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 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 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 323