1//===- Sequence.h - Utility for producing sequences of values ---*- 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 routine provides some synthesis utilities to produce sequences of
10/// values. The names are intentionally kept very short as they tend to occur
11/// in common and widely used contexts.
12///
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_ADT_SEQUENCE_H
16#define LLVM_ADT_SEQUENCE_H
17
18#include "llvm/ADT/iterator.h"
19#include "llvm/ADT/iterator_range.h"
20#include <algorithm>
21#include <iterator>
22#include <utility>
23
24namespace llvm {
25
26namespace detail {
27
28template <typename ValueT>
29class value_sequence_iterator
30    : public iterator_facade_base<value_sequence_iterator<ValueT>,
31                                  std::random_access_iterator_tag,
32                                  const ValueT> {
33  using BaseT = typename value_sequence_iterator::iterator_facade_base;
34
35  ValueT Value;
36
37public:
38  using difference_type = typename BaseT::difference_type;
39  using reference = typename BaseT::reference;
40
41  value_sequence_iterator() = default;
42  value_sequence_iterator(const value_sequence_iterator &) = default;
43  value_sequence_iterator(value_sequence_iterator &&Arg)
44      : Value(std::move(Arg.Value)) {}
45
46  template <typename U, typename Enabler = decltype(ValueT(std::declval<U>()))>
47  value_sequence_iterator(U &&Value) : Value(std::forward<U>(Value)) {}
48
49  value_sequence_iterator &operator+=(difference_type N) {
50    Value += N;
51    return *this;
52  }
53  value_sequence_iterator &operator-=(difference_type N) {
54    Value -= N;
55    return *this;
56  }
57  using BaseT::operator-;
58  difference_type operator-(const value_sequence_iterator &RHS) const {
59    return Value - RHS.Value;
60  }
61
62  bool operator==(const value_sequence_iterator &RHS) const {
63    return Value == RHS.Value;
64  }
65  bool operator<(const value_sequence_iterator &RHS) const {
66    return Value < RHS.Value;
67  }
68
69  reference operator*() const { return Value; }
70};
71
72} // end namespace detail
73
74template <typename ValueT>
75iterator_range<detail::value_sequence_iterator<ValueT>> seq(ValueT Begin,
76                                                            ValueT End) {
77  return make_range(detail::value_sequence_iterator<ValueT>(Begin),
78                    detail::value_sequence_iterator<ValueT>(End));
79}
80
81} // end namespace llvm
82
83#endif // LLVM_ADT_SEQUENCE_H
84