1#ifndef BASE_SCOPED_PTR_H
2#define BASE_SCOPED_PTR_H
3
4//  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
5//  Copyright (c) 2001, 2002 Peter Dimov
6//
7//  Permission to copy, use, modify, sell and distribute this software
8//  is granted provided this copyright notice appears in all copies.
9//  This software is provided "as is" without express or implied
10//  warranty, and with no claim as to its suitability for any purpose.
11//
12//  See http://www.boost.org/libs/smart_ptr/scoped_ptr.htm for documentation.
13//
14
15//  scoped_ptr mimics a built-in pointer except that it guarantees deletion
16//  of the object pointed to, either on destruction of the scoped_ptr or via
17//  an explicit reset(). scoped_ptr is a simple solution for simple needs;
18//  use shared_ptr or std::auto_ptr if your needs are more complex.
19
20//  *** NOTE ***
21//  If your scoped_ptr is a class member of class FOO pointing to a
22//  forward declared type BAR (as shown below), then you MUST use a non-inlined
23//  version of the destructor.  The destructor of a scoped_ptr (called from
24//  FOO's destructor) must have a complete definition of BAR in order to
25//  destroy it.  Example:
26//
27//  -- foo.h --
28//  class BAR;
29//
30//  class FOO {
31//   public:
32//    FOO();
33//    ~FOO();  // Required for sources that instantiate class FOO to compile!
34//
35//   private:
36//    scoped_ptr<BAR> bar_;
37//  };
38//
39//  -- foo.cc --
40//  #include "foo.h"
41//  FOO::~FOO() {} // Empty, but must be non-inlined to FOO's class definition.
42
43#include <cstddef>            // for std::ptrdiff_t
44#include <assert.h>           // for assert
45#include <stdlib.h>           // for free() decl
46
47template <typename T>
48class scoped_ptr {
49 private:
50
51  T* ptr;
52
53  scoped_ptr(scoped_ptr const &);
54  scoped_ptr & operator=(scoped_ptr const &);
55
56 public:
57
58  typedef T element_type;
59
60  explicit scoped_ptr(T* p = 0): ptr(p) {}
61
62  ~scoped_ptr() {
63    typedef char type_must_be_complete[sizeof(T)];
64    delete ptr;
65  }
66
67  void reset(T* p = 0) {
68    typedef char type_must_be_complete[sizeof(T)];
69
70    if (ptr != p) {
71      delete ptr;
72      ptr = p;
73    }
74  }
75
76  T& operator*() const {
77    assert(ptr != 0);
78    return *ptr;
79  }
80
81  T* operator->() const  {
82    assert(ptr != 0);
83    return ptr;
84  }
85
86  bool operator==(T* p) const {
87    return ptr == p;
88  }
89
90  bool operator!=(T* p) const {
91    return ptr != p;
92  }
93
94  T* get() const  {
95    return ptr;
96  }
97
98  void swap(scoped_ptr & b) {
99    T* tmp = b.ptr;
100    b.ptr = ptr;
101    ptr = tmp;
102  }
103
104  T* release() {
105    T* tmp = ptr;
106    ptr = 0;
107    return tmp;
108  }
109
110 private:
111
112  // no reason to use these: each scoped_ptr should have its own object
113  template <typename U> bool operator==(scoped_ptr<U> const& p) const;
114  template <typename U> bool operator!=(scoped_ptr<U> const& p) const;
115};
116
117template<typename T> inline
118void swap(scoped_ptr<T>& a, scoped_ptr<T>& b) {
119  a.swap(b);
120}
121
122template<typename T> inline
123bool operator==(T* p, const scoped_ptr<T>& b) {
124  return p == b.get();
125}
126
127template<typename T> inline
128bool operator!=(T* p, const scoped_ptr<T>& b) {
129  return p != b.get();
130}
131
132//  scoped_array extends scoped_ptr to arrays. Deletion of the array pointed to
133//  is guaranteed, either on destruction of the scoped_array or via an explicit
134//  reset(). Use shared_array or std::vector if your needs are more complex.
135
136template<typename T>
137class scoped_array {
138 private:
139
140  T* ptr;
141
142  scoped_array(scoped_array const &);
143  scoped_array & operator=(scoped_array const &);
144
145 public:
146
147  typedef T element_type;
148
149  explicit scoped_array(T* p = 0) : ptr(p) {}
150
151  ~scoped_array() {
152    typedef char type_must_be_complete[sizeof(T)];
153    delete[] ptr;
154  }
155
156  void reset(T* p = 0) {
157    typedef char type_must_be_complete[sizeof(T)];
158
159    if (ptr != p) {
160      delete [] ptr;
161      ptr = p;
162    }
163  }
164
165  T& operator[](std::ptrdiff_t i) const {
166    assert(ptr != 0);
167    assert(i >= 0);
168    return ptr[i];
169  }
170
171  bool operator==(T* p) const {
172    return ptr == p;
173  }
174
175  bool operator!=(T* p) const {
176    return ptr != p;
177  }
178
179  T* get() const {
180    return ptr;
181  }
182
183  void swap(scoped_array & b) {
184    T* tmp = b.ptr;
185    b.ptr = ptr;
186    ptr = tmp;
187  }
188
189  T* release() {
190    T* tmp = ptr;
191    ptr = 0;
192    return tmp;
193  }
194
195 private:
196
197  // no reason to use these: each scoped_array should have its own object
198  template <typename U> bool operator==(scoped_array<U> const& p) const;
199  template <typename U> bool operator!=(scoped_array<U> const& p) const;
200};
201
202template<class T> inline
203void swap(::scoped_array<T>& a, ::scoped_array<T>& b) {
204  a.swap(b);
205}
206
207template<typename T> inline
208bool operator==(T* p, const ::scoped_array<T>& b) {
209  return p == b.get();
210}
211
212template<typename T> inline
213bool operator!=(T* p, const ::scoped_array<T>& b) {
214  return p != b.get();
215}
216
217
218// This class wraps the c library function free() in a class that can be
219// passed as a template argument to scoped_ptr_malloc below.
220class ScopedPtrMallocFree {
221 public:
222  inline void operator()(void* x) const {
223    free(x);
224  }
225};
226
227// scoped_ptr_malloc<> is similar to scoped_ptr<>, but it accepts a
228// second template argument, the functor used to free the object.
229
230template<typename T, typename FreeProc = ScopedPtrMallocFree>
231class scoped_ptr_malloc {
232 private:
233
234  T* ptr;
235
236  scoped_ptr_malloc(scoped_ptr_malloc const &);
237  scoped_ptr_malloc & operator=(scoped_ptr_malloc const &);
238
239 public:
240
241  typedef T element_type;
242
243  explicit scoped_ptr_malloc(T* p = 0): ptr(p) {}
244
245  ~scoped_ptr_malloc() {
246    typedef char type_must_be_complete[sizeof(T)];
247    free_((void*) ptr);
248  }
249
250  void reset(T* p = 0) {
251    typedef char type_must_be_complete[sizeof(T)];
252
253    if (ptr != p) {
254      free_((void*) ptr);
255      ptr = p;
256    }
257  }
258
259  T& operator*() const {
260    assert(ptr != 0);
261    return *ptr;
262  }
263
264  T* operator->() const {
265    assert(ptr != 0);
266    return ptr;
267  }
268
269  bool operator==(T* p) const {
270    return ptr == p;
271  }
272
273  bool operator!=(T* p) const {
274    return ptr != p;
275  }
276
277  T* get() const {
278    return ptr;
279  }
280
281  void swap(scoped_ptr_malloc & b) {
282    T* tmp = b.ptr;
283    b.ptr = ptr;
284    ptr = tmp;
285  }
286
287  T* release() {
288    T* tmp = ptr;
289    ptr = 0;
290    return tmp;
291  }
292
293 private:
294
295  // no reason to use these: each scoped_ptr_malloc should have its own object
296  template <typename U, typename GP>
297  bool operator==(scoped_ptr_malloc<U, GP> const& p) const;
298  template <typename U, typename GP>
299  bool operator!=(scoped_ptr_malloc<U, GP> const& p) const;
300
301  static FreeProc const free_;
302};
303
304template<typename T, typename FP>
305FP const scoped_ptr_malloc<T,FP>::free_ = FP();
306
307template<typename T, typename FP> inline
308void swap(scoped_ptr_malloc<T,FP>& a, scoped_ptr_malloc<T,FP>& b) {
309  a.swap(b);
310}
311
312template<typename T, typename FP> inline
313bool operator==(T* p, const scoped_ptr_malloc<T,FP>& b) {
314  return p == b.get();
315}
316
317template<typename T, typename FP> inline
318bool operator!=(T* p, const scoped_ptr_malloc<T,FP>& b) {
319  return p != b.get();
320}
321
322#endif  // #ifndef BASE_SCOPED_PTR_H
323