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https://github.com/bkaradzic/bgfx.git
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73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
// Copyright 2025 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef SOURCE_UTIL_SPAN_H_
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#define SOURCE_UTIL_SPAN_H_
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#include <cstddef>
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#include <iterator>
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#include <type_traits>
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namespace spvtools {
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namespace utils {
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// Implement a subset of the C++20 std::span, using at most C++17 functionality.
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// Replace this when SPIRV-Tools can use C++20.
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template <class T>
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class Span {
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public:
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using element_type = T;
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using value_type = std::remove_cv_t<T>;
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using size_type = std::size_t;
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using difference_type = std::ptrdiff_t;
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using pointer = T*;
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using const_pointer = const T*;
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using reference = T&;
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using const_reference = const T&;
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using iterator = T*;
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using const_iterator = const T*;
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Span() {}
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Span(iterator first, size_type count) : first_(first), count_(count) {}
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iterator begin() const { return first_; }
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iterator end() const { return first_ ? first_ + count_ : nullptr; }
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const_iterator cbegin() const { return first_; }
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const_iterator cend() const { return first_ ? first_ + count_ : nullptr; }
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size_type size() const { return count_; }
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size_type size_bytes() const { return count_ * sizeof(T); }
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bool empty() const { return first_ == nullptr || count_ == 0; }
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reference front() const { return *first_; }
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reference back() const { return *(first_ + count_ - 1); }
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pointer data() const { return first_; }
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reference operator[](size_type idx) const { return first_[idx]; }
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Span<T> subspan(size_type offset) const {
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if (count_ > offset) {
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return Span(first_ + offset, count_ - offset);
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}
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return Span<T>();
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}
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private:
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T* first_ = nullptr;
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size_type count_ = 0;
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};
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} // namespace utils
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} // namespace spvtools
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#endif // SOURCE_UTIL_SPAN_H_
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