a372429440
SkSpan is a convenient type to use on API boundaries - callers can have their collection in a stack-allocated array, or any contiguous container (std::vector, etc). Those will all implicitly convert to SkSpan, making call-sites easy to read/write. Before making it part of Skia's public API, this CL removes parts of the API that aren't present in std::span -- when Skia moves to C++20, this should allow us to use std::span instead, and remove SkSpan entirely. The most disruptive change is the removal of `int count()`. That's replaced by a new free function `SkCount` that works on any container, and incorporates the overflow check from SkTo<int>. Change-Id: I86cdfad1700f341da3b81a965b396ca9d8b79df9 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/405816 Reviewed-by: Herb Derby <herb@google.com> Commit-Queue: Brian Osman <brianosman@google.com>
87 lines
3.4 KiB
C++
87 lines
3.4 KiB
C++
/*
|
|
* Copyright 2013 Google Inc.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*
|
|
*
|
|
* This header provides some std:: features early in the skstd namespace
|
|
* and several Skia-specific additions in the sknonstd namespace.
|
|
*/
|
|
|
|
#ifndef SkTLogic_DEFINED
|
|
#define SkTLogic_DEFINED
|
|
|
|
#include <cstddef>
|
|
#include <type_traits>
|
|
#include <utility>
|
|
#include "include/private/SkTo.h"
|
|
|
|
namespace skstd {
|
|
|
|
// C++17, <variant>
|
|
struct monostate {};
|
|
|
|
// C++17, <type_traits>
|
|
template<typename...> struct conjunction : std::true_type { };
|
|
template<typename T> struct conjunction<T> : T { };
|
|
template<typename T, typename... Ts>
|
|
struct conjunction<T, Ts...> : std::conditional<bool(T::value), conjunction<Ts...>, T>::type { };
|
|
|
|
// C++17, std::data, std::size
|
|
template<typename Container>
|
|
constexpr auto data(Container& c) -> decltype(c.data()) { return c.data(); }
|
|
template<typename Container>
|
|
constexpr auto data(const Container& c) -> decltype(c.data()) { return c.data(); }
|
|
template<typename Array, size_t N>
|
|
constexpr auto data(Array(&a)[N]) -> decltype(a) { return a; }
|
|
template<typename T>
|
|
constexpr const T* data(std::initializer_list<T> i) { return i.begin(); }
|
|
|
|
template<typename Container>
|
|
constexpr auto size(Container& c) -> decltype(c.size()) { return c.size(); }
|
|
template<typename Array, size_t N>
|
|
constexpr size_t size(Array(&)[N]) { return N; }
|
|
template<typename T>
|
|
constexpr const T* size(std::initializer_list<T> i) { return i.end() - i.begin(); }
|
|
} // namespace skstd
|
|
|
|
// The sknonstd namespace contains things we would like to be proposed and feel std-ish.
|
|
namespace sknonstd {
|
|
|
|
// The name 'copy' here is fraught with peril. In this case it means 'append', not 'overwrite'.
|
|
// Alternate proposed names are 'propagate', 'augment', or 'append' (and 'add', but already taken).
|
|
// std::experimental::propagate_const already exists for other purposes in TSv2.
|
|
// These also follow the <dest, source> pattern used by boost.
|
|
template <typename D, typename S> struct copy_const {
|
|
using type = std::conditional_t<std::is_const<S>::value, std::add_const_t<D>, D>;
|
|
};
|
|
template <typename D, typename S> using copy_const_t = typename copy_const<D, S>::type;
|
|
|
|
template <typename D, typename S> struct copy_volatile {
|
|
using type = std::conditional_t<std::is_volatile<S>::value, std::add_volatile_t<D>, D>;
|
|
};
|
|
template <typename D, typename S> using copy_volatile_t = typename copy_volatile<D, S>::type;
|
|
|
|
template <typename D, typename S> struct copy_cv {
|
|
using type = copy_volatile_t<copy_const_t<D, S>, S>;
|
|
};
|
|
template <typename D, typename S> using copy_cv_t = typename copy_cv<D, S>::type;
|
|
|
|
// The name 'same' here means 'overwrite'.
|
|
// Alternate proposed names are 'replace', 'transfer', or 'qualify_from'.
|
|
// same_xxx<D, S> can be written as copy_xxx<remove_xxx_t<D>, S>
|
|
template <typename D, typename S> using same_const = copy_const<std::remove_const_t<D>, S>;
|
|
template <typename D, typename S> using same_const_t = typename same_const<D, S>::type;
|
|
template <typename D, typename S> using same_volatile =copy_volatile<std::remove_volatile_t<D>,S>;
|
|
template <typename D, typename S> using same_volatile_t = typename same_volatile<D, S>::type;
|
|
template <typename D, typename S> using same_cv = copy_cv<std::remove_cv_t<D>, S>;
|
|
template <typename D, typename S> using same_cv_t = typename same_cv<D, S>::type;
|
|
|
|
} // namespace sknonstd
|
|
|
|
template <typename Container>
|
|
constexpr int SkCount(const Container& c) { return SkTo<int>(skstd::size(c)); }
|
|
|
|
#endif
|