xref: /netbsd-src/external/apache2/llvm/dist/llvm/include/llvm/ADT/Sequence.h (revision 82d56013d7b633d116a93943de88e08335357a7c)
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 
24 namespace llvm {
25 
26 namespace detail {
27 
28 template <typename ValueT>
29 class 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 
37 public:
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;
value_sequence_iterator(value_sequence_iterator && Arg)43   value_sequence_iterator(value_sequence_iterator &&Arg)
44       : Value(std::move(Arg.Value)) {}
45   value_sequence_iterator &operator=(const value_sequence_iterator &Arg) {
46     Value = Arg.Value;
47     return *this;
48   }
49 
50   template <typename U, typename Enabler = decltype(ValueT(std::declval<U>()))>
value_sequence_iterator(U && Value)51   value_sequence_iterator(U &&Value) : Value(std::forward<U>(Value)) {}
52 
53   value_sequence_iterator &operator+=(difference_type N) {
54     Value += N;
55     return *this;
56   }
57   value_sequence_iterator &operator-=(difference_type N) {
58     Value -= N;
59     return *this;
60   }
61   using BaseT::operator-;
62   difference_type operator-(const value_sequence_iterator &RHS) const {
63     return Value - RHS.Value;
64   }
65 
66   bool operator==(const value_sequence_iterator &RHS) const {
67     return Value == RHS.Value;
68   }
69   bool operator<(const value_sequence_iterator &RHS) const {
70     return Value < RHS.Value;
71   }
72 
73   reference operator*() const { return Value; }
74 };
75 
76 } // end namespace detail
77 
78 template <typename ValueT>
seq(ValueT Begin,ValueT End)79 iterator_range<detail::value_sequence_iterator<ValueT>> seq(ValueT Begin,
80                                                             ValueT End) {
81   return make_range(detail::value_sequence_iterator<ValueT>(Begin),
82                     detail::value_sequence_iterator<ValueT>(End));
83 }
84 
85 } // end namespace llvm
86 
87 #endif // LLVM_ADT_SEQUENCE_H
88