1 //===- iterator_range.h - A range adaptor for iterators ---------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// \file 9 /// This provides a very simple, boring adaptor for a begin and end iterator 10 /// into a range type. This should be used to build range views that work well 11 /// with range based for loops and range based constructors. 12 /// 13 /// Note that code here follows more standards-based coding conventions as it 14 /// is mirroring proposed interfaces for standardization. 15 /// 16 //===----------------------------------------------------------------------===// 17 18 #ifndef LLVM_ADT_ITERATOR_RANGE_H 19 #define LLVM_ADT_ITERATOR_RANGE_H 20 21 #include <utility> 22 23 namespace llvm { 24 25 /// A range adaptor for a pair of iterators. 26 /// 27 /// This just wraps two iterators into a range-compatible interface. Nothing 28 /// fancy at all. 29 template <typename IteratorT> 30 class iterator_range { 31 IteratorT begin_iterator, end_iterator; 32 33 public: 34 //TODO: Add SFINAE to test that the Container's iterators match the range's 35 // iterators. 36 template <typename Container> 37 iterator_range(Container &&c) 38 //TODO: Consider ADL/non-member begin/end calls. 39 : begin_iterator(c.begin()), end_iterator(c.end()) {} 40 iterator_range(IteratorT begin_iterator, IteratorT end_iterator) 41 : begin_iterator(std::move(begin_iterator)), 42 end_iterator(std::move(end_iterator)) {} 43 44 IteratorT begin() const { return begin_iterator; } 45 IteratorT end() const { return end_iterator; } 46 bool empty() const { return begin_iterator == end_iterator; } 47 }; 48 49 /// Convenience function for iterating over sub-ranges. 50 /// 51 /// This provides a bit of syntactic sugar to make using sub-ranges 52 /// in for loops a bit easier. Analogous to std::make_pair(). 53 template <class T> iterator_range<T> make_range(T x, T y) { 54 return iterator_range<T>(std::move(x), std::move(y)); 55 } 56 57 template <typename T> iterator_range<T> make_range(std::pair<T, T> p) { 58 return iterator_range<T>(std::move(p.first), std::move(p.second)); 59 } 60 61 } 62 63 #endif 64