1// Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
2// Copyright (C) 2019 Mail.ru Group.
3// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
4#ifndef QSTRINGVIEW_H
5#define QSTRINGVIEW_H
6
7#include <QtCore/qchar.h>
8#include <QtCore/qbytearray.h>
9#include <QtCore/qstringliteral.h>
10#include <QtCore/qstringalgorithms.h>
11
12#include <string>
13#include <string_view>
14#include <QtCore/q20type_traits.h>
15
16#if defined(Q_OS_DARWIN) || defined(Q_QDOC)
17Q_FORWARD_DECLARE_CF_TYPE(CFString);
18Q_FORWARD_DECLARE_OBJC_CLASS(NSString);
19#endif
20
21QT_BEGIN_NAMESPACE
22
23class QString;
24class QStringView;
25class QRegularExpression;
26class QRegularExpressionMatch;
27#ifdef Q_QDOC
28class QUtf8StringView;
29#endif
30
31namespace QtPrivate {
32template <typename Char>
33struct IsCompatibleCharTypeHelper
34 : std::integral_constant<bool,
35 std::is_same<Char, QChar>::value ||
36 std::is_same<Char, ushort>::value ||
37 std::is_same<Char, char16_t>::value ||
38 (std::is_same<Char, wchar_t>::value && sizeof(wchar_t) == sizeof(QChar))> {};
39template <typename Char>
40struct IsCompatibleCharType
41 : IsCompatibleCharTypeHelper<q20::remove_cvref_t<Char>> {};
42
43template <typename Pointer>
44struct IsCompatiblePointerHelper : std::false_type {};
45template <typename Char>
46struct IsCompatiblePointerHelper<Char*>
47 : IsCompatibleCharType<Char> {};
48template <typename Pointer>
49struct IsCompatiblePointer
50 : IsCompatiblePointerHelper<q20::remove_cvref_t<Pointer>> {};
51
52template <typename T, typename Enable = void>
53struct IsContainerCompatibleWithQStringView : std::false_type {};
54
55template <typename T>
56struct IsContainerCompatibleWithQStringView<T, std::enable_if_t<std::conjunction_v<
57 // lacking concepts and ranges, we accept any T whose std::data yields a suitable pointer ...
58 IsCompatiblePointer<decltype( std::data(std::declval<const T &>()) )>,
59 // ... and that has a suitable size ...
60 std::is_convertible<decltype( std::size(std::declval<const T &>()) ), qsizetype>,
61 // ... and it's a range as it defines an iterator-like API
62 IsCompatibleCharType<typename std::iterator_traits<decltype( std::begin(std::declval<const T &>()) )>::value_type>,
63 std::is_convertible<
64 decltype( std::begin(std::declval<const T &>()) != std::end(std::declval<const T &>()) ),
65 bool>,
66
67 // These need to be treated specially due to the empty vs null distinction
68 std::negation<std::is_same<std::decay_t<T>, QString>>,
69
70 // Don't make an accidental copy constructor
71 std::negation<std::is_same<std::decay_t<T>, QStringView>>
72 >>> : std::true_type {};
73
74} // namespace QtPrivate
75
76class QStringView
77{
78public:
79 typedef char16_t storage_type;
80 typedef const QChar value_type;
81 typedef std::ptrdiff_t difference_type;
82 typedef qsizetype size_type;
83 typedef value_type &reference;
84 typedef value_type &const_reference;
85 typedef value_type *pointer;
86 typedef value_type *const_pointer;
87
88 typedef pointer iterator;
89 typedef const_pointer const_iterator;
90 typedef std::reverse_iterator<iterator> reverse_iterator;
91 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
92
93private:
94 template <typename Char>
95 using if_compatible_char = typename std::enable_if<QtPrivate::IsCompatibleCharType<Char>::value, bool>::type;
96
97 template <typename Pointer>
98 using if_compatible_pointer = typename std::enable_if<QtPrivate::IsCompatiblePointer<Pointer>::value, bool>::type;
99
100 template <typename T>
101 using if_compatible_qstring_like = typename std::enable_if<std::is_same<T, QString>::value, bool>::type;
102
103 template <typename T>
104 using if_compatible_container = typename std::enable_if<QtPrivate::IsContainerCompatibleWithQStringView<T>::value, bool>::type;
105
106 template <typename Char>
107 static constexpr qsizetype lengthHelperPointer(const Char *str) noexcept
108 {
109 if (q20::is_constant_evaluated())
110 return std::char_traits<Char>::length(str);
111 return QtPrivate::qustrlen(str: reinterpret_cast<const char16_t *>(str));
112 }
113 static qsizetype lengthHelperPointer(const QChar *str) noexcept
114 {
115 return QtPrivate::qustrlen(str: reinterpret_cast<const char16_t *>(str));
116 }
117
118 template <typename Char>
119 static const storage_type *castHelper(const Char *str) noexcept
120 { return reinterpret_cast<const storage_type*>(str); }
121 static constexpr const storage_type *castHelper(const storage_type *str) noexcept
122 { return str; }
123
124public:
125 constexpr QStringView() noexcept {}
126 constexpr QStringView(std::nullptr_t) noexcept
127 : QStringView() {}
128
129 template <typename Char, if_compatible_char<Char> = true>
130 constexpr QStringView(const Char *str, qsizetype len)
131#if QT_VERSION >= QT_VERSION_CHECK(7, 0, 0) || defined(QT_BOOTSTRAPPED)
132 : m_data(castHelper(str)),
133 m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len))
134#else
135 : m_size((Q_ASSERT(len >= 0), Q_ASSERT(str || !len), len)),
136 m_data(castHelper(str))
137#endif
138 {}
139
140 template <typename Char, if_compatible_char<Char> = true>
141 constexpr QStringView(const Char *f, const Char *l)
142 : QStringView(f, l - f) {}
143
144#ifdef Q_QDOC
145 template <typename Char, size_t N>
146 constexpr QStringView(const Char (&array)[N]) noexcept;
147
148 template <typename Char>
149 constexpr QStringView(const Char *str) noexcept;
150#else
151
152 template <typename Pointer, if_compatible_pointer<Pointer> = true>
153 constexpr QStringView(const Pointer &str) noexcept
154 : QStringView(str, str ? lengthHelperPointer(str) : 0) {}
155#endif
156
157#ifdef Q_QDOC
158 QStringView(const QString &str) noexcept;
159#else
160 template <typename String, if_compatible_qstring_like<String> = true>
161 QStringView(const String &str) noexcept
162 : QStringView(str.isNull() ? nullptr : str.data(), qsizetype(str.size())) {}
163#endif
164
165 template <typename Container, if_compatible_container<Container> = true>
166 constexpr Q_ALWAYS_INLINE QStringView(const Container &c) noexcept
167 : QStringView(std::data(c), QtPrivate::lengthHelperContainer(c)) {}
168
169 template <typename Char, size_t Size, if_compatible_char<Char> = true>
170 [[nodiscard]] constexpr static QStringView fromArray(const Char (&string)[Size]) noexcept
171 { return QStringView(string, Size); }
172
173 [[nodiscard]] inline QString toString() const; // defined in qstring.h
174#if defined(Q_OS_DARWIN) || defined(Q_QDOC)
175 // defined in qcore_foundation.mm
176 [[nodiscard]] Q_CORE_EXPORT CFStringRef toCFString() const Q_DECL_CF_RETURNS_RETAINED;
177 [[nodiscard]] Q_CORE_EXPORT NSString *toNSString() const Q_DECL_NS_RETURNS_AUTORELEASED;
178#endif
179
180 [[nodiscard]] constexpr qsizetype size() const noexcept { return m_size; }
181 [[nodiscard]] const_pointer data() const noexcept { return reinterpret_cast<const_pointer>(m_data); }
182 [[nodiscard]] const_pointer constData() const noexcept { return data(); }
183 [[nodiscard]] constexpr const storage_type *utf16() const noexcept { return m_data; }
184
185 [[nodiscard]] constexpr QChar operator[](qsizetype n) const
186 { verify(pos: n, n: 1); return QChar(m_data[n]); }
187
188 //
189 // QString API
190 //
191
192 template <typename...Args>
193 [[nodiscard]] inline QString arg(Args &&...args) const; // defined in qstring.h
194
195 [[nodiscard]] QByteArray toLatin1() const { return QtPrivate::convertToLatin1(str: *this); }
196 [[nodiscard]] QByteArray toUtf8() const { return QtPrivate::convertToUtf8(str: *this); }
197 [[nodiscard]] QByteArray toLocal8Bit() const { return QtPrivate::convertToLocal8Bit(str: *this); }
198 [[nodiscard]] inline QList<uint> toUcs4() const; // defined in qlist.h ### Qt 7 char32_t
199
200 [[nodiscard]] constexpr QChar at(qsizetype n) const noexcept { return (*this)[n]; }
201
202 [[nodiscard]] constexpr QStringView mid(qsizetype pos, qsizetype n = -1) const noexcept
203 {
204 using namespace QtPrivate;
205 auto result = QContainerImplHelper::mid(originalLength: size(), position: &pos, length: &n);
206 return result == QContainerImplHelper::Null ? QStringView() : QStringView(m_data + pos, n);
207 }
208 [[nodiscard]] constexpr QStringView left(qsizetype n) const noexcept
209 {
210 if (size_t(n) >= size_t(size()))
211 n = size();
212 return QStringView(m_data, n);
213 }
214 [[nodiscard]] constexpr QStringView right(qsizetype n) const noexcept
215 {
216 if (size_t(n) >= size_t(size()))
217 n = size();
218 return QStringView(m_data + m_size - n, n);
219 }
220
221 [[nodiscard]] constexpr QStringView first(qsizetype n) const noexcept
222 { verify(pos: 0, n); return sliced(pos: 0, n); }
223 [[nodiscard]] constexpr QStringView last(qsizetype n) const noexcept
224 { verify(pos: 0, n); return sliced(pos: size() - n, n); }
225 [[nodiscard]] constexpr QStringView sliced(qsizetype pos) const noexcept
226 { verify(pos, n: 0); return QStringView(m_data + pos, size() - pos); }
227 [[nodiscard]] constexpr QStringView sliced(qsizetype pos, qsizetype n) const noexcept
228 { verify(pos, n); return QStringView(m_data + pos, n); }
229 [[nodiscard]] constexpr QStringView chopped(qsizetype n) const noexcept
230 { verify(pos: 0, n); return sliced(pos: 0, n: m_size - n); }
231
232 constexpr void truncate(qsizetype n) noexcept
233 { verify(pos: 0, n); ; m_size = n; }
234 constexpr void chop(qsizetype n) noexcept
235 { verify(pos: 0, n); m_size -= n; }
236
237 [[nodiscard]] QStringView trimmed() const noexcept { return QtPrivate::trimmed(s: *this); }
238
239 template <typename Needle, typename...Flags>
240 [[nodiscard]] constexpr inline auto tokenize(Needle &&needle, Flags...flags) const
241 noexcept(noexcept(qTokenize(std::declval<const QStringView&>(), std::forward<Needle>(needle), flags...)))
242 -> decltype(qTokenize(*this, std::forward<Needle>(needle), flags...))
243 { return qTokenize(*this, std::forward<Needle>(needle), flags...); }
244
245 [[nodiscard]] int compare(QStringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
246 { return QtPrivate::compareStrings(lhs: *this, rhs: other, cs); }
247 [[nodiscard]] inline int compare(QLatin1StringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
248 [[nodiscard]] inline int compare(QUtf8StringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
249 [[nodiscard]] constexpr int compare(QChar c) const noexcept
250 { return size() >= 1 ? compare_single_char_helper(diff: *utf16() - c.unicode()) : -1; }
251 [[nodiscard]] int compare(QChar c, Qt::CaseSensitivity cs) const noexcept
252 { return QtPrivate::compareStrings(lhs: *this, rhs: QStringView(&c, 1), cs); }
253
254 [[nodiscard]] inline int localeAwareCompare(QStringView other) const;
255
256 [[nodiscard]] bool startsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
257 { return QtPrivate::startsWith(haystack: *this, needle: s, cs); }
258 [[nodiscard]] inline bool startsWith(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
259 [[nodiscard]] bool startsWith(QChar c) const noexcept
260 { return !empty() && front() == c; }
261 [[nodiscard]] bool startsWith(QChar c, Qt::CaseSensitivity cs) const noexcept
262 { return QtPrivate::startsWith(haystack: *this, needle: QStringView(&c, 1), cs); }
263
264 [[nodiscard]] bool endsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
265 { return QtPrivate::endsWith(haystack: *this, needle: s, cs); }
266 [[nodiscard]] inline bool endsWith(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
267 [[nodiscard]] bool endsWith(QChar c) const noexcept
268 { return !empty() && back() == c; }
269 [[nodiscard]] bool endsWith(QChar c, Qt::CaseSensitivity cs) const noexcept
270 { return QtPrivate::endsWith(haystack: *this, needle: QStringView(&c, 1), cs); }
271
272 [[nodiscard]] qsizetype indexOf(QChar c, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
273 { return QtPrivate::findString(haystack: *this, from, needle: QStringView(&c, 1), cs); }
274 [[nodiscard]] qsizetype indexOf(QStringView s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
275 { return QtPrivate::findString(haystack: *this, from, needle: s, cs); }
276 [[nodiscard]] inline qsizetype indexOf(QLatin1StringView s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
277
278 [[nodiscard]] bool contains(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
279 { return indexOf(s: QStringView(&c, 1), from: 0, cs) != qsizetype(-1); }
280 [[nodiscard]] bool contains(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
281 { return indexOf(s, from: 0, cs) != qsizetype(-1); }
282 [[nodiscard]] inline bool contains(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
283
284 [[nodiscard]] qsizetype count(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
285 { return QtPrivate::count(haystack: *this, needle: c, cs); }
286 [[nodiscard]] qsizetype count(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
287 { return QtPrivate::count(haystack: *this, needle: s, cs); }
288 [[nodiscard]] inline qsizetype count(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
289
290 [[nodiscard]] qsizetype lastIndexOf(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
291 { return lastIndexOf(c, from: -1, cs); }
292 [[nodiscard]] qsizetype lastIndexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
293 { return QtPrivate::lastIndexOf(haystack: *this, from, needle: QStringView(&c, 1), cs); }
294 [[nodiscard]] qsizetype lastIndexOf(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
295 { return lastIndexOf(s, from: size(), cs); }
296 [[nodiscard]] qsizetype lastIndexOf(QStringView s, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
297 { return QtPrivate::lastIndexOf(haystack: *this, from, needle: s, cs); }
298 [[nodiscard]] inline qsizetype lastIndexOf(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
299 [[nodiscard]] inline qsizetype lastIndexOf(QLatin1StringView s, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
300
301#if QT_CONFIG(regularexpression)
302 [[nodiscard]] qsizetype indexOf(const QRegularExpression &re, qsizetype from = 0, QRegularExpressionMatch *rmatch = nullptr) const
303 {
304 return QtPrivate::indexOf(haystack: *this, re, from, rmatch);
305 }
306#ifdef Q_QDOC
307 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, QRegularExpressionMatch *rmatch = nullptr) const;
308#else
309 // prevent an ambiguity when called like this: lastIndexOf(re, 0)
310 template <typename T = QRegularExpressionMatch, std::enable_if_t<std::is_same_v<T, QRegularExpressionMatch>, bool> = false>
311 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, T *rmatch = nullptr) const
312 {
313 return QtPrivate::lastIndexOf(*this, re, size(), rmatch);
314 }
315#endif
316 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, qsizetype from, QRegularExpressionMatch *rmatch = nullptr) const
317 {
318 return QtPrivate::lastIndexOf(haystack: *this, re, from, rmatch);
319 }
320 [[nodiscard]] bool contains(const QRegularExpression &re, QRegularExpressionMatch *rmatch = nullptr) const
321 {
322 return QtPrivate::contains(haystack: *this, re, rmatch);
323 }
324 [[nodiscard]] qsizetype count(const QRegularExpression &re) const
325 {
326 return QtPrivate::count(haystack: *this, re);
327 }
328#endif
329
330 [[nodiscard]] bool isRightToLeft() const noexcept
331 { return QtPrivate::isRightToLeft(string: *this); }
332 [[nodiscard]] bool isValidUtf16() const noexcept
333 { return QtPrivate::isValidUtf16(s: *this); }
334
335 [[nodiscard]] bool isUpper() const noexcept
336 { return QtPrivate::isUpper(s: *this); }
337 [[nodiscard]] bool isLower() const noexcept
338 { return QtPrivate::isLower(s: *this); }
339
340 [[nodiscard]] inline short toShort(bool *ok = nullptr, int base = 10) const;
341 [[nodiscard]] inline ushort toUShort(bool *ok = nullptr, int base = 10) const;
342 [[nodiscard]] inline int toInt(bool *ok = nullptr, int base = 10) const;
343 [[nodiscard]] inline uint toUInt(bool *ok = nullptr, int base = 10) const;
344 [[nodiscard]] inline long toLong(bool *ok = nullptr, int base = 10) const;
345 [[nodiscard]] inline ulong toULong(bool *ok = nullptr, int base = 10) const;
346 [[nodiscard]] inline qlonglong toLongLong(bool *ok = nullptr, int base = 10) const;
347 [[nodiscard]] inline qulonglong toULongLong(bool *ok = nullptr, int base = 10) const;
348 [[nodiscard]] Q_CORE_EXPORT float toFloat(bool *ok = nullptr) const;
349 [[nodiscard]] Q_CORE_EXPORT double toDouble(bool *ok = nullptr) const;
350
351 [[nodiscard]] inline qsizetype toWCharArray(wchar_t *array) const; // defined in qstring.h
352
353
354 [[nodiscard]] Q_CORE_EXPORT
355 QList<QStringView> split(QStringView sep,
356 Qt::SplitBehavior behavior = Qt::KeepEmptyParts,
357 Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
358 [[nodiscard]] Q_CORE_EXPORT
359 QList<QStringView> split(QChar sep, Qt::SplitBehavior behavior = Qt::KeepEmptyParts,
360 Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
361
362#if QT_CONFIG(regularexpression)
363 [[nodiscard]] Q_CORE_EXPORT
364 QList<QStringView> split(const QRegularExpression &sep,
365 Qt::SplitBehavior behavior = Qt::KeepEmptyParts) const;
366#endif
367
368 // QStringView <> QStringView
369 friend bool operator==(QStringView lhs, QStringView rhs) noexcept { return lhs.size() == rhs.size() && QtPrivate::equalStrings(lhs, rhs); }
370 friend bool operator!=(QStringView lhs, QStringView rhs) noexcept { return !(lhs == rhs); }
371 friend bool operator< (QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) < 0; }
372 friend bool operator<=(QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) <= 0; }
373 friend bool operator> (QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) > 0; }
374 friend bool operator>=(QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) >= 0; }
375
376 // QStringView <> QChar
377 friend bool operator==(QStringView lhs, QChar rhs) noexcept { return lhs == QStringView(&rhs, 1); }
378 friend bool operator!=(QStringView lhs, QChar rhs) noexcept { return lhs != QStringView(&rhs, 1); }
379 friend bool operator< (QStringView lhs, QChar rhs) noexcept { return lhs < QStringView(&rhs, 1); }
380 friend bool operator<=(QStringView lhs, QChar rhs) noexcept { return lhs <= QStringView(&rhs, 1); }
381 friend bool operator> (QStringView lhs, QChar rhs) noexcept { return lhs > QStringView(&rhs, 1); }
382 friend bool operator>=(QStringView lhs, QChar rhs) noexcept { return lhs >= QStringView(&rhs, 1); }
383
384 friend bool operator==(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) == rhs; }
385 friend bool operator!=(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) != rhs; }
386 friend bool operator< (QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) < rhs; }
387 friend bool operator<=(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) <= rhs; }
388 friend bool operator> (QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) > rhs; }
389 friend bool operator>=(QChar lhs, QStringView rhs) noexcept { return QStringView(&lhs, 1) >= rhs; }
390
391 //
392 // STL compatibility API:
393 //
394 [[nodiscard]] const_iterator begin() const noexcept { return data(); }
395 [[nodiscard]] const_iterator end() const noexcept { return data() + size(); }
396 [[nodiscard]] const_iterator cbegin() const noexcept { return begin(); }
397 [[nodiscard]] const_iterator cend() const noexcept { return end(); }
398 [[nodiscard]] const_reverse_iterator rbegin() const noexcept { return const_reverse_iterator(end()); }
399 [[nodiscard]] const_reverse_iterator rend() const noexcept { return const_reverse_iterator(begin()); }
400 [[nodiscard]] const_reverse_iterator crbegin() const noexcept { return rbegin(); }
401 [[nodiscard]] const_reverse_iterator crend() const noexcept { return rend(); }
402
403 [[nodiscard]] constexpr bool empty() const noexcept { return size() == 0; }
404 [[nodiscard]] constexpr QChar front() const { return Q_ASSERT(!empty()), QChar(m_data[0]); }
405 [[nodiscard]] constexpr QChar back() const { return Q_ASSERT(!empty()), QChar(m_data[m_size - 1]); }
406
407 [[nodiscard]] Q_IMPLICIT operator std::u16string_view() const noexcept
408 { return std::u16string_view(m_data, size_t(m_size)); }
409
410 //
411 // Qt compatibility API:
412 //
413 [[nodiscard]] const_iterator constBegin() const noexcept { return begin(); }
414 [[nodiscard]] const_iterator constEnd() const noexcept { return end(); }
415 [[nodiscard]] constexpr bool isNull() const noexcept { return !m_data; }
416 [[nodiscard]] constexpr bool isEmpty() const noexcept { return empty(); }
417 [[nodiscard]] constexpr qsizetype length() const noexcept
418 { return size(); }
419 [[nodiscard]] constexpr QChar first() const { return front(); }
420 [[nodiscard]] constexpr QChar last() const { return back(); }
421private:
422#if QT_VERSION >= QT_VERSION_CHECK(7, 0, 0) || defined(QT_BOOTSTRAPPED)
423 const storage_type *m_data = nullptr;
424 qsizetype m_size = 0;
425#else
426 qsizetype m_size = 0;
427 const storage_type *m_data = nullptr;
428#endif
429
430 Q_ALWAYS_INLINE constexpr void verify([[maybe_unused]] qsizetype pos = 0,
431 [[maybe_unused]] qsizetype n = 1) const
432 {
433 Q_ASSERT(pos >= 0);
434 Q_ASSERT(pos <= size());
435 Q_ASSERT(n >= 0);
436 Q_ASSERT(n <= size() - pos);
437 }
438
439 constexpr int compare_single_char_helper(int diff) const noexcept
440 { return diff ? diff : size() > 1 ? 1 : 0; }
441};
442Q_DECLARE_TYPEINFO(QStringView, Q_PRIMITIVE_TYPE);
443
444template <typename QStringLike, typename std::enable_if<
445 std::is_same<QStringLike, QString>::value,
446 bool>::type = true>
447inline QStringView qToStringViewIgnoringNull(const QStringLike &s) noexcept
448{ return QStringView(s.data(), s.size()); }
449
450// QChar inline functions:
451
452[[nodiscard]] constexpr auto QChar::fromUcs4(char32_t c) noexcept
453{
454 struct R {
455 char16_t chars[2];
456 [[nodiscard]] constexpr operator QStringView() const noexcept { return {begin(), end()}; }
457 [[nodiscard]] constexpr qsizetype size() const noexcept { return chars[1] ? 2 : 1; }
458 [[nodiscard]] constexpr const char16_t *begin() const noexcept { return chars; }
459 [[nodiscard]] constexpr const char16_t *end() const noexcept { return begin() + size(); }
460 };
461 return requiresSurrogates(ucs4: c) ? R{.chars: {QChar::highSurrogate(ucs4: c),
462 QChar::lowSurrogate(ucs4: c)}} :
463 R{.chars: {char16_t(c), u'\0'}} ;
464}
465
466QT_END_NAMESPACE
467
468#endif /* QSTRINGVIEW_H */
469