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| 1 | +#ifndef DIFFSCOPE_DSPX_MODEL_RANGEHELPERS_H |
| 2 | +#define DIFFSCOPE_DSPX_MODEL_RANGEHELPERS_H |
| 3 | + |
| 4 | +#include <iterator> |
| 5 | + |
| 6 | +namespace dspx::impl { |
| 7 | + |
| 8 | + template<class SequenceType> |
| 9 | + class SequenceRange { |
| 10 | + public: |
| 11 | + SequenceRange(const SequenceType *sequence) : m_sequence(sequence) { |
| 12 | + } |
| 13 | + |
| 14 | + using ItemType = std::remove_pointer_t<decltype(std::declval<SequenceType>().firstItem())>; |
| 15 | + |
| 16 | + class iterator { |
| 17 | + public: |
| 18 | + using iterator_category = std::bidirectional_iterator_tag; |
| 19 | + using value_type = ItemType *; |
| 20 | + using difference_type = std::ptrdiff_t; |
| 21 | + using pointer = ItemType **; |
| 22 | + using reference = ItemType *&; |
| 23 | + |
| 24 | + iterator(const SequenceType *sequence, ItemType *item) : m_sequence(sequence), m_item(item) { |
| 25 | + } |
| 26 | + |
| 27 | + value_type operator*() const { |
| 28 | + return m_item; |
| 29 | + } |
| 30 | + |
| 31 | + iterator &operator++() { |
| 32 | + if (m_item) { |
| 33 | + m_item = m_sequence->nextItem(m_item); |
| 34 | + } |
| 35 | + return *this; |
| 36 | + } |
| 37 | + |
| 38 | + iterator operator++(int) { |
| 39 | + iterator temp = *this; |
| 40 | + ++(*this); |
| 41 | + return temp; |
| 42 | + } |
| 43 | + |
| 44 | + iterator &operator--() { |
| 45 | + if (m_item) { |
| 46 | + m_item = m_sequence->previousItem(m_item); |
| 47 | + } else { |
| 48 | + m_item = m_sequence->lastItem(); |
| 49 | + } |
| 50 | + return *this; |
| 51 | + } |
| 52 | + |
| 53 | + iterator operator--(int) { |
| 54 | + iterator temp = *this; |
| 55 | + --(*this); |
| 56 | + return temp; |
| 57 | + } |
| 58 | + |
| 59 | + bool operator==(const iterator &other) const { |
| 60 | + return m_item == other.m_item; |
| 61 | + } |
| 62 | + |
| 63 | + bool operator!=(const iterator &other) const { |
| 64 | + return m_item != other.m_item; |
| 65 | + } |
| 66 | + |
| 67 | + private: |
| 68 | + const SequenceType *m_sequence; |
| 69 | + ItemType *m_item; |
| 70 | + }; |
| 71 | + |
| 72 | + using const_iterator = iterator; |
| 73 | + using reverse_iterator = std::reverse_iterator<iterator>; |
| 74 | + using const_reverse_iterator = std::reverse_iterator<const_iterator>; |
| 75 | + |
| 76 | + iterator begin() const { |
| 77 | + return iterator(m_sequence, m_sequence->firstItem()); |
| 78 | + } |
| 79 | + |
| 80 | + iterator end() const { |
| 81 | + return iterator(m_sequence, nullptr); |
| 82 | + } |
| 83 | + |
| 84 | + const_iterator cbegin() const { |
| 85 | + return begin(); |
| 86 | + } |
| 87 | + |
| 88 | + const_iterator cend() const { |
| 89 | + return end(); |
| 90 | + } |
| 91 | + |
| 92 | + reverse_iterator rbegin() const { |
| 93 | + return reverse_iterator(end()); |
| 94 | + } |
| 95 | + |
| 96 | + reverse_iterator rend() const { |
| 97 | + return reverse_iterator(begin()); |
| 98 | + } |
| 99 | + |
| 100 | + const_reverse_iterator crbegin() const { |
| 101 | + return rbegin(); |
| 102 | + } |
| 103 | + |
| 104 | + const_reverse_iterator crend() const { |
| 105 | + return rend(); |
| 106 | + } |
| 107 | + |
| 108 | + private: |
| 109 | + const SequenceType *m_sequence; |
| 110 | + }; |
| 111 | + |
| 112 | +} |
| 113 | + |
| 114 | +#endif //DIFFSCOPE_DSPX_MODEL_RANGEHELPERS_H |
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