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function_base.hpp:

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- Switch over to using is_reference_wrapper instead of homegrown is_ref
  - Identify stateless function objects

function_template.hpp:
  - Optimize away construction/allocator for stateless function objects.


[SVN r12559]
This commit is contained in:
Douglas Gregor
2002-01-30 01:59:49 +00:00
parent aaa7f61b9e
commit 11187bcf3a
2 changed files with 87 additions and 34 deletions
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43
include/boost/function/function_base.hpp
View File

@ -77,37 +77,6 @@ namespace boost {
typedef typename select::template Result<Then,Else>::type type;
};
// Determine if the incoming argument is a reference_wrapper
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
template<typename T>
struct is_ref
{
BOOST_STATIC_CONSTANT(bool, value = false);
};
template<typename T>
struct is_ref<reference_wrapper<T> >
{
BOOST_STATIC_CONSTANT(bool, value = true);
};
#else // no partial specialization
typedef char yes_type;
typedef double no_type;
no_type is_ref_tester(...);
template<typename T>
yes_type is_ref_tester(reference_wrapper<T>*);
template<typename T>
struct is_ref
{
static T* t;
BOOST_STATIC_CONSTANT(bool,
value = (sizeof(is_ref_tester(t)) == sizeof(yes_type)));
};
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
/**
* A union of a function pointer and a void pointer. This is necessary
* because 5.2.10/6 allows reinterpret_cast<> to safely cast between
@ -161,6 +130,7 @@ namespace boost {
struct function_obj_tag {};
struct member_ptr_tag {};
struct function_obj_ref_tag {};
struct stateless_function_obj_tag {};
template<typename F>
class get_function_tag
@ -172,10 +142,15 @@ namespace boost {
typedef typename IF<(is_member_pointer<F>::value),
member_ptr_tag,
ptr_or_obj_tag>::type ptr_or_obj_or_mem_tag;
public:
typedef typename IF<(is_ref<F>::value),
typedef typename IF<(is_reference_wrapper<F>::value),
function_obj_ref_tag,
ptr_or_obj_or_mem_tag>::type type;
ptr_or_obj_or_mem_tag>::type or_ref_tag;
public:
typedef typename IF<(is_stateless<F>::value),
stateless_function_obj_tag,
or_ref_tag>::type type;
};
// The trivial manager does nothing but return the same pointer (if we

78
include/boost/function/function_template.hpp
View File

@ -50,10 +50,16 @@
BOOST_JOIN(function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER \
BOOST_JOIN(void_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER \
BOOST_JOIN(stateless_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER \
BOOST_JOIN(stateless_void_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_GET_FUNCTION_INVOKER \
BOOST_JOIN(get_function_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER \
BOOST_JOIN(get_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER \
BOOST_JOIN(get_stateless_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
namespace boost {
namespace detail {
@ -124,6 +130,37 @@ namespace boost {
}
};
template<
typename FunctionObj,
typename R BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_PARMS
>
struct BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER
{
static R invoke(any_pointer BOOST_FUNCTION_COMMA BOOST_FUNCTION_PARMS)
{
FunctionObj f;
return f(BOOST_FUNCTION_ARGS);
}
};
template<
typename FunctionObj,
typename R BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_PARMS
>
struct BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER
{
static unusable invoke(any_pointer BOOST_FUNCTION_COMMA
BOOST_FUNCTION_PARMS)
{
FunctionObj f;
f(BOOST_FUNCTION_ARGS);
return unusable();
}
};
template<
typename FunctionPtr,
typename R BOOST_FUNCTION_COMMA
@ -165,6 +202,28 @@ namespace boost {
>
>::type type;
};
template<
typename FunctionObj,
typename R BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_PARMS
>
struct BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER
{
typedef typename IF<(is_void<R>::value),
BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER<
FunctionObj,
R BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_ARGS
>,
BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER<
FunctionObj,
R BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_ARGS
>
>::type type;
};
} // end namespace function
} // end namespace detail
@ -390,6 +449,22 @@ namespace boost {
}
}
template<typename FunctionObj>
void assign_to(FunctionObj f, detail::function::stateless_function_obj_tag)
{
typedef
typename detail::function::
BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER<
FunctionObj,
R BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_ARGS
>::type
invoker_type;
invoker = &invoker_type::invoke;
function_base::manager = &detail::function::trivial_manager;
function_base::functor = detail::function::any_pointer(this);
}
typedef result_type (*invoker_type)(detail::function::any_pointer
BOOST_FUNCTION_COMMA
BOOST_FUNCTION_TEMPLATE_ARGS);
@ -428,7 +503,10 @@ namespace boost {
#undef BOOST_FUNCTION_VOID_FUNCTION_INVOKER
#undef BOOST_FUNCTION_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_GET_FUNCTION_INVOKER
#undef BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_GET_MEM_FUNCTION_INVOKER