f83bc66e08
We can use the native C++17 versions going forward, if we need them. Change-Id: I53be7ed4ec72602b978c1dad252dff7be9e0f392 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/503823 Auto-Submit: John Stiles <johnstiles@google.com> Reviewed-by: Ben Wagner <bungeman@google.com> Commit-Queue: Ben Wagner <bungeman@google.com>
57 lines
2.3 KiB
C++
57 lines
2.3 KiB
C++
/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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*
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* This header provides some std:: features early in the skstd namespace
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* and several Skia-specific additions in the sknonstd namespace.
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*/
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#ifndef SkTLogic_DEFINED
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#define SkTLogic_DEFINED
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#include <iterator>
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#include <type_traits>
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#include "include/private/SkTo.h"
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// The sknonstd namespace contains things we would like to be proposed and feel std-ish.
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namespace sknonstd {
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// The name 'copy' here is fraught with peril. In this case it means 'append', not 'overwrite'.
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// Alternate proposed names are 'propagate', 'augment', or 'append' (and 'add', but already taken).
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// std::experimental::propagate_const already exists for other purposes in TSv2.
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// These also follow the <dest, source> pattern used by boost.
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template <typename D, typename S> struct copy_const {
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using type = std::conditional_t<std::is_const<S>::value, std::add_const_t<D>, D>;
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};
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template <typename D, typename S> using copy_const_t = typename copy_const<D, S>::type;
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template <typename D, typename S> struct copy_volatile {
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using type = std::conditional_t<std::is_volatile<S>::value, std::add_volatile_t<D>, D>;
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};
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template <typename D, typename S> using copy_volatile_t = typename copy_volatile<D, S>::type;
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template <typename D, typename S> struct copy_cv {
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using type = copy_volatile_t<copy_const_t<D, S>, S>;
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};
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template <typename D, typename S> using copy_cv_t = typename copy_cv<D, S>::type;
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// The name 'same' here means 'overwrite'.
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// Alternate proposed names are 'replace', 'transfer', or 'qualify_from'.
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// same_xxx<D, S> can be written as copy_xxx<remove_xxx_t<D>, S>
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template <typename D, typename S> using same_const = copy_const<std::remove_const_t<D>, S>;
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template <typename D, typename S> using same_const_t = typename same_const<D, S>::type;
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template <typename D, typename S> using same_volatile =copy_volatile<std::remove_volatile_t<D>,S>;
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template <typename D, typename S> using same_volatile_t = typename same_volatile<D, S>::type;
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template <typename D, typename S> using same_cv = copy_cv<std::remove_cv_t<D>, S>;
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template <typename D, typename S> using same_cv_t = typename same_cv<D, S>::type;
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} // namespace sknonstd
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template <typename Container>
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constexpr int SkCount(const Container& c) { return SkTo<int>(std::size(c)); }
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#endif
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