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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
#ifndef INCLUDED_AI_BOOST_SHARED_ARRAY
#define INCLUDED_AI_BOOST_SHARED_ARRAY
#ifndef BOOST_SHARED_ARRAY_HPP_INCLUDED
// ------------------------------
// Internal stub
namespace boost {
namespace array_detail {
class controller {
public:
controller()
: cnt(1)
{}
public:
template <typename T>
controller* decref(T* pt) {
if (--cnt <= 0) {
delete this;
delete[] pt;
}
return NULL;
}
controller* incref() {
++cnt;
return this;
}
long get() const {
return cnt;
}
private:
long cnt;
};
struct empty {};
template <typename DEST, typename SRC>
struct is_convertible_stub {
struct yes {char s[1];};
struct no {char s[2];};
static yes foo(DEST*);
static no foo(...);
enum {result = (sizeof(foo((SRC*)0)) == sizeof(yes) ? 1 : 0)};
};
template <bool> struct enable_if {};
template <> struct enable_if<true> {
typedef empty result;
};
template <typename DEST, typename SRC>
struct is_convertible : public enable_if<is_convertible_stub<DEST,SRC>::result > {
};
}
// ------------------------------
// Small replacement for boost::shared_array, not threadsafe because no
// atomic reference counter is in use.
// ------------------------------
template <class T>
class shared_array
{
template <typename TT> friend class shared_array;
template<class TT> friend bool operator== (const shared_array<TT>& a, const shared_array<TT>& b);
template<class TT> friend bool operator!= (const shared_array<TT>& a, const shared_array<TT>& b);
template<class TT> friend bool operator< (const shared_array<TT>& a, const shared_array<TT>& b);
public:
typedef T element_type;
public:
// provide a default constructor
shared_array()
: ptr()
, ctr(NULL)
{
}
// construction from an existing object of type T
explicit shared_array(T* ptr)
: ptr(ptr)
, ctr(ptr ? new array_detail::controller() : NULL)
{
}
shared_array(const shared_array& r)
: ptr(r.ptr)
, ctr(r.ctr ? r.ctr->incref() : NULL)
{
}
template <typename Y>
shared_array(const shared_array<Y>& r,typename detail::is_convertible<T,Y>::result = detail::empty())
: ptr(r.ptr)
, ctr(r.ctr ? r.ctr->incref() : NULL)
{
}
// automatic destruction of the wrapped object when all
// references are freed.
~shared_array() {
if (ctr) {
ctr = ctr->decref(ptr);
}
}
shared_array& operator=(const shared_array& r) {
if (this == &r) {
return *this;
}
if (ctr) {
ctr->decref(ptr);
}
ptr = r.ptr;
ctr = ptr?r.ctr->incref():NULL;
return *this;
}
template <typename Y>
shared_array& operator=(const shared_array<Y>& r) {
if (this == &r) {
return *this;
}
if (ctr) {
ctr->decref(ptr);
}
ptr = r.ptr;
ctr = ptr?r.ctr->incref():NULL;
return *this;
}
// pointer access
inline operator T*() {
return ptr;
}
inline T* operator-> () const {
return ptr;
}
// standard semantics
inline T* get() {
return ptr;
}
T& operator[] (std::ptrdiff_t index) const {
return ptr[index];
}
inline const T* get() const {
return ptr;
}
inline operator bool () const {
return ptr != NULL;
}
inline bool unique() const {
return use_count() == 1;
}
inline long use_count() const {
return ctr->get();
}
inline void reset (T* t = 0) {
if (ctr) {
ctr->decref(ptr);
}
ptr = t;
ctr = ptr?new array_detail::controller():NULL;
}
void swap(shared_array & b) {
std::swap(ptr, b.ptr);
std::swap(ctr, b.ctr);
}
private:
// encapsulated object pointer
T* ptr;
// control block
array_detail::controller* ctr;
};
template<class T>
inline void swap(shared_array<T> & a, shared_array<T> & b)
{
a.swap(b);
}
template<class T>
bool operator== (const shared_array<T>& a, const shared_array<T>& b) {
return a.ptr == b.ptr;
}
template<class T>
bool operator!= (const shared_array<T>& a, const shared_array<T>& b) {
return a.ptr != b.ptr;
}
template<class T>
bool operator< (const shared_array<T>& a, const shared_array<T>& b) {
return a.ptr < b.ptr;
}
} // end of namespace boost
#else
# error "shared_array.h was already included"
#endif
#endif // INCLUDED_AI_BOOST_SHARED_ARRAY
|
