summaryrefslogtreecommitdiffstats
blob: 450c9bcf595a6c818a34d934624f8be99cef95a1 (plain)
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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
#ifndef BOOST_SMART_PTR_DETAIL_SHARED_ARRAY_NMT_HPP_INCLUDED
#define BOOST_SMART_PTR_DETAIL_SHARED_ARRAY_NMT_HPP_INCLUDED

//
//  detail/shared_array_nmt.hpp - shared_array.hpp without member templates
//
//  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
//  Copyright (c) 2001, 2002 Peter Dimov
//
//  Distributed under the Boost Software License, Version 1.0. (See
//  accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)
//
//  See http://www.boost.org/libs/smart_ptr/shared_array.htm for documentation.
//

#include <boost/assert.hpp>
#include <boost/checked_delete.hpp>
#include <boost/throw_exception.hpp>
#include <boost/smart_ptr/detail/atomic_count.hpp>

#include <cstddef>          // for std::ptrdiff_t
#include <algorithm>        // for std::swap
#include <functional>       // for std::less
#include <new>              // for std::bad_alloc

namespace boost
{

template<class T> class shared_array
{
private:

    typedef detail::atomic_count count_type;

public:

    typedef T element_type;
      
    explicit shared_array(T * p = 0): px(p)
    {
#ifndef BOOST_NO_EXCEPTIONS

        try  // prevent leak if new throws
        {
            pn = new count_type(1);
        }
        catch(...)
        {
            boost::checked_array_delete(p);
            throw;
        }

#else

        pn = new count_type(1);

        if(pn == 0)
        {
            boost::checked_array_delete(p);
            boost::throw_exception(std::bad_alloc());
        }

#endif
    }

    ~shared_array()
    {
        if(--*pn == 0)
        {
            boost::checked_array_delete(px);
            delete pn;
        }
    }

    shared_array(shared_array const & r) : px(r.px)  // never throws
    {
        pn = r.pn;
        ++*pn;
    }

    shared_array & operator=(shared_array const & r)
    {
        shared_array(r).swap(*this);
        return *this;
    }

    void reset(T * p = 0)
    {
        BOOST_ASSERT(p == 0 || p != px);
        shared_array(p).swap(*this);
    }

    T * get() const  // never throws
    {
        return px;
    }

    T & operator[](std::ptrdiff_t i) const  // never throws
    {
        BOOST_ASSERT(px != 0);
        BOOST_ASSERT(i >= 0);
        return px[i];
    }

    long use_count() const  // never throws
    {
        return *pn;
    }

    bool unique() const  // never throws
    {
        return *pn == 1;
    }

    void swap(shared_array<T> & other)  // never throws
    {
        std::swap(px, other.px);
        std::swap(pn, other.pn);
    }

private:

    T * px;            // contained pointer
    count_type * pn;   // ptr to reference counter
      
};  // shared_array

template<class T, class U> inline bool operator==(shared_array<T> const & a, shared_array<U> const & b)
{
    return a.get() == b.get();
}

template<class T, class U> inline bool operator!=(shared_array<T> const & a, shared_array<U> const & b)
{
    return a.get() != b.get();
}

template<class T> inline bool operator<(shared_array<T> const & a, shared_array<T> const & b)
{
    return std::less<T*>()(a.get(), b.get());
}

template<class T> void swap(shared_array<T> & a, shared_array<T> & b)
{
    a.swap(b);
}

} // namespace boost

#endif  // #ifndef BOOST_SMART_PTR_DETAIL_SHARED_ARRAY_NMT_HPP_INCLUDED