1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
// 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 assign (T* d, size_type s) {data_ = d; size_ = s;}
void clear () {data_ = nullptr; size_ = 0;}
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
|
