codekingpro/portable-devtools
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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
23U_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# 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 */
42class U_COMMON_API Char16Ptr U_FINAL {
43public:
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 inline operator char16_t *() const { return get(); }
91
92private:
93 Char16Ptr() = delete;
94
95#ifdef U_ALIASING_BARRIER
96 template<typename T> static char16_t *cast(T *t) {
97 U_ALIASING_BARRIER(t);
98 return reinterpret_cast<char16_t *>(t);
99 }
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
114Char16Ptr::Char16Ptr(char16_t *p) : p_(p) {}
115#if !U_CHAR16_IS_TYPEDEF
116Char16Ptr::Char16Ptr(uint16_t *p) : p_(cast(p)) {}
117#endif
118#if U_SIZEOF_WCHAR_T==2
119Char16Ptr::Char16Ptr(wchar_t *p) : p_(cast(p)) {}
120#endif
121Char16Ptr::Char16Ptr(std::nullptr_t p) : p_(p) {}
122Char16Ptr::~Char16Ptr() {
123 U_ALIASING_BARRIER(p_);
124}
125
126char16_t *Char16Ptr::get() const { return p_; }
127
128#else
129
130Char16Ptr::Char16Ptr(char16_t *p) { u_.cp = p; }
131#if !U_CHAR16_IS_TYPEDEF
132Char16Ptr::Char16Ptr(uint16_t *p) { u_.up = p; }
133#endif
134#if U_SIZEOF_WCHAR_T==2
135Char16Ptr::Char16Ptr(wchar_t *p) { u_.wp = p; }
136#endif
137Char16Ptr::Char16Ptr(std::nullptr_t p) { u_.cp = p; }
138Char16Ptr::~Char16Ptr() {}
139
140char16_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 */
149class U_COMMON_API ConstChar16Ptr U_FINAL {
150public:
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 inline operator const char16_t *() const { return get(); }
199
200private:
201 ConstChar16Ptr() = delete;
202
203#ifdef U_ALIASING_BARRIER
204 template<typename T> static const char16_t *cast(const T *t) {
205 U_ALIASING_BARRIER(t);
206 return reinterpret_cast<const char16_t *>(t);
207 }
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
222ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) : p_(p) {}
223#if !U_CHAR16_IS_TYPEDEF
224ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) : p_(cast(p)) {}
225#endif
226#if U_SIZEOF_WCHAR_T==2
227ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) : p_(cast(p)) {}
228#endif
229ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) : p_(p) {}
230ConstChar16Ptr::~ConstChar16Ptr() {
231 U_ALIASING_BARRIER(p_);
232}
233
234const char16_t *ConstChar16Ptr::get() const { return p_; }
235
236#else
237
238ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) { u_.cp = p; }
239#if !U_CHAR16_IS_TYPEDEF
240ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) { u_.up = p; }
241#endif
242#if U_SIZEOF_WCHAR_T==2
243ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) { u_.wp = p; }
244#endif
245ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) { u_.cp = p; }
246ConstChar16Ptr::~ConstChar16Ptr() {}
247
248const 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 */
260inline const UChar *toUCharPtr(const char16_t *p) {
261#ifdef U_ALIASING_BARRIER
262 U_ALIASING_BARRIER(p);
263#endif
264 return reinterpret_cast<const UChar *>(p);
265}
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 */
274inline UChar *toUCharPtr(char16_t *p) {
275#ifdef U_ALIASING_BARRIER
276 U_ALIASING_BARRIER(p);
277#endif
278 return reinterpret_cast<UChar *>(p);
279}
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 */
288inline const OldUChar *toOldUCharPtr(const char16_t *p) {
289#ifdef U_ALIASING_BARRIER
290 U_ALIASING_BARRIER(p);
291#endif
292 return reinterpret_cast<const OldUChar *>(p);
293}
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 */
302inline OldUChar *toOldUCharPtr(char16_t *p) {
303#ifdef U_ALIASING_BARRIER
304 U_ALIASING_BARRIER(p);
305#endif
306 return reinterpret_cast<OldUChar *>(p);
307}
308
309U_NAMESPACE_END
310
311#endif /* U_SHOW_CPLUSPLUS_API */
312
313#endif // __CHAR16PTR_H__
314