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
|
/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
#ifndef LUA_UNIQUE_BIN_H
#define LUA_UNIQUE_BIN_H
//
// A container that holds unique copies of a data type (with smart references).
//
// Accessing the data for any reference is always valid.
//
// Data Types that use this template must have the following properties:
//
// 1. the 'bool operator<(const T&) const' member function
//
// 2. the 'static T def' static variable that holds default values
//
#include <set>
/******************************************************************************/
/******************************************************************************/
//
// UniqueBin
//
template<typename T>
class UniqueBin
{
private:
class Data;
struct SortObj;
public:
class Ref;
typedef std::set<Data*, SortObj> DataSet;
typedef typename DataSet::const_iterator const_iterator;
const_iterator begin() const {
return dataSet.begin();
}
const_iterator end() const {
return dataSet.end();
}
unsigned int size() const {
return dataSet.size();
}
bool empty() const {
return dataSet.empty();
}
Ref GetRef(const T& t) {
Data* cmpPtr = (Data*) &t; // note the cast
const_iterator it = dataSet.find(cmpPtr);
if (it != dataSet.end()) {
return Ref(*it); // already in the set
}
Data* data = new Data(t);
dataSet.insert(data);
return Ref(data);
}
bool Exists(const T& t) const {
Data* cmpPtr = (Data*) &t; // note the cast
const_iterator it = dataSet.find(cmpPtr);
if (it != dataSet.end()) {
return true;
}
return false;
}
static UniqueBin handler;
private:
struct SortObj
{
bool operator()(const Data* a, const Data* b) {
return (*a < *b);
}
};
private:
typedef typename DataSet::iterator iterator;
private:
UniqueBin() {
defData = new Data(T::def);
defData->Ref(); // make it permanent
dataSet.insert(defData);
}
~UniqueBin() {
defData->UnRef();
for (iterator it = dataSet.begin(); it != dataSet.end(); ++it) {
delete *it;
}
}
void EraseData(Data* data) {
dataSet.erase(data);
delete data;
}
private:
Data* defData;
DataSet dataSet;
/******************************************************************************/
//
// Ref
//
public:
class Ref {
friend Ref UniqueBin::GetRef(const T& t); // for Ref(Data*) access
public:
Ref() {
dataPtr = UniqueBin::handler.defData;
}
const T& operator*() const {
return (**dataPtr);
}
const T* operator->() const {
return &(**dataPtr);
}
bool operator==(const Ref& r) const {
return dataPtr == r.dataPtr;
}
bool operator!=(const Ref& r) const {
return dataPtr != r.dataPtr;
}
void Reset() {
dataPtr->UnRef();
dataPtr = UniqueBin::handler->defData;
dataPtr->Ref();
}
~Ref() {
dataPtr->UnRef();
};
Ref(const Ref& r) {
dataPtr = r.dataPtr;
dataPtr->Ref();
}
Ref& operator=(const Ref& r) {
if (dataPtr != r.dataPtr) {
dataPtr->UnRef();
dataPtr = r.dataPtr;
dataPtr->Ref();
}
return *this;
}
private:
Ref(Data* dp) {
dataPtr = dp;
dataPtr->Ref();
}
private:
Data* dataPtr;
};
/******************************************************************************/
//
// Data
//
private:
class Data {
public:
bool operator<(const Data& d) const {
return (data < d.data);
}
const T& operator*() const {
return data;
}
void Ref() {
refCount++;
}
void UnRef() {
refCount--;
if (refCount <= 0) {
UniqueBin::handler.EraseData(this);
}
}
Data(const T& t)
: data(t), refCount(0) {}
private:
T data; // NOTE: must come first
unsigned int refCount;
};
};
/******************************************************************************/
/******************************************************************************/
template<typename T> UniqueBin<T> UniqueBin<T>::handler;
/******************************************************************************/
/******************************************************************************/
#endif // LUA_UNIQUE_BIN_H
|
