| Current File : //opt/alt/libicu/usr/include/unicode/uobject.h |
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
*
* Copyright (C) 2002-2012, International Business Machines
* Corporation and others. All Rights Reserved.
*
******************************************************************************
* file name: uobject.h
* encoding: UTF-8
* 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"
#include "unicode/platform.h"
/**
* \file
* \brief C++ API: Common ICU base class UObject.
*/
/**
* \def U_NO_THROW
* Since ICU 64, use U_NOEXCEPT instead.
*
* Previously, 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. Since ICU 64, Use U_NOEXCEPT instead. See ICU-20422.
*/
#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_NOEXCEPT;
/**
* Override for ICU4C C++ memory management.
* See new().
* @stable ICU 2.4
*/
static void * U_EXPORT2 operator new[](size_t size) U_NOEXCEPT;
/**
* 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_NOEXCEPT;
/**
* Override for ICU4C C++ memory management.
* See delete().
* @stable ICU 2.4
*/
static void U_EXPORT2 operator delete[](void *p) U_NOEXCEPT;
#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_NOEXCEPT { 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_NOEXCEPT {}
#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_NOEXCEPT;
/**
* 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_NOEXCEPT;
#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