1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef LIBTEXTCLASSIFIER_TENSOR_VIEW_H_ 18 #define LIBTEXTCLASSIFIER_TENSOR_VIEW_H_ 19 20 #include <algorithm> 21 #include <vector> 22 23 namespace libtextclassifier2 { 24 namespace internal { 25 // Computes the number of elements in a tensor of given shape. 26 int NumberOfElements(const std::vector<int>& shape); 27 } // namespace internal 28 29 // View of a tensor of given type. 30 // NOTE: Does not own the underlying memory, so the contract about its validity 31 // needs to be specified on the interface that returns it. 32 template <typename T> 33 class TensorView { 34 public: 35 TensorView(const T* data, const std::vector<int>& shape) 36 : data_(data), shape_(shape), size_(internal::NumberOfElements(shape)) {} 37 38 static TensorView Invalid() { 39 static std::vector<int>& invalid_shape = 40 *[]() { return new std::vector<int>(0); }(); 41 return TensorView(nullptr, invalid_shape); 42 } 43 44 bool is_valid() const { return data_ != nullptr; } 45 46 const std::vector<int>& shape() const { return shape_; } 47 48 int dim(int i) const { return shape_[i]; } 49 50 int dims() const { return shape_.size(); } 51 52 const T* data() const { return data_; } 53 54 int size() const { return size_; } 55 56 bool copy_to(T* dest, int dest_size) const { 57 if (dest_size < size_) { 58 return false; 59 } 60 std::copy(data_, data_ + size_, dest); 61 return true; 62 } 63 64 private: 65 const T* data_ = nullptr; 66 const std::vector<int> shape_; 67 const int size_; 68 }; 69 70 } // namespace libtextclassifier2 71 72 #endif // LIBTEXTCLASSIFIER_TENSOR_VIEW_H_ 73
