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
24namespace 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.
30template <typename IteratorT>
31class iterator_range {
32  IteratorT begin_iterator, end_iterator;
33
34public:
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().
54template <class T> iterator_range<T> make_range(T x, T y) {
55  return iterator_range<T>(std::move(x), std::move(y));
56}
57
58template <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