| /* |
| * Copyright 2018 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkSpan_DEFINED |
| #define SkSpan_DEFINED |
| |
| #include <cstddef> |
| #include <iterator> |
| #include <type_traits> |
| #include <utility> |
| #include "include/private/SkTLogic.h" |
| #include "include/private/SkTo.h" |
| |
| template <typename T> |
| class SkSpan { |
| public: |
| constexpr SkSpan() : fPtr{nullptr}, fSize{0} {} |
| constexpr SkSpan(T* ptr, size_t size) : fPtr{ptr}, fSize{size} {} |
| template <typename U, typename = typename std::enable_if<std::is_same<const U, T>::value>::type> |
| constexpr SkSpan(const SkSpan<U>& that) : fPtr(that.data()), fSize{that.size()} {} |
| constexpr SkSpan(const SkSpan& o) = default; |
| template<size_t N> constexpr SkSpan(T(&a)[N]) : SkSpan{a, N} { } |
| template<typename Container> |
| constexpr SkSpan(Container& c) : SkSpan{skstd::data(c), skstd::size(c)} { } |
| |
| constexpr SkSpan& operator=(const SkSpan& that) { |
| fPtr = that.fPtr; |
| fSize = that.fSize; |
| return *this; |
| } |
| constexpr T& operator [] (size_t i) const { |
| SkASSERT(i < this->size()); |
| return fPtr[i]; |
| } |
| constexpr T& front() const { return fPtr[0]; } |
| constexpr T& back() const { return fPtr[fSize - 1]; } |
| constexpr T* begin() const { return fPtr; } |
| constexpr T* end() const { return fPtr + fSize; } |
| constexpr const T* cbegin() const { return this->begin(); } |
| constexpr const T* cend() const { return this->end(); } |
| constexpr auto rbegin() const { return std::make_reverse_iterator(this->end()); } |
| constexpr auto rend() const { return std::make_reverse_iterator(this->begin()); } |
| constexpr auto crbegin() const { return std::make_reverse_iterator(this->cend()); } |
| constexpr auto crend() const { return std::make_reverse_iterator(this->cbegin()); } |
| constexpr T* data() const { return this->begin(); } |
| constexpr int count() const { return SkTo<int>(fSize); } |
| constexpr size_t size() const { return fSize; } |
| constexpr bool empty() const { return fSize == 0; } |
| constexpr size_t size_bytes() const { return fSize * sizeof(T); } |
| constexpr SkSpan<T> first(size_t prefixLen) const { |
| SkASSERT(prefixLen <= this->size()); |
| return SkSpan{fPtr, prefixLen}; |
| } |
| constexpr SkSpan<T> last(size_t postfixLen) const { |
| SkASSERT(postfixLen <= this->size()); |
| return SkSpan{fPtr + (this->size() - postfixLen), postfixLen}; |
| } |
| constexpr SkSpan<T> subspan(size_t offset, size_t count) const { |
| SkASSERT(offset <= this->size()); |
| SkASSERT(count <= this->size() - offset); |
| return SkSpan{fPtr + offset, count}; |
| } |
| |
| private: |
| T* fPtr; |
| size_t fSize; |
| }; |
| |
| template<typename Container> |
| SkSpan(Container&) -> SkSpan<std::remove_pointer_t<decltype( |
| skstd::data(std::declval<Container&>()))>>; |
| |
| #endif // SkSpan_DEFINED |