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72 lines
2.3 KiB
C++
72 lines
2.3 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_INDEX_RANGE_H_
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#define SOURCE_UTIL_INDEX_RANGE_H_
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#include <cassert>
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#include <cstddef>
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#include <cstdint>
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#include "source/util/span.h"
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namespace spvtools {
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namespace utils {
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// Implement a range of indicies, to index over an array of values of type T,
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// but whose base pointer is supplied externally. Think of this as a span
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// but without the base pointer, which is to be applied later. Parameterization
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// by T makes usage more readable and less error-prone.
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template <typename T, class IndexType = uint32_t, class CountType = IndexType>
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class IndexRange {
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public:
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static_assert(std::is_integral<IndexType>::value);
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static_assert(std::is_unsigned<IndexType>::value);
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static_assert(std::is_integral<CountType>::value);
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static_assert(std::is_unsigned<CountType>::value);
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using value_type = T;
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using index_type = IndexType;
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using size_type = CountType;
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constexpr IndexRange() {}
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constexpr IndexRange(index_type first, size_type count)
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: first_(first), count_(count) {}
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size_type count() const { return count_; }
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bool empty() const { return count() == size_type(0); }
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IndexType first() const { return first_; }
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// Returns the span of indexed elements using the given base pointer.
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template <typename E>
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spvtools::utils::Span<E> apply(E* base) const {
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using span_type = spvtools::utils::Span<E>;
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return base ? span_type(base + first_, count_) : span_type();
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}
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template <typename E = int>
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spvtools::utils::Span<E> apply(std::nullptr_t) const {
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using span_type = spvtools::utils::Span<E>;
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return span_type();
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}
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private:
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index_type first_ = 0;
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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_INDEX_RANGE_H_
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