compiler-rt/lib/orc/adt.h

   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