1/****************************************************************************
2**
3** Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
4** Copyright (C) 2019 Mail.ru Group.
5** Contact: http://www.qt.io/licensing/
6**
7** This file is part of the QtCore module of the Qt Toolkit.
8**
9** $QT_BEGIN_LICENSE:LGPL$
10** Commercial License Usage
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16** information use the contact form at https://www.qt.io/contact-us.
17**
18** GNU Lesser General Public License Usage
19** Alternatively, this file may be used under the terms of the GNU Lesser
20** General Public License version 3 as published by the Free Software
21** Foundation and appearing in the file LICENSE.LGPL3 included in the
22** packaging of this file. Please review the following information to
23** ensure the GNU Lesser General Public License version 3 requirements
24** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
25**
26** GNU General Public License Usage
27** Alternatively, this file may be used under the terms of the GNU
28** General Public License version 2.0 or (at your option) the GNU General
29** Public license version 3 or any later version approved by the KDE Free
30** Qt Foundation. The licenses are as published by the Free Software
31** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
32** included in the packaging of this file. Please review the following
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38**
39****************************************************************************/
40#ifndef QSTRINGVIEW_H
41#define QSTRINGVIEW_H
42
43/*
44 This macro enables three "levels" of QStringView support:
45
46 1. offer QStringView, overload some functions taking QString with
47 QStringView
48
49 2. Obsolete: QStringRef and its overloads have been removed.
50
51 3. like 2, but replace functions taking QString, too.
52*/
53#ifndef QT_STRINGVIEW_LEVEL
54# define QT_STRINGVIEW_LEVEL 1
55#endif
56
57#include <QtCore/qchar.h>
58#include <QtCore/qbytearray.h>
59#include <QtCore/qstringliteral.h>
60#include <QtCore/qstringalgorithms.h>
61
62#include <string>
63
64#if defined(Q_OS_DARWIN) || defined(Q_QDOC)
65Q_FORWARD_DECLARE_CF_TYPE(CFString);
66Q_FORWARD_DECLARE_OBJC_CLASS(NSString);
67#endif
68
69QT_BEGIN_NAMESPACE
70
71class QString;
72class QStringView;
73class QRegularExpression;
74class QRegularExpressionMatch;
75
76namespace QtPrivate {
77template <typename Char>
78struct IsCompatibleCharTypeHelper
79 : std::integral_constant<bool,
80 std::is_same<Char, QChar>::value ||
81 std::is_same<Char, ushort>::value ||
82 std::is_same<Char, char16_t>::value ||
83 (std::is_same<Char, wchar_t>::value && sizeof(wchar_t) == sizeof(QChar))> {};
84template <typename Char>
85struct IsCompatibleCharType
86 : IsCompatibleCharTypeHelper<typename std::remove_cv<typename std::remove_reference<Char>::type>::type> {};
87
88template <typename Pointer>
89struct IsCompatiblePointerHelper : std::false_type {};
90template <typename Char>
91struct IsCompatiblePointerHelper<Char*>
92 : IsCompatibleCharType<Char> {};
93template <typename Pointer>
94struct IsCompatiblePointer
95 : IsCompatiblePointerHelper<typename std::remove_cv<typename std::remove_reference<Pointer>::type>::type> {};
96
97template <typename T, typename Enable = void>
98struct IsContainerCompatibleWithQStringView : std::false_type {};
99
100template <typename T>
101struct IsContainerCompatibleWithQStringView<T, std::enable_if_t<std::conjunction_v<
102 // lacking concepts and ranges, we accept any T whose std::data yields a suitable pointer ...
103 IsCompatiblePointer<decltype( std::data(std::declval<const T &>()) )>,
104 // ... and that has a suitable size ...
105 std::is_convertible<decltype( std::size(std::declval<const T &>()) ), qsizetype>,
106 // ... and it's a range as it defines an iterator-like API
107 IsCompatibleCharType<typename std::iterator_traits<decltype( std::begin(std::declval<const T &>()) )>::value_type>,
108 std::is_convertible<
109 decltype( std::begin(std::declval<const T &>()) != std::end(std::declval<const T &>()) ),
110 bool>,
111
112 // These need to be treated specially due to the empty vs null distinction
113 std::negation<std::is_same<std::decay_t<T>, QString>>,
114
115 // Don't make an accidental copy constructor
116 std::negation<std::is_same<std::decay_t<T>, QStringView>>
117 >>> : std::true_type {};
118
119} // namespace QtPrivate
120
121class QStringView
122{
123public:
124 typedef char16_t storage_type;
125 typedef const QChar value_type;
126 typedef std::ptrdiff_t difference_type;
127 typedef qsizetype size_type;
128 typedef value_type &reference;
129 typedef value_type &const_reference;
130 typedef value_type *pointer;
131 typedef value_type *const_pointer;
132
133 typedef pointer iterator;
134 typedef const_pointer const_iterator;
135 typedef std::reverse_iterator<iterator> reverse_iterator;
136 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
137
138private:
139 template <typename Char>
140 using if_compatible_char = typename std::enable_if<QtPrivate::IsCompatibleCharType<Char>::value, bool>::type;
141
142 template <typename Pointer>
143 using if_compatible_pointer = typename std::enable_if<QtPrivate::IsCompatiblePointer<Pointer>::value, bool>::type;
144
145 template <typename T>
146 using if_compatible_qstring_like = typename std::enable_if<std::is_same<T, QString>::value, bool>::type;
147
148 template <typename T>
149 using if_compatible_container = typename std::enable_if<QtPrivate::IsContainerCompatibleWithQStringView<T>::value, bool>::type;
150
151 template <typename Char>
152 static qsizetype lengthHelperPointer(const Char *str) noexcept
153 {
154#if defined(__cpp_lib_is_constant_evaluated)
155 if (std::is_constant_evaluated())
156 return std::char_traits<Char>::length(str);
157#elif defined(Q_CC_GNU) && !defined(Q_CC_CLANG) && !defined(Q_CC_INTEL)
158 if (__builtin_constant_p(*str))
159 return std::char_traits<Char>::length(str);
160#endif
161 return QtPrivate::qustrlen(reinterpret_cast<const char16_t *>(str));
162 }
163 static qsizetype lengthHelperPointer(const QChar *str) noexcept
164 {
165 return QtPrivate::qustrlen(reinterpret_cast<const char16_t *>(str));
166 }
167
168 template <typename Container>
169 static constexpr qsizetype lengthHelperContainer(const Container &c) noexcept
170 {
171 return qsizetype(std::size(c));
172 }
173
174 template <typename Char, size_t N>
175 static constexpr qsizetype lengthHelperContainer(const Char (&str)[N]) noexcept
176 {
177 const auto it = std::char_traits<Char>::find(str, N, Char(0));
178 const auto end = it ? it : std::end(str);
179 return qsizetype(std::distance(str, end));
180 }
181
182 template <typename Char>
183 static const storage_type *castHelper(const Char *str) noexcept
184 { return reinterpret_cast<const storage_type*>(str); }
185 static constexpr const storage_type *castHelper(const storage_type *str) noexcept
186 { return str; }
187
188public:
189 constexpr QStringView() noexcept
190 : m_size(0), m_data(nullptr) {}
191 constexpr QStringView(std::nullptr_t) noexcept
192 : QStringView() {}
193
194 template <typename Char, if_compatible_char<Char> = true>
195 constexpr QStringView(const Char *str, qsizetype len)
196 : m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len)),
197 m_data(castHelper(str)) {}
198
199 template <typename Char, if_compatible_char<Char> = true>
200 constexpr QStringView(const Char *f, const Char *l)
201 : QStringView(f, l - f) {}
202
203#ifdef Q_CLANG_QDOC
204 template <typename Char, size_t N>
205 constexpr QStringView(const Char (&array)[N]) noexcept;
206
207 template <typename Char>
208 constexpr QStringView(const Char *str) noexcept;
209#else
210
211 template <typename Pointer, if_compatible_pointer<Pointer> = true>
212 constexpr QStringView(const Pointer &str) noexcept
213 : QStringView(str, str ? lengthHelperPointer(str) : 0) {}
214#endif
215
216#ifdef Q_CLANG_QDOC
217 QStringView(const QString &str) noexcept;
218#else
219 template <typename String, if_compatible_qstring_like<String> = true>
220 QStringView(const String &str) noexcept
221 : QStringView(str.isNull() ? nullptr : str.data(), qsizetype(str.size())) {}
222#endif
223
224 template <typename Container, if_compatible_container<Container> = true>
225 constexpr QStringView(const Container &c) noexcept
226 : QStringView(std::data(c), lengthHelperContainer(c)) {}
227
228 template <typename Char, size_t Size, if_compatible_char<Char> = true>
229 [[nodiscard]] constexpr static QStringView fromArray(const Char (&string)[Size]) noexcept
230 { return QStringView(string, Size); }
231
232 [[nodiscard]] inline QString toString() const; // defined in qstring.h
233#if defined(Q_OS_DARWIN) || defined(Q_QDOC)
234 // defined in qcore_foundation.mm
235 [[nodiscard]] Q_CORE_EXPORT CFStringRef toCFString() const Q_DECL_CF_RETURNS_RETAINED;
236 [[nodiscard]] Q_CORE_EXPORT NSString *toNSString() const Q_DECL_NS_RETURNS_AUTORELEASED;
237#endif
238
239 [[nodiscard]] constexpr qsizetype size() const noexcept { return m_size; }
240 [[nodiscard]] const_pointer data() const noexcept { return reinterpret_cast<const_pointer>(m_data); }
241 [[nodiscard]] const_pointer constData() const noexcept { return data(); }
242 [[nodiscard]] constexpr const storage_type *utf16() const noexcept { return m_data; }
243
244 [[nodiscard]] constexpr QChar operator[](qsizetype n) const
245 { return Q_ASSERT(n >= 0), Q_ASSERT(n < size()), QChar(m_data[n]); }
246
247 //
248 // QString API
249 //
250
251 template <typename...Args>
252 [[nodiscard]] inline QString arg(Args &&...args) const; // defined in qstring.h
253
254 [[nodiscard]] QByteArray toLatin1() const { return QtPrivate::convertToLatin1(*this); }
255 [[nodiscard]] QByteArray toUtf8() const { return QtPrivate::convertToUtf8(*this); }
256 [[nodiscard]] QByteArray toLocal8Bit() const { return QtPrivate::convertToLocal8Bit(*this); }
257 [[nodiscard]] inline QList<uint> toUcs4() const; // defined in qlist.h ### Qt 7 char32_t
258
259 [[nodiscard]] constexpr QChar at(qsizetype n) const noexcept { return (*this)[n]; }
260
261 [[nodiscard]] constexpr QStringView mid(qsizetype pos, qsizetype n = -1) const noexcept
262 {
263 using namespace QtPrivate;
264 auto result = QContainerImplHelper::mid(size(), &pos, &n);
265 return result == QContainerImplHelper::Null ? QStringView() : QStringView(m_data + pos, n);
266 }
267 [[nodiscard]] constexpr QStringView left(qsizetype n) const noexcept
268 {
269 if (size_t(n) >= size_t(size()))
270 n = size();
271 return QStringView(m_data, n);
272 }
273 [[nodiscard]] constexpr QStringView right(qsizetype n) const noexcept
274 {
275 if (size_t(n) >= size_t(size()))
276 n = size();
277 return QStringView(m_data + m_size - n, n);
278 }
279
280 [[nodiscard]] constexpr QStringView first(qsizetype n) const noexcept
281 { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); return QStringView(m_data, n); }
282 [[nodiscard]] constexpr QStringView last(qsizetype n) const noexcept
283 { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); return QStringView(m_data + size() - n, n); }
284 [[nodiscard]] constexpr QStringView sliced(qsizetype pos) const noexcept
285 { Q_ASSERT(pos >= 0); Q_ASSERT(pos <= size()); return QStringView(m_data + pos, size() - pos); }
286 [[nodiscard]] constexpr QStringView sliced(qsizetype pos, qsizetype n) const noexcept
287 { Q_ASSERT(pos >= 0); Q_ASSERT(n >= 0); Q_ASSERT(size_t(pos) + size_t(n) <= size_t(size())); return QStringView(m_data + pos, n); }
288 [[nodiscard]] constexpr QStringView chopped(qsizetype n) const noexcept
289 { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, m_size - n); }
290
291 constexpr void truncate(qsizetype n) noexcept
292 { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size = n; }
293 constexpr void chop(qsizetype n) noexcept
294 { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size -= n; }
295
296 [[nodiscard]] QStringView trimmed() const noexcept { return QtPrivate::trimmed(*this); }
297
298 template <typename Needle, typename...Flags>
299 [[nodiscard]] constexpr inline auto tokenize(Needle &&needle, Flags...flags) const
300 noexcept(noexcept(qTokenize(std::declval<const QStringView&>(), std::forward<Needle>(needle), flags...)))
301 -> decltype(qTokenize(*this, std::forward<Needle>(needle), flags...))
302 { return qTokenize(*this, std::forward<Needle>(needle), flags...); }
303
304 [[nodiscard]] int compare(QStringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
305 { return QtPrivate::compareStrings(*this, other, cs); }
306 [[nodiscard]] inline int compare(QLatin1String other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
307 [[nodiscard]] constexpr int compare(QChar c) const noexcept
308 { return size() >= 1 ? compare_single_char_helper(*utf16() - c.unicode()) : -1; }
309 [[nodiscard]] int compare(QChar c, Qt::CaseSensitivity cs) const noexcept
310 { return QtPrivate::compareStrings(*this, QStringView(&c, 1), cs); }
311
312 [[nodiscard]] bool startsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
313 { return QtPrivate::startsWith(*this, s, cs); }
314 [[nodiscard]] inline bool startsWith(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
315 [[nodiscard]] bool startsWith(QChar c) const noexcept
316 { return !empty() && front() == c; }
317 [[nodiscard]] bool startsWith(QChar c, Qt::CaseSensitivity cs) const noexcept
318 { return QtPrivate::startsWith(*this, QStringView(&c, 1), cs); }
319
320 [[nodiscard]] bool endsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
321 { return QtPrivate::endsWith(*this, s, cs); }
322 [[nodiscard]] inline bool endsWith(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
323 [[nodiscard]] bool endsWith(QChar c) const noexcept
324 { return !empty() && back() == c; }
325 [[nodiscard]] bool endsWith(QChar c, Qt::CaseSensitivity cs) const noexcept
326 { return QtPrivate::endsWith(*this, QStringView(&c, 1), cs); }
327
328 [[nodiscard]] qsizetype indexOf(QChar c, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
329 { return QtPrivate::findString(*this, from, QStringView(&c, 1), cs); }
330 [[nodiscard]] qsizetype indexOf(QStringView s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
331 { return QtPrivate::findString(*this, from, s, cs); }
332 [[nodiscard]] inline qsizetype indexOf(QLatin1String s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
333
334 [[nodiscard]] bool contains(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
335 { return indexOf(QStringView(&c, 1), 0, cs) != qsizetype(-1); }
336 [[nodiscard]] bool contains(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
337 { return indexOf(s, 0, cs) != qsizetype(-1); }
338 [[nodiscard]] inline bool contains(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
339
340 [[nodiscard]] qsizetype count(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
341 { return QtPrivate::count(*this, c, cs); }
342 [[nodiscard]] qsizetype count(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
343 { return QtPrivate::count(*this, s, cs); }
344
345 [[nodiscard]] qsizetype lastIndexOf(QChar c, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
346 { return QtPrivate::lastIndexOf(*this, from, QStringView(&c, 1), cs); }
347 [[nodiscard]] qsizetype lastIndexOf(QStringView s, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
348 { return QtPrivate::lastIndexOf(*this, from, s, cs); }
349 [[nodiscard]] inline qsizetype lastIndexOf(QLatin1String s, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
350
351#if QT_CONFIG(regularexpression)
352 [[nodiscard]] qsizetype indexOf(const QRegularExpression &re, qsizetype from = 0, QRegularExpressionMatch *rmatch = nullptr) const
353 {
354 return QtPrivate::indexOf(*this, re, from, rmatch);
355 }
356 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, qsizetype from = -1, QRegularExpressionMatch *rmatch = nullptr) const
357 {
358 return QtPrivate::lastIndexOf(*this, re, from, rmatch);
359 }
360 [[nodiscard]] bool contains(const QRegularExpression &re, QRegularExpressionMatch *rmatch = nullptr) const
361 {
362 return QtPrivate::contains(*this, re, rmatch);
363 }
364 [[nodiscard]] qsizetype count(const QRegularExpression &re) const
365 {
366 return QtPrivate::count(*this, re);
367 }
368#endif
369
370 [[nodiscard]] bool isRightToLeft() const noexcept
371 { return QtPrivate::isRightToLeft(*this); }
372 [[nodiscard]] bool isValidUtf16() const noexcept
373 { return QtPrivate::isValidUtf16(*this); }
374
375 [[nodiscard]] inline short toShort(bool *ok = nullptr, int base = 10) const;
376 [[nodiscard]] inline ushort toUShort(bool *ok = nullptr, int base = 10) const;
377 [[nodiscard]] inline int toInt(bool *ok = nullptr, int base = 10) const;
378 [[nodiscard]] inline uint toUInt(bool *ok = nullptr, int base = 10) const;
379 [[nodiscard]] inline long toLong(bool *ok = nullptr, int base = 10) const;
380 [[nodiscard]] inline ulong toULong(bool *ok = nullptr, int base = 10) const;
381 [[nodiscard]] inline qlonglong toLongLong(bool *ok = nullptr, int base = 10) const;
382 [[nodiscard]] inline qulonglong toULongLong(bool *ok = nullptr, int base = 10) const;
383 [[nodiscard]] Q_CORE_EXPORT float toFloat(bool *ok = nullptr) const;
384 [[nodiscard]] Q_CORE_EXPORT double toDouble(bool *ok = nullptr) const;
385
386 [[nodiscard]] inline qsizetype toWCharArray(wchar_t *array) const; // defined in qstring.h
387
388
389 [[nodiscard]] Q_CORE_EXPORT
390 QList<QStringView> split(QStringView sep,
391 Qt::SplitBehavior behavior = Qt::KeepEmptyParts,
392 Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
393 [[nodiscard]] Q_CORE_EXPORT
394 QList<QStringView> split(QChar sep, Qt::SplitBehavior behavior = Qt::KeepEmptyParts,
395 Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
396
397#if QT_CONFIG(regularexpression)
398 [[nodiscard]] Q_CORE_EXPORT
399 QList<QStringView> split(const QRegularExpression &sep,
400 Qt::SplitBehavior behavior = Qt::KeepEmptyParts) const;
401#endif
402
403 // QStringView <> QStringView
404 friend bool operator==(QStringView lhs, QStringView rhs) noexcept { return lhs.size() == rhs.size() && QtPrivate::equalStrings(lhs, rhs); }
405 friend bool operator!=(QStringView lhs, QStringView rhs) noexcept { return !(lhs == rhs); }
406 friend bool operator< (QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) < 0; }
407 friend bool operator<=(QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) <= 0; }
408 friend bool operator> (QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) > 0; }
409 friend bool operator>=(QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) >= 0; }
410
411 // QStringView <> QChar
412 friend bool operator==(QStringView lhs, QChar rhs) noexcept { return lhs == QStringView(&rhs, 1); }
413 friend bool operator!=(QStringView lhs, QChar rhs) noexcept { return lhs != QStringView(&rhs, 1); }
414 friend bool operator< (QStringView lhs, QChar rhs) noexcept { return lhs < QStringView(&rhs, 1); }
415 friend bool operator<=(QStringView lhs, QChar rhs) noexcept { return lhs <= QStringView(&rhs, 1); }
416 friend bool operator> (QStringView lhs, QChar rhs) noexcept { return lhs > QStringView(&rhs, 1); }
417 friend bool operator>=(QStringView lhs, QChar rhs) noexcept { return lhs >= QStringView(&rhs, 1); }
418
419 friend bool operator==(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) == rhs; }
420 friend bool operator!=(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) != rhs; }
421 friend bool operator< (QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) < rhs; }
422 friend bool operator<=(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) <= rhs; }
423 friend bool operator> (QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) > rhs; }
424 friend bool operator>=(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) >= rhs; }
425
426 //
427 // STL compatibility API:
428 //
429 [[nodiscard]] const_iterator begin() const noexcept { return data(); }
430 [[nodiscard]] const_iterator end() const noexcept { return data() + size(); }
431 [[nodiscard]] const_iterator cbegin() const noexcept { return begin(); }
432 [[nodiscard]] const_iterator cend() const noexcept { return end(); }
433 [[nodiscard]] const_reverse_iterator rbegin() const noexcept { return const_reverse_iterator(end()); }
434 [[nodiscard]] const_reverse_iterator rend() const noexcept { return const_reverse_iterator(begin()); }
435 [[nodiscard]] const_reverse_iterator crbegin() const noexcept { return rbegin(); }
436 [[nodiscard]] const_reverse_iterator crend() const noexcept { return rend(); }
437
438 [[nodiscard]] constexpr bool empty() const noexcept { return size() == 0; }
439 [[nodiscard]] constexpr QChar front() const { return Q_ASSERT(!empty()), QChar(m_data[0]); }
440 [[nodiscard]] constexpr QChar back() const { return Q_ASSERT(!empty()), QChar(m_data[m_size - 1]); }
441
442 //
443 // Qt compatibility API:
444 //
445 [[nodiscard]] const_iterator constBegin() const noexcept { return begin(); }
446 [[nodiscard]] const_iterator constEnd() const noexcept { return end(); }
447 [[nodiscard]] constexpr bool isNull() const noexcept { return !m_data; }
448 [[nodiscard]] constexpr bool isEmpty() const noexcept { return empty(); }
449 [[nodiscard]] constexpr qsizetype length() const noexcept
450 { return size(); }
451 [[nodiscard]] constexpr QChar first() const { return front(); }
452 [[nodiscard]] constexpr QChar last() const { return back(); }
453private:
454 qsizetype m_size;
455 const storage_type *m_data;
456
457 constexpr int compare_single_char_helper(int diff) const noexcept
458 { return diff ? diff : size() > 1 ? 1 : 0; }
459};
460Q_DECLARE_TYPEINFO(QStringView, Q_PRIMITIVE_TYPE);
461
462template <typename QStringLike, typename std::enable_if<
463 std::is_same<QStringLike, QString>::value,
464 bool>::type = true>
465inline QStringView qToStringViewIgnoringNull(const QStringLike &s) noexcept
466{ return QStringView(s.data(), s.size()); }
467
468// QChar inline functions:
469
470[[nodiscard]] constexpr auto QChar::fromUcs4(char32_t c) noexcept
471{
472 struct R {
473 char16_t chars[2];
474 [[nodiscard]] constexpr operator QStringView() const noexcept { return {begin(), end()}; }
475 [[nodiscard]] constexpr qsizetype size() const noexcept { return chars[1] ? 2 : 1; }
476 [[nodiscard]] constexpr const char16_t *begin() const noexcept { return chars; }
477 [[nodiscard]] constexpr const char16_t *end() const noexcept { return begin() + size(); }
478 };
479 return requiresSurrogates(c) ? R{{QChar::highSurrogate(c),
480 QChar::lowSurrogate(c)}} :
481 R{{char16_t(c), u'\0'}} ;
482}
483
484QT_END_NAMESPACE
485
486#endif /* QSTRINGVIEW_H */
487