsize_stack {
+private:
+    std::size_t     size_;
+
+public:
+    typedef traitsT traits_type;
+
+    basic_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
+        size_( size) {
+    }
+
+    stack_context allocate() {
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+        void * vp = ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_STACK, -1, 0);
+        if ( vp == MAP_FAILED) {
+            throw std::bad_alloc();
+        }
+#else
+        void * vp = std::malloc( size_);
+        if ( ! vp) {
+            throw std::bad_alloc();
+        }
+#endif
+        stack_context sctx;
+        sctx.size = size_;
+        sctx.sp = static_cast< char * >( vp) + sctx.size;
+#if defined(BOOST_USE_VALGRIND)
+        sctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( sctx.sp, vp);
+#endif
+        return sctx;
+    }
+
+    void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
+        BOOST_ASSERT( sctx.sp);
+
+#if defined(BOOST_USE_VALGRIND)
+        VALGRIND_STACK_DEREGISTER( sctx.valgrind_stack_id);
+#endif
+        void * vp = static_cast< char * >( sctx.sp) - sctx.size;
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+        ::munmap( vp, sctx.size);
+#else
+        std::free( vp);
+#endif
+    }
+};
+
+typedef basic_fixedsize_stack< stack_traits >  fixedsize_stack;
+# if ! defined(BOOST_USE_SEGMENTED_STACKS)
+typedef fixedsize_stack default_stack;
+# endif
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_FIXEDSIZE_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/flags.hpp

@@ -0,0 +1,28 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_FLAGS_H
+#define BOOST_CONTEXT_FLAGS_H
+
+# include <boost/config.hpp>
+
+# ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+# endif
+
+namespace boost {
+namespace context {
+
+struct exec_ontop_arg_t {};
+const exec_ontop_arg_t exec_ontop_arg{};
+
+}}
+
+# ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+# endif
+
+#endif // BOOST_CONTEXT_FLAGS_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/pooled_fixedsize_stack.hpp

@@ -0,0 +1,152 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_POOLED_pooled_fixedsize_H
+#define BOOST_CONTEXT_POOLED_pooled_fixedsize_H
+
+#include <atomic>
+#include <cstddef>
+#include <cstdlib>
+#include <new>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/intrusive_ptr.hpp>
+#include <boost/pool/pool.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/stack_context.hpp>
+#include <boost/context/stack_traits.hpp>
+
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+extern "C" {
+#include <sys/mman.h>
+#include <stdlib.h>
+}
+#endif
+
+#if defined(BOOST_USE_VALGRIND)
+#include <valgrind/valgrind.h>
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+namespace detail {
+template< typename traitsT >
+struct map_stack_allocator {
+    typedef std::size_t size_type;
+    typedef std::ptrdiff_t difference_type;
+
+    static char * malloc( const size_type bytes) {
+        void * block;
+        if ( ::posix_memalign( &block, traitsT::page_size(), bytes) != 0) {
+            return 0;
+        }
+        if ( mmap( block, bytes, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_STACK, -1, 0) == MAP_FAILED) {
+            std::free( block);
+            return 0;
+        }
+        return reinterpret_cast< char * >( block);
+    }
+    static void free( char * const block) {
+        std::free( block);
+    }
+};
+}
+#endif
+
+template< typename traitsT >
+class basic_pooled_fixedsize_stack {
+private:
+    class storage {
+    private:
+        std::atomic< std::size_t >                                  use_count_;
+        std::size_t                                                 stack_size_;
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+        boost::pool< detail::map_stack_allocator< traitsT > >       storage_;
+#else
+        boost::pool< boost::default_user_allocator_malloc_free >    storage_;
+#endif
+
+    public:
+        storage( std::size_t stack_size, std::size_t next_size, std::size_t max_size) :
+                use_count_( 0),
+                stack_size_( stack_size),
+                storage_( stack_size, next_size, max_size) {
+            BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= stack_size_) );
+        }
+
+        stack_context allocate() {
+            void * vp = storage_.malloc();
+            if ( ! vp) {
+                throw std::bad_alloc();
+            }
+            stack_context sctx;
+            sctx.size = stack_size_;
+            sctx.sp = static_cast< char * >( vp) + sctx.size;
+#if defined(BOOST_USE_VALGRIND)
+            sctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( sctx.sp, vp);
+#endif
+            return sctx;
+        }
+
+        void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
+            BOOST_ASSERT( sctx.sp);
+            BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= sctx.size) );
+
+#if defined(BOOST_USE_VALGRIND)
+            VALGRIND_STACK_DEREGISTER( sctx.valgrind_stack_id);
+#endif
+            void * vp = static_cast< char * >( sctx.sp) - sctx.size;
+            storage_.free( vp);
+        }
+
+        friend void intrusive_ptr_add_ref( storage * s) noexcept {
+            ++s->use_count_;
+        }
+
+        friend void intrusive_ptr_release( storage * s) noexcept {
+            if ( 0 == --s->use_count_) {
+                delete s;
+            }
+        }
+    };
+
+    intrusive_ptr< storage >    storage_;
+
+public:
+    typedef traitsT traits_type;
+
+    basic_pooled_fixedsize_stack( std::size_t stack_size = traits_type::default_size(),
+                           std::size_t next_size = 32,
+                           std::size_t max_size = 0) BOOST_NOEXCEPT_OR_NOTHROW :
+        storage_( new storage( stack_size, next_size, max_size) ) {
+    }
+
+    stack_context allocate() {
+        return storage_->allocate();
+    }
+
+    void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
+        storage_->deallocate( sctx);
+    }
+};
+
+typedef basic_pooled_fixedsize_stack< stack_traits >  pooled_fixedsize_stack;
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_POOLED_pooled_fixedsize_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/posix/protected_fixedsize_stack.hpp

@@ -0,0 +1,102 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
+#define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
+
+extern "C" {
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+}
+
+#include <cmath>
+#include <cstddef>
+#include <new>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/core/ignore_unused.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/stack_context.hpp>
+#include <boost/context/stack_traits.hpp>
+
+#if defined(BOOST_USE_VALGRIND)
+#include <valgrind/valgrind.h>
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+template< typename traitsT >
+class basic_protected_fixedsize_stack {
+private:
+    std::size_t     size_;
+
+public:
+    typedef traitsT traits_type;
+
+    basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
+        size_( size) {
+    }
+
+    stack_context allocate() {
+        // calculate how many pages are required
+        const std::size_t pages = (size_ + traits_type::page_size() - 1) / traits_type::page_size();
+        // add one page at bottom that will be used as guard-page
+        const std::size_t size__ = ( pages + 1) * traits_type::page_size();
+
+#if defined(BOOST_CONTEXT_USE_MAP_STACK)
+        void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_STACK, -1, 0);
+#elif defined(MAP_ANON)
+        void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
+#else
+        void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+#endif
+        if ( MAP_FAILED == vp) throw std::bad_alloc();
+
+        // conforming to POSIX.1-2001
+        const int result( ::mprotect( vp, traits_type::page_size(), PROT_NONE) );
+        boost::ignore_unused(result);
+        BOOST_ASSERT( 0 == result);
+
+        stack_context sctx;
+        sctx.size = size__;
+        sctx.sp = static_cast< char * >( vp) + sctx.size;
+#if defined(BOOST_USE_VALGRIND)
+        sctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( sctx.sp, vp);
+#endif
+        return sctx;
+    }
+
+    void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
+        BOOST_ASSERT( sctx.sp);
+
+#if defined(BOOST_USE_VALGRIND)
+        VALGRIND_STACK_DEREGISTER( sctx.valgrind_stack_id);
+#endif
+
+        void * vp = static_cast< char * >( sctx.sp) - sctx.size;
+        // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
+        ::munmap( vp, sctx.size);
+    }
+};
+
+typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/posix/segmented_stack.hpp

@@ -0,0 +1,82 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_SEGMENTED_H
+#define BOOST_CONTEXT_SEGMENTED_H
+
+#include <cstddef>
+#include <new>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/stack_context.hpp>
+#include <boost/context/stack_traits.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+// forward declaration for splitstack-functions defined in libgcc
+extern "C" {
+void *__splitstack_makecontext( std::size_t,
+                                void * [BOOST_CONTEXT_SEGMENTS],
+                                std::size_t *);
+
+void __splitstack_releasecontext( void * [BOOST_CONTEXT_SEGMENTS]);
+
+void __splitstack_resetcontext( void * [BOOST_CONTEXT_SEGMENTS]);
+
+void __splitstack_block_signals_context( void * [BOOST_CONTEXT_SEGMENTS],
+                                         int * new_value, int * old_value);
+}
+
+namespace boost {
+namespace context {
+
+template< typename traitsT >
+class basic_segmented_stack {
+private:
+    std::size_t     size_;
+
+public:
+    typedef traitsT traits_type;
+
+    basic_segmented_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
+        size_( size) {
+    }
+
+    stack_context allocate() {
+        stack_context sctx;
+        void * vp = __splitstack_makecontext( size_, sctx.segments_ctx, & sctx.size);
+        if ( ! vp) throw std::bad_alloc();
+
+        // sctx.size is already filled by __splitstack_makecontext
+        sctx.sp = static_cast< char * >( vp) + sctx.size;
+
+        int off = 0;
+        __splitstack_block_signals_context( sctx.segments_ctx, & off, 0);
+
+        return sctx;
+    }
+
+    void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
+        __splitstack_releasecontext( sctx.segments_ctx);
+    }
+};
+
+typedef basic_segmented_stack< stack_traits > segmented_stack;
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+typedef segmented_stack default_stack;
+# endif
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_SEGMENTED_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/preallocated.hpp

@@ -0,0 +1,39 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_PREALLOCATED_H
+#define BOOST_CONTEXT_PREALLOCATED_H
+
+#include <cstddef>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+struct preallocated {
+    void        *   sp;
+    std::size_t     size;
+    stack_context   sctx;
+
+    preallocated( void * sp_, std::size_t size_, stack_context sctx_) noexcept :
+        sp( sp_), size( size_), sctx( sctx_) {
+    }
+};
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_PREALLOCATED_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/protected_fixedsize_stack.hpp

@@ -0,0 +1,13 @@
+
+//          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)
+
+#include <boost/config.hpp>
+
+#if defined(BOOST_WINDOWS)
+# include <boost/context/windows/protected_fixedsize_stack.hpp>
+#else
+# include <boost/context/posix/protected_fixedsize_stack.hpp>
+#endif

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/segmented_stack.hpp

@@ -0,0 +1,13 @@
+
+//          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)
+
+#include <boost/config.hpp>
+
+#if defined(BOOST_USE_SEGMENTED_STACKS)
+# if ! defined(BOOST_WINDOWS)
+#  include <boost/context/posix/segmented_stack.hpp>
+# endif
+#endif

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/stack_context.hpp

@@ -0,0 +1,72 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_STACK_CONTEXT_H
+#define BOOST_CONTEXT_STACK_CONTEXT_H
+
+#include <cstddef>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+#if ! defined(BOOST_CONTEXT_NO_CXX11)
+struct BOOST_CONTEXT_DECL stack_context {
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+    typedef void *  segments_context[BOOST_CONTEXT_SEGMENTS];
+# endif
+
+    std::size_t             size{ 0 };
+    void                *   sp{ nullptr };
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+    segments_context        segments_ctx{};
+# endif
+# if defined(BOOST_USE_VALGRIND)
+    unsigned                valgrind_stack_id{ 0 };
+# endif
+};
+#else
+struct BOOST_CONTEXT_DECL stack_context {
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+    typedef void *  segments_context[BOOST_CONTEXT_SEGMENTS];
+# endif
+
+    std::size_t             size;
+    void                *   sp;
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+    segments_context        segments_ctx;
+# endif
+# if defined(BOOST_USE_VALGRIND)
+    unsigned                valgrind_stack_id;
+# endif
+
+    stack_context() :
+        size( 0),
+        sp( 0)
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+        , segments_ctx()
+# endif
+# if defined(BOOST_USE_VALGRIND)
+        , valgrind_stack_id( 0)
+# endif
+        {}
+};
+#endif
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_STACK_CONTEXT_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/stack_traits.hpp

@@ -0,0 +1,42 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_STACK_TRAITS_H
+#define BOOST_CONTEXT_STACK_TRAITS_H
+
+#include <cstddef>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+struct BOOST_CONTEXT_DECL stack_traits
+{
+    static bool is_unbounded() BOOST_NOEXCEPT_OR_NOTHROW;
+
+    static std::size_t page_size() BOOST_NOEXCEPT_OR_NOTHROW;
+
+    static std::size_t default_size() BOOST_NOEXCEPT_OR_NOTHROW;
+
+    static std::size_t minimum_size() BOOST_NOEXCEPT_OR_NOTHROW;
+
+    static std::size_t maximum_size() BOOST_NOEXCEPT_OR_NOTHROW;
+};
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_STACK_TRAITS_H

externals/vcpkg/packages/boost-context_x64-windows/include/boost/context/windows/protected_fixedsize_stack.hpp

@@ -0,0 +1,81 @@
+
+//          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)
+
+#ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
+#define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
+
+extern "C" {
+#include <windows.h>
+}
+
+#include <cmath>
+#include <cstddef>
+#include <new>
+
+#include <boost/config.hpp>
+#include <boost/core/ignore_unused.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/stack_context.hpp>
+#include <boost/context/stack_traits.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace context {
+
+template< typename traitsT >
+class basic_protected_fixedsize_stack {
+private:
+    std::size_t     size_;
+
+public:
+    typedef traitsT traits_type;
+
+    basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
+        size_( size) {
+    }
+
+    stack_context allocate() {
+        // calculate how many pages are required
+        const std::size_t pages = (size_ + traits_type::page_size() - 1) / traits_type::page_size();
+        // add one page at bottom that will be used as guard-page
+        const std::size_t size__ = ( pages + 1) * traits_type::page_size();
+
+        void * vp = ::VirtualAlloc( 0, size__, MEM_COMMIT, PAGE_READWRITE);
+        if ( ! vp) throw std::bad_alloc();
+
+        DWORD old_options;
+        const BOOL result = ::VirtualProtect(
+            vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
+        boost::ignore_unused(result);
+        BOOST_ASSERT( FALSE != result);
+
+        stack_context sctx;
+        sctx.size = size__;
+        sctx.sp = static_cast< char * >( vp) + sctx.size;
+        return sctx;
+    }
+
+    void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
+        BOOST_ASSERT( sctx.sp);
+
+        void * vp = static_cast< char * >( sctx.sp) - sctx.size;
+        ::VirtualFree( vp, 0, MEM_RELEASE);
+    }
+};
+
+typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H