1/*
2******************************************************************************
3*
4*   Copyright (C) 2002-2012, 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/**
23 * \file
24 * \brief C++ API: Common ICU base class UObject.
25 */
26
27/**
28 * @{
29 * \def U_NO_THROW
30 *         Define this to define the throw() specification so
31 *                 certain functions do not throw any exceptions
32 *
33 *         UMemory operator new methods should have the throw() specification
34 *         appended to them, so that the compiler adds the additional NULL check
35 *         before calling constructors. Without, if <code>operator new</code> returns NULL the
36 *         constructor is still called, and if the constructor references member
37 *         data, (which it typically does), the result is a segmentation violation.
38 *
39 * @stable ICU 4.2
40 */
41#ifndef U_NO_THROW
42#define U_NO_THROW throw()
43#endif
44
45/** @} */
46
47/*===========================================================================*/
48/* UClassID-based RTTI */
49/*===========================================================================*/
50
51/**
52 * UClassID is used to identify classes without using the compiler's RTTI.
53 * This was used before C++ compilers consistently supported RTTI.
54 * ICU 4.6 requires compiler RTTI to be turned on.
55 *
56 * Each class hierarchy which needs
57 * to implement polymorphic clone() or operator==() defines two methods,
58 * described in detail below.  UClassID values can be compared using
59 * operator==(). Nothing else should be done with them.
60 *
61 * \par
62 * In class hierarchies that implement "poor man's RTTI",
63 * each concrete subclass implements getDynamicClassID() in the same way:
64 *
65 * \code
66 *      class Derived {
67 *      public:
68 *          virtual UClassID getDynamicClassID() const
69 *            { return Derived::getStaticClassID(); }
70 *      }
71 * \endcode
72 *
73 * Each concrete class implements getStaticClassID() as well, which allows
74 * clients to test for a specific type.
75 *
76 * \code
77 *      class Derived {
78 *      public:
79 *          static UClassID U_EXPORT2 getStaticClassID();
80 *      private:
81 *          static char fgClassID;
82 *      }
83 *
84 *      // In Derived.cpp:
85 *      UClassID Derived::getStaticClassID()
86 *        { return (UClassID)&Derived::fgClassID; }
87 *      char Derived::fgClassID = 0; // Value is irrelevant
88 * \endcode
89 * @stable ICU 2.0
90 */
91typedef void* UClassID;
92
93U_NAMESPACE_BEGIN
94
95/**
96 * UMemory is the common ICU base class.
97 * All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
98 *
99 * This is primarily to make it possible and simple to override the
100 * C++ memory management by adding new/delete operators to this base class.
101 *
102 * To override ALL ICU memory management, including that from plain C code,
103 * replace the allocation functions declared in cmemory.h
104 *
105 * UMemory does not contain any virtual functions.
106 * Common "boilerplate" functions are defined in UObject.
107 *
108 * @stable ICU 2.4
109 */
110class U_COMMON_API UMemory {
111public:
112
113/* test versions for debugging shaper heap memory problems */
114#ifdef SHAPER_MEMORY_DEBUG
115    static void * NewArray(int size, int count);
116    static void * GrowArray(void * array, int newSize );
117    static void   FreeArray(void * array );
118#endif
119
120#if U_OVERRIDE_CXX_ALLOCATION
121    /**
122     * Override for ICU4C C++ memory management.
123     * simple, non-class types are allocated using the macros in common/cmemory.h
124     * (uprv_malloc(), uprv_free(), uprv_realloc());
125     * they or something else could be used here to implement C++ new/delete
126     * for ICU4C C++ classes
127     * @stable ICU 2.4
128     */
129    static void * U_EXPORT2 operator new(size_t size) U_NO_THROW;
130
131    /**
132     * Override for ICU4C C++ memory management.
133     * See new().
134     * @stable ICU 2.4
135     */
136    static void * U_EXPORT2 operator new[](size_t size) U_NO_THROW;
137
138    /**
139     * Override for ICU4C C++ memory management.
140     * simple, non-class types are allocated using the macros in common/cmemory.h
141     * (uprv_malloc(), uprv_free(), uprv_realloc());
142     * they or something else could be used here to implement C++ new/delete
143     * for ICU4C C++ classes
144     * @stable ICU 2.4
145     */
146    static void U_EXPORT2 operator delete(void *p) U_NO_THROW;
147
148    /**
149     * Override for ICU4C C++ memory management.
150     * See delete().
151     * @stable ICU 2.4
152     */
153    static void U_EXPORT2 operator delete[](void *p) U_NO_THROW;
154
155#if U_HAVE_PLACEMENT_NEW
156    /**
157     * Override for ICU4C C++ memory management for STL.
158     * See new().
159     * @stable ICU 2.6
160     */
161    static inline void * U_EXPORT2 operator new(size_t, void *ptr) U_NO_THROW { return ptr; }
162
163    /**
164     * Override for ICU4C C++ memory management for STL.
165     * See delete().
166     * @stable ICU 2.6
167     */
168    static inline void U_EXPORT2 operator delete(void *, void *) U_NO_THROW {}
169#endif /* U_HAVE_PLACEMENT_NEW */
170#if U_HAVE_DEBUG_LOCATION_NEW
171    /**
172      * This method overrides the MFC debug version of the operator new
173      *
174      * @param size   The requested memory size
175      * @param file   The file where the allocation was requested
176      * @param line   The line where the allocation was requested
177      */
178    static void * U_EXPORT2 operator new(size_t size, const char* file, int line) U_NO_THROW;
179    /**
180      * This method provides a matching delete for the MFC debug new
181      *
182      * @param p      The pointer to the allocated memory
183      * @param file   The file where the allocation was requested
184      * @param line   The line where the allocation was requested
185      */
186    static void U_EXPORT2 operator delete(void* p, const char* file, int line) U_NO_THROW;
187#endif /* U_HAVE_DEBUG_LOCATION_NEW */
188#endif /* U_OVERRIDE_CXX_ALLOCATION */
189
190    /*
191     * Assignment operator not declared. The compiler will provide one
192     * which does nothing since this class does not contain any data members.
193     * API/code coverage may show the assignment operator as present and
194     * untested - ignore.
195     * Subclasses need this assignment operator if they use compiler-provided
196     * assignment operators of their own. An alternative to not declaring one
197     * here would be to declare and empty-implement a protected or public one.
198    UMemory &UMemory::operator=(const UMemory &);
199     */
200};
201
202/**
203 * UObject is the common ICU "boilerplate" class.
204 * UObject inherits UMemory (starting with ICU 2.4),
205 * and all other public ICU C++ classes
206 * are derived from UObject (starting with ICU 2.2).
207 *
208 * UObject contains common virtual functions, in particular a virtual destructor.
209 *
210 * The clone() function is not available in UObject because it is not
211 * implemented by all ICU classes.
212 * Many ICU services provide a clone() function for their class trees,
213 * defined on the service's C++ base class, and all subclasses within that
214 * service class tree return a pointer to the service base class
215 * (which itself is a subclass of UObject).
216 * This is because some compilers do not support covariant (same-as-this)
217 * return types; cast to the appropriate subclass if necessary.
218 *
219 * @stable ICU 2.2
220 */
221class U_COMMON_API UObject : public UMemory {
222public:
223    /**
224     * Destructor.
225     *
226     * @stable ICU 2.2
227     */
228    virtual ~UObject();
229
230    /**
231     * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
232     * The base class implementation returns a dummy value.
233     *
234     * Use compiler RTTI rather than ICU's "poor man's RTTI".
235     * Since ICU 4.6, new ICU C++ class hierarchies do not implement "poor man's RTTI".
236     *
237     * @stable ICU 2.2
238     */
239    virtual UClassID getDynamicClassID() const;
240
241protected:
242    // the following functions are protected to prevent instantiation and
243    // direct use of UObject itself
244
245    // default constructor
246    // inline UObject() {}
247
248    // copy constructor
249    // inline UObject(const UObject &other) {}
250
251#if 0
252    // TODO Sometime in the future. Implement operator==().
253    // (This comment inserted in 2.2)
254    // some or all of the following "boilerplate" functions may be made public
255    // in a future ICU4C release when all subclasses implement them
256
257    // assignment operator
258    // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
259    // commented out because the implementation is the same as a compiler's default
260    // UObject &operator=(const UObject &other) { return *this; }
261
262    // comparison operators
263    virtual inline UBool operator==(const UObject &other) const { return this==&other; }
264    inline UBool operator!=(const UObject &other) const { return !operator==(other); }
265
266    // clone() commented out from the base class:
267    // some compilers do not support co-variant return types
268    // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
269    // see also UObject class documentation.
270    // virtual UObject *clone() const;
271#endif
272
273    /*
274     * Assignment operator not declared. The compiler will provide one
275     * which does nothing since this class does not contain any data members.
276     * API/code coverage may show the assignment operator as present and
277     * untested - ignore.
278     * Subclasses need this assignment operator if they use compiler-provided
279     * assignment operators of their own. An alternative to not declaring one
280     * here would be to declare and empty-implement a protected or public one.
281    UObject &UObject::operator=(const UObject &);
282     */
283};
284
285#ifndef U_HIDE_INTERNAL_API
286/**
287 * This is a simple macro to add ICU RTTI to an ICU object implementation.
288 * This does not go into the header. This should only be used in *.cpp files.
289 *
290 * @param myClass The name of the class that needs RTTI defined.
291 * @internal
292 */
293#define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
294    UClassID U_EXPORT2 myClass::getStaticClassID() { \
295        static char classID = 0; \
296        return (UClassID)&classID; \
297    } \
298    UClassID myClass::getDynamicClassID() const \
299    { return myClass::getStaticClassID(); }
300
301
302/**
303 * This macro adds ICU RTTI to an ICU abstract class implementation.
304 * This macro should be invoked in *.cpp files.  The corresponding
305 * header should declare getStaticClassID.
306 *
307 * @param myClass The name of the class that needs RTTI defined.
308 * @internal
309 */
310#define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
311    UClassID U_EXPORT2 myClass::getStaticClassID() { \
312        static char classID = 0; \
313        return (UClassID)&classID; \
314    }
315
316#endif  /* U_HIDE_INTERNAL_API */
317
318U_NAMESPACE_END
319
320#endif
321