blob: 2b0db4e5be933b94be7f54d4f080b7ed22054702 (
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
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#pragma once
#include <sal/config.h>
#include <compare>
#include <concepts>
#include <cstdint>
#include <cstring>
#include <limits>
#include <config_global.h>
namespace o3tl
{
// An approximation of C++20 <compare> std::strong_order that should work at least for IEC559 float
// and double on platforms that have correspondingly-sized std::int32_t and std::int64_t:
#if HAVE_CPP_STRONG_ORDER
inline constexpr auto strong_order = std::strong_order;
#else
namespace detail
{
template<typename To, typename From> To bit_cast(From val) requires (sizeof (To) == sizeof (From)) {
char buf alignas(To)[sizeof (From)];
std::memcpy(buf, &val, sizeof (From));
return *reinterpret_cast<To const *>(buf);
}
struct strong_order
{
template <typename T> auto operator ()(T x, T y) const
requires std::same_as<T, float> && std::numeric_limits<T>::is_iec559
{
return bit_cast<std::int32_t>(x) <=> bit_cast<std::int32_t>(y);
}
template <typename T> auto operator ()(T x, T y) const
requires std::same_as<T, double> && std::numeric_limits<T>::is_iec559
{
return bit_cast<std::int64_t>(x) <=> bit_cast<std::int64_t>(y);
}
};
}
inline constexpr auto strong_order = detail::strong_order();
#endif
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
|
