1 files changed, 98 insertions, 2 deletions
diff --git a/src/corelib/text/qstringalgorithms.h b/src/corelib/text/qstringalgorithms.h
index 52bb9736ba..538ae892b0 100644
--- a/src/corelib/text/qstringalgorithms.h
+++ b/src/corelib/text/qstringalgorithms.h
@@ -4,19 +4,27 @@
 #ifndef QSTRINGALGORITHMS_H
 #define QSTRINGALGORITHMS_H
 
+#include <QtCore/qbytearrayalgorithms.h>
+#include <QtCore/qcontainerfwd.h>
 #include <QtCore/qnamespace.h>
 #include <QtCore/qstringfwd.h>
-#include <QtCore/qcontainerfwd.h>
 #if 0
 #pragma qt_class(QStringAlgorithms)
 #endif
 
+#include <algorithm>        // std::find
+#include <iterator>         // std::size
+
+#include <QtCore/q20type_traits.h>      // q20::is_constant_evaluated
+
 QT_BEGIN_NAMESPACE
 
 namespace QtPrivate {
 
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype qustrlen(const char16_t *str) noexcept;
+[[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype qustrnlen(const char16_t *str, qsizetype maxlen) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION const char16_t *qustrchr(QStringView str, char16_t ch) noexcept;
+[[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION const char16_t *qustrcasechr(QStringView str, char16_t ch) noexcept;
 
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int compareStrings(QStringView   lhs, QStringView   rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int compareStrings(QStringView   lhs, QLatin1StringView rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
@@ -48,11 +56,14 @@ namespace QtPrivate {
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION bool endsWith(QLatin1StringView haystack, QStringView   needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION bool endsWith(QLatin1StringView haystack, QLatin1StringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 
+[[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype findStringInsensitive(QStringView haystack, qsizetype from, char16_t needle) noexcept;
+[[nodiscard]]                             inline qsizetype findString(QStringView str, qsizetype from, QChar needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype findString(QStringView haystack, qsizetype from, QStringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype findString(QStringView haystack, qsizetype from, QLatin1StringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype findString(QLatin1StringView haystack, qsizetype from, QStringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype findString(QLatin1StringView haystack, qsizetype from, QLatin1StringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 
+[[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype lastIndexOf(QStringView haystack, qsizetype from, char16_t needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype lastIndexOf(QStringView haystack, qsizetype from, QStringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype lastIndexOf(QStringView haystack, qsizetype from, QLatin1StringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype lastIndexOf(QLatin1StringView haystack, qsizetype from, QStringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
@@ -61,6 +72,9 @@ namespace QtPrivate {
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION QStringView   trimmed(QStringView   s) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION QLatin1StringView trimmed(QLatin1StringView s) noexcept;
 
+[[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION bool isLower(QStringView s) noexcept;
+[[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION bool isUpper(QStringView s) noexcept;
+
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype count(QStringView haystack, QChar needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype count(QStringView haystack, QStringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype count(QStringView haystack, QLatin1StringView needle, Qt::CaseSensitivity cs = Qt::CaseSensitive);
@@ -69,14 +83,30 @@ namespace QtPrivate {
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qsizetype count(QLatin1StringView haystack, QChar needle, Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
 
 #if QT_CONFIG(regularexpression)
+// ### Qt 7: unify these overloads;
+// remove the ones taking only a QStringView, export the others, adjust callers
+[[nodiscard]] qsizetype indexOf(QStringView viewHaystack,
+                                const QString *stringHaystack,
+                                const QRegularExpression &re,
+                                qsizetype from = 0,
+                                QRegularExpressionMatch *rmatch = nullptr);
 [[nodiscard]] Q_CORE_EXPORT qsizetype indexOf(QStringView haystack,
                                               const QRegularExpression &re,
                                               qsizetype from = 0,
                                               QRegularExpressionMatch *rmatch = nullptr);
+[[nodiscard]] qsizetype lastIndexOf(QStringView viewHaystack,
+                                    const QString *stringHaystack,
+                                    const QRegularExpression &re,
+                                    qsizetype from = -1,
+                                    QRegularExpressionMatch *rmatch = nullptr);
 [[nodiscard]] Q_CORE_EXPORT qsizetype lastIndexOf(QStringView haystack,
                                                   const QRegularExpression &re,
                                                   qsizetype from = -1,
                                                   QRegularExpressionMatch *rmatch = nullptr);
+[[nodiscard]] bool contains(QStringView viewHaystack,
+                            const QString *stringHaystack,
+                            const QRegularExpression &re,
+                            QRegularExpressionMatch *rmatch = nullptr);
 [[nodiscard]] Q_CORE_EXPORT bool contains(QStringView haystack,
                                           const QRegularExpression &re,
                                           QRegularExpressionMatch *rmatch = nullptr);
@@ -98,7 +128,73 @@ namespace QtPrivate {
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION bool isLatin1(QStringView   s) noexcept;
 [[nodiscard]] Q_CORE_EXPORT Q_DECL_PURE_FUNCTION bool isValidUtf16(QStringView s) noexcept;
 
-} // namespace QtPRivate
+template <typename Char, size_t N> [[nodiscard]] constexpr Q_ALWAYS_INLINE
+qsizetype lengthHelperContainerLoop(const Char (&str)[N])
+{
+#if defined(__cpp_lib_constexpr_algorithms) && defined(Q_CC_GNU_ONLY)
+    // libstdc++'s std::find / std::find_if manages to execute more steps
+    // than the loop below
+    const auto it = std::find(str, str + N, Char(0));
+    return it - str;
+#else
+    // std::char_traits<C> is deprecated for C not one of the standard char
+    // types, so we have to roll out our own loop.
+    for (size_t i = 0; i < N; ++i) {
+        if (str[i] == Char(0))
+            return qsizetype(i);
+    }
+    return qsizetype(N);
+#endif
+}
+
+template <typename Char, size_t N> [[nodiscard]] constexpr Q_ALWAYS_INLINE
+std::enable_if_t<sizeof(Char) == sizeof(char16_t), qsizetype>
+lengthHelperContainer(const Char (&str)[N])
+{
+    // The following values were empirically determined to detect the threshold
+    // at which the compiler gives up pre-calculating the std::find() below and
+    // instead inserts code to be executed at runtime.
+    constexpr size_t RuntimeThreshold =
+#if defined(Q_CC_CLANG)
+            // tested on Clang 15, 16 & 17
+            1023
+#elif defined(Q_CC_GNU)
+            // tested through GCC 13.1 at -O3 compilation level
+            // note: at -O2, GCC always generates a loop!
+            __cplusplus >= 202002L ? 39 : 17
+#else
+            0
+#endif
+            ;
+    if constexpr (N == 1) {
+        return str[0] == Char(0) ? 0 : 1;
+    } else if constexpr (N > RuntimeThreshold) {
+#ifdef QT_SUPPORTS_IS_CONSTANT_EVALUATED
+        if (!q20::is_constant_evaluated())
+            return QtPrivate::qustrnlen(reinterpret_cast<const char16_t *>(str), N);
+#endif
+    }
+
+    return lengthHelperContainerLoop(str);
+}
+
+template <typename Char, size_t N> [[nodiscard]] constexpr inline
+std::enable_if_t<sizeof(Char) == 1, qsizetype> lengthHelperContainer(const Char (&str)[N])
+{
+#ifdef QT_SUPPORTS_IS_CONSTANT_EVALUATED
+    if (!q20::is_constant_evaluated())
+        return qstrnlen(reinterpret_cast<const char *>(str), N);
+#endif
+
+    return lengthHelperContainerLoop(str);
+}
+
+template <typename Container>
+constexpr qsizetype lengthHelperContainer(const Container &c) noexcept
+{
+    return qsizetype(std::size(c));
+}
+} // namespace QtPrivate
 
 QT_END_NAMESPACE