/src/icu/source/common/unicode/char16ptr.h
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1  |  | // © 2017 and later: Unicode, Inc. and others.  | 
2  |  | // License & terms of use: http://www.unicode.org/copyright.html  | 
3  |  |  | 
4  |  | // char16ptr.h  | 
5  |  | // created: 2017feb28 Markus W. Scherer  | 
6  |  |  | 
7  |  | #ifndef __CHAR16PTR_H__  | 
8  |  | #define __CHAR16PTR_H__  | 
9  |  |  | 
10  |  | #include "unicode/utypes.h"  | 
11  |  |  | 
12  |  | #if U_SHOW_CPLUSPLUS_API  | 
13  |  |  | 
14  |  | #include <cstddef>  | 
15  |  |  | 
16  |  | /**  | 
17  |  |  * \file  | 
18  |  |  * \brief C++ API: char16_t pointer wrappers with  | 
19  |  |  *        implicit conversion from bit-compatible raw pointer types.  | 
20  |  |  *        Also conversion functions from char16_t * to UChar * and OldUChar *.  | 
21  |  |  */  | 
22  |  |  | 
23  |  | U_NAMESPACE_BEGIN  | 
24  |  |  | 
25  |  | /**  | 
26  |  |  * \def U_ALIASING_BARRIER  | 
27  |  |  * Barrier for pointer anti-aliasing optimizations even across function boundaries.  | 
28  |  |  * @internal  | 
29  |  |  */  | 
30  |  | #ifdef U_ALIASING_BARRIER  | 
31  |  |     // Use the predefined value.  | 
32  |  | #elif (defined(__clang__) || defined(__GNUC__)) && U_PLATFORM != U_PF_BROWSER_NATIVE_CLIENT  | 
33  | 0  | #   define U_ALIASING_BARRIER(ptr) asm volatile("" : : "rm"(ptr) : "memory") | 
34  |  | #elif defined(U_IN_DOXYGEN)  | 
35  |  | #   define U_ALIASING_BARRIER(ptr)  | 
36  |  | #endif  | 
37  |  |  | 
38  |  | /**  | 
39  |  |  * char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.  | 
40  |  |  * @stable ICU 59  | 
41  |  |  */  | 
42  |  | class U_COMMON_API Char16Ptr U_FINAL { | 
43  |  | public:  | 
44  |  |     /**  | 
45  |  |      * Copies the pointer.  | 
46  |  |      * @param p pointer  | 
47  |  |      * @stable ICU 59  | 
48  |  |      */  | 
49  |  |     inline Char16Ptr(char16_t *p);  | 
50  |  | #if !U_CHAR16_IS_TYPEDEF  | 
51  |  |     /**  | 
52  |  |      * Converts the pointer to char16_t *.  | 
53  |  |      * @param p pointer to be converted  | 
54  |  |      * @stable ICU 59  | 
55  |  |      */  | 
56  |  |     inline Char16Ptr(uint16_t *p);  | 
57  |  | #endif  | 
58  |  | #if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)  | 
59  |  |     /**  | 
60  |  |      * Converts the pointer to char16_t *.  | 
61  |  |      * (Only defined if U_SIZEOF_WCHAR_T==2.)  | 
62  |  |      * @param p pointer to be converted  | 
63  |  |      * @stable ICU 59  | 
64  |  |      */  | 
65  |  |     inline Char16Ptr(wchar_t *p);  | 
66  |  | #endif  | 
67  |  |     /**  | 
68  |  |      * nullptr constructor.  | 
69  |  |      * @param p nullptr  | 
70  |  |      * @stable ICU 59  | 
71  |  |      */  | 
72  |  |     inline Char16Ptr(std::nullptr_t p);  | 
73  |  |     /**  | 
74  |  |      * Destructor.  | 
75  |  |      * @stable ICU 59  | 
76  |  |      */  | 
77  |  |     inline ~Char16Ptr();  | 
78  |  |  | 
79  |  |     /**  | 
80  |  |      * Pointer access.  | 
81  |  |      * @return the wrapped pointer  | 
82  |  |      * @stable ICU 59  | 
83  |  |      */  | 
84  |  |     inline char16_t *get() const;  | 
85  |  |     /**  | 
86  |  |      * char16_t pointer access via type conversion (e.g., static_cast).  | 
87  |  |      * @return the wrapped pointer  | 
88  |  |      * @stable ICU 59  | 
89  |  |      */  | 
90  | 0  |     inline operator char16_t *() const { return get(); } | 
91  |  |  | 
92  |  | private:  | 
93  |  |     Char16Ptr() = delete;  | 
94  |  |  | 
95  |  | #ifdef U_ALIASING_BARRIER  | 
96  | 0  |     template<typename T> static char16_t *cast(T *t) { | 
97  | 0  |         U_ALIASING_BARRIER(t);  | 
98  | 0  |         return reinterpret_cast<char16_t *>(t);  | 
99  | 0  |     }  | 
100  |  |  | 
101  |  |     char16_t *p_;  | 
102  |  | #else  | 
103  |  |     union { | 
104  |  |         char16_t *cp;  | 
105  |  |         uint16_t *up;  | 
106  |  |         wchar_t *wp;  | 
107  |  |     } u_;  | 
108  |  | #endif  | 
109  |  | };  | 
110  |  |  | 
111  |  | /// \cond  | 
112  |  | #ifdef U_ALIASING_BARRIER  | 
113  |  |  | 
114  | 0  | Char16Ptr::Char16Ptr(char16_t *p) : p_(p) {} | 
115  |  | #if !U_CHAR16_IS_TYPEDEF  | 
116  |  | Char16Ptr::Char16Ptr(uint16_t *p) : p_(cast(p)) {} | 
117  |  | #endif  | 
118  |  | #if U_SIZEOF_WCHAR_T==2  | 
119  |  | Char16Ptr::Char16Ptr(wchar_t *p) : p_(cast(p)) {} | 
120  |  | #endif  | 
121  |  | Char16Ptr::Char16Ptr(std::nullptr_t p) : p_(p) {} | 
122  | 0  | Char16Ptr::~Char16Ptr() { | 
123  | 0  |     U_ALIASING_BARRIER(p_);  | 
124  | 0  | }  | 
125  |  |  | 
126  | 0  | char16_t *Char16Ptr::get() const { return p_; } | 
127  |  |  | 
128  |  | #else  | 
129  |  |  | 
130  |  | Char16Ptr::Char16Ptr(char16_t *p) { u_.cp = p; } | 
131  |  | #if !U_CHAR16_IS_TYPEDEF  | 
132  |  | Char16Ptr::Char16Ptr(uint16_t *p) { u_.up = p; } | 
133  |  | #endif  | 
134  |  | #if U_SIZEOF_WCHAR_T==2  | 
135  |  | Char16Ptr::Char16Ptr(wchar_t *p) { u_.wp = p; } | 
136  |  | #endif  | 
137  |  | Char16Ptr::Char16Ptr(std::nullptr_t p) { u_.cp = p; } | 
138  |  | Char16Ptr::~Char16Ptr() {} | 
139  |  |  | 
140  |  | char16_t *Char16Ptr::get() const { return u_.cp; } | 
141  |  |  | 
142  |  | #endif  | 
143  |  | /// \endcond  | 
144  |  |  | 
145  |  | /**  | 
146  |  |  * const char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.  | 
147  |  |  * @stable ICU 59  | 
148  |  |  */  | 
149  |  | class U_COMMON_API ConstChar16Ptr U_FINAL { | 
150  |  | public:  | 
151  |  |     /**  | 
152  |  |      * Copies the pointer.  | 
153  |  |      * @param p pointer  | 
154  |  |      * @stable ICU 59  | 
155  |  |      */  | 
156  |  |     inline ConstChar16Ptr(const char16_t *p);  | 
157  |  | #if !U_CHAR16_IS_TYPEDEF  | 
158  |  |     /**  | 
159  |  |      * Converts the pointer to char16_t *.  | 
160  |  |      * @param p pointer to be converted  | 
161  |  |      * @stable ICU 59  | 
162  |  |      */  | 
163  |  |     inline ConstChar16Ptr(const uint16_t *p);  | 
164  |  | #endif  | 
165  |  | #if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)  | 
166  |  |     /**  | 
167  |  |      * Converts the pointer to char16_t *.  | 
168  |  |      * (Only defined if U_SIZEOF_WCHAR_T==2.)  | 
169  |  |      * @param p pointer to be converted  | 
170  |  |      * @stable ICU 59  | 
171  |  |      */  | 
172  |  |     inline ConstChar16Ptr(const wchar_t *p);  | 
173  |  | #endif  | 
174  |  |     /**  | 
175  |  |      * nullptr constructor.  | 
176  |  |      * @param p nullptr  | 
177  |  |      * @stable ICU 59  | 
178  |  |      */  | 
179  |  |     inline ConstChar16Ptr(const std::nullptr_t p);  | 
180  |  |  | 
181  |  |     /**  | 
182  |  |      * Destructor.  | 
183  |  |      * @stable ICU 59  | 
184  |  |      */  | 
185  |  |     inline ~ConstChar16Ptr();  | 
186  |  |  | 
187  |  |     /**  | 
188  |  |      * Pointer access.  | 
189  |  |      * @return the wrapped pointer  | 
190  |  |      * @stable ICU 59  | 
191  |  |      */  | 
192  |  |     inline const char16_t *get() const;  | 
193  |  |     /**  | 
194  |  |      * char16_t pointer access via type conversion (e.g., static_cast).  | 
195  |  |      * @return the wrapped pointer  | 
196  |  |      * @stable ICU 59  | 
197  |  |      */  | 
198  | 0  |     inline operator const char16_t *() const { return get(); } | 
199  |  |  | 
200  |  | private:  | 
201  |  |     ConstChar16Ptr() = delete;  | 
202  |  |  | 
203  |  | #ifdef U_ALIASING_BARRIER  | 
204  | 0  |     template<typename T> static const char16_t *cast(const T *t) { | 
205  | 0  |         U_ALIASING_BARRIER(t);  | 
206  | 0  |         return reinterpret_cast<const char16_t *>(t);  | 
207  | 0  |     }  | 
208  |  |  | 
209  |  |     const char16_t *p_;  | 
210  |  | #else  | 
211  |  |     union { | 
212  |  |         const char16_t *cp;  | 
213  |  |         const uint16_t *up;  | 
214  |  |         const wchar_t *wp;  | 
215  |  |     } u_;  | 
216  |  | #endif  | 
217  |  | };  | 
218  |  |  | 
219  |  | /// \cond  | 
220  |  | #ifdef U_ALIASING_BARRIER  | 
221  |  |  | 
222  | 0  | ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) : p_(p) {} | 
223  |  | #if !U_CHAR16_IS_TYPEDEF  | 
224  |  | ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) : p_(cast(p)) {} | 
225  |  | #endif  | 
226  |  | #if U_SIZEOF_WCHAR_T==2  | 
227  |  | ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) : p_(cast(p)) {} | 
228  |  | #endif  | 
229  |  | ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) : p_(p) {} | 
230  | 0  | ConstChar16Ptr::~ConstChar16Ptr() { | 
231  | 0  |     U_ALIASING_BARRIER(p_);  | 
232  | 0  | }  | 
233  |  |  | 
234  | 0  | const char16_t *ConstChar16Ptr::get() const { return p_; } | 
235  |  |  | 
236  |  | #else  | 
237  |  |  | 
238  |  | ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) { u_.cp = p; } | 
239  |  | #if !U_CHAR16_IS_TYPEDEF  | 
240  |  | ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) { u_.up = p; } | 
241  |  | #endif  | 
242  |  | #if U_SIZEOF_WCHAR_T==2  | 
243  |  | ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) { u_.wp = p; } | 
244  |  | #endif  | 
245  |  | ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) { u_.cp = p; } | 
246  |  | ConstChar16Ptr::~ConstChar16Ptr() {} | 
247  |  |  | 
248  |  | const char16_t *ConstChar16Ptr::get() const { return u_.cp; } | 
249  |  |  | 
250  |  | #endif  | 
251  |  | /// \endcond  | 
252  |  |  | 
253  |  | /**  | 
254  |  |  * Converts from const char16_t * to const UChar *.  | 
255  |  |  * Includes an aliasing barrier if available.  | 
256  |  |  * @param p pointer  | 
257  |  |  * @return p as const UChar *  | 
258  |  |  * @stable ICU 59  | 
259  |  |  */  | 
260  | 0  | inline const UChar *toUCharPtr(const char16_t *p) { | 
261  | 0  | #ifdef U_ALIASING_BARRIER  | 
262  | 0  |     U_ALIASING_BARRIER(p);  | 
263  | 0  | #endif  | 
264  | 0  |     return reinterpret_cast<const UChar *>(p);  | 
265  | 0  | }  | 
266  |  |  | 
267  |  | /**  | 
268  |  |  * Converts from char16_t * to UChar *.  | 
269  |  |  * Includes an aliasing barrier if available.  | 
270  |  |  * @param p pointer  | 
271  |  |  * @return p as UChar *  | 
272  |  |  * @stable ICU 59  | 
273  |  |  */  | 
274  | 0  | inline UChar *toUCharPtr(char16_t *p) { | 
275  | 0  | #ifdef U_ALIASING_BARRIER  | 
276  | 0  |     U_ALIASING_BARRIER(p);  | 
277  | 0  | #endif  | 
278  | 0  |     return reinterpret_cast<UChar *>(p);  | 
279  | 0  | }  | 
280  |  |  | 
281  |  | /**  | 
282  |  |  * Converts from const char16_t * to const OldUChar *.  | 
283  |  |  * Includes an aliasing barrier if available.  | 
284  |  |  * @param p pointer  | 
285  |  |  * @return p as const OldUChar *  | 
286  |  |  * @stable ICU 59  | 
287  |  |  */  | 
288  | 0  | inline const OldUChar *toOldUCharPtr(const char16_t *p) { | 
289  | 0  | #ifdef U_ALIASING_BARRIER  | 
290  | 0  |     U_ALIASING_BARRIER(p);  | 
291  | 0  | #endif  | 
292  | 0  |     return reinterpret_cast<const OldUChar *>(p);  | 
293  | 0  | }  | 
294  |  |  | 
295  |  | /**  | 
296  |  |  * Converts from char16_t * to OldUChar *.  | 
297  |  |  * Includes an aliasing barrier if available.  | 
298  |  |  * @param p pointer  | 
299  |  |  * @return p as OldUChar *  | 
300  |  |  * @stable ICU 59  | 
301  |  |  */  | 
302  | 0  | inline OldUChar *toOldUCharPtr(char16_t *p) { | 
303  | 0  | #ifdef U_ALIASING_BARRIER  | 
304  | 0  |     U_ALIASING_BARRIER(p);  | 
305  | 0  | #endif  | 
306  | 0  |     return reinterpret_cast<OldUChar *>(p);  | 
307  | 0  | }  | 
308  |  |  | 
309  |  | U_NAMESPACE_END  | 
310  |  |  | 
311  |  | #endif /* U_SHOW_CPLUSPLUS_API */  | 
312  |  |  | 
313  |  | #endif  // __CHAR16PTR_H__  |