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
23namespace 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.
29template <typename IteratorT>
30class iterator_range {
31 IteratorT begin_iterator, end_iterator;
32
33public:
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().
53template <class T> iterator_range<T> make_range(T x, T y) {
54 return iterator_range<T>(std::move(x), std::move(y));
55}
56
57template <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