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#if U_SHOW_CPLUSPLUS_API
25
26#include "unicode/platform.h"
27
28/**
29 * \file
30 * \brief C++ API: Common ICU base class UObject.
31 */
32
33/**
34 * \def U_NO_THROW
35 * Since ICU 64, use U_NOEXCEPT instead.
36 *
37 * Previously, define this to define the throw() specification so
38 * certain functions do not throw any exceptions
39 *
40 * UMemory operator new methods should have the throw() specification
41 * appended to them, so that the compiler adds the additional NULL check
42 * before calling constructors. Without, if <code>operator new</code> returns NULL the
43 * constructor is still called, and if the constructor references member
44 * data, (which it typically does), the result is a segmentation violation.
45 *
46 * @stable ICU 4.2. Since ICU 64, Use U_NOEXCEPT instead. See ICU-20422.
47 */
48#ifndef U_NO_THROW
49#define U_NO_THROW U_NOEXCEPT
50#endif
51
52/*===========================================================================*/
53/* UClassID-based RTTI */
54/*===========================================================================*/
55
56/**
57 * UClassID is used to identify classes without using the compiler's RTTI.
58 * This was used before C++ compilers consistently supported RTTI.
59 * ICU 4.6 requires compiler RTTI to be turned on.
60 *
61 * Each class hierarchy which needs
62 * to implement polymorphic clone() or operator==() defines two methods,
63 * described in detail below. UClassID values can be compared using
64 * operator==(). Nothing else should be done with them.
65 *
66 * \par
67 * In class hierarchies that implement "poor man's RTTI",
68 * each concrete subclass implements getDynamicClassID() in the same way:
69 *
70 * \code
71 * class Derived {
72 * public:
73 * virtual UClassID getDynamicClassID() const
74 * { return Derived::getStaticClassID(); }
75 * }
76 * \endcode
77 *
78 * Each concrete class implements getStaticClassID() as well, which allows
79 * clients to test for a specific type.
80 *
81 * \code
82 * class Derived {
83 * public:
84 * static UClassID U_EXPORT2 getStaticClassID();
85 * private:
86 * static char fgClassID;
87 * }
88 *
89 * // In Derived.cpp:
90 * UClassID Derived::getStaticClassID()
91 * { return (UClassID)&Derived::fgClassID; }
92 * char Derived::fgClassID = 0; // Value is irrelevant
93 * \endcode
94 * @stable ICU 2.0
95 */
96typedef void* UClassID;
97
98U_NAMESPACE_BEGIN
99
100/**
101 * UMemory is the common ICU base class.
102 * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
103 *
104 * This is primarily to make it possible and simple to override the
105 * C++ memory management by adding new/delete operators to this base class.
106 *
107 * To override ALL ICU memory management, including that from plain C code,
108 * replace the allocation functions declared in cmemory.h
109 *
110 * UMemory does not contain any virtual functions.
111 * Common "boilerplate" functions are defined in UObject.
112 *
113 * @stable ICU 2.4
114 */
115class U_COMMON_API UMemory {
116public:
117
118/* test versions for debugging shaper heap memory problems */
119#ifdef SHAPER_MEMORY_DEBUG
120 static void * NewArray(int size, int count);
121 static void * GrowArray(void * array, int newSize );
122 static void FreeArray(void * array );
123#endif
124
125#if U_OVERRIDE_CXX_ALLOCATION
126 /**
127 * Override for ICU4C C++ memory management.
128 * simple, non-class types are allocated using the macros in common/cmemory.h
129 * (uprv_malloc(), uprv_free(), uprv_realloc());
130 * they or something else could be used here to implement C++ new/delete
131 * for ICU4C C++ classes
132 * @stable ICU 2.4
133 */
134 static void * U_EXPORT2 operator new(size_t size) U_NOEXCEPT;
135
136 /**
137 * Override for ICU4C C++ memory management.
138 * See new().
139 * @stable ICU 2.4
140 */
141 static void * U_EXPORT2 operator new[](size_t size) U_NOEXCEPT;
142
143 /**
144 * Override for ICU4C C++ memory management.
145 * simple, non-class types are allocated using the macros in common/cmemory.h
146 * (uprv_malloc(), uprv_free(), uprv_realloc());
147 * they or something else could be used here to implement C++ new/delete
148 * for ICU4C C++ classes
149 * @stable ICU 2.4
150 */
151 static void U_EXPORT2 operator delete(void *p) U_NOEXCEPT;
152
153 /**
154 * Override for ICU4C C++ memory management.
155 * See delete().
156 * @stable ICU 2.4
157 */
158 static void U_EXPORT2 operator delete[](void *p) U_NOEXCEPT;
159
160#if U_HAVE_PLACEMENT_NEW
161 /**
162 * Override for ICU4C C++ memory management for STL.
163 * See new().
164 * @stable ICU 2.6
165 */
166 static inline void * U_EXPORT2 operator new(size_t, void *ptr) U_NOEXCEPT { return ptr; }
167
168 /**
169 * Override for ICU4C C++ memory management for STL.
170 * See delete().
171 * @stable ICU 2.6
172 */
173 static inline void U_EXPORT2 operator delete(void *, void *) U_NOEXCEPT {}
174#endif /* U_HAVE_PLACEMENT_NEW */
175#if U_HAVE_DEBUG_LOCATION_NEW
176 /**
177 * This method overrides the MFC debug version of the operator new
178 *
179 * @param size The requested memory size
180 * @param file The file where the allocation was requested
181 * @param line The line where the allocation was requested
182 */
183 static void * U_EXPORT2 operator new(size_t size, const char* file, int line) U_NOEXCEPT;
184 /**
185 * This method provides a matching delete for the MFC debug new
186 *
187 * @param p The pointer to the allocated memory
188 * @param file The file where the allocation was requested
189 * @param line The line where the allocation was requested
190 */
191 static void U_EXPORT2 operator delete(void* p, const char* file, int line) U_NOEXCEPT;
192#endif /* U_HAVE_DEBUG_LOCATION_NEW */
193#endif /* U_OVERRIDE_CXX_ALLOCATION */
194
195 /*
196 * Assignment operator not declared. The compiler will provide one
197 * which does nothing since this class does not contain any data members.
198 * API/code coverage may show the assignment operator as present and
199 * untested - ignore.
200 * Subclasses need this assignment operator if they use compiler-provided
201 * assignment operators of their own. An alternative to not declaring one
202 * here would be to declare and empty-implement a protected or public one.
203 UMemory &UMemory::operator=(const UMemory &);
204 */
205};
206
207/**
208 * UObject is the common ICU "boilerplate" class.
209 * UObject inherits UMemory (starting with ICU 2.4),
210 * and all other public ICU C++ classes
211 * are derived from UObject (starting with ICU 2.2).
212 *
213 * UObject contains common virtual functions, in particular a virtual destructor.
214 *
215 * The clone() function is not available in UObject because it is not
216 * implemented by all ICU classes.
217 * Many ICU services provide a clone() function for their class trees,
218 * defined on the service's C++ base class
219 * (which itself is a subclass of UObject).
220 *
221 * @stable ICU 2.2
222 */
223class U_COMMON_API UObject : public UMemory {
224public:
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
243protected:
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
320U_NAMESPACE_END
321
322#endif /* U_SHOW_CPLUSPLUS_API */
323
324#endif
325