1 /* 2 * Copyright 2022 Google LLC 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 FCP_AGGREGATION_CORE_AGG_VECTOR_ITERATOR_H_ 18 #define FCP_AGGREGATION_CORE_AGG_VECTOR_ITERATOR_H_ 19 20 #include "fcp/aggregation/core/tensor_data.h" 21 #include "fcp/base/monitoring.h" 22 23 namespace fcp { 24 namespace aggregation { 25 26 // Iterator for AggVector which allows to iterate over sparse values 27 // as a collection of {index, value} pairs. 28 // 29 // This allows a simple iteration loops like the following: 30 // for (auto [index, value] : agg_vector) { 31 // ... aggregate the value at the given dense index 32 // } 33 template <typename T> 34 struct AggVectorIterator { 35 struct IndexValuePair { 36 size_t index; 37 T value; 38 39 friend bool operator==(const IndexValuePair& a, const IndexValuePair& b) { 40 return a.index == b.index && a.value == b.value; 41 } 42 43 friend bool operator!=(const IndexValuePair& a, const IndexValuePair& b) { 44 return a.index != b.index || a.value != b.value; 45 } 46 }; 47 48 using value_type = IndexValuePair; 49 using pointer = value_type*; 50 using reference = value_type&; 51 AggVectorIteratorAggVectorIterator52 explicit AggVectorIterator(const TensorData* data) 53 : AggVectorIterator(get_start_ptr(data), get_end_ptr(data), 0) {} 54 55 // Current dense index corresponding to the current value. indexAggVectorIterator56 size_t index() const { return dense_index; } 57 // Current value. valueAggVectorIterator58 T value() const { return *ptr; } 59 // The current interator {index, value} pair value. This is used by 60 // for loop iterators. 61 IndexValuePair operator*() const { return {dense_index, *ptr}; } 62 63 AggVectorIterator& operator++() { 64 FCP_CHECK(ptr != end_ptr); 65 if (++ptr == end_ptr) { 66 *this = end(); 67 } else { 68 dense_index++; 69 } 70 return *this; 71 } 72 73 AggVectorIterator operator++(int) { 74 AggVectorIterator tmp = *this; 75 ++(*this); 76 return tmp; 77 } 78 79 friend bool operator==(const AggVectorIterator& a, 80 const AggVectorIterator& b) { 81 return a.ptr == b.ptr; 82 } 83 84 friend bool operator!=(const AggVectorIterator& a, 85 const AggVectorIterator& b) { 86 return a.ptr != b.ptr; 87 } 88 endAggVectorIterator89 static AggVectorIterator end() { 90 return AggVectorIterator(nullptr, nullptr, 0); 91 } 92 93 private: AggVectorIteratorAggVectorIterator94 AggVectorIterator(const T* ptr, const T* end_ptr, size_t dense_index) 95 : ptr(ptr), end_ptr(end_ptr), dense_index(dense_index) {} 96 get_start_ptrAggVectorIterator97 static const T* get_start_ptr(const TensorData* data) { 98 return static_cast<const T*>(data->data()); 99 } 100 get_end_ptrAggVectorIterator101 static const T* get_end_ptr(const TensorData* data) { 102 return get_start_ptr(data) + data->byte_size() / sizeof(T); 103 } 104 105 const T* ptr; 106 const T* end_ptr; 107 size_t dense_index; 108 }; 109 110 } // namespace aggregation 111 } // namespace fcp 112 113 #endif // FCP_AGGREGATION_CORE_AGG_VECTOR_ITERATOR_H_ 114