1 //===- iterator_range.h - A range adaptor for iterators ---------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 /// \file 10 /// This provides a very simple, boring adaptor for a begin and end iterator 11 /// into a range type. This should be used to build range views that work well 12 /// with range based for loops and range based constructors. 13 /// 14 /// Note that code here follows more standards-based coding conventions as it 15 /// is mirroring proposed interfaces for standardization. 16 /// 17 //===----------------------------------------------------------------------===// 18 19 #ifndef LLVM_ADT_ITERATOR_RANGE_H 20 #define LLVM_ADT_ITERATOR_RANGE_H 21 22 #include <iterator> 23 #include <utility> 24 25 namespace llvm { 26 27 /// \brief A range adaptor for a pair of iterators. 28 /// 29 /// This just wraps two iterators into a range-compatible interface. Nothing 30 /// fancy at all. 31 template <typename IteratorT> 32 class iterator_range { 33 IteratorT begin_iterator, end_iterator; 34 35 public: 36 //TODO: Add SFINAE to test that the Container's iterators match the range's 37 // iterators. 38 template <typename Container> 39 iterator_range(Container &&c) 40 //TODO: Consider ADL/non-member begin/end calls. 41 : begin_iterator(c.begin()), end_iterator(c.end()) {} 42 iterator_range(IteratorT begin_iterator, IteratorT end_iterator) 43 : begin_iterator(std::move(begin_iterator)), 44 end_iterator(std::move(end_iterator)) {} 45 46 IteratorT begin() const { return begin_iterator; } 47 IteratorT end() const { return end_iterator; } 48 }; 49 50 /// \brief Convenience function for iterating over sub-ranges. 51 /// 52 /// This provides a bit of syntactic sugar to make using sub-ranges 53 /// in for loops a bit easier. Analogous to std::make_pair(). 54 template <class T> iterator_range<T> make_range(T x, T y) { 55 return iterator_range<T>(std::move(x), std::move(y)); 56 } 57 58 template <typename T> iterator_range<T> make_range(std::pair<T, T> p) { 59 return iterator_range<T>(std::move(p.first), std::move(p.second)); 60 } 61 62 template<typename T> 63 iterator_range<decltype(begin(std::declval<T>()))> drop_begin(T &&t, int n) { 64 return make_range(std::next(begin(t), n), end(t)); 65 } 66 } 67 68 #endif 69
