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 <iterator> 22 #include <utility> 23 24 namespace llvm { 25 26 /// A range adaptor for a pair of iterators. 27 /// 28 /// This just wraps two iterators into a range-compatible interface. Nothing 29 /// fancy at all. 30 template <typename IteratorT> 31 class iterator_range { 32 IteratorT begin_iterator, end_iterator; 33 34 public: 35 //TODO: Add SFINAE to test that the Container's iterators match the range's 36 // iterators. 37 template <typename Container> 38 iterator_range(Container &&c) 39 //TODO: Consider ADL/non-member begin/end calls. 40 : begin_iterator(c.begin()), end_iterator(c.end()) {} 41 iterator_range(IteratorT begin_iterator, IteratorT end_iterator) 42 : begin_iterator(std::move(begin_iterator)), 43 end_iterator(std::move(end_iterator)) {} 44 45 IteratorT begin() const { return begin_iterator; } 46 IteratorT end() const { return end_iterator; } 47 bool empty() const { return begin_iterator == end_iterator; } 48 }; 49 50 /// 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 } 63 64 #endif 65