104 lines
2.8 KiB
C++
104 lines
2.8 KiB
C++
// Copyright 2020 The Dawn Authors
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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 COMMON_ITYP_SPAN_H_
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#define COMMON_ITYP_SPAN_H_
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#include "common/TypedInteger.h"
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#include "common/UnderlyingType.h"
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#include <type_traits>
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namespace ityp {
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// ityp::span is a helper class that wraps an unowned packed array of type |Value|.
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// It stores the size and pointer to first element. It has the restriction that
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// indices must be a particular type |Index|. This provides a type-safe way to index
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// raw pointers.
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template <typename Index, typename Value>
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class span {
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using I = UnderlyingType<Index>;
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public:
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constexpr span() : mData(nullptr), mSize(0) {
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}
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constexpr span(Value* data, Index size) : mData(data), mSize(size) {
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}
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constexpr Value& operator[](Index i) const {
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ASSERT(i < mSize);
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return mData[static_cast<I>(i)];
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}
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Value* data() noexcept {
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return mData;
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}
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const Value* data() const noexcept {
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return mData;
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}
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Value* begin() noexcept {
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return mData;
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}
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const Value* begin() const noexcept {
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return mData;
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}
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Value* end() noexcept {
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return mData + static_cast<I>(mSize);
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}
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const Value* end() const noexcept {
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return mData + static_cast<I>(mSize);
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}
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Value& front() {
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ASSERT(mData != nullptr);
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ASSERT(static_cast<I>(mSize) >= 0);
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return *mData;
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}
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const Value& front() const {
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ASSERT(mData != nullptr);
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ASSERT(static_cast<I>(mSize) >= 0);
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return *mData;
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}
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Value& back() {
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ASSERT(mData != nullptr);
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ASSERT(static_cast<I>(mSize) >= 0);
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return *(mData + static_cast<I>(mSize) - 1);
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}
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const Value& back() const {
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ASSERT(mData != nullptr);
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ASSERT(static_cast<I>(mSize) >= 0);
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return *(mData + static_cast<I>(mSize) - 1);
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}
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Index size() const {
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return mSize;
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}
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private:
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Value* mData;
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Index mSize;
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};
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} // namespace ityp
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#endif // COMMON_ITYP_SPAN_H_
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