icuSources/common/unicode/uobject.h

   1 /*
   2 ******************************************************************************
   3 *
   4 *   Copyright (C) 2002-2010, 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 U_NAMESPACE_BEGIN
  23
  24 /**
  25  * \file
  26  * \brief C++ API: Common ICU base class UObject.
  27  */
  28
  29 /**  U_OVERRIDE_CXX_ALLOCATION - Define this to override operator new and
  30  *                               delete in UMemory. Enabled by default for ICU.
  31  *
  32  *         Enabling forces all allocation of ICU object types to use ICU's
  33  *         memory allocation. On Windows, this allows the ICU DLL to be used by
  34  *         applications that statically link the C Runtime library, meaning that
  35  *         the app and ICU will be using different heaps.
  36  *
  37  * @stable ICU 2.2
  38  */
  39 #ifndef U_OVERRIDE_CXX_ALLOCATION
  40 #define U_OVERRIDE_CXX_ALLOCATION 1
  41 #endif
  42
  43 /**
  44  * \def U_HAVE_PLACEMENT_NEW
  45  *  Define this to define the placement new and
  46  *                          delete in UMemory for STL.
  47  *
  48  * @stable ICU 2.6
  49  */
  50 #ifndef U_HAVE_PLACEMENT_NEW
  51 #define U_HAVE_PLACEMENT_NEW 1
  52 #endif
  53
  54
  55 /**
  56  * \def U_HAVE_DEBUG_LOCATION_NEW
  57  * Define this to define the MFC debug
  58  * version of the operator new.
  59  *
  60  * @stable ICU 3.4
  61  */
  62 #ifndef U_HAVE_DEBUG_LOCATION_NEW
  63 #define U_HAVE_DEBUG_LOCATION_NEW 0
  64 #endif
  65
  66 /**
  67  * @{
  68  * \def U_NO_THROW
  69  *         Define this to define the throw() specification so
  70  *                 certain functions do not throw any exceptions
  71  *
  72  *         UMemory operator new methods should have the throw() specification
  73  *         appended to them, so that the compiler adds the additional NULL check
  74  *         before calling constructors. Without, if <code>operator new</code> returns NULL the
  75  *         constructor is still called, and if the constructor references member
  76  *         data, (which it typically does), the result is a segmentation violation.
  77  *
  78  * @draft ICU 4.2
  79  */
  80 #ifndef U_NO_THROW
  81 #define U_NO_THROW throw()
  82 #endif
  83
  84 /** @} */
  85
  86 /**
  87  * UMemory is the common ICU base class.
  88  * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
  89  *
  90  * This is primarily to make it possible and simple to override the
  91  * C++ memory management by adding new/delete operators to this base class.
  92  *
  93  * To override ALL ICU memory management, including that from plain C code,
  94  * replace the allocation functions declared in cmemory.h
  95  *
  96  * UMemory does not contain any virtual functions.
  97  * Common "boilerplate" functions are defined in UObject.
  98  *
  99  * @stable ICU 2.4
 100  */
 101 class U_COMMON_API UMemory {
 102 public:
 103
 104 /* test versions for debugging shaper heap memory problems */
 105 #ifdef SHAPER_MEMORY_DEBUG
 106     static void * NewArray(int size, int count);
 107     static void * GrowArray(void * array, int newSize );
 108     static void   FreeArray(void * array );
 109 #endif
 110
 111 #if U_OVERRIDE_CXX_ALLOCATION
 112     /**
 113      * Override for ICU4C C++ memory management.
 114      * simple, non-class types are allocated using the macros in common/cmemory.h
 115      * (uprv_malloc(), uprv_free(), uprv_realloc());
 116      * they or something else could be used here to implement C++ new/delete
 117      * for ICU4C C++ classes
 118      * @stable ICU 2.4
 119      */
 120     static void * U_EXPORT2 operator new(size_t size) U_NO_THROW;
 121
 122     /**
 123      * Override for ICU4C C++ memory management.
 124      * See new().
 125      * @stable ICU 2.4
 126      */
 127     static void * U_EXPORT2 operator new[](size_t size) U_NO_THROW;
 128
 129     /**
 130      * Override for ICU4C C++ memory management.
 131      * simple, non-class types are allocated using the macros in common/cmemory.h
 132      * (uprv_malloc(), uprv_free(), uprv_realloc());
 133      * they or something else could be used here to implement C++ new/delete
 134      * for ICU4C C++ classes
 135      * @stable ICU 2.4
 136      */
 137     static void U_EXPORT2 operator delete(void *p) U_NO_THROW;
 138
 139     /**
 140      * Override for ICU4C C++ memory management.
 141      * See delete().
 142      * @stable ICU 2.4
 143      */
 144     static void U_EXPORT2 operator delete[](void *p) U_NO_THROW;
 145
 146 #if U_HAVE_PLACEMENT_NEW
 147     /**
 148      * Override for ICU4C C++ memory management for STL.
 149      * See new().
 150      * @stable ICU 2.6
 151      */
 152     static inline void * U_EXPORT2 operator new(size_t, void *ptr) U_NO_THROW { return ptr; }
 153
 154     /**
 155      * Override for ICU4C C++ memory management for STL.
 156      * See delete().
 157      * @stable ICU 2.6
 158      */
 159     static inline void U_EXPORT2 operator delete(void *, void *) U_NO_THROW {}
 160 #endif /* U_HAVE_PLACEMENT_NEW */
 161 #if U_HAVE_DEBUG_LOCATION_NEW
 162     /**
 163       * This method overrides the MFC debug version of the operator new
 164       *
 165       * @param size   The requested memory size
 166       * @param file   The file where the allocation was requested
 167       * @param line   The line where the allocation was requested
 168       */
 169     static void * U_EXPORT2 operator new(size_t size, const char* file, int line) U_NO_THROW;
 170     /**
 171       * This method provides a matching delete for the MFC debug new
 172       *
 173       * @param p      The pointer to the allocated memory
 174       * @param file   The file where the allocation was requested
 175       * @param line   The line where the allocation was requested
 176       */
 177     static void U_EXPORT2 operator delete(void* p, const char* file, int line) U_NO_THROW;
 178 #endif /* U_HAVE_DEBUG_LOCATION_NEW */
 179 #endif /* U_OVERRIDE_CXX_ALLOCATION */
 180
 181     /*
 182      * Assignment operator not declared. The compiler will provide one
 183      * which does nothing since this class does not contain any data members.
 184      * API/code coverage may show the assignment operator as present and
 185      * untested - ignore.
 186      * Subclasses need this assignment operator if they use compiler-provided
 187      * assignment operators of their own. An alternative to not declaring one
 188      * here would be to declare and empty-implement a protected or public one.
 189     UMemory &UMemory::operator=(const UMemory &);
 190      */
 191 };
 192
 193 /**
 194  * UObject is the common ICU "boilerplate" class.
 195  * UObject inherits UMemory (starting with ICU 2.4),
 196  * and all other public ICU C++ classes
 197  * are derived from UObject (starting with ICU 2.2).
 198  *
 199  * UObject contains common virtual functions like for ICU's "poor man's RTTI".
 200  * It does not contain default implementations of virtual methods
 201  * like getDynamicClassID to allow derived classes such as Format
 202  * to declare these as pure virtual.
 203  *
 204  * The clone() function is not available in UObject because it is not
 205  * implemented by all ICU classes.
 206  * Many ICU services provide a clone() function for their class trees,
 207  * defined on the service's C++ base class, and all subclasses within that
 208  * service class tree return a pointer to the service base class
 209  * (which itself is a subclass of UObject).
 210  * This is because some compilers do not support covariant (same-as-this)
 211  * return types; cast to the appropriate subclass if necessary.
 212  *
 213  * @stable ICU 2.2
 214  */
 215 class U_COMMON_API UObject : public UMemory {
 216 public:
 217     /**
 218      * Destructor.
 219      *
 220      * @stable ICU 2.2
 221      */
 222     virtual ~UObject();
 223
 224     /**
 225      * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
 226      *
 227      * @stable ICU 2.2
 228      */
 229     virtual UClassID getDynamicClassID() const = 0;
 230
 231 protected:
 232     // the following functions are protected to prevent instantiation and
 233     // direct use of UObject itself
 234
 235     // default constructor
 236     // commented out because UObject is abstract (see getDynamicClassID)
 237     // inline UObject() {}
 238
 239     // copy constructor
 240     // commented out because UObject is abstract (see getDynamicClassID)
 241     // inline UObject(const UObject &other) {}
 242
 243 #if 0
 244     // TODO Sometime in the future. Implement operator==().
 245     // (This comment inserted in 2.2)
 246     // some or all of the following "boilerplate" functions may be made public
 247     // in a future ICU4C release when all subclasses implement them
 248
 249     // assignment operator
 250     // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
 251     // commented out because the implementation is the same as a compiler's default
 252     // UObject &operator=(const UObject &other) { return *this; }
 253
 254     // comparison operators
 255     virtual inline UBool operator==(const UObject &other) const { return this==&other; }
 256     inline UBool operator!=(const UObject &other) const { return !operator==(other); }
 257
 258     // clone() commented out from the base class:
 259     // some compilers do not support co-variant return types
 260     // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
 261     // see also UObject class documentation.
 262     // virtual UObject *clone() const;
 263 #endif
 264
 265     /*
 266      * Assignment operator not declared. The compiler will provide one
 267      * which does nothing since this class does not contain any data members.
 268      * API/code coverage may show the assignment operator as present and
 269      * untested - ignore.
 270      * Subclasses need this assignment operator if they use compiler-provided
 271      * assignment operators of their own. An alternative to not declaring one
 272      * here would be to declare and empty-implement a protected or public one.
 273     UObject &UObject::operator=(const UObject &);
 274      */
 275
 276 // Future implementation for RTTI that support subtyping. [alan]
 277 //
 278 //  public:
 279 //     /**
 280 //      * @internal
 281 //      */
 282 //     static UClassID getStaticClassID();
 283 //
 284 //     /**
 285 //      * @internal
 286 //      */
 287 //     UBool instanceOf(UClassID type) const;
 288 };
 289
 290 /**
 291  * This is a simple macro to add ICU RTTI to an ICU object implementation.
 292  * This does not go into the header. This should only be used in *.cpp files.
 293  *
 294  * @param myClass The name of the class that needs RTTI defined.
 295  * @internal
 296  */
 297 #define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
 298     UClassID U_EXPORT2 myClass::getStaticClassID() { \
 299         static char classID = 0; \
 300         return (UClassID)&classID; \
 301     } \
 302     UClassID myClass::getDynamicClassID() const \
 303     { return myClass::getStaticClassID(); }
 304
 305
 306 /**
 307  * This macro adds ICU RTTI to an ICU abstract class implementation.
 308  * This macro should be invoked in *.cpp files.  The corresponding
 309  * header should declare getStaticClassID.
 310  *
 311  * @param myClass The name of the class that needs RTTI defined.
 312  * @internal
 313  */
 314 #define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
 315     UClassID U_EXPORT2 myClass::getStaticClassID() { \
 316         static char classID = 0; \
 317         return (UClassID)&classID; \
 318     }
 319
 320 /**
 321  * This is a simple macro to express that a class and its subclasses do not offer
 322  * ICU's "poor man's RTTI".
 323  * Beginning with ICU 4.6, ICU requires C++ compiler RTTI.
 324  * This does not go into the header. This should only be used in *.cpp files.
 325  * Use this with a private getDynamicClassID() in an immediate subclass of UObject.
 326  *
 327  * @param myClass The name of the class that needs RTTI defined.
 328  * @internal
 329  */
 330 #define UOBJECT_DEFINE_NO_RTTI_IMPLEMENTATION(myClass) \
 331     UClassID myClass::getDynamicClassID() const { return NULL; }
 332
 333 // /**
 334 //  * This macro adds ICU RTTI to an ICU concrete class implementation.
 335 //  * This macro should be invoked in *.cpp files.  The corresponding
 336 //  * header should declare getDynamicClassID and getStaticClassID.
 337 //  *
 338 //  * @param myClass The name of the class that needs RTTI defined.
 339 //  * @param myParent The name of the myClass's parent.
 340 //  * @internal
 341 //  */
 342 /*#define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass, myParent) \
 343     UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass, myParent) \
 344     UClassID myClass::getDynamicClassID() const { \
 345         return myClass::getStaticClassID(); \
 346     }
 347 */
 348
 349
 350 U_NAMESPACE_END
 351
 352 #endif