/src/node/deps/icu-small/source/common/unicode/char16ptr.h

Source
// © 2017 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html

// char16ptr.h
// created: 2017feb28 Markus W. Scherer

#ifndef __CHAR16PTR_H__
#define __CHAR16PTR_H__

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API

#include <cstddef>
#include <string_view>
#include <type_traits>

#endif

/**
 * \file
 * \brief C++ API: char16_t pointer wrappers with
 *        implicit conversion from bit-compatible raw pointer types.
 *        Also conversion functions from char16_t * to UChar * and OldUChar *.
 */

/**
 * \def U_ALIASING_BARRIER
 * Barrier for pointer anti-aliasing optimizations even across function boundaries.
 * @internal
 */
#ifdef U_ALIASING_BARRIER
    // Use the predefined value.
#elif (defined(__clang__) || defined(__GNUC__)) && U_PLATFORM != U_PF_BROWSER_NATIVE_CLIENT
#   define U_ALIASING_BARRIER(ptr) asm volatile("" : : "rm"(ptr) : "memory")
#elif defined(U_IN_DOXYGEN)
#   define U_ALIASING_BARRIER(ptr)
#endif

// ICU DLL-exported
#if U_SHOW_CPLUSPLUS_API

U_NAMESPACE_BEGIN

/**
 * char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.
 * @stable ICU 59
 */
class U_COMMON_API Char16Ptr final {
public:
    /**
     * Copies the pointer.
     * @param p pointer
     * @stable ICU 59
     */
    inline Char16Ptr(char16_t *p);
#if !U_CHAR16_IS_TYPEDEF
    /**
     * Converts the pointer to char16_t *.
     * @param p pointer to be converted
     * @stable ICU 59
     */
    inline Char16Ptr(uint16_t *p);
#endif
#if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)
    /**
     * Converts the pointer to char16_t *.
     * (Only defined if U_SIZEOF_WCHAR_T==2.)
     * @param p pointer to be converted
     * @stable ICU 59
     */
    inline Char16Ptr(wchar_t *p);
#endif
    /**
     * nullptr constructor.
     * @param p nullptr
     * @stable ICU 59
     */
    inline Char16Ptr(std::nullptr_t p);
    /**
     * Destructor.
     * @stable ICU 59
     */
    inline ~Char16Ptr();

    /**
     * Pointer access.
     * @return the wrapped pointer
     * @stable ICU 59
     */
    inline char16_t *get() const;
    /**
     * char16_t pointer access via type conversion (e.g., static_cast).
     * @return the wrapped pointer
     * @stable ICU 59
     */
    inline operator char16_t *() const { return get(); }

private:
    Char16Ptr() = delete;

#ifdef U_ALIASING_BARRIER
    template<typename T> static char16_t *cast(T *t) {
        U_ALIASING_BARRIER(t);
        return reinterpret_cast<char16_t *>(t);
    }

    char16_t *p_;
#else
    union {
        char16_t *cp;
        uint16_t *up;
        wchar_t *wp;
    } u_;
#endif
};

/// \cond
#ifdef U_ALIASING_BARRIER

Char16Ptr::Char16Ptr(char16_t *p) : p_(p) {}
#if !U_CHAR16_IS_TYPEDEF
Char16Ptr::Char16Ptr(uint16_t *p) : p_(cast(p)) {}
#endif
#if U_SIZEOF_WCHAR_T==2
Char16Ptr::Char16Ptr(wchar_t *p) : p_(cast(p)) {}
#endif
Char16Ptr::Char16Ptr(std::nullptr_t p) : p_(p) {}
Char16Ptr::~Char16Ptr() {
    U_ALIASING_BARRIER(p_);
}

char16_t *Char16Ptr::get() const { return p_; }

#else

Char16Ptr::Char16Ptr(char16_t *p) { u_.cp = p; }
#if !U_CHAR16_IS_TYPEDEF
Char16Ptr::Char16Ptr(uint16_t *p) { u_.up = p; }
#endif
#if U_SIZEOF_WCHAR_T==2
Char16Ptr::Char16Ptr(wchar_t *p) { u_.wp = p; }
#endif
Char16Ptr::Char16Ptr(std::nullptr_t p) { u_.cp = p; }
Char16Ptr::~Char16Ptr() {}

char16_t *Char16Ptr::get() const { return u_.cp; }

#endif
/// \endcond

/**
 * const char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.
 * @stable ICU 59
 */
class U_COMMON_API ConstChar16Ptr final {
public:
    /**
     * Copies the pointer.
     * @param p pointer
     * @stable ICU 59
     */
    inline ConstChar16Ptr(const char16_t *p);
#if !U_CHAR16_IS_TYPEDEF
    /**
     * Converts the pointer to char16_t *.
     * @param p pointer to be converted
     * @stable ICU 59
     */
    inline ConstChar16Ptr(const uint16_t *p);
#endif
#if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)
    /**
     * Converts the pointer to char16_t *.
     * (Only defined if U_SIZEOF_WCHAR_T==2.)
     * @param p pointer to be converted
     * @stable ICU 59
     */
    inline ConstChar16Ptr(const wchar_t *p);
#endif
    /**
     * nullptr constructor.
     * @param p nullptr
     * @stable ICU 59
     */
    inline ConstChar16Ptr(const std::nullptr_t p);

    /**
     * Destructor.
     * @stable ICU 59
     */
    inline ~ConstChar16Ptr();

    /**
     * Pointer access.
     * @return the wrapped pointer
     * @stable ICU 59
     */
    inline const char16_t *get() const;
    /**
     * char16_t pointer access via type conversion (e.g., static_cast).
     * @return the wrapped pointer
     * @stable ICU 59
     */
    inline operator const char16_t *() const { return get(); }

private:
    ConstChar16Ptr() = delete;

#ifdef U_ALIASING_BARRIER
    template<typename T> static const char16_t *cast(const T *t) {
        U_ALIASING_BARRIER(t);
        return reinterpret_cast<const char16_t *>(t);
    }

    const char16_t *p_;
#else
    union {
        const char16_t *cp;
        const uint16_t *up;
        const wchar_t *wp;
    } u_;
#endif
};

/// \cond
#ifdef U_ALIASING_BARRIER

ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) : p_(p) {}
#if !U_CHAR16_IS_TYPEDEF
ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) : p_(cast(p)) {}
#endif
#if U_SIZEOF_WCHAR_T==2
ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) : p_(cast(p)) {}
#endif
ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) : p_(p) {}
ConstChar16Ptr::~ConstChar16Ptr() {
    U_ALIASING_BARRIER(p_);
}

const char16_t *ConstChar16Ptr::get() const { return p_; }

#else

ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) { u_.cp = p; }
#if !U_CHAR16_IS_TYPEDEF
ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) { u_.up = p; }
#endif
#if U_SIZEOF_WCHAR_T==2
ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) { u_.wp = p; }
#endif
ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) { u_.cp = p; }
ConstChar16Ptr::~ConstChar16Ptr() {}

const char16_t *ConstChar16Ptr::get() const { return u_.cp; }

#endif
/// \endcond

U_NAMESPACE_END

#endif  // U_SHOW_CPLUSPLUS_API

// Usable in header-only definitions
#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API

namespace U_ICU_NAMESPACE_OR_INTERNAL {

#ifndef U_FORCE_HIDE_INTERNAL_API
/** @internal */
template<typename T, typename = std::enable_if_t<std::is_same_v<T, UChar>>>
inline const char16_t *uprv_char16PtrFromUChar(const T *p) {
    if constexpr (std::is_same_v<UChar, char16_t>) {
        return p;
    } else {
#if U_SHOW_CPLUSPLUS_API
        return ConstChar16Ptr(p).get();
#else
#ifdef U_ALIASING_BARRIER
        U_ALIASING_BARRIER(p);
#endif
        return reinterpret_cast<const char16_t *>(p);
#endif
    }
}
#if !U_CHAR16_IS_TYPEDEF && (!defined(_LIBCPP_VERSION) || _LIBCPP_VERSION < 180000)
/** @internal */
inline const char16_t *uprv_char16PtrFromUint16(const uint16_t *p) {
#if U_SHOW_CPLUSPLUS_API
    return ConstChar16Ptr(p).get();
#else
#ifdef U_ALIASING_BARRIER
    U_ALIASING_BARRIER(p);
#endif
    return reinterpret_cast<const char16_t *>(p);
#endif
}
#endif
#if U_SIZEOF_WCHAR_T==2
/** @internal */
inline const char16_t *uprv_char16PtrFromWchar(const wchar_t *p) {
#if U_SHOW_CPLUSPLUS_API
    return ConstChar16Ptr(p).get();
#else
#ifdef U_ALIASING_BARRIER
    U_ALIASING_BARRIER(p);
#endif
    return reinterpret_cast<const char16_t *>(p);
#endif
}
#endif
#endif

/**
 * Converts from const char16_t * to const UChar *.
 * Includes an aliasing barrier if available.
 * @param p pointer
 * @return p as const UChar *
 * @stable ICU 59
 */
inline const UChar *toUCharPtr(const char16_t *p) {
#ifdef U_ALIASING_BARRIER
    U_ALIASING_BARRIER(p);
#endif
    return reinterpret_cast<const UChar *>(p);
}

/**
 * Converts from char16_t * to UChar *.
 * Includes an aliasing barrier if available.
 * @param p pointer
 * @return p as UChar *
 * @stable ICU 59
 */
inline UChar *toUCharPtr(char16_t *p) {
#ifdef U_ALIASING_BARRIER
    U_ALIASING_BARRIER(p);
#endif
    return reinterpret_cast<UChar *>(p);
}

/**
 * Converts from const char16_t * to const OldUChar *.
 * Includes an aliasing barrier if available.
 * @param p pointer
 * @return p as const OldUChar *
 * @stable ICU 59
 */
inline const OldUChar *toOldUCharPtr(const char16_t *p) {
#ifdef U_ALIASING_BARRIER
    U_ALIASING_BARRIER(p);
#endif
    return reinterpret_cast<const OldUChar *>(p);
}

/**
 * Converts from char16_t * to OldUChar *.
 * Includes an aliasing barrier if available.
 * @param p pointer
 * @return p as OldUChar *
 * @stable ICU 59
 */
inline OldUChar *toOldUCharPtr(char16_t *p) {
#ifdef U_ALIASING_BARRIER
    U_ALIASING_BARRIER(p);
#endif
    return reinterpret_cast<OldUChar *>(p);
}

}  // U_ICU_NAMESPACE_OR_INTERNAL

#endif  // U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API

// ICU DLL-exported
#if U_SHOW_CPLUSPLUS_API

U_NAMESPACE_BEGIN

#ifndef U_FORCE_HIDE_INTERNAL_API
/**
 * Is T convertible to a std::u16string_view or some other 16-bit string view?
 * @internal
 */
template<typename T>
constexpr bool ConvertibleToU16StringView =
    std::is_convertible_v<T, std::u16string_view>
#if !U_CHAR16_IS_TYPEDEF && (!defined(_LIBCPP_VERSION) || _LIBCPP_VERSION < 180000)
    || std::is_convertible_v<T, std::basic_string_view<uint16_t>>
#endif
#if U_SIZEOF_WCHAR_T==2
    || std::is_convertible_v<T, std::wstring_view>
#endif
    ;

namespace internal {
/**
 * Pass-through overload.
 * @internal
 */
inline std::u16string_view toU16StringView(std::u16string_view sv) { return sv; }

#if !U_CHAR16_IS_TYPEDEF && (!defined(_LIBCPP_VERSION) || _LIBCPP_VERSION < 180000)
/**
 * Basically undefined behavior but sometimes necessary conversion
 * from std::basic_string_view<uint16_t> to std::u16string_view.
 * @internal
 */
inline std::u16string_view toU16StringView(std::basic_string_view<uint16_t> sv) {
    return { ConstChar16Ptr(sv.data()), sv.length() };
}
#endif

#if U_SIZEOF_WCHAR_T==2
/**
 * Basically undefined behavior but sometimes necessary conversion
 * from std::wstring_view to std::u16string_view.
 * @internal
 */
inline std::u16string_view toU16StringView(std::wstring_view sv) {
    return { ConstChar16Ptr(sv.data()), sv.length() };
}
#endif

/**
 * Pass-through overload.
 * @internal
 */
template <typename T,
          typename = typename std::enable_if_t<!std::is_pointer_v<std::remove_reference_t<T>>>>
inline std::u16string_view toU16StringViewNullable(const T& text) {
    return toU16StringView(text);
}

/**
 * In case of nullptr, return an empty view.
 * @internal
 */
template <typename T,
          typename = typename std::enable_if_t<std::is_pointer_v<std::remove_reference_t<T>>>,
          typename = void>
inline std::u16string_view toU16StringViewNullable(const T& text) {
    if (text == nullptr) return {};  // For backward compatibility.
    return toU16StringView(text);
}

}  // internal
#endif  // U_FORCE_HIDE_INTERNAL_API

U_NAMESPACE_END

#endif  // U_SHOW_CPLUSPLUS_API

#endif  // __CHAR16PTR_H__

Coverage Report

Created: 2025-12-30 08:42

Line	Count	Source
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 \|\| U_SHOW_CPLUSPLUS_HEADER_API
13
14		#include <cstddef>
15		#include <string_view>
16		#include <type_traits>
17
18		#endif
19
20		/**
21		* \file
22		* \brief C++ API: char16_t pointer wrappers with
23		* implicit conversion from bit-compatible raw pointer types.
24		* Also conversion functions from char16_t * to UChar * and OldUChar *.
25		*/
26
27		/**
28		* \def U_ALIASING_BARRIER
29		* Barrier for pointer anti-aliasing optimizations even across function boundaries.
30		* @internal
31		*/
32		#ifdef U_ALIASING_BARRIER
33		// Use the predefined value.
34		#elif (defined(__clang__) \|\| defined(__GNUC__)) && U_PLATFORM != U_PF_BROWSER_NATIVE_CLIENT
35		# define U_ALIASING_BARRIER(ptr) asm volatile("" : : "rm"(ptr) : "memory")
36		#elif defined(U_IN_DOXYGEN)
37		# define U_ALIASING_BARRIER(ptr)
38		#endif
39
40		// ICU DLL-exported
41		#if U_SHOW_CPLUSPLUS_API
42
43		U_NAMESPACE_BEGIN
44
45		/**
46		* char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.
47		* @stable ICU 59
48		*/
49		class U_COMMON_API Char16Ptr final {
50		public:
51		/**
52		* Copies the pointer.
53		* @param p pointer
54		* @stable ICU 59
55		*/
56		inline Char16Ptr(char16_t *p);
57		#if !U_CHAR16_IS_TYPEDEF
58		/**
59		* Converts the pointer to char16_t *.
60		* @param p pointer to be converted
61		* @stable ICU 59
62		*/
63		inline Char16Ptr(uint16_t *p);
64		#endif
65		#if U_SIZEOF_WCHAR_T==2 \|\| defined(U_IN_DOXYGEN)
66		/**
67		* Converts the pointer to char16_t *.
68		* (Only defined if U_SIZEOF_WCHAR_T==2.)
69		* @param p pointer to be converted
70		* @stable ICU 59
71		*/
72		inline Char16Ptr(wchar_t *p);
73		#endif
74		/**
75		* nullptr constructor.
76		* @param p nullptr
77		* @stable ICU 59
78		*/
79		inline Char16Ptr(std::nullptr_t p);
80		/**
81		* Destructor.
82		* @stable ICU 59
83		*/
84		inline ~Char16Ptr();
85
86		/**
87		* Pointer access.
88		* @return the wrapped pointer
89		* @stable ICU 59
90		*/
91		inline char16_t *get() const;
92		/**
93		* char16_t pointer access via type conversion (e.g., static_cast).
94		* @return the wrapped pointer
95		* @stable ICU 59
96		*/
97	0	inline operator char16_t *() const { return get(); }
98
99		private:
100		Char16Ptr() = delete;
101
102		#ifdef U_ALIASING_BARRIER
103	0	template<typename T> static char16_t cast(T t) {
104	0	U_ALIASING_BARRIER(t);
105	0	return reinterpret_cast<char16_t *>(t);
106	0	}
107
108		char16_t *p_;
109		#else
110		union {
111		char16_t *cp;
112		uint16_t *up;
113		wchar_t *wp;
114		} u_;
115		#endif
116		};
117
118		/// \cond
119		#ifdef U_ALIASING_BARRIER
120
121		Char16Ptr::Char16Ptr(char16_t *p) : p_(p) {}
122		#if !U_CHAR16_IS_TYPEDEF
123		Char16Ptr::Char16Ptr(uint16_t *p) : p_(cast(p)) {}
124		#endif
125		#if U_SIZEOF_WCHAR_T==2
126		Char16Ptr::Char16Ptr(wchar_t *p) : p_(cast(p)) {}
127		#endif
128		Char16Ptr::Char16Ptr(std::nullptr_t p) : p_(p) {}
129		Char16Ptr::~Char16Ptr() {
130		U_ALIASING_BARRIER(p_);
131		}
132
133	0	char16_t *Char16Ptr::get() const { return p_; }
134
135		#else
136
137		Char16Ptr::Char16Ptr(char16_t *p) { u_.cp = p; }
138		#if !U_CHAR16_IS_TYPEDEF
139		Char16Ptr::Char16Ptr(uint16_t *p) { u_.up = p; }
140		#endif
141		#if U_SIZEOF_WCHAR_T==2
142		Char16Ptr::Char16Ptr(wchar_t *p) { u_.wp = p; }
143		#endif
144		Char16Ptr::Char16Ptr(std::nullptr_t p) { u_.cp = p; }
145		Char16Ptr::~Char16Ptr() {}
146
147		char16_t *Char16Ptr::get() const { return u_.cp; }
148
149		#endif
150		/// \endcond
151
152		/**
153		* const char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.
154		* @stable ICU 59
155		*/
156		class U_COMMON_API ConstChar16Ptr final {
157		public:
158		/**
159		* Copies the pointer.
160		* @param p pointer
161		* @stable ICU 59
162		*/
163		inline ConstChar16Ptr(const char16_t *p);
164		#if !U_CHAR16_IS_TYPEDEF
165		/**
166		* Converts the pointer to char16_t *.
167		* @param p pointer to be converted
168		* @stable ICU 59
169		*/
170		inline ConstChar16Ptr(const uint16_t *p);
171		#endif
172		#if U_SIZEOF_WCHAR_T==2 \|\| defined(U_IN_DOXYGEN)
173		/**
174		* Converts the pointer to char16_t *.
175		* (Only defined if U_SIZEOF_WCHAR_T==2.)
176		* @param p pointer to be converted
177		* @stable ICU 59
178		*/
179		inline ConstChar16Ptr(const wchar_t *p);
180		#endif
181		/**
182		* nullptr constructor.
183		* @param p nullptr
184		* @stable ICU 59
185		*/
186		inline ConstChar16Ptr(const std::nullptr_t p);
187
188		/**
189		* Destructor.
190		* @stable ICU 59
191		*/
192		inline ~ConstChar16Ptr();
193
194		/**
195		* Pointer access.
196		* @return the wrapped pointer
197		* @stable ICU 59
198		*/
199		inline const char16_t *get() const;
200		/**
201		* char16_t pointer access via type conversion (e.g., static_cast).
202		* @return the wrapped pointer
203		* @stable ICU 59
204		*/
205	0	inline operator const char16_t *() const { return get(); }
206
207		private:
208		ConstChar16Ptr() = delete;
209
210		#ifdef U_ALIASING_BARRIER
211	0	template<typename T> static const char16_t cast(const T t) {
212	0	U_ALIASING_BARRIER(t);
213	0	return reinterpret_cast<const char16_t *>(t);
214	0	}
215
216		const char16_t *p_;
217		#else
218		union {
219		const char16_t *cp;
220		const uint16_t *up;
221		const wchar_t *wp;
222		} u_;
223		#endif
224		};
225
226		/// \cond
227		#ifdef U_ALIASING_BARRIER
228
229		ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) : p_(p) {}
230		#if !U_CHAR16_IS_TYPEDEF
231		ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) : p_(cast(p)) {}
232		#endif
233		#if U_SIZEOF_WCHAR_T==2
234		ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) : p_(cast(p)) {}
235		#endif
236		ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) : p_(p) {}
237		ConstChar16Ptr::~ConstChar16Ptr() {
238		U_ALIASING_BARRIER(p_);
239		}
240
241	0	const char16_t *ConstChar16Ptr::get() const { return p_; }
242
243		#else
244
245		ConstChar16Ptr::ConstChar16Ptr(const char16_t *p) { u_.cp = p; }
246		#if !U_CHAR16_IS_TYPEDEF
247		ConstChar16Ptr::ConstChar16Ptr(const uint16_t *p) { u_.up = p; }
248		#endif
249		#if U_SIZEOF_WCHAR_T==2
250		ConstChar16Ptr::ConstChar16Ptr(const wchar_t *p) { u_.wp = p; }
251		#endif
252		ConstChar16Ptr::ConstChar16Ptr(const std::nullptr_t p) { u_.cp = p; }
253		ConstChar16Ptr::~ConstChar16Ptr() {}
254
255		const char16_t *ConstChar16Ptr::get() const { return u_.cp; }
256
257		#endif
258		/// \endcond
259
260		U_NAMESPACE_END
261
262		#endif // U_SHOW_CPLUSPLUS_API
263
264		// Usable in header-only definitions
265		#if U_SHOW_CPLUSPLUS_API \|\| U_SHOW_CPLUSPLUS_HEADER_API
266
267		namespace U_ICU_NAMESPACE_OR_INTERNAL {
268
269		#ifndef U_FORCE_HIDE_INTERNAL_API
270		/** @internal */
271		template<typename T, typename = std::enable_if_t<std::is_same_v<T, UChar>>>
272	0	inline const char16_t uprv_char16PtrFromUChar(const T p) {
273	0	if constexpr (std::is_same_v<UChar, char16_t>) {
274	0	return p;
275	0	} else {
276	0	#if U_SHOW_CPLUSPLUS_API
277	0	return ConstChar16Ptr(p).get();
278	0	#else
279	0	#ifdef U_ALIASING_BARRIER
280	0	U_ALIASING_BARRIER(p);
281	0	#endif
282	0	return reinterpret_cast<const char16_t *>(p);
283	0	#endif
284	0	}
285	0	}
286		#if !U_CHAR16_IS_TYPEDEF && (!defined(_LIBCPP_VERSION) \|\| _LIBCPP_VERSION < 180000)
287		/** @internal */
288		inline const char16_t uprv_char16PtrFromUint16(const uint16_t p) {
289		#if U_SHOW_CPLUSPLUS_API
290		return ConstChar16Ptr(p).get();
291		#else
292		#ifdef U_ALIASING_BARRIER
293		U_ALIASING_BARRIER(p);
294		#endif
295		return reinterpret_cast<const char16_t *>(p);
296		#endif
297		}
298		#endif
299		#if U_SIZEOF_WCHAR_T==2
300		/** @internal */
301		inline const char16_t uprv_char16PtrFromWchar(const wchar_t p) {
302		#if U_SHOW_CPLUSPLUS_API
303		return ConstChar16Ptr(p).get();
304		#else
305		#ifdef U_ALIASING_BARRIER
306		U_ALIASING_BARRIER(p);
307		#endif
308		return reinterpret_cast<const char16_t *>(p);
309		#endif
310		}
311		#endif
312		#endif
313
314		/**
315		* Converts from const char16_t * to const UChar *.
316		* Includes an aliasing barrier if available.
317		* @param p pointer
318		* @return p as const UChar *
319		* @stable ICU 59
320		*/
321	0	inline const UChar toUCharPtr(const char16_t p) {
322	0	#ifdef U_ALIASING_BARRIER
323	0	U_ALIASING_BARRIER(p);
324	0	#endif
325	0	return reinterpret_cast<const UChar *>(p);
326	0	}
327
328		/**
329		* Converts from char16_t * to UChar *.
330		* Includes an aliasing barrier if available.
331		* @param p pointer
332		* @return p as UChar *
333		* @stable ICU 59
334		*/
335	0	inline UChar toUCharPtr(char16_t p) {
336	0	#ifdef U_ALIASING_BARRIER
337	0	U_ALIASING_BARRIER(p);
338	0	#endif
339	0	return reinterpret_cast<UChar *>(p);
340	0	}
341
342		/**
343		* Converts from const char16_t * to const OldUChar *.
344		* Includes an aliasing barrier if available.
345		* @param p pointer
346		* @return p as const OldUChar *
347		* @stable ICU 59
348		*/
349	0	inline const OldUChar toOldUCharPtr(const char16_t p) {
350	0	#ifdef U_ALIASING_BARRIER
351	0	U_ALIASING_BARRIER(p);
352	0	#endif
353	0	return reinterpret_cast<const OldUChar *>(p);
354	0	}
355
356		/**
357		* Converts from char16_t * to OldUChar *.
358		* Includes an aliasing barrier if available.
359		* @param p pointer
360		* @return p as OldUChar *
361		* @stable ICU 59
362		*/
363	0	inline OldUChar toOldUCharPtr(char16_t p) {
364	0	#ifdef U_ALIASING_BARRIER
365	0	U_ALIASING_BARRIER(p);
366	0	#endif
367	0	return reinterpret_cast<OldUChar *>(p);
368	0	}
369
370		} // U_ICU_NAMESPACE_OR_INTERNAL
371
372		#endif // U_SHOW_CPLUSPLUS_API \|\| U_SHOW_CPLUSPLUS_HEADER_API
373
374		// ICU DLL-exported
375		#if U_SHOW_CPLUSPLUS_API
376
377		U_NAMESPACE_BEGIN
378
379		#ifndef U_FORCE_HIDE_INTERNAL_API
380		/**
381		* Is T convertible to a std::u16string_view or some other 16-bit string view?
382		* @internal
383		*/
384		template<typename T>
385		constexpr bool ConvertibleToU16StringView =
386		std::is_convertible_v<T, std::u16string_view>
387		#if !U_CHAR16_IS_TYPEDEF && (!defined(_LIBCPP_VERSION) \|\| _LIBCPP_VERSION < 180000)
388		\|\| std::is_convertible_v<T, std::basic_string_view<uint16_t>>
389		#endif
390		#if U_SIZEOF_WCHAR_T==2
391		\|\| std::is_convertible_v<T, std::wstring_view>
392		#endif
393		;
394
395		namespace internal {
396		/**
397		* Pass-through overload.
398		* @internal
399		*/
400	0	inline std::u16string_view toU16StringView(std::u16string_view sv) { return sv; }
401
402		#if !U_CHAR16_IS_TYPEDEF && (!defined(_LIBCPP_VERSION) \|\| _LIBCPP_VERSION < 180000)
403		/**
404		* Basically undefined behavior but sometimes necessary conversion
405		* from std::basic_string_view<uint16_t> to std::u16string_view.
406		* @internal
407		*/
408		inline std::u16string_view toU16StringView(std::basic_string_view<uint16_t> sv) {
409		return { ConstChar16Ptr(sv.data()), sv.length() };
410		}
411		#endif
412
413		#if U_SIZEOF_WCHAR_T==2
414		/**
415		* Basically undefined behavior but sometimes necessary conversion
416		* from std::wstring_view to std::u16string_view.
417		* @internal
418		*/
419		inline std::u16string_view toU16StringView(std::wstring_view sv) {
420		return { ConstChar16Ptr(sv.data()), sv.length() };
421		}
422		#endif
423
424		/**
425		* Pass-through overload.
426		* @internal
427		*/
428		template <typename T,
429		typename = typename std::enable_if_t<!std::is_pointer_v<std::remove_reference_t<T>>>>
430		inline std::u16string_view toU16StringViewNullable(const T& text) {
431		return toU16StringView(text);
432		}
433
434		/**
435		* In case of nullptr, return an empty view.
436		* @internal
437		*/
438		template <typename T,
439		typename = typename std::enable_if_t<std::is_pointer_v<std::remove_reference_t<T>>>,
440		typename = void>
441		inline std::u16string_view toU16StringViewNullable(const T& text) {
442		if (text == nullptr) return {}; // For backward compatibility.
443		return toU16StringView(text);
444		}
445
446		} // internal
447		#endif // U_FORCE_HIDE_INTERNAL_API
448
449		U_NAMESPACE_END
450
451		#endif // U_SHOW_CPLUSPLUS_API
452
453		#endif // __CHAR16PTR_H__