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 * getDynamicClassID() is declared in the base class of the hierarchy as 63 * a pure virtual. Each concrete subclass implements it in the same way: 64 * 65 * \code 66 * class Base { 67 * public: 68 * virtual UClassID getDynamicClassID() const = 0; 69 * } 70 * 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 */ 96 typedef void* UClassID; 97 98 U_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 */ 115 class U_COMMON_API UMemory { 116 public: 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_NO_THROW; 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_NO_THROW; 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_NO_THROW; 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_NO_THROW; 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_NO_THROW { 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_NO_THROW {} 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_NO_THROW; 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_NO_THROW; 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 like for ICU's "poor man's RTTI". 214 * It does not contain default implementations of virtual methods 215 * like getDynamicClassID to allow derived classes such as Format 216 * to declare these as pure virtual. 217 * 218 * The clone() function is not available in UObject because it is not 219 * implemented by all ICU classes. 220 * Many ICU services provide a clone() function for their class trees, 221 * defined on the service's C++ base class, and all subclasses within that 222 * service class tree return a pointer to the service base class 223 * (which itself is a subclass of UObject). 224 * This is because some compilers do not support covariant (same-as-this) 225 * return types; cast to the appropriate subclass if necessary. 226 * 227 * @stable ICU 2.2 228 */ 229 class U_COMMON_API UObject : public UMemory { 230 public: 231 /** 232 * Destructor. 233 * 234 * @stable ICU 2.2 235 */ 236 virtual ~UObject(); 237 238 /** 239 * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class. 240 * 241 * @stable ICU 2.2 242 */ 243 virtual UClassID getDynamicClassID() const; // Android patch: tiny part of ICU 51's r32776 244 245 protected: 246 // the following functions are protected to prevent instantiation and 247 // direct use of UObject itself 248 249 // default constructor 250 // commented out because UObject is abstract (see getDynamicClassID) 251 // inline UObject() {} 252 253 // copy constructor 254 // commented out because UObject is abstract (see getDynamicClassID) 255 // inline UObject(const UObject &other) {} 256 257 #if 0 258 // TODO Sometime in the future. Implement operator==(). 259 // (This comment inserted in 2.2) 260 // some or all of the following "boilerplate" functions may be made public 261 // in a future ICU4C release when all subclasses implement them 262 263 // assignment operator 264 // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74) 265 // commented out because the implementation is the same as a compiler's default 266 // UObject &operator=(const UObject &other) { return *this; } 267 268 // comparison operators 269 virtual inline UBool operator==(const UObject &other) const { return this==&other; } 270 inline UBool operator!=(const UObject &other) const { return !operator==(other); } 271 272 // clone() commented out from the base class: 273 // some compilers do not support co-variant return types 274 // (i.e., subclasses would have to return UObject * as well, instead of SubClass *) 275 // see also UObject class documentation. 276 // virtual UObject *clone() const; 277 #endif 278 279 /* 280 * Assignment operator not declared. The compiler will provide one 281 * which does nothing since this class does not contain any data members. 282 * API/code coverage may show the assignment operator as present and 283 * untested - ignore. 284 * Subclasses need this assignment operator if they use compiler-provided 285 * assignment operators of their own. An alternative to not declaring one 286 * here would be to declare and empty-implement a protected or public one. 287 UObject &UObject::operator=(const UObject &); 288 */ 289 290 // Future implementation for RTTI that support subtyping. [alan] 291 // 292 // public: 293 // /** 294 // * @internal 295 // */ 296 // static UClassID getStaticClassID(); 297 // 298 // /** 299 // * @internal 300 // */ 301 // UBool instanceOf(UClassID type) const; 302 }; 303 304 #ifndef U_HIDE_INTERNAL_API 305 /** 306 * This is a simple macro to add ICU RTTI to an ICU object implementation. 307 * This does not go into the header. This should only be used in *.cpp files. 308 * 309 * @param myClass The name of the class that needs RTTI defined. 310 * @internal 311 */ 312 #define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \ 313 UClassID U_EXPORT2 myClass::getStaticClassID() { \ 314 static char classID = 0; \ 315 return (UClassID)&classID; \ 316 } \ 317 UClassID myClass::getDynamicClassID() const \ 318 { return myClass::getStaticClassID(); } 319 320 321 /** 322 * This macro adds ICU RTTI to an ICU abstract class implementation. 323 * This macro should be invoked in *.cpp files. The corresponding 324 * header should declare getStaticClassID. 325 * 326 * @param myClass The name of the class that needs RTTI defined. 327 * @internal 328 */ 329 #define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \ 330 UClassID U_EXPORT2 myClass::getStaticClassID() { \ 331 static char classID = 0; \ 332 return (UClassID)&classID; \ 333 } 334 335 /** 336 * This is a simple macro to express that a class and its subclasses do not offer 337 * ICU's "poor man's RTTI". 338 * Beginning with ICU 4.6, ICU requires C++ compiler RTTI. 339 * This does not go into the header. This should only be used in *.cpp files. 340 * Use this with a private getDynamicClassID() in an immediate subclass of UObject. 341 * 342 * @param myClass The name of the class that needs RTTI defined. 343 * @internal 344 */ 345 #define UOBJECT_DEFINE_NO_RTTI_IMPLEMENTATION(myClass) \ 346 UClassID myClass::getDynamicClassID() const { return NULL; } 347 348 // /** 349 // * This macro adds ICU RTTI to an ICU concrete class implementation. 350 // * This macro should be invoked in *.cpp files. The corresponding 351 // * header should declare getDynamicClassID and getStaticClassID. 352 // * 353 // * @param myClass The name of the class that needs RTTI defined. 354 // * @param myParent The name of the myClass's parent. 355 // * @internal 356 // */ 357 /*#define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass, myParent) \ 358 UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass, myParent) \ 359 UClassID myClass::getDynamicClassID() const { \ 360 return myClass::getStaticClassID(); \ 361 } 362 */ 363 #endif /* U_HIDE_INTERNAL_API */ 364 365 U_NAMESPACE_END 366 367 #endif 368