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1 : // © 2016 and later: Unicode, Inc. and others.
2 : // License & terms of use: http://www.unicode.org/copyright.html
3 : /*
4 : ******************************************************************************
5 : *
6 : * Copyright (C) 2002-2012, International Business Machines
7 : * Corporation and others. All Rights Reserved.
8 : *
9 : ******************************************************************************
10 : * file name: uobject.h
11 : * encoding: UTF-8
12 : * tab size: 8 (not used)
13 : * indentation:4
14 : *
15 : * created on: 2002jun26
16 : * created by: Markus W. Scherer
17 : */
18 :
19 : #ifndef __UOBJECT_H__
20 : #define __UOBJECT_H__
21 :
22 : #include "unicode/utypes.h"
23 :
24 : /**
25 : * \file
26 : * \brief C++ API: Common ICU base class UObject.
27 : */
28 :
29 : /**
30 : * @{
31 : * \def U_NO_THROW
32 : * Define this to define the throw() specification so
33 : * certain functions do not throw any exceptions
34 : *
35 : * UMemory operator new methods should have the throw() specification
36 : * appended to them, so that the compiler adds the additional NULL check
37 : * before calling constructors. Without, if <code>operator new</code> returns NULL the
38 : * constructor is still called, and if the constructor references member
39 : * data, (which it typically does), the result is a segmentation violation.
40 : *
41 : * @stable ICU 4.2
42 : */
43 : #ifndef U_NO_THROW
44 : #define U_NO_THROW throw()
45 : #endif
46 :
47 : /** @} */
48 :
49 : /*===========================================================================*/
50 : /* UClassID-based RTTI */
51 : /*===========================================================================*/
52 :
53 : /**
54 : * UClassID is used to identify classes without using the compiler's RTTI.
55 : * This was used before C++ compilers consistently supported RTTI.
56 : * ICU 4.6 requires compiler RTTI to be turned on.
57 : *
58 : * Each class hierarchy which needs
59 : * to implement polymorphic clone() or operator==() defines two methods,
60 : * described in detail below. UClassID values can be compared using
61 : * operator==(). Nothing else should be done with them.
62 : *
63 : * \par
64 : * In class hierarchies that implement "poor man's RTTI",
65 : * each concrete subclass implements getDynamicClassID() in the same way:
66 : *
67 : * \code
68 : * class Derived {
69 : * public:
70 : * virtual UClassID getDynamicClassID() const
71 : * { return Derived::getStaticClassID(); }
72 : * }
73 : * \endcode
74 : *
75 : * Each concrete class implements getStaticClassID() as well, which allows
76 : * clients to test for a specific type.
77 : *
78 : * \code
79 : * class Derived {
80 : * public:
81 : * static UClassID U_EXPORT2 getStaticClassID();
82 : * private:
83 : * static char fgClassID;
84 : * }
85 : *
86 : * // In Derived.cpp:
87 : * UClassID Derived::getStaticClassID()
88 : * { return (UClassID)&Derived::fgClassID; }
89 : * char Derived::fgClassID = 0; // Value is irrelevant
90 : * \endcode
91 : * @stable ICU 2.0
92 : */
93 : typedef void* UClassID;
94 :
95 : U_NAMESPACE_BEGIN
96 :
97 : /**
98 : * UMemory is the common ICU base class.
99 : * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
100 : *
101 : * This is primarily to make it possible and simple to override the
102 : * C++ memory management by adding new/delete operators to this base class.
103 : *
104 : * To override ALL ICU memory management, including that from plain C code,
105 : * replace the allocation functions declared in cmemory.h
106 : *
107 : * UMemory does not contain any virtual functions.
108 : * Common "boilerplate" functions are defined in UObject.
109 : *
110 : * @stable ICU 2.4
111 : */
112 225 : class U_COMMON_API UMemory {
113 : public:
114 :
115 : /* test versions for debugging shaper heap memory problems */
116 : #ifdef SHAPER_MEMORY_DEBUG
117 : static void * NewArray(int size, int count);
118 : static void * GrowArray(void * array, int newSize );
119 : static void FreeArray(void * array );
120 : #endif
121 :
122 : #if U_OVERRIDE_CXX_ALLOCATION
123 : /**
124 : * Override for ICU4C C++ memory management.
125 : * simple, non-class types are allocated using the macros in common/cmemory.h
126 : * (uprv_malloc(), uprv_free(), uprv_realloc());
127 : * they or something else could be used here to implement C++ new/delete
128 : * for ICU4C C++ classes
129 : * @stable ICU 2.4
130 : */
131 : static void * U_EXPORT2 operator new(size_t size) U_NO_THROW;
132 :
133 : /**
134 : * Override for ICU4C C++ memory management.
135 : * See new().
136 : * @stable ICU 2.4
137 : */
138 : static void * U_EXPORT2 operator new[](size_t size) U_NO_THROW;
139 :
140 : /**
141 : * Override for ICU4C C++ memory management.
142 : * simple, non-class types are allocated using the macros in common/cmemory.h
143 : * (uprv_malloc(), uprv_free(), uprv_realloc());
144 : * they or something else could be used here to implement C++ new/delete
145 : * for ICU4C C++ classes
146 : * @stable ICU 2.4
147 : */
148 : static void U_EXPORT2 operator delete(void *p) U_NO_THROW;
149 :
150 : /**
151 : * Override for ICU4C C++ memory management.
152 : * See delete().
153 : * @stable ICU 2.4
154 : */
155 : static void U_EXPORT2 operator delete[](void *p) U_NO_THROW;
156 :
157 : #if U_HAVE_PLACEMENT_NEW
158 : /**
159 : * Override for ICU4C C++ memory management for STL.
160 : * See new().
161 : * @stable ICU 2.6
162 : */
163 : static inline void * U_EXPORT2 operator new(size_t, void *ptr) U_NO_THROW { return ptr; }
164 :
165 : /**
166 : * Override for ICU4C C++ memory management for STL.
167 : * See delete().
168 : * @stable ICU 2.6
169 : */
170 : static inline void U_EXPORT2 operator delete(void *, void *) U_NO_THROW {}
171 : #endif /* U_HAVE_PLACEMENT_NEW */
172 : #if U_HAVE_DEBUG_LOCATION_NEW
173 : /**
174 : * This method overrides the MFC debug version of the operator new
175 : *
176 : * @param size The requested memory size
177 : * @param file The file where the allocation was requested
178 : * @param line The line where the allocation was requested
179 : */
180 : static void * U_EXPORT2 operator new(size_t size, const char* file, int line) U_NO_THROW;
181 : /**
182 : * This method provides a matching delete for the MFC debug new
183 : *
184 : * @param p The pointer to the allocated memory
185 : * @param file The file where the allocation was requested
186 : * @param line The line where the allocation was requested
187 : */
188 : static void U_EXPORT2 operator delete(void* p, const char* file, int line) U_NO_THROW;
189 : #endif /* U_HAVE_DEBUG_LOCATION_NEW */
190 : #endif /* U_OVERRIDE_CXX_ALLOCATION */
191 :
192 : /*
193 : * Assignment operator not declared. The compiler will provide one
194 : * which does nothing since this class does not contain any data members.
195 : * API/code coverage may show the assignment operator as present and
196 : * untested - ignore.
197 : * Subclasses need this assignment operator if they use compiler-provided
198 : * assignment operators of their own. An alternative to not declaring one
199 : * here would be to declare and empty-implement a protected or public one.
200 : UMemory &UMemory::operator=(const UMemory &);
201 : */
202 : };
203 :
204 : /**
205 : * UObject is the common ICU "boilerplate" class.
206 : * UObject inherits UMemory (starting with ICU 2.4),
207 : * and all other public ICU C++ classes
208 : * are derived from UObject (starting with ICU 2.2).
209 : *
210 : * UObject contains common virtual functions, in particular a virtual destructor.
211 : *
212 : * The clone() function is not available in UObject because it is not
213 : * implemented by all ICU classes.
214 : * Many ICU services provide a clone() function for their class trees,
215 : * defined on the service's C++ base class, and all subclasses within that
216 : * service class tree return a pointer to the service base class
217 : * (which itself is a subclass of UObject).
218 : * This is because some compilers do not support covariant (same-as-this)
219 : * return types; cast to the appropriate subclass if necessary.
220 : *
221 : * @stable ICU 2.2
222 : */
223 31 : class U_COMMON_API UObject : public UMemory {
224 : public:
225 : /**
226 : * Destructor.
227 : *
228 : * @stable ICU 2.2
229 : */
230 : virtual ~UObject();
231 :
232 : /**
233 : * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
234 : * The base class implementation returns a dummy value.
235 : *
236 : * Use compiler RTTI rather than ICU's "poor man's RTTI".
237 : * Since ICU 4.6, new ICU C++ class hierarchies do not implement "poor man's RTTI".
238 : *
239 : * @stable ICU 2.2
240 : */
241 : virtual UClassID getDynamicClassID() const;
242 :
243 : protected:
244 : // the following functions are protected to prevent instantiation and
245 : // direct use of UObject itself
246 :
247 : // default constructor
248 : // inline UObject() {}
249 :
250 : // copy constructor
251 : // inline UObject(const UObject &other) {}
252 :
253 : #if 0
254 : // TODO Sometime in the future. Implement operator==().
255 : // (This comment inserted in 2.2)
256 : // some or all of the following "boilerplate" functions may be made public
257 : // in a future ICU4C release when all subclasses implement them
258 :
259 : // assignment operator
260 : // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
261 : // commented out because the implementation is the same as a compiler's default
262 : // UObject &operator=(const UObject &other) { return *this; }
263 :
264 : // comparison operators
265 : virtual inline UBool operator==(const UObject &other) const { return this==&other; }
266 : inline UBool operator!=(const UObject &other) const { return !operator==(other); }
267 :
268 : // clone() commented out from the base class:
269 : // some compilers do not support co-variant return types
270 : // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
271 : // see also UObject class documentation.
272 : // virtual UObject *clone() const;
273 : #endif
274 :
275 : /*
276 : * Assignment operator not declared. The compiler will provide one
277 : * which does nothing since this class does not contain any data members.
278 : * API/code coverage may show the assignment operator as present and
279 : * untested - ignore.
280 : * Subclasses need this assignment operator if they use compiler-provided
281 : * assignment operators of their own. An alternative to not declaring one
282 : * here would be to declare and empty-implement a protected or public one.
283 : UObject &UObject::operator=(const UObject &);
284 : */
285 : };
286 :
287 : #ifndef U_HIDE_INTERNAL_API
288 : /**
289 : * This is a simple macro to add ICU RTTI to an ICU object implementation.
290 : * This does not go into the header. This should only be used in *.cpp files.
291 : *
292 : * @param myClass The name of the class that needs RTTI defined.
293 : * @internal
294 : */
295 : #define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
296 : UClassID U_EXPORT2 myClass::getStaticClassID() { \
297 : static char classID = 0; \
298 : return (UClassID)&classID; \
299 : } \
300 : UClassID myClass::getDynamicClassID() const \
301 : { return myClass::getStaticClassID(); }
302 :
303 :
304 : /**
305 : * This macro adds ICU RTTI to an ICU abstract class implementation.
306 : * This macro should be invoked in *.cpp files. The corresponding
307 : * header should declare getStaticClassID.
308 : *
309 : * @param myClass The name of the class that needs RTTI defined.
310 : * @internal
311 : */
312 : #define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
313 : UClassID U_EXPORT2 myClass::getStaticClassID() { \
314 : static char classID = 0; \
315 : return (UClassID)&classID; \
316 : }
317 :
318 : #endif /* U_HIDE_INTERNAL_API */
319 :
320 : U_NAMESPACE_END
321 :
322 : #endif
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