// Copyright (C) 2011 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#undef DLIB_AnY_FUNCTION_ABSTRACT_H_
#ifdef DLIB_AnY_FUNCTION_ABSTRACT_H_
#include "any_abstract.h"
#include "../algs.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
template <
typename function_type
>
class any_function
{
/*!
REQUIREMENTS ON function_type
This type should be a function signature. Some examples are:
void (int,int) // a function returning nothing and taking two ints
void () // a function returning nothing and taking no arguments
char (double&) // a function returning a char and taking a reference to a double
The number of arguments in the function must be no greater than 10.
INITIAL VALUE
- is_empty() == true
- for all T: contains<T>() == false
WHAT THIS OBJECT REPRESENTS
This object is a version of dlib::any that is restricted to containing
elements which are some kind of function object with an operator() which
matches the function signature defined by function_type.
Here is an example:
#include <iostream>
#include <string>
#include "dlib/any.h"
using namespace std;
void print_message(string str) { cout << str << endl; }
int main()
{
dlib::any_function<void(string)> f;
f = print_message;
f("hello world"); // calls print_message("hello world")
}
Note that any_function objects can be used to store general function
objects (i.e. defined by a class with an overloaded operator()) in
addition to regular global functions.
!*/
public:
// This is the type of object returned by function_type functions.
typedef result_type_for_function_type result_type;
// Typedefs defining the argument types. If an argument does not exist
// then it is set to void.
typedef type_of_first_argument_in_funct_type arg1_type;
typedef type_of_second_argument_in_funct_type arg2_type;
...
typedef type_of_last_argument_in_funct_type arg10_type;
const static unsigned long num_args = total_number_of_non_void_arguments;
any_function(
);
/*!
ensures
- this object is properly initialized
!*/
any_function (
const any_function& item
);
/*!
ensures
- copies the state of item into *this.
- Note that *this and item will contain independent copies of the
contents of item. That is, this function performs a deep
copy and therefore does not result in *this containing
any kind of reference to item.
!*/
template < typename T >
any_function (
const T& item
);
/*!
ensures
- #contains<T>() == true
- #cast_to<T>() == item
(i.e. a copy of item will be stored in *this)
!*/
void clear (
);
/*!
ensures
- #*this will have its default value. I.e. #is_empty() == true
!*/
template <typename T>
bool contains (
) const;
/*!
ensures
- if (this object currently contains an object of type T) then
- returns true
- else
- returns false
!*/
bool is_empty(
) const;
/*!
ensures
- if (this object contains any kind of object) then
- returns false
- else
- returns true
!*/
bool is_set (
) const;
/*!
ensures
- returns !is_empty()
!*/
result_type operator() (
) const;
/*!
requires
- is_empty() == false
- the signature defined by function_type takes no arguments
ensures
- Let F denote the function object contained within *this. Then
this function performs:
return F()
or if result_type is void then this function performs:
F()
!*/
result_type operator() (
const arg1_type& a1
) const;
/*!
requires
- is_empty() == false
- the signature defined by function_type takes one argument
ensures
- Let F denote the function object contained within *this. Then
this function performs:
return F(a1)
or if result_type is void then this function performs:
F(a1)
!*/
result_type operator() (
const arg1_type& a1,
const arg2_type& a2
) const;
/*!
requires
- is_empty() == false
- the signature defined by function_type takes two arguments
ensures
- Let F denote the function object contained within *this. Then
this function performs:
return F(a1,a2)
or if result_type is void then this function performs:
F(a1,a2)
!*/
/* !!!!!!!!! NOTE !!!!!!!!!
In addition to the above, operator() is defined for up to 10 arguments.
They are not listed here because it would clutter the documentation.
!!!!!!!!! NOTE !!!!!!!!! */
template <typename T>
T& cast_to(
);
/*!
ensures
- if (contains<T>() == true) then
- returns a non-const reference to the object contained within *this
- else
- throws bad_any_cast
!*/
template <typename T>
const T& cast_to(
) const;
/*!
ensures
- if (contains<T>() == true) then
- returns a const reference to the object contained within *this
- else
- throws bad_any_cast
!*/
template <typename T>
T& get(
);
/*!
ensures
- #is_empty() == false
- #contains<T>() == true
- if (contains<T>() == true)
- returns a non-const reference to the object contained in *this.
- else
- Constructs an object of type T inside *this
- Any previous object stored in this any_function object is destructed and its
state is lost.
- returns a non-const reference to the newly created T object.
!*/
any_function& operator= (
const any_function& item
);
/*!
ensures
- copies the state of item into *this.
- Note that *this and item will contain independent copies of the
contents of item. That is, this function performs a deep
copy and therefore does not result in *this containing
any kind of reference to item.
!*/
void swap (
any_function& item
);
/*!
ensures
- swaps *this and item
!*/
};
// ----------------------------------------------------------------------------------------
template <
typename function_type
>
inline void swap (
any_function<function_type>& a,
any_function<function_type>& b
) { a.swap(b); }
/*!
provides a global swap function
!*/
// ----------------------------------------------------------------------------------------
template <
typename T,
typename function_type
>
T& any_cast(
any_function<function_type>& a
) { return a.cast_to<T>(); }
/*!
ensures
- returns a.cast_to<T>()
!*/
// ----------------------------------------------------------------------------------------
template <
typename T,
typename function_type
>
const T& any_cast(
const any_function<function_type>& a
) { return a.cast_to<T>(); }
/*!
ensures
- returns a.cast_to<T>()
!*/
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_AnY_FUNCTION_ABSTRACT_H_