src/cpp-common/bt2/common-iter.hpp

   1 /*
   2  * Copyright (c) 2022 Francis Deslauriers <francis.deslauriers@efficios.com>
   3  *
   4  * SPDX-License-Identifier: MIT
   5  */
   6
   7 #ifndef BABELTRACE_CPP_COMMON_BT2_COMMON_ITER_HPP
   8 #define BABELTRACE_CPP_COMMON_BT2_COMMON_ITER_HPP
   9
  10 #include <iterator>
  11 #include <type_traits>
  12
  13 #include "cpp-common/optional.hpp"
  14
  15 namespace bt2 {
  16
  17 template <typename ContainerT, typename ElemT>
  18 class CommonIterator
  19 {
  20     friend ContainerT;
  21
  22 public:
  23     using difference_type = std::ptrdiff_t;
  24     using value_type = ElemT;
  25     using pointer = value_type *;
  26     using reference = value_type&;
  27     using iterator_category = std::input_iterator_tag;
  28
  29 private:
  30     explicit CommonIterator(const ContainerT container, const uint64_t idx) :
  31         _mContainer {container}, _mIdx {idx}
  32     {
  33         this->_updateCurrentValue();
  34     }
  35
  36 public:
  37     CommonIterator(const CommonIterator&) = default;
  38     CommonIterator(CommonIterator&&) = default;
  39     CommonIterator& operator=(const CommonIterator&) = default;
  40     CommonIterator& operator=(CommonIterator&&) = default;
  41
  42     CommonIterator& operator++() noexcept
  43     {
  44         ++_mIdx;
  45         this->_updateCurrentValue();
  46         return *this;
  47     }
  48
  49     CommonIterator operator++(int) noexcept
  50     {
  51         const auto tmp = *this;
  52
  53         ++(*this);
  54         return tmp;
  55     }
  56
  57     bool operator==(const CommonIterator& other) const noexcept
  58     {
  59         return _mIdx == other._mIdx;
  60     }
  61
  62     bool operator!=(const CommonIterator& other) const noexcept
  63     {
  64         return !(*this == other);
  65     }
  66
  67     reference operator*() noexcept
  68     {
  69         return *_mCurrVal;
  70     }
  71
  72     pointer operator->() noexcept
  73     {
  74         return &(*_mCurrVal);
  75     }
  76
  77 private:
  78     void _updateCurrentValue() noexcept
  79     {
  80         if (_mIdx < _mContainer.size()) {
  81             _mCurrVal = _mContainer[_mIdx];
  82         } else {
  83             _mCurrVal = nonstd::nullopt;
  84         }
  85     }
  86
  87     nonstd::optional<value_type> _mCurrVal;
  88     ContainerT _mContainer;
  89     uint64_t _mIdx;
  90 };
  91 } /* namespace bt2 */
  92
  93 #endif /* BABELTRACE_CPP_COMMON_BT2_COMMON_ITER_HPP */