/*
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* Copyright (C) 2018 The Android Open Source Project
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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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*/
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#ifndef LIBTEXTCLASSIFIER_UTILS_TENSOR_VIEW_H_
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#define LIBTEXTCLASSIFIER_UTILS_TENSOR_VIEW_H_
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#include <algorithm>
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#include <vector>
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namespace libtextclassifier3 {
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namespace internal {
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// Computes the number of elements in a tensor of given shape.
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int NumberOfElements(const std::vector<int>& shape);
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} // namespace internal
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// View of a tensor of given type.
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// NOTE: Does not own the underlying memory, so the contract about its validity
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// needs to be specified on the interface that returns it.
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template <typename T>
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class TensorView {
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public:
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TensorView(const T* data, const std::vector<int>& shape)
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: data_(data), shape_(shape), size_(internal::NumberOfElements(shape)) {}
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static TensorView Invalid() {
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static std::vector<int>& invalid_shape =
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*[]() { return new std::vector<int>(0); }();
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return TensorView(nullptr, invalid_shape);
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}
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bool is_valid() const { return data_ != nullptr; }
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const std::vector<int>& shape() const { return shape_; }
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int dim(int i) const { return shape_[i]; }
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int dims() const { return shape_.size(); }
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const T* data() const { return data_; }
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int size() const {
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if (!is_valid()) {
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return 0;
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}
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return size_;
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}
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bool copy_to(T* dest, int dest_size) const {
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if (dest_size < size_) {
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return false;
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}
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std::copy(data_, data_ + size_, dest);
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return true;
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}
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private:
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const T* data_ = nullptr;
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const std::vector<int> shape_;
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const int size_;
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};
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} // namespace libtextclassifier3
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#endif // LIBTEXTCLASSIFIER_UTILS_TENSOR_VIEW_H_
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