1 //===----------------------- adt.h - Handy ADTs -----------------*- 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 //
9 // This file is a part of the ORC runtime support library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef ORC_RT_ADT_H
14 #define ORC_RT_ADT_H
15 
16 #include <cstring>
17 #include <limits>
18 #include <ostream>
19 #include <string>
20 
21 namespace __orc_rt {
22 
23 constexpr std::size_t dynamic_extent = std::numeric_limits<std::size_t>::max();
24 
25 /// A substitute for std::span (and llvm::ArrayRef).
26 /// FIXME: Remove in favor of std::span once we can use c++20.
27 template <typename T, std::size_t Extent = dynamic_extent> class span {
28 public:
29   typedef T element_type;
30   typedef std::remove_cv<T> value_type;
31   typedef std::size_t size_type;
32   typedef std::ptrdiff_t difference_type;
33   typedef T *pointer;
34   typedef const T *const_pointer;
35   typedef T &reference;
36   typedef const T &const_reference;
37 
38   typedef pointer iterator;
39 
40   static constexpr std::size_t extent = Extent;
41 
42   constexpr span() noexcept = default;
43   constexpr span(T *first, size_type count) noexcept
44       : Data(first), Size(count) {}
45 
46   template <std::size_t N>
47   constexpr span(T (&arr)[N]) noexcept : Data(&arr[0]), Size(N) {}
48 
49   constexpr iterator begin() const noexcept { return Data; }
50   constexpr iterator end() const noexcept { return Data + Size; }
51   constexpr pointer data() const noexcept { return Data; }
52   constexpr reference operator[](size_type idx) const { return Data[idx]; }
53   constexpr size_type size() const noexcept { return Size; }
54   constexpr bool empty() const noexcept { return Size == 0; }
55 
56 private:
57   T *Data = nullptr;
58   size_type Size = 0;
59 };
60 
61 } // end namespace __orc_rt
62 
63 #endif // ORC_RT_ADT_H
64