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>
iterator_range(Container && c)37 iterator_range(Container &&c)
38 //TODO: Consider ADL/non-member begin/end calls.
39 : begin_iterator(c.begin()), end_iterator(c.end()) {}
iterator_range(IteratorT begin_iterator,IteratorT end_iterator)40 iterator_range(IteratorT begin_iterator, IteratorT end_iterator)
41 : begin_iterator(std::move(begin_iterator)),
42 end_iterator(std::move(end_iterator)) {}
43
begin()44 IteratorT begin() const { return begin_iterator; }
end()45 IteratorT end() const { return end_iterator; }
empty()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().
make_range(T x,T y)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
make_range(std::pair<T,T> p)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