function_template.hpp

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// Boost.Function library

//  Copyright Douglas Gregor 2001-2003. 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

// Note: this header is a header template and must NOT have multiple-inclusion
// protection.
#include <boost/function/detail/prologue.hpp>

#define BOOST_FUNCTION_TEMPLATE_PARMS BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS, typename T)

#define BOOST_FUNCTION_TEMPLATE_ARGS BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS, T)

#define BOOST_FUNCTION_PARM(J,I,D) BOOST_PP_CAT(T,I) BOOST_PP_CAT(a,I)

#define BOOST_FUNCTION_PARMS BOOST_PP_ENUM(BOOST_FUNCTION_NUM_ARGS,BOOST_FUNCTION_PARM,BOOST_PP_EMPTY)

#define BOOST_FUNCTION_ARGS BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS, a)

#define BOOST_FUNCTION_ARG_TYPE(J,I,D) \
  typedef BOOST_PP_CAT(T,I) BOOST_PP_CAT(arg, BOOST_PP_CAT(BOOST_PP_INC(I),_type));

#define BOOST_FUNCTION_ARG_TYPES BOOST_PP_REPEAT(BOOST_FUNCTION_NUM_ARGS,BOOST_FUNCTION_ARG_TYPE,BOOST_PP_EMPTY)

// Type of the default allocator
#ifndef BOOST_NO_STD_ALLOCATOR
#  define BOOST_FUNCTION_DEFAULT_ALLOCATOR std::allocator<function_base>
#else
#  define BOOST_FUNCTION_DEFAULT_ALLOCATOR int
#endif // BOOST_NO_STD_ALLOCATOR

// Comma if nonzero number of arguments
#if BOOST_FUNCTION_NUM_ARGS == 0
#  define BOOST_FUNCTION_COMMA
#else
#  define BOOST_FUNCTION_COMMA ,
#endif // BOOST_FUNCTION_NUM_ARGS > 0

// Class names used in this version of the code
#define BOOST_FUNCTION_FUNCTION BOOST_JOIN(function,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_FUNCTION_INVOKER \
  BOOST_JOIN(function_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_VOID_FUNCTION_INVOKER \
  BOOST_JOIN(void_function_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_FUNCTION_OBJ_INVOKER \
  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 {
    namespace function {
      template<
        typename FunctionPtr,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
        >
      struct BOOST_FUNCTION_FUNCTION_INVOKER
      {
        static R invoke(any_pointer function_ptr BOOST_FUNCTION_COMMA
                        BOOST_FUNCTION_PARMS)
        {
          FunctionPtr f = reinterpret_cast<FunctionPtr>(function_ptr.func_ptr);
          return f(BOOST_FUNCTION_ARGS);
        }
      };

      template<
        typename FunctionPtr,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
        >
      struct BOOST_FUNCTION_VOID_FUNCTION_INVOKER
      {
        static unusable invoke(any_pointer function_ptr BOOST_FUNCTION_COMMA
                               BOOST_FUNCTION_PARMS)

        {
          FunctionPtr f = reinterpret_cast<FunctionPtr>(function_ptr.func_ptr);
          f(BOOST_FUNCTION_ARGS);
          return unusable();
        }
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_FUNCTION_OBJ_INVOKER
      {
        static R invoke(any_pointer function_obj_ptr BOOST_FUNCTION_COMMA
                        BOOST_FUNCTION_PARMS)

        {
          FunctionObj* f = (FunctionObj*)(function_obj_ptr.obj_ptr);
          return (*f)(BOOST_FUNCTION_ARGS);
        }
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER
      {
        static unusable invoke(any_pointer function_obj_ptr
                               BOOST_FUNCTION_COMMA
                               BOOST_FUNCTION_PARMS)

        {
          FunctionObj* f = (FunctionObj*)(function_obj_ptr.obj_ptr);
          (*f)(BOOST_FUNCTION_ARGS);
          return unusable();
        }
      };

      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 = FunctionObj();
          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 = FunctionObj();
          f(BOOST_FUNCTION_ARGS);
          return unusable();
        }
      };

      template<
        typename FunctionPtr,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_GET_FUNCTION_INVOKER
      {
        typedef typename ct_if<(is_void<R>::value),
                            BOOST_FUNCTION_VOID_FUNCTION_INVOKER<
                            FunctionPtr,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >,
                          BOOST_FUNCTION_FUNCTION_INVOKER<
                            FunctionPtr,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >
                       >::type type;
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
       >
      struct BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER
      {
        typedef typename ct_if<(is_void<R>::value),
                            BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER<
                            FunctionObj,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >,
                          BOOST_FUNCTION_FUNCTION_OBJ_INVOKER<
                            FunctionObj,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >
                       >::type type;
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
       >
      struct BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER
      {
        typedef typename ct_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

  template<
    typename R BOOST_FUNCTION_COMMA
    BOOST_FUNCTION_TEMPLATE_PARMS,
    typename Allocator = BOOST_FUNCTION_DEFAULT_ALLOCATOR
  >
  class BOOST_FUNCTION_FUNCTION : public function_base
  {
  public:
    typedef typename detail::function::function_return_type<R>::type
      internal_result_type;

  private:
    struct clear_type {};

  public:
    BOOST_STATIC_CONSTANT(int, args = BOOST_FUNCTION_NUM_ARGS);

    // add signature for boost::lambda
    template<typename Args>
    struct sig
    {
      typedef internal_result_type type;
    };

#if BOOST_FUNCTION_NUM_ARGS == 1
    typedef T0 argument_type;
#elif BOOST_FUNCTION_NUM_ARGS == 2
    typedef T0 first_argument_type;
    typedef T1 second_argument_type;
#endif

    BOOST_STATIC_CONSTANT(int, arity = BOOST_FUNCTION_NUM_ARGS);
    BOOST_FUNCTION_ARG_TYPES

#ifndef BOOST_NO_VOID_RETURNS
    typedef R         result_type;
#else
    typedef internal_result_type result_type;
#endif // BOOST_NO_VOID_RETURNS
    typedef Allocator allocator_type;
    typedef BOOST_FUNCTION_FUNCTION self_type;

    BOOST_FUNCTION_FUNCTION() : function_base()
                              , invoker(0) {}

    // MSVC chokes if the following two constructors are collapsed into
    // one with a default parameter.
    template<typename Functor>
    BOOST_FUNCTION_FUNCTION(Functor BOOST_FUNCTION_TARGET_FIX(const &) f
#ifndef BOOST_NO_SFINAE
                            ,typename enable_if_c<
                            (::boost::type_traits::ice_not<
                             (is_integral<Functor>::value)>::value),
                                        int>::type = 0
#endif // BOOST_NO_SFINAE
                            ) :
      function_base(),
      invoker(0)
    {
      this->assign_to(f);
    }

#ifndef BOOST_NO_SFINAE
    BOOST_FUNCTION_FUNCTION(clear_type*) : function_base(), invoker(0) {}
#else
    BOOST_FUNCTION_FUNCTION(int zero) : function_base(), invoker(0)
    {
      BOOST_ASSERT(zero == 0);
    }
#endif

    BOOST_FUNCTION_FUNCTION(const BOOST_FUNCTION_FUNCTION& f) :
      function_base(),
      invoker(0)
    {
      this->assign_to_own(f);
    }

    ~BOOST_FUNCTION_FUNCTION() { clear(); }

#if BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
    // MSVC 6.0 and prior require all definitions to be inline, but
    // these definitions can become very costly.
    result_type operator()(BOOST_FUNCTION_PARMS) const
    {
      if (this->empty())
        boost::throw_exception(bad_function_call());

      internal_result_type result = invoker(this->functor
                                            BOOST_FUNCTION_COMMA
                                            BOOST_FUNCTION_ARGS);

#ifndef BOOST_NO_VOID_RETURNS
      return static_cast<result_type>(result);
#else
      return result;
#endif // BOOST_NO_VOID_RETURNS
    }
#else
    result_type operator()(BOOST_FUNCTION_PARMS) const;
#endif

    // The distinction between when to use BOOST_FUNCTION_FUNCTION and
    // when to use self_type is obnoxious. MSVC cannot handle self_type as
    // the return type of these assignment operators, but Borland C++ cannot
    // handle BOOST_FUNCTION_FUNCTION as the type of the temporary to
    // construct.
    template<typename Functor>
#ifndef BOOST_NO_SFINAE
    typename enable_if_c<
               (::boost::type_traits::ice_not<
                 (is_integral<Functor>::value)>::value),
               BOOST_FUNCTION_FUNCTION&>::type
#else
    BOOST_FUNCTION_FUNCTION&
#endif
    operator=(Functor BOOST_FUNCTION_TARGET_FIX(const &) f)
    {
      self_type(f).swap(*this);
      return *this;
    }

#ifndef BOOST_NO_SFINAE
    BOOST_FUNCTION_FUNCTION& operator=(clear_type*)
    {
      this->clear();
      return *this;
    }
#else
    BOOST_FUNCTION_FUNCTION& operator=(int zero)
    {
      BOOST_ASSERT(zero == 0);