blob: b9db2e5b497d5d1e70ccdb836b9114932a5d1a36 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
#pragma once
#include "borrowed-ptr-fwd.hpp"
#include "compat/assert.hpp"
namespace floormat::detail_borrowed_ptr {
//static_assert(std::is_same_v<T, U> || std::has_virtual_destructor_v<T> && std::has_virtual_destructor_v<T>); // todo! for simple_bptr
template<typename From, typename To>
concept StaticCastable = requires(From* from) {
static_cast<To*>(from);
};
} // namespace floormat::detail_borrowed_ptr
namespace floormat {
template<typename To, typename From>
bptr<To> static_pointer_cast(const bptr<From>& p) noexcept
{
// hack to generate better error message
if constexpr (detail_borrowed_ptr::StaticCastable<From, To>)
{
if (p.blk && p.blk->_ptr) [[likely]]
{
fm_assert(p.casted_ptr);
auto* ret = static_cast<To*>(p.casted_ptr);
return bptr<To>{DirectInit, ret, p.blk};
}
}
else
{
using detail_borrowed_ptr::StaticCastable;
// concepts can't be forward-declared so use static_assert
static_assert(StaticCastable<From, To>,
"cannot static_cast, classes must be related by inheritance");
}
return bptr<To>{nullptr};
}
} // namespace floormat
|
