text: /*
  ******************************************************************************
  *
  *   Copyright (C) 2002-2012, International Business Machines
  *   Corporation and others.  All Rights Reserved.
  *
  ******************************************************************************
  *   file name:  uobject.h
  *   encoding:   US-ASCII
  *   tab size:   8 (not used)
  *   indentation:4
  *
  *   created on: 2002jun26
  *   created by: Markus W. Scherer
  */
  
  #ifndef __UOBJECT_H__
  #define __UOBJECT_H__
  
  #include "unicode/utypes.h"
  
  /**
   * \file
   * \brief C++ API: Common ICU base class UObject.
   */
  
  /**
   * @{
   * \def U_NO_THROW
   *         Define this to define the throw() specification so
   *                 certain functions do not throw any exceptions
   *
   *         UMemory operator new methods should have the throw() specification
   *         appended to them, so that the compiler adds the additional NULL check
   *         before calling constructors. Without, if <code>operator new</code> returns NULL the
   *         constructor is still called, and if the constructor references member
   *         data, (which it typically does), the result is a segmentation violation.
   *
   * @stable ICU 4.2
   */
  #ifndef U_NO_THROW
  #define U_NO_THROW throw()
  #endif
  
  /** @} */
  
  /*===========================================================================*/
  /* UClassID-based RTTI */
  /*===========================================================================*/
  
  /**
   * UClassID is used to identify classes without using the compiler's RTTI.
   * This was used before C++ compilers consistently supported RTTI.
   * ICU 4.6 requires compiler RTTI to be turned on.
   *
   * Each class hierarchy which needs
   * to implement polymorphic clone() or operator==() defines two methods,
   * described in detail below.  UClassID values can be compared using
   * operator==(). Nothing else should be done with them.
   *
   * \par
   * In class hierarchies that implement "poor man's RTTI",
   * each concrete subclass implements getDynamicClassID() in the same way:
   *
   * \code
   *      class Derived {
   *      public:
   *          virtual UClassID getDynamicClassID() const
   *            { return Derived::getStaticClassID(); }
   *      }
   * \endcode
   *
   * Each concrete class implements getStaticClassID() as well, which allows
   * clients to test for a specific type.
   *
   * \code
   *      class Derived {
   *      public:
   *          static UClassID U_EXPORT2 getStaticClassID();
   *      private:
   *          static char fgClassID;
   *      }
   *
   *      // In Derived.cpp:
   *      UClassID Derived::getStaticClassID()
   *        { return (UClassID)&Derived::fgClassID; }
   *      char Derived::fgClassID = 0; // Value is irrelevant
   * \endcode
   * @stable ICU 2.0
   */
  typedef void* UClassID;
  
  U_NAMESPACE_BEGIN
  
  /**
   * UMemory is the common ICU base class.
   * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
   *
   * This is primarily to make it possible and simple to override the
   * C++ memory management by adding new/delete operators to this base class.
   *
   * To override ALL ICU memory management, including that from plain C code,
   * replace the allocation functions declared in cmemory.h
   *
   * UMemory does not contain any virtual functions.
   * Common "boilerplate" functions are defined in UObject.
   *
   * @stable ICU 2.4
   */
  class U_COMMON_API UMemory {
  public:
  
  /* test versions for debugging shaper heap memory problems */
  #ifdef SHAPER_MEMORY_DEBUG
      static void * NewArray(int size, int count);
      static void * GrowArray(void * array, int newSize );
      static void   FreeArray(void * array );
  #endif
  
  #if U_OVERRIDE_CXX_ALLOCATION
      /**
       * Override for ICU4C C++ memory management.
       * simple, non-class types are allocated using the macros in common/cmemory.h
       * (uprv_malloc(), uprv_free(), uprv_realloc());
       * they or something else could be used here to implement C++ new/delete
       * for ICU4C C++ classes
       * @stable ICU 2.4
       */
      static void * U_EXPORT2 operator new(size_t size) U_NO_THROW;
  
      /**
       * Override for ICU4C C++ memory management.
       * See new().
       * @stable ICU 2.4
       */
      static void * U_EXPORT2 operator new[](size_t size) U_NO_THROW;
  
      /**
       * Override for ICU4C C++ memory management.
       * simple, non-class types are allocated using the macros in common/cmemory.h
       * (uprv_malloc(), uprv_free(), uprv_realloc());
       * they or something else could be used here to implement C++ new/delete
       * for ICU4C C++ classes
       * @stable ICU 2.4
       */
      static void U_EXPORT2 operator delete(void *p) U_NO_THROW;
  
      /**
       * Override for ICU4C C++ memory management.
       * See delete().
       * @stable ICU 2.4
       */
      static void U_EXPORT2 operator delete[](void *p) U_NO_THROW;
  
  #if U_HAVE_PLACEMENT_NEW
      /**
       * Override for ICU4C C++ memory management for STL.
       * See new().
       * @stable ICU 2.6
       */
      static inline void * U_EXPORT2 operator new(size_t, void *ptr) U_NO_THROW { return ptr; }
  
      /**
       * Override for ICU4C C++ memory management for STL.
       * See delete().
       * @stable ICU 2.6
       */
      static inline void U_EXPORT2 operator delete(void *, void *) U_NO_THROW {}
  #endif /* U_HAVE_PLACEMENT_NEW */
  #if U_HAVE_DEBUG_LOCATION_NEW
      /**
        * This method overrides the MFC debug version of the operator new
        *
        * @param size   The requested memory size
        * @param file   The file where the allocation was requested
        * @param line   The line where the allocation was requested
        */
      static void * U_EXPORT2 operator new(size_t size, const char* file, int line) U_NO_THROW;
      /**
        * This method provides a matching delete for the MFC debug new
        *
        * @param p      The pointer to the allocated memory
        * @param file   The file where the allocation was requested
        * @param line   The line where the allocation was requested
        */
      static void U_EXPORT2 operator delete(void* p, const char* file, int line) U_NO_THROW;
  #endif /* U_HAVE_DEBUG_LOCATION_NEW */
  #endif /* U_OVERRIDE_CXX_ALLOCATION */
  
      /*
       * Assignment operator not declared. The compiler will provide one
       * which does nothing since this class does not contain any data members.
       * API/code coverage may show the assignment operator as present and
       * untested - ignore.
       * Subclasses need this assignment operator if they use compiler-provided
       * assignment operators of their own. An alternative to not declaring one
       * here would be to declare and empty-implement a protected or public one.
      UMemory &UMemory::operator=(const UMemory &);
       */
  };
  
  /**
   * UObject is the common ICU "boilerplate" class.
   * UObject inherits UMemory (starting with ICU 2.4),
   * and all other public ICU C++ classes
   * are derived from UObject (starting with ICU 2.2).
   *
   * UObject contains common virtual functions, in particular a virtual destructor.
   *
   * The clone() function is not available in UObject because it is not
   * implemented by all ICU classes.
   * Many ICU services provide a clone() function for their class trees,
   * defined on the service's C++ base class, and all subclasses within that
   * service class tree return a pointer to the service base class
   * (which itself is a subclass of UObject).
   * This is because some compilers do not support covariant (same-as-this)
   * return types; cast to the appropriate subclass if necessary.
   *
   * @stable ICU 2.2
   */
  class U_COMMON_API UObject : public UMemory {
  public:
      /**
       * Destructor.
       *
       * @stable ICU 2.2
       */
      virtual ~UObject();
  
      /**
       * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
       * The base class implementation returns a dummy value.
       *
       * Use compiler RTTI rather than ICU's "poor man's RTTI".
       * Since ICU 4.6, new ICU C++ class hierarchies do not implement "poor man's RTTI".
       *
       * @stable ICU 2.2
       */
      virtual UClassID getDynamicClassID() const;
  
  protected:
      // the following functions are protected to prevent instantiation and
      // direct use of UObject itself
  
      // default constructor
      // inline UObject() {}
  
      // copy constructor
      // inline UObject(const UObject &other) {}
  
  #if 0
      // TODO Sometime in the future. Implement operator==().
      // (This comment inserted in 2.2)
      // some or all of the following "boilerplate" functions may be made public
      // in a future ICU4C release when all subclasses implement them
  
      // assignment operator
      // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
      // commented out because the implementation is the same as a compiler's default
      // UObject &operator=(const UObject &other) { return *this; }
  
      // comparison operators
      virtual inline UBool operator==(const UObject &other) const { return this==&other; }
      inline UBool operator!=(const UObject &other) const { return !operator==(other); }
  
      // clone() commented out from the base class:
      // some compilers do not support co-variant return types
      // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
      // see also UObject class documentation.
      // virtual UObject *clone() const;
  #endif
  
      /*
       * Assignment operator not declared. The compiler will provide one
       * which does nothing since this class does not contain any data members.
       * API/code coverage may show the assignment operator as present and
       * untested - ignore.
       * Subclasses need this assignment operator if they use compiler-provided
       * assignment operators of their own. An alternative to not declaring one
       * here would be to declare and empty-implement a protected or public one.
      UObject &UObject::operator=(const UObject &);
       */
  };
  
  #ifndef U_HIDE_INTERNAL_API
  /**
   * This is a simple macro to add ICU RTTI to an ICU object implementation.
   * This does not go into the header. This should only be used in *.cpp files.
   *
   * @param myClass The name of the class that needs RTTI defined.
   * @internal
   */
  #define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
      UClassID U_EXPORT2 myClass::getStaticClassID() { \
          static char classID = 0; \
          return (UClassID)&classID; \
      } \
      UClassID myClass::getDynamicClassID() const \
      { return myClass::getStaticClassID(); }
  
  
  /**
   * This macro adds ICU RTTI to an ICU abstract class implementation.
   * This macro should be invoked in *.cpp files.  The corresponding
   * header should declare getStaticClassID.
   *
   * @param myClass The name of the class that needs RTTI defined.
   * @internal
   */
  #define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
      UClassID U_EXPORT2 myClass::getStaticClassID() { \
          static char classID = 0; \
          return (UClassID)&classID; \
      }
  
  #endif  /* U_HIDE_INTERNAL_API */
  
  U_NAMESPACE_END
  
  #endif
  