mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-05 00:36:57 +00:00
76 lines
2.4 KiB
C++
76 lines
2.4 KiB
C++
/**
|
|
* Boost Software License - Version 1.0 - August 17th, 2003
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person or organization
|
|
* obtaining a copy of the software and accompanying documentation covered by
|
|
* this license (the "Software") to use, reproduce, display, distribute,
|
|
* execute, and transmit the Software, and to prepare derivative works of the
|
|
* Software, and to permit third-parties to whom the Software is furnished to
|
|
* do so, all subject to the following:
|
|
*
|
|
* The copyright notices in the Software and this entire statement, including
|
|
* the above license grant, this restriction and the following disclaimer,
|
|
* must be included in all copies of the Software, in whole or in part, and
|
|
* all derivative works of the Software, unless such copies or derivative
|
|
* works are solely in the form of machine-executable object code generated by
|
|
* a source language processor.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
|
|
* SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
|
|
* FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
|
|
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
|
* DEALINGS IN THE SOFTWARE.
|
|
*/
|
|
|
|
#ifndef COMMON_SAFE_BOOL_H
|
|
#define COMMON_SAFE_BOOL_H
|
|
|
|
namespace Common {
|
|
namespace impl {
|
|
template <typename T>
|
|
struct no_base {};
|
|
|
|
template <typename T>
|
|
struct safe_bool_impl {
|
|
typedef T *TP; // workaround to make parsing easier
|
|
TP stub;
|
|
typedef TP safe_bool_impl::*type;
|
|
};
|
|
}
|
|
|
|
/**
|
|
* @defgroup common_safe_bool Safe Boolean
|
|
* @ingroup common
|
|
*
|
|
* @brief Template for a SafeBool function.
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Prevents `operator bool` from implicitly converting to other types.
|
|
*/
|
|
template <typename DerivedT, typename BaseT = impl::no_base<DerivedT> >
|
|
struct SafeBool : BaseT {
|
|
private:
|
|
typedef impl::safe_bool_impl<DerivedT> impl_t;
|
|
typedef typename impl_t::type bool_type;
|
|
|
|
public:
|
|
operator bool_type() const {
|
|
return static_cast<const DerivedT *>(this)->operator_bool() ?
|
|
&impl_t::stub : nullptr;
|
|
}
|
|
|
|
operator bool_type() {
|
|
return static_cast<DerivedT *>(this)->operator_bool() ?
|
|
&impl_t::stub : 0;
|
|
}
|
|
};
|
|
/** @} */
|
|
} // End of namespace Common
|
|
|
|
#endif
|