boost/function/function_base.hpp
// Boost.Function library // Copyright Douglas Gregor 2001-2006 // Copyright Emil Dotchevski 2007 // Use, modification and distribution is subject to 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) // For more information, see http://www.boost.org #ifndef BOOST_FUNCTION_BASE_HEADER #define BOOST_FUNCTION_BASE_HEADER #include <stdexcept> #include <string> #include <memory> #include <new> #include <typeinfo> #include <boost/config.hpp> #include <boost/assert.hpp> #include <boost/type_traits/is_integral.hpp> #include <boost/type_traits/composite_traits.hpp> #include <boost/ref.hpp> #include <boost/mpl/if.hpp> #include <boost/detail/workaround.hpp> #include <boost/type_traits/alignment_of.hpp> #ifndef BOOST_NO_SFINAE # include "boost/utility/enable_if.hpp" #else # include "boost/mpl/bool.hpp" #endif #include <boost/function_equal.hpp> #if defined(BOOST_MSVC) # pragma warning( push ) # pragma warning( disable : 4793 ) // complaint about native code generation # pragma warning( disable : 4127 ) // "conditional expression is constant" #endif // Define BOOST_FUNCTION_STD_NS to the namespace that contains type_info. #ifdef BOOST_NO_EXCEPTION_STD_NAMESPACE // Embedded VC++ does not have type_info in namespace std # define BOOST_FUNCTION_STD_NS #else # define BOOST_FUNCTION_STD_NS std #endif // Borrowed from Boost.Python library: determines the cases where we // need to use std::type_info::name to compare instead of operator==. # if (defined(__GNUC__) && __GNUC__ >= 3) \ || defined(_AIX) \ || ( defined(__sgi) && defined(__host_mips)) # include <cstring> # define BOOST_FUNCTION_COMPARE_TYPE_ID(X,Y) \ (std::strcmp((X).name(),(Y).name()) == 0) # else # define BOOST_FUNCTION_COMPARE_TYPE_ID(X,Y) ((X)==(Y)) #endif #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 || defined(__ICL) && __ICL <= 600 || defined(__MWERKS__) && __MWERKS__ < 0x2406 && !defined(BOOST_STRICT_CONFIG) # define BOOST_FUNCTION_TARGET_FIX(x) x #else # define BOOST_FUNCTION_TARGET_FIX(x) #endif // not MSVC #if defined(__sgi) && defined(_COMPILER_VERSION) && _COMPILER_VERSION <= 730 && !defined(BOOST_STRICT_CONFIG) // Work around a compiler bug. // boost::python::objects::function has to be seen by the compiler before the // boost::function class template. namespace boost { namespace python { namespace objects { class function; }}} #endif #if defined (BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \ || defined(BOOST_BCB_PARTIAL_SPECIALIZATION_BUG) \ || !(BOOST_STRICT_CONFIG || !defined(__SUNPRO_CC) || __SUNPRO_CC > 0x540) # define BOOST_FUNCTION_NO_FUNCTION_TYPE_SYNTAX #endif #if !BOOST_WORKAROUND(__BORLANDC__, < 0x600) # define BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor,Type) \ typename ::boost::enable_if_c<(::boost::type_traits::ice_not< \ (::boost::is_integral<Functor>::value)>::value), \ Type>::type #else // BCC doesn't recognize this depends on a template argument and complains // about the use of 'typename' # define BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor,Type) \ ::boost::enable_if_c<(::boost::type_traits::ice_not< \ (::boost::is_integral<Functor>::value)>::value), \ Type>::type #endif #if !defined(BOOST_FUNCTION_NO_FUNCTION_TYPE_SYNTAX) namespace boost { template<typename Signature> class function; template<typename Signature> inline void swap(function<Signature>& f1, function<Signature>& f2) { f1.swap(f2); } } // end namespace boost #endif // have partial specialization namespace boost { namespace detail { namespace function { class X; /** * A buffer used to store small function objects in * boost::function. It is a union containing function pointers, * object pointers, and a structure that resembles a bound * member function pointer. */ union function_buffer { // For pointers to function objects void* obj_ptr; // For pointers to std::type_info objects // (get_functor_type_tag, check_functor_type_tag). const void* const_obj_ptr; // For function pointers of all kinds mutable void (*func_ptr)(); // For bound member pointers struct bound_memfunc_ptr_t { void (X::*memfunc_ptr)(int); void* obj_ptr; } bound_memfunc_ptr; // To relax aliasing constraints mutable char data; }; /** * The unusable class is a placeholder for unused function arguments * It is also completely unusable except that it constructable from * anything. This helps compilers without partial specialization to * handle Boost.Function objects returning void. */ struct unusable { unusable() {} template<typename T> unusable(const T&) {} }; /* Determine the return type. This supports compilers that do not support * void returns or partial specialization by silently changing the return * type to "unusable". */ template<typename T> struct function_return_type { typedef T type; }; template<> struct function_return_type<void> { typedef unusable type; }; // The operation type to perform on the given functor/function pointer enum functor_manager_operation_type { clone_functor_tag, destroy_functor_tag, check_functor_type_tag, get_functor_type_tag }; // Tags used to decide between different types of functions struct function_ptr_tag {}; struct function_obj_tag {}; struct member_ptr_tag {}; struct function_obj_ref_tag {}; template<typename F> class get_function_tag { typedef typename mpl::if_c<(is_pointer<F>::value), function_ptr_tag, function_obj_tag>::type ptr_or_obj_tag; typedef typename mpl::if_c<(is_member_pointer<F>::value), member_ptr_tag, ptr_or_obj_tag>::type ptr_or_obj_or_mem_tag; typedef typename mpl::if_c<(is_reference_wrapper<F>::value), function_obj_ref_tag, ptr_or_obj_or_mem_tag>::type or_ref_tag; public: typedef or_ref_tag type; }; // The trivial manager does nothing but return the same pointer (if we // are cloning) or return the null pointer (if we are deleting). template<typename F> struct reference_manager { static inline void get(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op) { switch (op) { case clone_functor_tag: out_buffer.obj_ptr = in_buffer.obj_ptr; return; case destroy_functor_tag: out_buffer.obj_ptr = 0; return; case check_functor_type_tag: { // DPG TBD: Since we're only storing a pointer, it's // possible that the user could ask for a base class or // derived class. Is that okay? const BOOST_FUNCTION_STD_NS::type_info& check_type = *static_cast<const BOOST_FUNCTION_STD_NS::type_info*>(out_buffer.const_obj_ptr); if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(F))) out_buffer.obj_ptr = in_buffer.obj_ptr; else out_buffer.obj_ptr = 0; } return; case get_functor_type_tag: out_buffer.const_obj_ptr = &typeid(F); return; } } }; /** * Determine if boost::function can use the small-object * optimization with the function object type F. */ template<typename F> struct function_allows_small_object_optimization { BOOST_STATIC_CONSTANT (bool, value = ((sizeof(F) <= sizeof(function_buffer) && (alignment_of<function_buffer>::value % alignment_of<F>::value == 0)))); }; template <typename F,typename A> struct functor_wrapper: public F, public A { functor_wrapper( F f, A a ): F(f), A(a) { } }; /** * The functor_manager class contains a static function "manage" which * can clone or destroy the given function/function object pointer. */ template<typename Functor> struct functor_manager_common { typedef Functor functor_type; // Function pointers static inline void manage_ptr(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op) { if (op == clone_functor_tag) out_buffer.func_ptr = in_buffer.func_ptr; else if (op == destroy_functor_tag) out_buffer.func_ptr = 0; else /* op == check_functor_type_tag */ { const BOOST_FUNCTION_STD_NS::type_info& check_type = *static_cast<const BOOST_FUNCTION_STD_NS::type_info*>(out_buffer.const_obj_ptr); if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor))) out_buffer.obj_ptr = &in_buffer.func_ptr; else out_buffer.obj_ptr = 0; } } // Function objects that fit in the small-object buffer. static inline void manage_small(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op) { if (op == clone_functor_tag) { const functor_type* in_functor = reinterpret_cast<const functor_type*>(&in_buffer.data); new ((void*)&out_buffer.data) functor_type(*in_functor); } else if (op == destroy_functor_tag) { // Some compilers (Borland, vc6, ...) are unhappy with ~functor_type. reinterpret_cast<functor_type*>(&out_buffer.data)->~Functor(); } else /* op == check_functor_type_tag */ { const BOOST_FUNCTION_STD_NS::type_info& check_type = *static_cast<const BOOST_FUNCTION_STD_NS::type_info*>(out_buffer.const_obj_ptr); if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor))) out_buffer.obj_ptr = &in_buffer.data; else out_buffer.obj_ptr = 0; } } }; template<typename Functor> struct functor_manager { private: typedef Functor functor_type; // Function pointers static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, function_ptr_tag) { functor_manager_common<Functor>::manage_ptr(in_buffer,out_buffer,op); } // Function objects that fit in the small-object buffer. static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, mpl::true_) { functor_manager_common<Functor>::manage_small(in_buffer,out_buffer,op); } // Function objects that require heap allocation static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, mpl::false_) { if (op == clone_functor_tag) { // Clone the functor // GCC 2.95.3 gets the CV qualifiers wrong here, so we // can't do the static_cast that we should do. const functor_type* f = (const functor_type*)(in_buffer.obj_ptr); functor_type* new_f = new functor_type(*f); out_buffer.obj_ptr = new_f; } else if (op == destroy_functor_tag) { /* Cast from the void pointer to the functor pointer type */ functor_type* f = static_cast<functor_type*>(out_buffer.obj_ptr); delete f; out_buffer.obj_ptr = 0; } else /* op == check_functor_type_tag */ { const BOOST_FUNCTION_STD_NS::type_info& check_type = *static_cast<const BOOST_FUNCTION_STD_NS::type_info*>(out_buffer.const_obj_ptr); if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor))) out_buffer.obj_ptr = in_buffer.obj_ptr; else out_buffer.obj_ptr = 0; } } // For function objects, we determine whether the function // object can use the small-object optimization buffer or // whether we need to allocate it on the heap. static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, function_obj_tag) { manager(in_buffer, out_buffer, op, mpl::bool_<(function_allows_small_object_optimization<functor_type>::value)>()); } public: /* Dispatch to an appropriate manager based on whether we have a function pointer or a function object pointer. */ static inline void manage(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op) { typedef typename get_function_tag<functor_type>::type tag_type; switch (op) { case get_functor_type_tag: out_buffer.const_obj_ptr = &typeid(functor_type); return; default: manager(in_buffer, out_buffer, op, tag_type()); return; } } }; template<typename Functor, typename Allocator> struct functor_manager_a { private: typedef Functor functor_type; // Function pointers static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, function_ptr_tag) { functor_manager_common<Functor>::manage_ptr(in_buffer,out_buffer,op); } // Function objects that fit in the small-object buffer. static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, mpl::true_) { functor_manager_common<Functor>::manage_small(in_buffer,out_buffer,op); } // Function objects that require heap allocation static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, mpl::false_) { typedef functor_wrapper<Functor,Allocator> functor_wrapper_type; typedef typename Allocator::template rebind<functor_wrapper_type>::other wrapper_allocator_type; typedef typename wrapper_allocator_type::pointer wrapper_allocator_pointer_type; if (op == clone_functor_tag) { // Clone the functor // GCC 2.95.3 gets the CV qualifiers wrong here, so we // can't do the static_cast that we should do. const functor_wrapper_type* f = (const functor_wrapper_type*)(in_buffer.obj_ptr); wrapper_allocator_type wrapper_allocator(static_cast<Allocator const &>(*f)); wrapper_allocator_pointer_type copy = wrapper_allocator.allocate(1); wrapper_allocator.construct(copy, *f); // Get back to the original pointer type functor_wrapper_type* new_f = static_cast<functor_wrapper_type*>(copy); out_buffer.obj_ptr = new_f; } else if (op == destroy_functor_tag) { /* Cast from the void pointer to the functor_wrapper_type */ functor_wrapper_type* victim = static_cast<functor_wrapper_type*>(in_buffer.obj_ptr); wrapper_allocator_type wrapper_allocator(static_cast<Allocator const &>(*victim)); wrapper_allocator.destroy(victim); wrapper_allocator.deallocate(victim,1); out_buffer.obj_ptr = 0; } else /* op == check_functor_type_tag */ { const BOOST_FUNCTION_STD_NS::type_info& check_type = *static_cast<const BOOST_FUNCTION_STD_NS::type_info*>(out_buffer.const_obj_ptr); if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor))) out_buffer.obj_ptr = in_buffer.obj_ptr; else out_buffer.obj_ptr = 0; } } // For function objects, we determine whether the function // object can use the small-object optimization buffer or // whether we need to allocate it on the heap. static inline void manager(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op, function_obj_tag) { manager(in_buffer, out_buffer, op, mpl::bool_<(function_allows_small_object_optimization<functor_type>::value)>()); } public: /* Dispatch to an appropriate manager based on whether we have a function pointer or a function object pointer. */ static inline void manage(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op) { typedef typename get_function_tag<functor_type>::type tag_type; switch (op) { case get_functor_type_tag: out_buffer.const_obj_ptr = &typeid(functor_type); return; default: manager(in_buffer, out_buffer, op, tag_type()); return; } } }; // A type that is only used for comparisons against zero struct useless_clear_type {}; #ifdef BOOST_NO_SFINAE // These routines perform comparisons between a Boost.Function // object and an arbitrary function object (when the last // parameter is mpl::bool_<false>) or against zero (when the // last parameter is mpl::bool_<true>). They are only necessary // for compilers that don't support SFINAE. template<typename Function, typename Functor> bool compare_equal(const Function& f, const Functor&, int, mpl::bool_<true>) { return f.empty(); } template<typename Function, typename Functor> bool compare_not_equal(const Function& f, const Functor&, int, mpl::bool_<true>) { return !f.empty(); } template<typename Function, typename Functor> bool compare_equal(const Function& f, const Functor& g, long, mpl::bool_<false>) { if (const Functor* fp = f.template target<Functor>()) return function_equal(*fp, g); else return false; } template<typename Function, typename Functor> bool compare_equal(const Function& f, const reference_wrapper<Functor>& g, int, mpl::bool_<false>) { if (const Functor* fp = f.template target<Functor>()) return fp == g.get_pointer(); else return false; } template<typename Function, typename Functor> bool compare_not_equal(const Function& f, const Functor& g, long, mpl::bool_<false>) { if (const Functor* fp = f.template target<Functor>()) return !function_equal(*fp, g); else return true; } template<typename Function, typename Functor> bool compare_not_equal(const Function& f, const reference_wrapper<Functor>& g, int, mpl::bool_<false>) { if (const Functor* fp = f.template target<Functor>()) return fp != g.get_pointer(); else return true; } #endif // BOOST_NO_SFINAE /** * Stores the "manager" portion of the vtable for a * boost::function object. */ struct vtable_base { vtable_base() : manager(0) { } void (*manager)(const function_buffer& in_buffer, function_buffer& out_buffer, functor_manager_operation_type op); }; } // end namespace function } // end namespace detail /** * The function_base class contains the basic elements needed for the * function1, function2, function3, etc. classes. It is common to all * functions (and as such can be used to tell if we have one of the * functionN objects). */ class function_base { public: function_base() : vtable(0) { } /** Determine if the function is empty (i.e., has no target). */ bool empty() const { return !vtable; } /** Retrieve the type of the stored function object, or typeid(void) if this is empty. */ const BOOST_FUNCTION_STD_NS::type_info& target_type() const { if (!vtable) return typeid(void); detail::function::function_buffer type; vtable->manager(functor, type, detail::function::get_functor_type_tag); return *static_cast<const BOOST_FUNCTION_STD_NS::type_info*>(type.const_obj_ptr); } template<typename Functor> Functor* target() { if (!vtable) return 0; detail::function::function_buffer type_result; type_result.const_obj_ptr = &typeid(Functor); vtable->manager(functor, type_result, detail::function::check_functor_type_tag); return static_cast<Functor*>(type_result.obj_ptr); } template<typename Functor> #if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, < 1300) const Functor* target( Functor * = 0 ) const #else const Functor* target() const #endif { if (!vtable) return 0; detail::function::function_buffer type_result; type_result.const_obj_ptr = &typeid(Functor); vtable->manager(functor, type_result, detail::function::check_functor_type_tag); // GCC 2.95.3 gets the CV qualifiers wrong here, so we // can't do the static_cast that we should do. return (const Functor*)(type_result.obj_ptr); } template<typename F> bool contains(const F& f) const { #if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, < 1300) if (const F* fp = this->target( (F*)0 )) #else if (const F* fp = this->template target<F>()) #endif { return function_equal(*fp, f); } else { return false; } } #if defined(__GNUC__) && __GNUC__ == 3 && __GNUC_MINOR__ <= 3 // GCC 3.3 and newer cannot copy with the global operator==, due to // problems with instantiation of function return types before it // has been verified that the argument types match up. template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator==(Functor g) const { if (const Functor* fp = target<Functor>()) return function_equal(*fp, g); else return false; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator!=(Functor g) const { if (const Functor* fp = target<Functor>()) return !function_equal(*fp, g); else return true; } #endif public: // should be protected, but GCC 2.95.3 will fail to allow access detail::function::vtable_base* vtable; mutable detail::function::function_buffer functor; }; /** * The bad_function_call exception class is thrown when a boost::function * object is invoked */ class bad_function_call : public std::runtime_error { public: bad_function_call() : std::runtime_error("call to empty boost::function") {} }; #ifndef BOOST_NO_SFINAE inline bool operator==(const function_base& f, detail::function::useless_clear_type*) { return f.empty(); } inline bool operator!=(const function_base& f, detail::function::useless_clear_type*) { return !f.empty(); } inline bool operator==(detail::function::useless_clear_type*, const function_base& f) { return f.empty(); } inline bool operator!=(detail::function::useless_clear_type*, const function_base& f) { return !f.empty(); } #endif #ifdef BOOST_NO_SFINAE // Comparisons between boost::function objects and arbitrary function objects template<typename Functor> inline bool operator==(const function_base& f, Functor g) { typedef mpl::bool_<(is_integral<Functor>::value)> integral; return detail::function::compare_equal(f, g, 0, integral()); } template<typename Functor> inline bool operator==(Functor g, const function_base& f) { typedef mpl::bool_<(is_integral<Functor>::value)> integral; return detail::function::compare_equal(f, g, 0, integral()); } template<typename Functor> inline bool operator!=(const function_base& f, Functor g) { typedef mpl::bool_<(is_integral<Functor>::value)> integral; return detail::function::compare_not_equal(f, g, 0, integral()); } template<typename Functor> inline bool operator!=(Functor g, const function_base& f) { typedef mpl::bool_<(is_integral<Functor>::value)> integral; return detail::function::compare_not_equal(f, g, 0, integral()); } #else # if !(defined(__GNUC__) && __GNUC__ == 3 && __GNUC_MINOR__ <= 3) // Comparisons between boost::function objects and arbitrary function // objects. GCC 3.3 and before has an obnoxious bug that prevents this // from working. template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator==(const function_base& f, Functor g) { if (const Functor* fp = f.template target<Functor>()) return function_equal(*fp, g); else return false; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator==(Functor g, const function_base& f) { if (const Functor* fp = f.template target<Functor>()) return function_equal(g, *fp); else return false; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator!=(const function_base& f, Functor g) { if (const Functor* fp = f.template target<Functor>()) return !function_equal(*fp, g); else return true; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator!=(Functor g, const function_base& f) { if (const Functor* fp = f.template target<Functor>()) return !function_equal(g, *fp); else return true; } # endif template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator==(const function_base& f, reference_wrapper<Functor> g) { if (const Functor* fp = f.template target<Functor>()) return fp == g.get_pointer(); else return false; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator==(reference_wrapper<Functor> g, const function_base& f) { if (const Functor* fp = f.template target<Functor>()) return g.get_pointer() == fp; else return false; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator!=(const function_base& f, reference_wrapper<Functor> g) { if (const Functor* fp = f.template target<Functor>()) return fp != g.get_pointer(); else return true; } template<typename Functor> BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool) operator!=(reference_wrapper<Functor> g, const function_base& f) { if (const Functor* fp = f.template target<Functor>()) return g.get_pointer() != fp; else return true; } #endif // Compiler supporting SFINAE namespace detail { namespace function { inline bool has_empty_target(const function_base* f) { return f->empty(); } #if BOOST_WORKAROUND(BOOST_MSVC, <= 1310) inline bool has_empty_target(const void*) { return false; } #else inline bool has_empty_target(...) { return false; } #endif } // end namespace function } // end namespace detail } // end namespace boost #undef BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL #undef BOOST_FUNCTION_COMPARE_TYPE_ID #endif // BOOST_FUNCTION_BASE_HEADER