1 /* 2 * Copyright (C) 2018 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_UTILS_TENSOR_VIEW_H_ 18 #define LIBTEXTCLASSIFIER_UTILS_TENSOR_VIEW_H_ 19 20 #include <algorithm> 21 #include <vector> 22 23 namespace libtextclassifier3 { 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: TensorView(const T * data,const std::vector<int> & shape)35 TensorView(const T* data, const std::vector<int>& shape) 36 : data_(data), shape_(shape), size_(internal::NumberOfElements(shape)) {} 37 Invalid()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 is_valid()44 bool is_valid() const { return data_ != nullptr; } 45 shape()46 const std::vector<int>& shape() const { return shape_; } 47 dim(int i)48 int dim(int i) const { return shape_[i]; } 49 dims()50 int dims() const { return shape_.size(); } 51 data()52 const T* data() const { return data_; } 53 size()54 int size() const { 55 if (!is_valid()) { 56 return 0; 57 } 58 return size_; 59 } 60 copy_to(T * dest,int dest_size)61 bool copy_to(T* dest, int dest_size) const { 62 if (dest_size < size_) { 63 return false; 64 } 65 std::copy(data_, data_ + size_, dest); 66 return true; 67 } 68 69 private: 70 const T* data_ = nullptr; 71 const std::vector<int> shape_; 72 const int size_; 73 }; 74 75 } // namespace libtextclassifier3 76 77 #endif // LIBTEXTCLASSIFIER_UTILS_TENSOR_VIEW_H_ 78