icuSources/common/unicode/uobject.h

   1 /*
   2 ******************************************************************************
   3 *
   4 *   Copyright (C) 2002-2007, 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 /**  U_HAVE_DEBUG_LOCATION_NEW - Define this to define the MFC debug
  54  * version of the operator new.
  55  *
  56  * @stable ICU 3.4
  57  */
  58 #ifndef U_HAVE_DEBUG_LOCATION_NEW
  59 #define U_HAVE_DEBUG_LOCATION_NEW 0
  60 #endif
  61
  62 /**
  63  * UMemory is the common ICU base class.
  64  * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
  65  *
  66  * This is primarily to make it possible and simple to override the
  67  * C++ memory management by adding new/delete operators to this base class.
  68  *
  69  * To override ALL ICU memory management, including that from plain C code,
  70  * replace the allocation functions declared in cmemory.h
  71  *
  72  * UMemory does not contain any virtual functions.
  73  * Common "boilerplate" functions are defined in UObject.
  74  *
  75  * @stable ICU 2.4
  76  */
  77 class U_COMMON_API UMemory {
  78 public:
  79
  80 #if U_OVERRIDE_CXX_ALLOCATION
  81     /**
  82      * Override for ICU4C C++ memory management.
  83      * simple, non-class types are allocated using the macros in common/cmemory.h
  84      * (uprv_malloc(), uprv_free(), uprv_realloc());
  85      * they or something else could be used here to implement C++ new/delete
  86      * for ICU4C C++ classes
  87      * @stable ICU 2.4
  88      */
  89     static void * U_EXPORT2 operator new(size_t size);
  90
  91     /**
  92      * Override for ICU4C C++ memory management.
  93      * See new().
  94      * @stable ICU 2.4
  95      */
  96     static void * U_EXPORT2 operator new[](size_t size);
  97
  98     /**
  99      * Override for ICU4C C++ memory management.
 100      * simple, non-class types are allocated using the macros in common/cmemory.h
 101      * (uprv_malloc(), uprv_free(), uprv_realloc());
 102      * they or something else could be used here to implement C++ new/delete
 103      * for ICU4C C++ classes
 104      * @stable ICU 2.4
 105      */
 106     static void U_EXPORT2 operator delete(void *p);
 107
 108     /**
 109      * Override for ICU4C C++ memory management.
 110      * See delete().
 111      * @stable ICU 2.4
 112      */
 113     static void U_EXPORT2 operator delete[](void *p);
 114
 115 #if U_HAVE_PLACEMENT_NEW
 116     /**
 117      * Override for ICU4C C++ memory management for STL.
 118      * See new().
 119      * @stable ICU 2.6
 120      */
 121     static inline void * U_EXPORT2 operator new(size_t, void *ptr) { return ptr; }
 122
 123     /**
 124      * Override for ICU4C C++ memory management for STL.
 125      * See delete().
 126      * @stable ICU 2.6
 127      */
 128     static inline void U_EXPORT2 operator delete(void *, void *) {}
 129 #endif /* U_HAVE_PLACEMENT_NEW */
 130 #if U_HAVE_DEBUG_LOCATION_NEW
 131     /**
 132       * This method overrides the MFC debug version of the operator new
 133       *
 134       * @param size   The requested memory size
 135       * @param file   The file where the allocation was requested
 136       * @param line   The line where the allocation was requested
 137       */
 138     static void * U_EXPORT2 operator new(size_t size, const char* file, int line);
 139     /**
 140       * This method provides a matching delete for the MFC debug new
 141       *
 142       * @param p      The pointer to the allocated memory
 143       * @param file   The file where the allocation was requested
 144       * @param line   The line where the allocation was requested
 145       */
 146     static void U_EXPORT2 operator delete(void* p, const char* file, int line);
 147 #endif /* U_HAVE_DEBUG_LOCATION_NEW */
 148 #endif /* U_OVERRIDE_CXX_ALLOCATION */
 149
 150     /*
 151      * Assignment operator not declared. The compiler will provide one
 152      * which does nothing since this class does not contain any data members.
 153      * API/code coverage may show the assignment operator as present and
 154      * untested - ignore.
 155      * Subclasses need this assignment operator if they use compiler-provided
 156      * assignment operators of their own. An alternative to not declaring one
 157      * here would be to declare and empty-implement a protected or public one.
 158     UMemory &UMemory::operator=(const UMemory &);
 159      */
 160 };
 161
 162 /**
 163  * UObject is the common ICU "boilerplate" class.
 164  * UObject inherits UMemory (starting with ICU 2.4),
 165  * and all other public ICU C++ classes
 166  * are derived from UObject (starting with ICU 2.2).
 167  *
 168  * UObject contains common virtual functions like for ICU's "poor man's RTTI".
 169  * It does not contain default implementations of virtual methods
 170  * like getDynamicClassID to allow derived classes such as Format
 171  * to declare these as pure virtual.
 172  *
 173  * The clone() function is not available in UObject because it is not
 174  * implemented by all ICU classes.
 175  * Many ICU services provide a clone() function for their class trees,
 176  * defined on the service's C++ base class, and all subclasses within that
 177  * service class tree return a pointer to the service base class
 178  * (which itself is a subclass of UObject).
 179  * This is because some compilers do not support covariant (same-as-this)
 180  * return types; cast to the appropriate subclass if necessary.
 181  *
 182  * @stable ICU 2.2
 183  */
 184 class U_COMMON_API UObject : public UMemory {
 185 public:
 186     /**
 187      * Destructor.
 188      *
 189      * @stable ICU 2.2
 190      */
 191     virtual ~UObject();
 192
 193     /**
 194      * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
 195      *
 196      * @stable ICU 2.2
 197      */
 198     virtual UClassID getDynamicClassID() const = 0;
 199
 200 protected:
 201     // the following functions are protected to prevent instantiation and
 202     // direct use of UObject itself
 203
 204     // default constructor
 205     // commented out because UObject is abstract (see getDynamicClassID)
 206     // inline UObject() {}
 207
 208     // copy constructor
 209     // commented out because UObject is abstract (see getDynamicClassID)
 210     // inline UObject(const UObject &other) {}
 211
 212 #if 0
 213     // TODO Sometime in the future. Implement operator==().
 214     // (This comment inserted in 2.2)
 215     // some or all of the following "boilerplate" functions may be made public
 216     // in a future ICU4C release when all subclasses implement them
 217
 218     // assignment operator
 219     // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
 220     // commented out because the implementation is the same as a compiler's default
 221     // UObject &operator=(const UObject &other) { return *this; }
 222
 223     // comparison operators
 224     virtual inline UBool operator==(const UObject &other) const { return this==&other; }
 225     inline UBool operator!=(const UObject &other) const { return !operator==(other); }
 226
 227     // clone() commented out from the base class:
 228     // some compilers do not support co-variant return types
 229     // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
 230     // see also UObject class documentation.
 231     // virtual UObject *clone() const;
 232 #endif
 233
 234     /*
 235      * Assignment operator not declared. The compiler will provide one
 236      * which does nothing since this class does not contain any data members.
 237      * API/code coverage may show the assignment operator as present and
 238      * untested - ignore.
 239      * Subclasses need this assignment operator if they use compiler-provided
 240      * assignment operators of their own. An alternative to not declaring one
 241      * here would be to declare and empty-implement a protected or public one.
 242     UObject &UObject::operator=(const UObject &);
 243      */
 244
 245 // Future implementation for RTTI that support subtyping. [alan]
 246 //
 247 //  public:
 248 //     /**
 249 //      * @internal
 250 //      */
 251 //     static UClassID getStaticClassID();
 252 //
 253 //     /**
 254 //      * @internal
 255 //      */
 256 //     UBool instanceOf(UClassID type) const;
 257 };
 258
 259 /**
 260  * This is a simple macro to add ICU RTTI to an ICU object implementation.
 261  * This does not go into the header. This should only be used in *.cpp files.
 262  *
 263  * @param myClass The name of the class that needs RTTI defined.
 264  * @internal
 265  */
 266 #define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
 267     UClassID U_EXPORT2 myClass::getStaticClassID() { \
 268         static char classID = 0; \
 269         return (UClassID)&classID; \
 270     } \
 271     UClassID myClass::getDynamicClassID() const \
 272     { return myClass::getStaticClassID(); }
 273
 274
 275 /**
 276  * This macro adds ICU RTTI to an ICU abstract class implementation.
 277  * This macro should be invoked in *.cpp files.  The corresponding
 278  * header should declare getStaticClassID.
 279  *
 280  * @param myClass The name of the class that needs RTTI defined.
 281  * @internal
 282  */
 283 #define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
 284     UClassID U_EXPORT2 myClass::getStaticClassID() { \
 285         static char classID = 0; \
 286         return (UClassID)&classID; \
 287     }
 288
 289 // /**
 290 //  * This macro adds ICU RTTI to an ICU concrete class implementation.
 291 //  * This macro should be invoked in *.cpp files.  The corresponding
 292 //  * header should declare getDynamicClassID and getStaticClassID.
 293 //  *
 294 //  * @param myClass The name of the class that needs RTTI defined.
 295 //  * @param myParent The name of the myClass's parent.
 296 //  * @internal
 297 //  */
 298 /*#define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass, myParent) \
 299     UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass, myParent) \
 300     UClassID myClass::getDynamicClassID() const { \
 301         return myClass::getStaticClassID(); \
 302     }
 303 */
 304
 305
 306 U_NAMESPACE_END
 307
 308 #endif