icuSources/common/unicode/uobject.h

   1 /*
   2 ******************************************************************************
   3 *
   4 *   Copyright (C) 2002-2006, 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 /**  U_HAVE_PLACEMENT_NEW - Define this to define the placement new and
  44  *                          delete in UMemory for STL.
  45  *
  46  * @stable ICU 2.6
  47  */
  48 #ifndef U_HAVE_PLACEMENT_NEW
  49 #define U_HAVE_PLACEMENT_NEW 1
  50 #endif
  51
  52
  53 #ifndef U_HIDE_DRAFT_API
  54 /**  U_HAVE_DEBUG_LOCATION_NEW - Define this to define the MFC debug
  55  * version of the operator new.
  56  *
  57  * @draft ICU 3.4
  58  */
  59 #ifndef U_HAVE_DEBUG_LOCATION_NEW
  60 #define U_HAVE_DEBUG_LOCATION_NEW 0
  61 #endif
  62 #endif /*U_HIDE_DRAFT_API*/
  63
  64 /**
  65  * UMemory is the common ICU base class.
  66  * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
  67  *
  68  * This is primarily to make it possible and simple to override the
  69  * C++ memory management by adding new/delete operators to this base class.
  70  *
  71  * To override ALL ICU memory management, including that from plain C code,
  72  * replace the allocation functions declared in cmemory.h
  73  *
  74  * UMemory does not contain any virtual functions.
  75  * Common "boilerplate" functions are defined in UObject.
  76  *
  77  * @stable ICU 2.4
  78  */
  79 class U_COMMON_API UMemory {
  80 public:
  81
  82 #if U_OVERRIDE_CXX_ALLOCATION
  83     /**
  84      * Override for ICU4C C++ memory management.
  85      * simple, non-class types are allocated using the macros in common/cmemory.h
  86      * (uprv_malloc(), uprv_free(), uprv_realloc());
  87      * they or something else could be used here to implement C++ new/delete
  88      * for ICU4C C++ classes
  89      * @stable ICU 2.4
  90      */
  91     static void * U_EXPORT2 operator new(size_t size);
  92
  93     /**
  94      * Override for ICU4C C++ memory management.
  95      * See new().
  96      * @stable ICU 2.4
  97      */
  98     static void * U_EXPORT2 operator new[](size_t size);
  99
 100     /**
 101      * Override for ICU4C C++ memory management.
 102      * simple, non-class types are allocated using the macros in common/cmemory.h
 103      * (uprv_malloc(), uprv_free(), uprv_realloc());
 104      * they or something else could be used here to implement C++ new/delete
 105      * for ICU4C C++ classes
 106      * @stable ICU 2.4
 107      */
 108     static void U_EXPORT2 operator delete(void *p);
 109
 110     /**
 111      * Override for ICU4C C++ memory management.
 112      * See delete().
 113      * @stable ICU 2.4
 114      */
 115     static void U_EXPORT2 operator delete[](void *p);
 116
 117 #if U_HAVE_PLACEMENT_NEW
 118     /**
 119      * Override for ICU4C C++ memory management for STL.
 120      * See new().
 121      * @stable ICU 2.6
 122      */
 123     static inline void * U_EXPORT2 operator new(size_t, void *ptr) { return ptr; }
 124
 125     /**
 126      * Override for ICU4C C++ memory management for STL.
 127      * See delete().
 128      * @stable ICU 2.6
 129      */
 130     static inline void U_EXPORT2 operator delete(void *, void *) {}
 131 #endif /* U_HAVE_PLACEMENT_NEW */
 132 #if U_HAVE_DEBUG_LOCATION_NEW
 133     /**
 134       * This method overrides the MFC debug version of the operator new
 135       *
 136       * @param size   The requested memory size
 137       * @param file   The file where the allocation was requested
 138       * @param line   The line where the allocation was requested
 139       */
 140     static void * U_EXPORT2 operator new(size_t size, const char* file, int line);
 141     /**
 142       * This method provides a matching delete for the MFC debug new
 143       *
 144       * @param p      The pointer to the allocated memory
 145       * @param file   The file where the allocation was requested
 146       * @param line   The line where the allocation was requested
 147       */
 148     static void U_EXPORT2 operator delete(void* p, const char* file, int line);
 149 #endif /* U_HAVE_DEBUG_LOCATION_NEW */
 150 #endif /* U_OVERRIDE_CXX_ALLOCATION */
 151
 152     /*
 153      * Assignment operator not declared. The compiler will provide one
 154      * which does nothing since this class does not contain any data members.
 155      * API/code coverage may show the assignment operator as present and
 156      * untested - ignore.
 157      * Subclasses need this assignment operator if they use compiler-provided
 158      * assignment operators of their own. An alternative to not declaring one
 159      * here would be to declare and empty-implement a protected or public one.
 160     UMemory &UMemory::operator=(const UMemory &);
 161      */
 162 };
 163
 164 /**
 165  * UObject is the common ICU "boilerplate" class.
 166  * UObject inherits UMemory (starting with ICU 2.4),
 167  * and all other public ICU C++ classes
 168  * are derived from UObject (starting with ICU 2.2).
 169  *
 170  * UObject contains common virtual functions like for ICU's "poor man's RTTI".
 171  * It does not contain default implementations of virtual methods
 172  * like getDynamicClassID to allow derived classes such as Format
 173  * to declare these as pure virtual.
 174  *
 175  * The clone() function is not available in UObject because it is not
 176  * implemented by all ICU classes.
 177  * Many ICU services provide a clone() function for their class trees,
 178  * defined on the service's C++ base class, and all subclasses within that
 179  * service class tree return a pointer to the service base class
 180  * (which itself is a subclass of UObject).
 181  * This is because some compilers do not support covariant (same-as-this)
 182  * return types; cast to the appropriate subclass if necessary.
 183  *
 184  * @stable ICU 2.2
 185  */
 186 class U_COMMON_API UObject : public UMemory {
 187 public:
 188     /**
 189      * Destructor.
 190      *
 191      * @stable ICU 2.2
 192      */
 193     virtual ~UObject();
 194
 195     /**
 196      * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
 197      *
 198      * @stable ICU 2.2
 199      */
 200     virtual UClassID getDynamicClassID() const = 0;
 201
 202 protected:
 203     // the following functions are protected to prevent instantiation and
 204     // direct use of UObject itself
 205
 206     // default constructor
 207     // commented out because UObject is abstract (see getDynamicClassID)
 208     // inline UObject() {}
 209
 210     // copy constructor
 211     // commented out because UObject is abstract (see getDynamicClassID)
 212     // inline UObject(const UObject &other) {}
 213
 214 #if 0
 215     // TODO Sometime in the future. Implement operator==().
 216     // (This comment inserted in 2.2)
 217     // some or all of the following "boilerplate" functions may be made public
 218     // in a future ICU4C release when all subclasses implement them
 219
 220     // assignment operator
 221     // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
 222     // commented out because the implementation is the same as a compiler's default
 223     // UObject &operator=(const UObject &other) { return *this; }
 224
 225     // comparison operators
 226     virtual inline UBool operator==(const UObject &other) const { return this==&other; }
 227     inline UBool operator!=(const UObject &other) const { return !operator==(other); }
 228
 229     // clone() commented out from the base class:
 230     // some compilers do not support co-variant return types
 231     // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
 232     // see also UObject class documentation.
 233     // virtual UObject *clone() const;
 234 #endif
 235
 236     /*
 237      * Assignment operator not declared. The compiler will provide one
 238      * which does nothing since this class does not contain any data members.
 239      * API/code coverage may show the assignment operator as present and
 240      * untested - ignore.
 241      * Subclasses need this assignment operator if they use compiler-provided
 242      * assignment operators of their own. An alternative to not declaring one
 243      * here would be to declare and empty-implement a protected or public one.
 244     UObject &UObject::operator=(const UObject &);
 245      */
 246
 247 // Future implementation for RTTI that support subtyping. [alan]
 248 //
 249 //  public:
 250 //     /**
 251 //      * @internal
 252 //      */
 253 //     static UClassID getStaticClassID();
 254 //
 255 //     /**
 256 //      * @internal
 257 //      */
 258 //     UBool instanceOf(UClassID type) const;
 259 };
 260
 261 /**
 262  * This is a simple macro to add ICU RTTI to an ICU object implementation.
 263  * This does not go into the header. This should only be used in *.cpp files.
 264  *
 265  * @param myClass The name of the class that needs RTTI defined.
 266  * @internal
 267  */
 268 #define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
 269     UClassID U_EXPORT2 myClass::getStaticClassID() { \
 270         static char classID = 0; \
 271         return (UClassID)&classID; \
 272     } \
 273     UClassID myClass::getDynamicClassID() const \
 274     { return myClass::getStaticClassID(); }
 275
 276
 277 /**
 278  * This macro adds ICU RTTI to an ICU abstract class implementation.
 279  * This macro should be invoked in *.cpp files.  The corresponding
 280  * header should declare getStaticClassID.
 281  *
 282  * @param myClass The name of the class that needs RTTI defined.
 283  * @internal
 284  */
 285 #define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
 286     UClassID U_EXPORT2 myClass::getStaticClassID() { \
 287         static char classID = 0; \
 288         return (UClassID)&classID; \
 289     }
 290
 291 // /**
 292 //  * This macro adds ICU RTTI to an ICU concrete class implementation.
 293 //  * This macro should be invoked in *.cpp files.  The corresponding
 294 //  * header should declare getDynamicClassID and getStaticClassID.
 295 //  *
 296 //  * @param myClass The name of the class that needs RTTI defined.
 297 //  * @param myParent The name of the myClass's parent.
 298 //  * @internal
 299 //  */
 300 /*#define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass, myParent) \
 301     UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass, myParent) \
 302     UClassID myClass::getDynamicClassID() const { \
 303         return myClass::getStaticClassID(); \
 304     }
 305 */
 306
 307
 308 U_NAMESPACE_END
 309
 310 #endif