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| -rw-r--r-- | butl/vector-view | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/butl/vector-view b/butl/vector-view new file mode 100644 index 0000000..30a786c --- /dev/null +++ b/butl/vector-view @@ -0,0 +1,109 @@ +// file : butl/vector-view -*- C++ -*- +// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd +// license : MIT; see accompanying LICENSE file + +#ifndef BUTL_VECTOR_VIEW +#define BUTL_VECTOR_VIEW + +#include <vector> +#include <cstddef> // size_t, ptrdiff_t +#include <utility> // swap() +#include <iterator> // reverse_iterator +#include <stdexcept> // out_of_range + +namespace butl +{ + // In our version a const view allows the modification of the elements + // unless T is made const (the same semantics as in smart pointers). + // + // @@ If T is const T1, could be useful to have a c-tor from vector<T1>. + // + template <typename T> + class vector_view + { + public: + using value_type = T; + using pointer = T*; + using reference = T&; + using const_pointer = const T*; + using const_reference = const T&; + using size_type = std::size_t; + using difference_type = std::ptrdiff_t; + + using iterator = T*; + using const_iterator = const T*; + using reverse_iterator = std::reverse_iterator<iterator>; + using const_reverse_iterator = std::reverse_iterator<const_iterator>; + + // construct/copy/destroy: + // + vector_view (): data_ (nullptr), size_ (0) {} + vector_view (T* d, size_type s): data_ (d), size_ (s) {} + + template <typename T1, typename A> + vector_view (std::vector<T1, A>& v) + : data_ (v.data ()), size_ (v.size ()) {} + + template <typename T1, typename A> + vector_view (const std::vector<T1, A>& v) + : data_ (v.data ()), size_ (v.size ()) {} + + vector_view (vector_view&&) = default; + vector_view (const vector_view&) = default; + vector_view& operator= (vector_view&&) = default; + vector_view& operator= (const vector_view&) = default; + + // iterators: + // + iterator begin() const {return data_;} + iterator end() const {return data_ + size_;} + + const_iterator cbegin() const {return data_;} + const_iterator cend() const {return data_ + size_;} + + reverse_iterator rbegin() const {return reverse_iterator (end ());} + reverse_iterator rend() const {return reverse_iterator (begin ());} + + const_reverse_iterator crbegin() const { + return const_reverse_iterator (cend ());} + const_reverse_iterator crend() const { + return const_reverse_iterator (cbegin ());} + + // capacity: + // + size_type size() const {return size_;} + bool empty() const {return size_ == 0;} + + // element access: + // + reference operator[](size_type n) const {return data_[n];} + reference at(size_type n) const { + if (n >= size_) throw std::out_of_range (); return data_[n];} + reference front() const {return data_[0];} + reference back() const {return data_[size_ - 1];} + + // data access: + // + T* data() const {return data_;} + + // modifiers: + // + void swap (vector_view& v) { + std::swap (data_, v.data_); std::swap (size_, v.size_);} + + private: + T* data_; + size_type size_; + }; + + //@@ TODO. + // + template<typename T> bool operator== (vector_view<T> l, vector_view<T> r); + template<typename T> bool operator!= (vector_view<T> l, vector_view<T> r); + template<typename T> bool operator< (vector_view<T> l, vector_view<T> r); + template<typename T> bool operator> (vector_view<T> l, vector_view<T> r); + template<typename T> bool operator<= (vector_view<T> l, vector_view<T> r); + template<typename T> bool operator>= (vector_view<T> l, vector_view<T> r); +} + +#endif // BUTL_VECTOR_VIEW |