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