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