1 /* Copyright 2015 The TensorFlow Authors. All Rights Reserved. 2 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 ==============================================================================*/ 15 16 // This file provides utility functions for use with STL 17 18 #ifndef TENSORFLOW_LIB_GTL_STL_UTIL_H_ 19 #define TENSORFLOW_LIB_GTL_STL_UTIL_H_ 20 21 #include <stddef.h> 22 #include <algorithm> 23 #include <iterator> 24 #include <memory> 25 #include <string> 26 #include <utility> 27 #include <vector> 28 29 namespace tensorflow { 30 namespace gtl { 31 32 // Returns a char* pointing to the beginning of a string's internal buffer. 33 // The result is a valid "null-terminated byte string", even if *str is empty. 34 // Up to C++14 it is not valid to *write* to the null terminator; as of C++17, 35 // it is valid to write zero to the null terminator (but not any other value). 36 inline char* string_as_array(string* str) { return &*str->begin(); } 37 38 // The following vector_as_array functions return raw pointers to the underlying 39 // data buffer. The return value is unspecified (but valid) if the input range 40 // is empty. 41 template <typename T, typename Allocator> 42 inline T* vector_as_array(std::vector<T, Allocator>* v) { 43 return v->data(); 44 } 45 46 template <typename T, typename Allocator> 47 inline const T* vector_as_array(const std::vector<T, Allocator>* v) { 48 return v->data(); 49 } 50 51 // Like str->resize(new_size), except any new characters added to "*str" as a 52 // result of resizing may be left uninitialized, rather than being filled with 53 // '0' bytes. Typically used when code is then going to overwrite the backing 54 // store of the string with known data. Uses a Google extension to ::string. 55 inline void STLStringResizeUninitialized(string* s, size_t new_size) { 56 #if __google_stl_resize_uninitialized_string 57 s->resize_uninitialized(new_size); 58 #else 59 s->resize(new_size); 60 #endif 61 } 62 63 // Calls delete (non-array version) on the SECOND item (pointer) in each pair in 64 // the range [begin, end). 65 // 66 // Note: If you're calling this on an entire container, you probably want to 67 // call STLDeleteValues(&container) instead, or use ValueDeleter. 68 template <typename ForwardIterator> 69 void STLDeleteContainerPairSecondPointers(ForwardIterator begin, 70 ForwardIterator end) { 71 while (begin != end) { 72 ForwardIterator temp = begin; 73 ++begin; 74 delete temp->second; 75 } 76 } 77 78 // Deletes all the elements in an STL container and clears the container. This 79 // function is suitable for use with a vector, set, hash_set, or any other STL 80 // container which defines sensible begin(), end(), and clear() methods. 81 // 82 // If container is NULL, this function is a no-op. 83 template <typename T> 84 void STLDeleteElements(T* container) { 85 if (!container) return; 86 auto it = container->begin(); 87 while (it != container->end()) { 88 auto temp = it; 89 ++it; 90 delete *temp; 91 } 92 container->clear(); 93 } 94 95 // Given an STL container consisting of (key, value) pairs, STLDeleteValues 96 // deletes all the "value" components and clears the container. Does nothing in 97 // the case it's given a NULL pointer. 98 template <typename T> 99 void STLDeleteValues(T* container) { 100 if (!container) return; 101 auto it = container->begin(); 102 while (it != container->end()) { 103 auto temp = it; 104 ++it; 105 delete temp->second; 106 } 107 container->clear(); 108 } 109 110 // Sorts and removes duplicates from a sequence container. 111 template <typename T> 112 inline void STLSortAndRemoveDuplicates(T* v) { 113 std::sort(v->begin(), v->end()); 114 v->erase(std::unique(v->begin(), v->end()), v->end()); 115 } 116 117 } // namespace gtl 118 } // namespace tensorflow 119 120 #endif // TENSORFLOW_LIB_GTL_STL_UTIL_H_ 121
