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/qcompare.h>
9#include <QtCore/qcontainerfwd.h>
10#include <QtCore/qbytearray.h>
11#include <QtCore/qstringfwd.h>
12#include <QtCore/qstringliteral.h>
13#include <QtCore/qstringalgorithms.h>
14
15#include <string>
16#include <string_view>
17#include <QtCore/q20type_traits.h>
18
19#if defined(Q_OS_DARWIN) || defined(Q_QDOC)
20Q_FORWARD_DECLARE_CF_TYPE(CFString);
21Q_FORWARD_DECLARE_OBJC_CLASS(NSString);
22#endif
23
24QT_BEGIN_NAMESPACE
25
26class QRegularExpression;
27class QRegularExpressionMatch;
28
29namespace QtPrivate {
30template <typename Char>
31struct IsCompatibleCharTypeHelper
32 : std::integral_constant<bool,
33 std::is_same<Char, QChar>::value ||
34 std::is_same<Char, ushort>::value ||
35 std::is_same<Char, char16_t>::value ||
36 (std::is_same<Char, wchar_t>::value && sizeof(wchar_t) == sizeof(QChar))> {};
37template <typename Char>
38struct IsCompatibleCharType
39 : IsCompatibleCharTypeHelper<q20::remove_cvref_t<Char>> {};
40
41template <typename Pointer>
42struct IsCompatiblePointerHelper : std::false_type {};
43template <typename Char>
44struct IsCompatiblePointerHelper<Char*>
45 : IsCompatibleCharType<Char> {};
46template <typename Pointer>
47struct IsCompatiblePointer
48 : IsCompatiblePointerHelper<q20::remove_cvref_t<Pointer>> {};
49
50template <typename T, typename Enable = void>
51struct IsContainerCompatibleWithQStringView : std::false_type {};
52
53template <typename T>
54struct IsContainerCompatibleWithQStringView<T, std::enable_if_t<std::conjunction_v<
55 // lacking concepts and ranges, we accept any T whose std::data yields a suitable pointer ...
56 IsCompatiblePointer<decltype( std::data(std::declval<const T &>()) )>,
57 // ... and that has a suitable size ...
58 std::is_convertible<decltype( std::size(std::declval<const T &>()) ), qsizetype>,
59 // ... and it's a range as it defines an iterator-like API
60 IsCompatibleCharType<typename std::iterator_traits<decltype( std::begin(std::declval<const T &>()) )>::value_type>,
61 std::is_convertible<
62 decltype( std::begin(std::declval<const T &>()) != std::end(std::declval<const T &>()) ),
63 bool>,
64
65 // These need to be treated specially due to the empty vs null distinction
66 std::negation<std::is_same<std::decay_t<T>, QString>>,
67#define QSTRINGVIEW_REFUSES_QSTRINGREF 1
68 std::negation<std::is_same<q20::remove_cvref_t<T>, QStringRef>>, // QStringRef::op QStringView()
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 QtPrivate::lengthHelperPointer(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 template <typename Pointer, if_compatible_pointer<Pointer> = true>
152 constexpr QStringView(const Pointer &str) noexcept
153 : QStringView(str, str ? lengthHelperPointer(str) : 0) {}
154
155 template <typename Char, if_compatible_char<Char> = true>
156 constexpr QStringView(const Char (&str)[]) noexcept // array of unknown bounds
157 : QStringView{&*str} {} // decay to pointer
158#endif
159
160#ifdef Q_QDOC
161 QStringView(const QString &str) noexcept;
162#else
163 template <typename String, if_compatible_qstring_like<String> = true>
164 QStringView(const String &str) noexcept
165 : QStringView{str.begin(), str.size()} {}
166#endif
167
168 template <typename Container, if_compatible_container<Container> = true>
169 constexpr Q_ALWAYS_INLINE QStringView(const Container &c) noexcept
170 : QStringView(std::data(c), QtPrivate::lengthHelperContainer(c)) {}
171
172 template <typename Char, size_t Size, if_compatible_char<Char> = true>
173 [[nodiscard]] constexpr static QStringView fromArray(const Char (&string)[Size]) noexcept
174 { return QStringView(string, Size); }
175
176 [[nodiscard]] inline QString toString() const; // defined in qstring.h
177#if defined(Q_OS_DARWIN) || defined(Q_QDOC)
178 // defined in qcore_foundation.mm
179 [[nodiscard]] Q_CORE_EXPORT CFStringRef toCFString() const Q_DECL_CF_RETURNS_RETAINED;
180 [[nodiscard]] Q_CORE_EXPORT NSString *toNSString() const Q_DECL_NS_RETURNS_AUTORELEASED;
181#endif
182
183 [[nodiscard]] constexpr qsizetype size() const noexcept { return m_size; }
184 [[nodiscard]] const_pointer data() const noexcept { return reinterpret_cast<const_pointer>(m_data); }
185 [[nodiscard]] const_pointer constData() const noexcept { return data(); }
186 [[nodiscard]] constexpr const storage_type *utf16() const noexcept { return m_data; }
187
188 [[nodiscard]] constexpr QChar operator[](qsizetype n) const
189 { verify(pos: n, n: 1); return QChar(m_data[n]); }
190
191 //
192 // QString API
193 //
194
195 template <typename...Args>
196 [[nodiscard]] inline QString arg(Args &&...args) const; // defined in qstring.h
197
198 [[nodiscard]] QByteArray toLatin1() const { return QtPrivate::convertToLatin1(str: *this); }
199 [[nodiscard]] QByteArray toUtf8() const { return QtPrivate::convertToUtf8(str: *this); }
200 [[nodiscard]] QByteArray toLocal8Bit() const { return QtPrivate::convertToLocal8Bit(str: *this); }
201 [[nodiscard]] inline QList<uint> toUcs4() const; // defined in qlist.h ### Qt 7 char32_t
202
203 [[nodiscard]] constexpr QChar at(qsizetype n) const noexcept { return (*this)[n]; }
204
205 [[nodiscard]] constexpr QStringView mid(qsizetype pos, qsizetype n = -1) const noexcept
206 {
207 using namespace QtPrivate;
208 auto result = QContainerImplHelper::mid(originalLength: size(), position: &pos, length: &n);
209 return result == QContainerImplHelper::Null ? QStringView() : QStringView(m_data + pos, n);
210 }
211 [[nodiscard]] constexpr QStringView left(qsizetype n) const noexcept
212 {
213 if (size_t(n) >= size_t(size()))
214 n = size();
215 return QStringView(m_data, n);
216 }
217 [[nodiscard]] constexpr QStringView right(qsizetype n) const noexcept
218 {
219 if (size_t(n) >= size_t(size()))
220 n = size();
221 return QStringView(m_data + m_size - n, n);
222 }
223
224 [[nodiscard]] constexpr QStringView first(qsizetype n) const noexcept
225 { verify(pos: 0, n); return sliced(pos: 0, n); }
226 [[nodiscard]] constexpr QStringView last(qsizetype n) const noexcept
227 { verify(pos: 0, n); return sliced(pos: size() - n, n); }
228 [[nodiscard]] constexpr QStringView sliced(qsizetype pos) const noexcept
229 { verify(pos, n: 0); return QStringView(m_data + pos, size() - pos); }
230 [[nodiscard]] constexpr QStringView sliced(qsizetype pos, qsizetype n) const noexcept
231 { verify(pos, n); return QStringView(m_data + pos, n); }
232 [[nodiscard]] constexpr QStringView chopped(qsizetype n) const noexcept
233 { verify(pos: 0, n); return sliced(pos: 0, n: m_size - n); }
234
235 constexpr void truncate(qsizetype n) noexcept
236 { verify(pos: 0, n); ; m_size = n; }
237 constexpr void chop(qsizetype n) noexcept
238 { verify(pos: 0, n); m_size -= n; }
239
240 [[nodiscard]] QStringView trimmed() const noexcept { return QtPrivate::trimmed(s: *this); }
241
242 constexpr QStringView &slice(qsizetype pos)
243 { *this = sliced(pos); return *this; }
244 constexpr QStringView &slice(qsizetype pos, qsizetype n)
245 { *this = sliced(pos, n); return *this; }
246
247 template <typename Needle, typename...Flags>
248 [[nodiscard]] constexpr inline auto tokenize(Needle &&needle, Flags...flags) const
249 noexcept(noexcept(qTokenize(std::declval<const QStringView&>(), std::forward<Needle>(needle), flags...)))
250 -> decltype(qTokenize(*this, std::forward<Needle>(needle), flags...))
251 { return qTokenize(*this, std::forward<Needle>(needle), flags...); }
252
253 [[nodiscard]] int compare(QStringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
254 { return QtPrivate::compareStrings(lhs: *this, rhs: other, cs); }
255 [[nodiscard]] inline int compare(QLatin1StringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
256 [[nodiscard]] inline int compare(QUtf8StringView other, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
257 [[nodiscard]] constexpr int compare(QChar c) const noexcept
258 { return size() >= 1 ? compare_single_char_helper(diff: *utf16() - c.unicode()) : -1; }
259 [[nodiscard]] int compare(QChar c, Qt::CaseSensitivity cs) const noexcept
260 { return QtPrivate::compareStrings(lhs: *this, rhs: QStringView(&c, 1), cs); }
261
262 [[nodiscard]] inline int localeAwareCompare(QStringView other) const;
263
264 [[nodiscard]] bool startsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
265 { return QtPrivate::startsWith(haystack: *this, needle: s, cs); }
266 [[nodiscard]] inline bool startsWith(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
267 [[nodiscard]] bool startsWith(QChar c) const noexcept
268 { return !empty() && front() == c; }
269 [[nodiscard]] bool startsWith(QChar c, Qt::CaseSensitivity cs) const noexcept
270 { return QtPrivate::startsWith(haystack: *this, needle: QStringView(&c, 1), cs); }
271
272 [[nodiscard]] bool endsWith(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
273 { return QtPrivate::endsWith(haystack: *this, needle: s, cs); }
274 [[nodiscard]] inline bool endsWith(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
275 [[nodiscard]] bool endsWith(QChar c) const noexcept
276 { return !empty() && back() == c; }
277 [[nodiscard]] bool endsWith(QChar c, Qt::CaseSensitivity cs) const noexcept
278 { return QtPrivate::endsWith(haystack: *this, needle: QStringView(&c, 1), cs); }
279
280 [[nodiscard]] qsizetype indexOf(QChar c, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
281 { return QtPrivate::findString(str: *this, from, needle: c.unicode(), cs); }
282 [[nodiscard]] qsizetype indexOf(QStringView s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
283 { return QtPrivate::findString(haystack: *this, from, needle: s, cs); }
284 [[nodiscard]] inline qsizetype indexOf(QLatin1StringView s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
285
286 [[nodiscard]] bool contains(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
287 { return indexOf(s: QStringView(&c, 1), from: 0, cs) != qsizetype(-1); }
288 [[nodiscard]] bool contains(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
289 { return indexOf(s, from: 0, cs) != qsizetype(-1); }
290 [[nodiscard]] inline bool contains(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
291
292 [[nodiscard]] qsizetype count(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
293 { return QtPrivate::count(haystack: *this, needle: c, cs); }
294 [[nodiscard]] qsizetype count(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
295 { return QtPrivate::count(haystack: *this, needle: s, cs); }
296 [[nodiscard]] inline qsizetype count(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
297
298 [[nodiscard]] qsizetype lastIndexOf(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
299 { return lastIndexOf(c, from: -1, cs); }
300 [[nodiscard]] qsizetype lastIndexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
301 { return QtPrivate::lastIndexOf(haystack: *this, from, needle: c.unicode(), cs); }
302 [[nodiscard]] qsizetype lastIndexOf(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
303 { return lastIndexOf(s, from: size(), cs); }
304 [[nodiscard]] qsizetype lastIndexOf(QStringView s, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
305 { return QtPrivate::lastIndexOf(haystack: *this, from, needle: s, cs); }
306 [[nodiscard]] inline qsizetype lastIndexOf(QLatin1StringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
307 [[nodiscard]] inline qsizetype lastIndexOf(QLatin1StringView s, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
308
309#if QT_CONFIG(regularexpression)
310 [[nodiscard]] qsizetype indexOf(const QRegularExpression &re, qsizetype from = 0, QRegularExpressionMatch *rmatch = nullptr) const
311 {
312 return QtPrivate::indexOf(haystack: *this, re, from, rmatch);
313 }
314#ifdef Q_QDOC
315 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, QRegularExpressionMatch *rmatch = nullptr) const;
316#else
317 // prevent an ambiguity when called like this: lastIndexOf(re, 0)
318 template <typename T = QRegularExpressionMatch, std::enable_if_t<std::is_same_v<T, QRegularExpressionMatch>, bool> = false>
319 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, T *rmatch = nullptr) const
320 {
321 return QtPrivate::lastIndexOf(*this, re, size(), rmatch);
322 }
323#endif
324 [[nodiscard]] qsizetype lastIndexOf(const QRegularExpression &re, qsizetype from, QRegularExpressionMatch *rmatch = nullptr) const
325 {
326 return QtPrivate::lastIndexOf(haystack: *this, re, from, rmatch);
327 }
328 [[nodiscard]] bool contains(const QRegularExpression &re, QRegularExpressionMatch *rmatch = nullptr) const
329 {
330 return QtPrivate::contains(haystack: *this, re, rmatch);
331 }
332 [[nodiscard]] qsizetype count(const QRegularExpression &re) const
333 {
334 return QtPrivate::count(haystack: *this, re);
335 }
336#endif
337
338 [[nodiscard]] bool isRightToLeft() const noexcept
339 { return QtPrivate::isRightToLeft(string: *this); }
340 [[nodiscard]] bool isValidUtf16() const noexcept
341 { return QtPrivate::isValidUtf16(s: *this); }
342
343 [[nodiscard]] bool isUpper() const noexcept
344 { return QtPrivate::isUpper(s: *this); }
345 [[nodiscard]] bool isLower() const noexcept
346 { return QtPrivate::isLower(s: *this); }
347
348 [[nodiscard]] inline short toShort(bool *ok = nullptr, int base = 10) const;
349 [[nodiscard]] inline ushort toUShort(bool *ok = nullptr, int base = 10) const;
350 [[nodiscard]] inline int toInt(bool *ok = nullptr, int base = 10) const;
351 [[nodiscard]] inline uint toUInt(bool *ok = nullptr, int base = 10) const;
352 [[nodiscard]] inline long toLong(bool *ok = nullptr, int base = 10) const;
353 [[nodiscard]] inline ulong toULong(bool *ok = nullptr, int base = 10) const;
354 [[nodiscard]] inline qlonglong toLongLong(bool *ok = nullptr, int base = 10) const;
355 [[nodiscard]] inline qulonglong toULongLong(bool *ok = nullptr, int base = 10) const;
356 [[nodiscard]] Q_CORE_EXPORT float toFloat(bool *ok = nullptr) const;
357 [[nodiscard]] Q_CORE_EXPORT double toDouble(bool *ok = nullptr) const;
358
359 [[nodiscard]] inline qsizetype toWCharArray(wchar_t *array) const; // defined in qstring.h
360
361
362 [[nodiscard]] Q_CORE_EXPORT
363 QList<QStringView> split(QStringView sep,
364 Qt::SplitBehavior behavior = Qt::KeepEmptyParts,
365 Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
366 [[nodiscard]] Q_CORE_EXPORT
367 QList<QStringView> split(QChar sep, Qt::SplitBehavior behavior = Qt::KeepEmptyParts,
368 Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
369
370#if QT_CONFIG(regularexpression)
371 [[nodiscard]] Q_CORE_EXPORT
372 QList<QStringView> split(const QRegularExpression &sep,
373 Qt::SplitBehavior behavior = Qt::KeepEmptyParts) const;
374#endif
375
376 // QStringView <> QStringView
377 friend bool comparesEqual(const QStringView &lhs, const QStringView &rhs) noexcept
378 { return lhs.size() == rhs.size() && QtPrivate::equalStrings(lhs, rhs); }
379 friend Qt::strong_ordering
380 compareThreeWay(const QStringView &lhs, const QStringView &rhs) noexcept
381 {
382 const int res = QtPrivate::compareStrings(lhs, rhs);
383 return Qt::compareThreeWay(lhs: res, rhs: 0);
384 }
385 Q_DECLARE_STRONGLY_ORDERED(QStringView)
386
387 // QStringView <> QChar
388 friend bool comparesEqual(const QStringView &lhs, QChar rhs) noexcept
389 { return lhs.size() == 1 && lhs[0] == rhs; }
390 friend Qt::strong_ordering compareThreeWay(const QStringView &lhs, QChar rhs) noexcept
391 { return compareThreeWay(lhs, rhs: QStringView(&rhs, 1)); }
392 Q_DECLARE_STRONGLY_ORDERED(QStringView, QChar)
393
394 //
395 // STL compatibility API:
396 //
397 [[nodiscard]] const_iterator begin() const noexcept { return data(); }
398 [[nodiscard]] const_iterator end() const noexcept { return data() + size(); }
399 [[nodiscard]] const_iterator cbegin() const noexcept { return begin(); }
400 [[nodiscard]] const_iterator cend() const noexcept { return end(); }
401 [[nodiscard]] const_reverse_iterator rbegin() const noexcept { return const_reverse_iterator(end()); }
402 [[nodiscard]] const_reverse_iterator rend() const noexcept { return const_reverse_iterator(begin()); }
403 [[nodiscard]] const_reverse_iterator crbegin() const noexcept { return rbegin(); }
404 [[nodiscard]] const_reverse_iterator crend() const noexcept { return rend(); }
405
406 [[nodiscard]] constexpr bool empty() const noexcept { return size() == 0; }
407 [[nodiscard]] constexpr QChar front() const { return Q_ASSERT(!empty()), QChar(m_data[0]); }
408 [[nodiscard]] constexpr QChar back() const { return Q_ASSERT(!empty()), QChar(m_data[m_size - 1]); }
409
410 [[nodiscard]] Q_IMPLICIT operator std::u16string_view() const noexcept
411 { return std::u16string_view(m_data, size_t(m_size)); }
412
413 [[nodiscard]] constexpr qsizetype max_size() const noexcept { return maxSize(); }
414
415 //
416 // Qt compatibility API:
417 //
418 [[nodiscard]] const_iterator constBegin() const noexcept { return begin(); }
419 [[nodiscard]] const_iterator constEnd() const noexcept { return end(); }
420 [[nodiscard]] constexpr bool isNull() const noexcept { return !m_data; }
421 [[nodiscard]] constexpr bool isEmpty() const noexcept { return empty(); }
422 [[nodiscard]] constexpr qsizetype length() const noexcept
423 { return size(); }
424 [[nodiscard]] constexpr QChar first() const { return front(); }
425 [[nodiscard]] constexpr QChar last() const { return back(); }
426
427 [[nodiscard]] static constexpr qsizetype maxSize() noexcept
428 {
429 // -1 to deal with the pointer one-past-the-end;
430 return QtPrivate::MaxAllocSize / sizeof(storage_type) - 1;
431 }
432private:
433#if QT_VERSION >= QT_VERSION_CHECK(7, 0, 0) || defined(QT_BOOTSTRAPPED)
434 const storage_type *m_data = nullptr;
435 qsizetype m_size = 0;
436#else
437 qsizetype m_size = 0;
438 const storage_type *m_data = nullptr;
439#endif
440
441 Q_ALWAYS_INLINE constexpr void verify([[maybe_unused]] qsizetype pos = 0,
442 [[maybe_unused]] qsizetype n = 1) const
443 {
444 Q_ASSERT(pos >= 0);
445 Q_ASSERT(pos <= size());
446 Q_ASSERT(n >= 0);
447 Q_ASSERT(n <= size() - pos);
448 }
449
450 constexpr int compare_single_char_helper(int diff) const noexcept
451 { return diff ? diff : size() > 1 ? 1 : 0; }
452
453 Q_CORE_EXPORT static bool equal_helper(QStringView sv, const char *data, qsizetype len);
454 Q_CORE_EXPORT static int compare_helper(QStringView sv, const char *data, qsizetype len);
455
456#if !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
457 friend bool comparesEqual(const QStringView &lhs, const QByteArrayView &rhs) noexcept
458 { return equal_helper(sv: lhs, data: rhs.data(), len: rhs.size()); }
459 friend Qt::strong_ordering
460 compareThreeWay(const QStringView &lhs, const QByteArrayView &rhs) noexcept
461 {
462 const int res = compare_helper(sv: lhs, data: rhs.data(), len: rhs.size());
463 return Qt::compareThreeWay(lhs: res, rhs: 0);
464 }
465 Q_DECLARE_STRONGLY_ORDERED(QStringView, QByteArrayView, QT_ASCII_CAST_WARN)
466 Q_DECLARE_STRONGLY_ORDERED(QStringView, QByteArray, QT_ASCII_CAST_WARN)
467 Q_DECLARE_STRONGLY_ORDERED(QStringView, const char *, QT_ASCII_CAST_WARN)
468#endif // !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
469};
470Q_DECLARE_TYPEINFO(QStringView, Q_PRIMITIVE_TYPE);
471
472template <typename QStringLike, typename std::enable_if<
473 std::is_same<QStringLike, QString>::value,
474 bool>::type = true>
475inline QStringView qToStringViewIgnoringNull(const QStringLike &s) noexcept
476{ return QStringView(s.begin(), s.size()); }
477
478// QChar inline functions:
479
480[[nodiscard]] constexpr auto QChar::fromUcs4(char32_t c) noexcept
481{
482 struct R {
483 char16_t chars[2];
484 [[nodiscard]] constexpr operator QStringView() const noexcept { return {begin(), end()}; }
485 [[nodiscard]] constexpr qsizetype size() const noexcept { return chars[1] ? 2 : 1; }
486 [[nodiscard]] constexpr const char16_t *begin() const noexcept { return chars; }
487 [[nodiscard]] constexpr const char16_t *end() const noexcept { return begin() + size(); }
488 };
489 return requiresSurrogates(ucs4: c) ? R{.chars: {QChar::highSurrogate(ucs4: c),
490 QChar::lowSurrogate(ucs4: c)}} :
491 R{.chars: {char16_t(c), u'\0'}} ;
492}
493
494qsizetype QtPrivate::findString(QStringView str, qsizetype from, QChar ch, Qt::CaseSensitivity cs) noexcept
495{
496 if (from < -str.size()) // from < 0 && abs(from) > str.size(), avoiding overflow
497 return -1;
498 if (from < 0)
499 from = qMax(a: from + str.size(), b: qsizetype(0));
500 if (from < str.size()) {
501 const char16_t *s = str.utf16();
502 char16_t c = ch.unicode();
503 const char16_t *n = s + from;
504 const char16_t *e = s + str.size();
505 if (cs == Qt::CaseSensitive)
506 n = qustrchr(str: QStringView(n, e), ch: c);
507 else
508 n = qustrcasechr(str: QStringView(n, e), ch: c);
509 if (n != e)
510 return n - s;
511 }
512 return -1;
513}
514
515QT_END_NAMESPACE
516
517#endif /* QSTRINGVIEW_H */
518

source code of qtbase/src/corelib/text/qstringview.h