// 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 <
class Storage,
typename function_type
>
class any_function_basic
{
/*!
REQUIREMENTS ON Storage
This must be one of the storage types from dlib/any/storage.hh
E.g. storage_heap, storage_stack, etc.
It determines the method by which any_function_basic holds onto the function it uses.
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"
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_basic 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;
any_function_basic(
);
/*!
ensures
- this object is properly initialized
!*/
any_function_basic (
const any_function_basic& 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.
!*/
any_function_basic (
any_function_basic&& item
);
/*!
ensures
- moves item into *this.
- The exact move semantics are determined by which Storage type is used. E.g.
storage_heap will result in #item.is_empty()==true but storage_view would result
in #item.is_empty() == false
!*/
template < typename Funct >
any_function_basic (
Funct&& funct
);
/*!
ensures
- #contains<T>() == true
- #cast_to<T>() == item
(i.e. calling operator() will invoke funct())
!*/
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()
!*/
explicit operator bool(
) const;
/*!
ensures
- returns is_set()
!*/
result_type operator(Args... args) (
) 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(std::forward<Args>(args)...)
!*/
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_basic object is destructed and its
state is lost.
- returns a non-const reference to the newly created T object.
!*/
any_function_basic& operator= (
const any_function_basic& item
);
/*!
ensures
- copies the state of item into *this.
- Note that the type of copy is determined by the Storage template argument. E.g.
storage_sbo will result in a deep copy, while storage_view would result in *this
and item referring to the same underlying function.
!*/
void swap (
any_function_basic& item
);
/*!
ensures
- swaps *this and item
!*/
};
// ----------------------------------------------------------------------------------------
template <
typename T,
typename function_type
>
T& any_cast(
any_function_basic<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_basic<function_type>& a
) { return a.cast_to<T>(); }
/*!
ensures
- returns a.cast_to<T>()
!*/
// ----------------------------------------------------------------------------------------
/*!A any_function
A version of any_function_basic (defined above) that owns the function it contains. Uses
the small buffer optimization to make working with small lambdas faster.
!*/
template <class F>
using any_function = any_function_basic<te::storage_sbo<16>, F>;
/*!A any_function_view
A version of any_function_basic (defined above) that *DOES NOT* own the function it
contains. It merely holds a pointer to the function given to its constructor.
!*/
template <class F>
using any_function_view = any_function_basic<te::storage_view, F>;
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_AnY_FUNCTION_ABSTRACT_H_