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util/Concepts: compatibility wrapper for std::predicate

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This commit is contained in:
Max Kellermann 2022-12-01 14:53:49 +01:00
parent 5945877313
commit 00b7535cf1
2 changed files with 49 additions and 11 deletions
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46
src/util/Concepts.hxx Normal file
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@ -0,0 +1,46 @@
/*
* Copyright 2022 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <concepts>
/**
* Compatibility wrapper for std::predicate which is unavailable in
* the Android NDK r25b and Apple Xcode.
*/
#if !defined(ANDROID) && !defined(__APPLE__)
template<typename F, typename... Args>
concept Predicate = std::predicate<F, Args...>;
#else
template<typename F, typename... Args>
concept Predicate = requires(F f, Args... args) {
{ f(args...) } -> std::same_as<bool>;
};
#endif

14
src/util/SortList.hxx
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@ -29,10 +29,10 @@
#pragma once
#include "Concepts.hxx"
#include "StaticVector.hxx"
#include <algorithm> // for std::find_if()
#include <concepts> // for std::predicate
/**
* Move all items from #src to #dest, keeping both sorted.
@ -43,11 +43,7 @@
template<typename List>
constexpr void
MergeList(List &dest, List &src,
#if !defined(ANDROID) && !defined(__APPLE__)
/* Android NDK r25b has no std::predicate */
std::predicate<typename List::const_reference, typename List::const_reference>
#endif
auto p) noexcept
Predicate<typename List::const_reference, typename List::const_reference> auto p) noexcept
{
const auto dest_end = dest.end(), src_end = src.end();
@ -89,11 +85,7 @@ MergeList(List &dest, List &src,
template<typename List>
constexpr void
SortList(List &list,
#if !defined(ANDROID) && !defined(__APPLE__)
/* Android NDK r25b has no std::predicate */
std::predicate<typename List::const_reference, typename List::const_reference>
#endif
auto p) noexcept
Predicate <typename List::const_reference, typename List::const_reference> auto p) noexcept
{
using std::swap;