QtMiscUtils: add some more character helpers

isHexDigit, isOctalDigit, isAsciiDigit, isAsciiLower, isAsciiUpper,
isAsciiLetterOrNumber.

This de-duplicates some code through out.

Rename two local lambdas that were called "isAsciiLetterOrNumber" to not
conflict with the method in QtMiscUtils.

Change-Id: I5b631f95b9f109136d19515f7e20b8e2fbca3d43
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 498f3452285aa44580e1d03baeec126d475f8401)
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/corelib/io/qsettings.cpp

@@ -66,6 +66,7 @@
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 struct QConfFileCustomFormat
 {
@@ -515,8 +516,7 @@ void QSettingsPrivate::iniEscapedKey(const QString &key, QByteArray &result)
 
         if (ch == '/') {
             result += '\\';
-        } else if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9')
+        } else if (isAsciiLetterOrNumber(ch) || ch == '_' || ch == '-' || ch == '.') {
-                || ch == '_' || ch == '-' || ch == '.') {
             result += (char)ch;
         } else if (ch <= 0xFF) {
             result += '%';
@@ -608,10 +608,7 @@ void QSettingsPrivate::iniEscapedString(const QString &str, QByteArray &result)
         if (ch == ';' || ch == ',' || ch == '=')
             needsQuotes = true;
 
-        if (escapeNextIfDigit
+        if (escapeNextIfDigit && isHexDigit(ch)) {
-                && ((ch >= '0' && ch <= '9')
-                    || (ch >= 'a' && ch <= 'f')
-                    || (ch >= 'A' && ch <= 'F'))) {
             result += "\\x" + QByteArray::number(ch, 16);
             continue;
         }
@@ -754,9 +751,9 @@ StNormal:
                     goto end;
 
                 ch = str.at(i);
-                if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'F') || (ch >= 'a' && ch <= 'f'))
+                if (isHexDigit(ch))
                     goto StHexEscape;
-            } else if (ch >= '0' && ch <= '7') {
+            } else if (isOctalDigit(ch)) {
                 escapeVal = ch - '0';
                 goto StOctEscape;
             } else if (ch == '\n' || ch == '\r') {

src/corelib/io/qurl.cpp

@@ -402,10 +402,12 @@
 #include "private/qipaddress_p.h"
 #include "qurlquery.h"
 #include "private/qdir_p.h"
+#include <private/qtools_p.h>
 
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 // in qstring.cpp:
 void qt_from_latin1(char16_t *dst, const char *str, size_t size) noexcept;
@@ -413,7 +415,7 @@ void qt_from_latin1(char16_t *dst, const char *str, size_t size) noexcept;
 inline static bool isHex(char c)
 {
     c |= 0x20;
-    return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f');
+    return isAsciiDigit(c) || (c >= 'a' && c <= 'f');
 }
 
 static inline QString ftpScheme()
@@ -964,14 +966,14 @@ inline bool QUrlPrivate::setScheme(const QString &value, qsizetype len, bool doS
     qsizetype needsLowercasing = -1;
     const ushort *p = reinterpret_cast<const ushort *>(value.data());
     for (qsizetype i = 0; i < len; ++i) {
-        if (p[i] >= 'a' && p[i] <= 'z')
+        if (isAsciiLower(p[i]))
             continue;
-        if (p[i] >= 'A' && p[i] <= 'Z') {
+        if (isAsciiUpper(p[i])) {
             needsLowercasing = i;
             continue;
         }
         if (i) {
-            if (p[i] >= '0' && p[i] <= '9')
+            if (isAsciiDigit(p[i]))
                 continue;
             if (p[i] == '+' || p[i] == '-' || p[i] == '.')
                 continue;
@@ -992,7 +994,7 @@ inline bool QUrlPrivate::setScheme(const QString &value, qsizetype len, bool doS
         QChar *schemeData = scheme.data(); // force detaching here
         for (qsizetype i = needsLowercasing; i >= 0; --i) {
             ushort c = schemeData[i].unicode();
-            if (c >= 'A' && c <= 'Z')
+            if (isAsciiUpper(c))
                 schemeData[i] = QChar(c + 0x20);
         }
     }
@@ -1044,7 +1046,7 @@ inline void QUrlPrivate::setAuthority(const QString &auth, qsizetype from, qsize
             unsigned long x = 0;
             for (qsizetype i = colonIndex + 1; i < end; ++i) {
                 ushort c = auth.at(i).unicode();
-                if (c >= '0' && c <= '9') {
+                if (isAsciiDigit(c)) {
                     x *= 10;
                     x += c - '0';
                 } else {
@@ -1186,9 +1188,7 @@ static const QChar *parseIpFuture(QString &host, const QChar *begin, const QChar
     const QChar *const origBegin = begin;
     if (begin[3].unicode() != '.')
         return &begin[3];
-    if ((begin[2].unicode() >= 'A' && begin[2].unicode() <= 'F') ||
+    if (isHexDigit(begin[2].unicode())) {
-            (begin[2].unicode() >= 'a' && begin[2].unicode() <= 'f') ||
-            (begin[2].unicode() >= '0' && begin[2].unicode() <= '9')) {
         // this is so unlikely that we'll just go down the slow path
         // decode the whole string, skipping the "[vH." and "]" which we already know to be there
         host += QStringView(begin, 4);
@@ -1207,11 +1207,7 @@ static const QChar *parseIpFuture(QString &host, const QChar *begin, const QChar
         }
 
         for ( ; begin != end; ++begin) {
-            if (begin->unicode() >= 'A' && begin->unicode() <= 'Z')
+            if (isAsciiLetterOrNumber(begin->unicode()))
-                host += *begin;
-            else if (begin->unicode() >= 'a' && begin->unicode() <= 'z')
-                host += *begin;
-            else if (begin->unicode() >= '0' && begin->unicode() <= '9')
                 host += *begin;
             else if (begin->unicode() < 0x80 && strchr(acceptable, begin->unicode()) != nullptr)
                 host += *begin;

src/corelib/kernel/qmetaobject_p.h

@@ -23,11 +23,14 @@
 #ifndef QT_NO_QOBJECT
 #include <private/qobject_p.h> // For QObjectPrivate::Connection
 #endif
+#include <private/qtools_p.h>
 #include <QtCore/qvarlengtharray.h>
 
 QT_BEGIN_NAMESPACE
 // ### TODO - QTBUG-87869: wrap in a proper Q_NAMESPACE and use scoped enums, to avoid name clashes
 
+using namespace QtMiscUtils;
+
 enum PropertyFlags {
     Invalid = 0x00000000,
     Readable = 0x00000001,
@@ -265,11 +268,7 @@ enum { MetaObjectPrivateFieldCount = sizeof(QMetaObjectPrivate) / sizeof(int) };
 // mirrored in moc's utils.h
 static inline bool is_ident_char(char s)
 {
-    return ((s >= 'a' && s <= 'z')
+    return isAsciiLetterOrNumber(s) || s == '_';
-            || (s >= 'A' && s <= 'Z')
-            || (s >= '0' && s <= '9')
-            || s == '_'
-       );
 }
 
 static inline bool is_space(char s)

src/corelib/mimetypes/qmimemagicrule.cpp

@@ -13,10 +13,12 @@
 #include <qendian.h>
 
 #include <private/qoffsetstringarray_p.h>
+#include <private/qtools_p.h>
 
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 // in the same order as Type!
 static constexpr auto magicRuleTypes = qOffsetStringArray(
@@ -156,11 +158,11 @@ static inline QByteArray makePattern(const QByteArray &value)
                         continue;
                 }
                 *data++ = c;
-            } else if (*p >= '0' && *p <= '7') { // oct (\\7, or \\77, or \\377)
+            } else if (isOctalDigit(*p)) { // oct (\\7, or \\77, or \\377)
                 char c = *p - '0';
-                if (p + 1 < e && p[1] >= '0' && p[1] <= '7') {
+                if (p + 1 < e && isOctalDigit(p[1])) {
                     c = (c << 3) + *(++p) - '0';
-                    if (p + 1 < e && p[1] >= '0' && p[1] <= '7' && p[-1] <= '3')
+                    if (p + 1 < e && isOctalDigit(p[1]) && p[-1] <= '3')
                         c = (c << 3) + *(++p) - '0';
                 }
                 *data++ = c;

src/corelib/serialization/qjsonparser.cpp

@@ -11,6 +11,7 @@
 #include "private/qstringconverter_p.h"
 #include "private/qcborvalue_p.h"
 #include "private/qnumeric_p.h"
+#include <private/qtools_p.h>
 
 //#define PARSER_DEBUG
 #ifdef PARSER_DEBUG
@@ -28,6 +29,8 @@ static const int nestingLimit = 1024;
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 // error strings for the JSON parser
 #define JSONERR_OK          QT_TRANSLATE_NOOP("QJsonParseError", "no error occurred")
 #define JSONERR_UNTERM_OBJ  QT_TRANSLATE_NOOP("QJsonParseError", "unterminated object")
@@ -693,14 +696,14 @@ bool Parser::parseNumber()
     if (json < end && *json == '0') {
         ++json;
     } else {
-        while (json < end && *json >= '0' && *json <= '9')
+        while (json < end && isAsciiDigit(*json))
             ++json;
     }
 
     // frac = decimal-point 1*DIGIT
     if (json < end && *json == '.') {
         ++json;
-        while (json < end && *json >= '0' && *json <= '9') {
+        while (json < end && isAsciiDigit(*json)) {
             isInt = isInt && *json == '0';
             ++json;
         }
@@ -712,7 +715,7 @@ bool Parser::parseNumber()
         ++json;
         if (json < end && (*json == '-' || *json == '+'))
             ++json;
-        while (json < end && *json >= '0' && *json <= '9')
+        while (json < end && isAsciiDigit(*json))
             ++json;
     }
 

src/corelib/serialization/qtextstream.cpp

@@ -196,6 +196,7 @@ static const int QTEXTSTREAM_BUFFERSIZE = 16384;
 #include "qnumeric.h"
 #include "qvarlengtharray.h"
 #include <private/qdebug_p.h>
+#include <private/qtools_p.h>
 
 #include <locale.h>
 #include "private/qlocale_p.h"
@@ -245,6 +246,7 @@ static const int QTEXTSTREAM_BUFFERSIZE = 16384;
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 //-------------------------------------------------------------------
 
@@ -1686,7 +1688,7 @@ QTextStreamPrivate::NumberParsingStatus QTextStreamPrivate::getNumber(qulonglong
         int ndigits = 0;
         while (getChar(&dig)) {
             int n = dig.toLower().unicode();
-            if (n >= '0' && n <= '7') {
+            if (isOctalDigit(n)) {
                 val *= 8;
                 val += n - '0';
             } else {

src/corelib/serialization/qxmlstream.cpp

@@ -16,6 +16,7 @@
 #include <qcoreapplication.h>
 
 #include <private/qoffsetstringarray_p.h>
+#include <private/qtools_p.h>
 
 #include <iterator>
 #include "qxmlstream_p.h"
@@ -26,6 +27,7 @@ QT_BEGIN_NAMESPACE
 
 using namespace QtPrivate;
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 enum { StreamEOF = ~0U };
 
@@ -1731,9 +1733,7 @@ void QXmlStreamReaderPrivate::checkPublicLiteral(QStringView publicId)
             case '$': case '_': case '%': case '\'': case '\"':
                 continue;
             default:
-                if ((c >= 'a' && c <= 'z')
+                if (isAsciiLetterOrNumber(c))
-                    || (c >= 'A' && c <= 'Z')
-                    || (c >= '0' && c <= '9'))
                     continue;
             }
         break;

src/corelib/serialization/qxmlutils.cpp

@@ -5,8 +5,12 @@
 
 #include "qxmlutils_p.h"
 
+#include <private/qtools_p.h>
+
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 /* TODO:
  * - isNameChar() doesn't have to be public, it's only needed in
  *   qdom.cpp -- refactor fixedXmlName() to use isNCName()
@@ -197,16 +201,12 @@ bool QXmlUtils::isEncName(QStringView encName)
     if (encName.isEmpty())
         return false;
     const auto first = encName.front().unicode();
-    if (!((first >= 'a' && first <= 'z') || (first >= 'A' && first <= 'Z')))
+    if (!(isAsciiLower(first) || isAsciiUpper(first)))
         return false;
     for (QChar ch : encName.mid(1)) {
         const auto cp = ch.unicode();
-        if ((cp >= 'a' && cp <= 'z')
+        if (isAsciiLetterOrNumber(cp) || cp == '.' || cp == '_' || cp == '-')
-            || (cp >= 'A' && cp <= 'Z')
-            || (cp >= '0' && cp <= '9')
-            || cp == '.' || cp == '_' || cp == '-') {
             continue;
-        }
         return false;
     }
     return true;
@@ -285,12 +285,8 @@ bool QXmlUtils::isPublicID(QStringView candidate)
     for (QChar ch : candidate) {
         const ushort cp = ch.unicode();
 
-        if ((cp >= 'a' && cp <= 'z')
+        if (isAsciiLetterOrNumber(cp))
-            || (cp >= 'A' && cp <= 'Z')
-            || (cp >= '0' && cp <= '9'))
-        {
             continue;
-        }
 
         switch (cp)
         {

src/corelib/text/qlocale.cpp

@@ -22,6 +22,7 @@ QT_WARNING_DISABLE_GCC("-Wfree-nonheap-object") // false positive tracking
 #include "qlocale.h"
 #include "qlocale_p.h"
 #include "qlocale_tools_p.h"
+#include <private/qtools_p.h>
 #if QT_CONFIG(datetimeparser)
 #include "private/qdatetimeparser_p.h"
 #endif
@@ -60,6 +61,7 @@ QT_IMPL_METATYPE_EXTERN_TAGGED(QSystemLocale::CurrencyToStringArgument,
 #endif
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 #ifndef QT_NO_SYSTEMLOCALE
 Q_CONSTINIT static QSystemLocale *_systemLocale = nullptr;
@@ -542,7 +544,7 @@ static bool validTag(QStringView tag)
     // Is tag is a non-empty sequence of ASCII letters and/or digits ?
     for (QChar uc : tag) {
         const char16_t ch = uc.unicode();
-        if (!((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9')))
+        if (!isAsciiLetterOrNumber(ch))
             return false;
     }
     return tag.size() > 0;
@@ -2603,11 +2605,6 @@ QString QLocale::exponential() const
     return d->m_data->exponentSeparator();
 }
 
-static bool qIsUpper(char c)
-{
-    return c >= 'A' && c <= 'Z';
-}
-
 /*!
     \overload
     Returns a string representing the floating-point number \a f.
@@ -2645,7 +2642,7 @@ static bool qIsUpper(char c)
 QString QLocale::toString(double f, char format, int precision) const
 {
     QLocaleData::DoubleForm form = QLocaleData::DFDecimal;
-    uint flags = qIsUpper(format) ? QLocaleData::CapitalEorX : 0;
+    uint flags = isAsciiUpper(format) ? QLocaleData::CapitalEorX : 0;
 
     switch (QtMiscUtils::toAsciiLower(format)) {
         case 'f':
@@ -4023,7 +4020,7 @@ bool QLocaleData::validateChars(QStringView str, NumberMode numMode, QByteArray
         const QStringView in = str.mid(i, str.at(i).isHighSurrogate() ? 2 : 1);
         char c = numericToCLocale(in);
 
-        if (c >= '0' && c <= '9') {
+        if (isAsciiDigit(c)) {
             switch (state) {
             case Whole:
                 // Nothing special to do (unless we want to check grouping sizes).

src/corelib/text/qlocale_tools.cpp

@@ -7,6 +7,7 @@
 #include "qlocale_p.h"
 #include "qstring.h"
 
+#include <private/qtools_p.h>
 #include <private/qnumeric_p.h>
 
 #include <ctype.h>
@@ -37,6 +38,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 QT_CLOCALE_HOLDER
 
 void qt_doubleToAscii(double d, QLocaleData::DoubleForm form, int precision,
@@ -371,7 +374,7 @@ static auto scanPrefix(const char *p, const char *stop, int base)
         const char *next;
         int base;
     };
-    if (p < stop && *p >= '0' && *p <= '9') {
+    if (p < stop && isAsciiDigit(*p)) {
         if (*p == '0') {
             const char *x_or_b = p + 1;
             if (x_or_b < stop) {

src/corelib/text/qstring.cpp

@@ -74,6 +74,7 @@
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 const char16_t QString::_empty = 0;
 
@@ -86,16 +87,6 @@ enum StringComparisonMode {
     CompareStringsForOrdering
 };
 
-inline bool qIsUpper(char ch)
-{
-    return ch >= 'A' && ch <= 'Z';
-}
-
-inline bool qIsDigit(char ch)
-{
-    return ch >= '0' && ch <= '9';
-}
-
 template <typename Pointer>
 char32_t foldCaseHelper(Pointer ch, Pointer start) = delete;
 
@@ -1350,13 +1341,6 @@ static int ucstrncmp(const char16_t *a, const char *b, size_t l)
     return 0;
 }
 
-constexpr int lencmp(qsizetype lhs, qsizetype rhs) noexcept
-{
-    return lhs == rhs ? 0 :
-           lhs >  rhs ? 1 :
-           /* else */  -1 ;
-}
-
 // Unicode case-sensitive equality
 template <typename Char2>
 static bool ucstreq(const char16_t *a, size_t alen, const Char2 *b, size_t blen)
@@ -1380,7 +1364,7 @@ static int ucstrcmp(const char16_t *a, size_t alen, const Char2 *b, size_t blen)
     }
     const size_t l = qMin(alen, blen);
     int cmp = ucstrncmp<CompareStringsForOrdering>(a, b, l);
-    return cmp ? cmp : lencmp(alen, blen);
+    return cmp ? cmp : qt_lencmp(alen, blen);
 }
 
 static constexpr uchar latin1Lower[256] = {
@@ -1419,7 +1403,7 @@ static int latin1nicmp(const char *lhsChar, qsizetype lSize, const char *rhsChar
         if (int res = latin1Lower[lhs[i]] - latin1Lower[rhs[i]])
             return res;
     }
-    return lencmp(lSize, rSize);
+    return qt_lencmp(lSize, rSize);
 }
 
 bool QtPrivate::equalStrings(QStringView lhs, QStringView rhs) noexcept
@@ -1564,12 +1548,12 @@ int QtPrivate::compareStrings(QLatin1StringView lhs, QStringView rhs, Qt::CaseSe
 int QtPrivate::compareStrings(QLatin1StringView lhs, QLatin1StringView rhs, Qt::CaseSensitivity cs) noexcept
 {
     if (lhs.isEmpty())
-        return lencmp(qsizetype(0), rhs.size());
+        return qt_lencmp(qsizetype(0), rhs.size());
     if (cs == Qt::CaseInsensitive)
         return latin1nicmp(lhs.data(), lhs.size(), rhs.data(), rhs.size());
     const auto l = std::min(lhs.size(), rhs.size());
     int r = memcmp(lhs.data(), rhs.data(), l);
-    return r ? r : lencmp(lhs.size(), rhs.size());
+    return r ? r : qt_lencmp(lhs.size(), rhs.size());
 }
 
 /*!
@@ -6881,7 +6865,7 @@ static uint parse_flag_characters(const char * &c) noexcept
 
 static int parse_field_width(const char *&c, qsizetype size)
 {
-    Q_ASSERT(qIsDigit(*c));
+    Q_ASSERT(isAsciiDigit(*c));
     const char *const stop = c + size;
 
     // can't be negative - started with a digit
@@ -6891,7 +6875,7 @@ static int parse_field_width(const char *&c, qsizetype size)
     if (used <= 0)
         return false;
     // preserve Qt 5.5 behavior of consuming all digits, no matter how many
-    while (c < stop && qIsDigit(*c))
+    while (c < stop && isAsciiDigit(*c))
         ++c;
     return result < qulonglong(std::numeric_limits<int>::max()) ? int(result) : 0;
 }
@@ -6981,7 +6965,7 @@ QString QString::vasprintf(const char *cformat, va_list ap)
 
         // Parse field width
         int width = -1; // -1 means unspecified
-        if (qIsDigit(*c)) {
+        if (isAsciiDigit(*c)) {
             width = parse_field_width(c, formatEnd - c);
         } else if (*c == '*') { // can't parse this in another function, not portably, at least
             width = va_arg(ap, int);
@@ -7000,7 +6984,7 @@ QString QString::vasprintf(const char *cformat, va_list ap)
         if (*c == '.') {
             ++c;
             precision = 0;
-            if (qIsDigit(*c)) {
+            if (isAsciiDigit(*c)) {
                 precision = parse_field_width(c, formatEnd - c);
             } else if (*c == '*') { // can't parse this in another function, not portably, at least
                 precision = va_arg(ap, int);
@@ -7061,7 +7045,7 @@ QString QString::vasprintf(const char *cformat, va_list ap)
                     default: u = 0; break;
                 }
 
-                if (qIsUpper(*c))
+                if (isAsciiUpper(*c))
                     flags |= QLocaleData::CapitalEorX;
 
                 int base = 10;
@@ -7092,7 +7076,7 @@ QString QString::vasprintf(const char *cformat, va_list ap)
                 else
                     d = va_arg(ap, double);
 
-                if (qIsUpper(*c))
+                if (isAsciiUpper(*c))
                     flags |= QLocaleData::CapitalEorX;
 
                 QLocaleData::DoubleForm form = QLocaleData::DFDecimal;
@@ -7738,7 +7722,7 @@ QString QString::number(double n, char format, int precision)
             break;
     }
 
-    return qdtoBasicLatin(n, form, precision, qIsUpper(format));
+    return qdtoBasicLatin(n, form, precision, isAsciiUpper(format));
 }
 
 namespace {
@@ -8605,7 +8589,7 @@ QString QString::arg(double a, int fieldWidth, char format, int precision, QChar
     if (fillChar == u'0')
         flags |= QLocaleData::ZeroPadded;
 
-    if (qIsUpper(format))
+    if (isAsciiUpper(format))
         flags |= QLocaleData::CapitalEorX;
 
     QLocaleData::DoubleForm form = QLocaleData::DFDecimal;

src/corelib/text/qstringconverter.cpp

@@ -31,6 +31,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 static_assert(std::is_nothrow_move_constructible_v<QStringEncoder>);
 static_assert(std::is_nothrow_move_assignable_v<QStringEncoder>);
 static_assert(std::is_nothrow_move_constructible_v<QStringDecoder>);
@@ -890,22 +892,15 @@ int QUtf8::compareUtf8(QByteArrayView utf8, QLatin1StringView s, Qt::CaseSensiti
     return (end1 > src1) - (end2 > src2);
 }
 
-static inline int lencmp(qsizetype lhs, qsizetype rhs) noexcept
-{
-    return lhs == rhs ? 0 :
-           lhs >  rhs ? 1 :
-           /* else */  -1 ;
-}
-
 int QUtf8::compareUtf8(QByteArrayView lhs, QByteArrayView rhs, Qt::CaseSensitivity cs) noexcept
 {
     if (lhs.isEmpty())
-        return lencmp(0, rhs.size());
+        return qt_lencmp(0, rhs.size());
 
     if (cs == Qt::CaseSensitive) {
         const auto l = std::min(lhs.size(), rhs.size());
         int r = memcmp(lhs.data(), rhs.data(), l);
-        return r ? r : lencmp(lhs.size(), rhs.size());
+        return r ? r : qt_lencmp(lhs.size(), rhs.size());
     }
 
     char32_t uc1 = QChar::Null;

src/corelib/time/qtimezoneprivate.cpp

@@ -8,6 +8,7 @@
 #include "qtimezoneprivate_data_p.h"
 
 #include <private/qnumeric_p.h>
+#include <private/qtools_p.h>
 #include <qdatastream.h>
 #include <qdebug.h>
 
@@ -15,6 +16,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 /*
     Static utilities for looking up Windows ID tables
 */
@@ -597,12 +600,12 @@ bool QTimeZonePrivate::isValidId(const QByteArray &ianaId)
         } else if (ch == '-') {
             if (sectionLength == 0)
                 return false; // violates (4)
-        } else if (!(ch >= 'a' && ch <= 'z')
+        } else if (!isAsciiLower(ch)
-                && !(ch >= 'A' && ch <= 'Z')
+                && !isAsciiUpper(ch)
                 && !(ch == '_')
                 && !(ch == '.')
                    // Should ideally check these only happen as an offset:
-                && !(ch >= '0' && ch <= '9')
+                && !isAsciiDigit(ch)
                 && !(ch == '+')
                 && !(ch == ':')) {
             return false; // violates (2)

src/corelib/tools/qtools_p.h

@@ -31,6 +31,13 @@ constexpr inline char toHexLower(uint value) noexcept
     return "0123456789abcdef"[value & 0xF];
 }
 
+[[nodiscard]] constexpr inline int isHexDigit(char32_t c) noexcept
+{
+    return (c >= '0' && c <= '9')
+           || (c >= 'A' && c <= 'F')
+           || (c >= 'a' && c <= 'f');
+}
+
 constexpr inline int fromHex(uint c) noexcept
 {
     return ((c >= '0') && (c <= '9')) ? int(c - '0') :
@@ -44,19 +51,44 @@ constexpr inline char toOct(uint value) noexcept
     return char('0' + (value & 0x7));
 }
 
+[[nodiscard]] constexpr inline int isOctalDigit(char32_t c) noexcept
+{
+    return c >= '0' && c <= '7';
+}
+
 constexpr inline int fromOct(uint c) noexcept
 {
-    return ((c >= '0') && (c <= '7')) ? int(c - '0') : -1;
+    return isOctalDigit(c) ? int(c - '0') : -1;
+}
+
+[[nodiscard]] constexpr inline bool isAsciiDigit(char32_t c) noexcept
+{
+    return c >= '0' && c <= '9';
+}
+
+constexpr inline bool isAsciiUpper(char32_t c) noexcept
+{
+    return c >= 'A' && c <= 'Z';
+}
+
+constexpr inline bool isAsciiLower(char32_t c) noexcept
+{
+    return c >= 'a' && c <= 'z';
+}
+
+constexpr inline bool isAsciiLetterOrNumber(char32_t c) noexcept
+{
+    return  isAsciiDigit(c) || isAsciiLower(c) || isAsciiUpper(c);
 }
 
 constexpr inline char toAsciiLower(char ch) noexcept
 {
-    return (ch >= 'A' && ch <= 'Z') ? ch - 'A' + 'a' : ch;
+    return isAsciiUpper(ch) ? ch - 'A' + 'a' : ch;
 }
 
 constexpr inline char toAsciiUpper(char ch) noexcept
 {
-    return (ch >= 'a' && ch <= 'z') ? ch - 'a' + 'A' : ch;
+    return isAsciiLower(ch) ? ch - 'a' + 'A' : ch;
 }
 
 constexpr inline int caseCompareAscii(char lhs, char rhs) noexcept
@@ -66,7 +98,12 @@ constexpr inline int caseCompareAscii(char lhs, char rhs) noexcept
     return int(uchar(lhsLower)) - int(uchar(rhsLower));
 }
 
-
+constexpr inline int qt_lencmp(qsizetype lhs, qsizetype rhs) noexcept
+{
+    return lhs == rhs ? 0 :
+           lhs >  rhs ? 1 :
+           /* else */  -1 ;
+}
 }
 
 // We typically need an extra bit for qNextPowerOfTwo when determining the next allocation size.

src/dbus/qdbusutil.cpp

@@ -7,6 +7,7 @@
 
 #include <QtCore/qlist.h>
 #include <QtCore/qstringlist.h>
+#include <private/qtools_p.h>
 
 #include "qdbusargument.h"
 #include "qdbusunixfiledescriptor.h"
@@ -16,29 +17,24 @@
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 static inline bool isValidCharacterNoDash(QChar c)
 {
     ushort u = c.unicode();
-    return (u >= 'a' && u <= 'z')
+    return isAsciiLetterOrNumber(u) || (u == '_');
-            || (u >= 'A' && u <= 'Z')
-            || (u >= '0' && u <= '9')
-            || (u == '_');
 }
 
 static inline bool isValidCharacter(QChar c)
 {
     ushort u = c.unicode();
-    return (u >= 'a' && u <= 'z')
+    return isAsciiLetterOrNumber(u)
-            || (u >= 'A' && u <= 'Z')
-            || (u >= '0' && u <= '9')
             || (u == '_') || (u == '-');
 }
 
 static inline bool isValidNumber(QChar c)
 {
-    ushort u = c.unicode();
+    return (isAsciiDigit(c.toLatin1()));
-    return (u >= '0' && u <= '9');
 }
 
 #ifndef QT_BOOTSTRAPPED

src/gui/image/qxbmhandler.cpp

@@ -16,6 +16,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 Q_DECLARE_LOGGING_CATEGORY(lcImageIo)
 
 /*****************************************************************************
@@ -54,11 +56,9 @@ static bool read_xbm_header(QIODevice *device, int& w, int& h)
     }
 
     auto parseDefine = [] (const char *buf, int len) -> int {
-        auto isAsciiLetterOrNumber = [] (char ch) -> bool {
+        auto checkChar = [] (char ch) -> bool {
-            return (ch >= '0' && ch <= '9') ||
+            return isAsciiLetterOrNumber(ch)
-                    (ch >= 'A' && ch <= 'Z') ||
+                || ch == '_' || ch == '.';
-                    (ch >= 'a' && ch <= 'z') ||
-                    ch == '_' || ch == '.';
         };
         auto isAsciiSpace = [] (char ch) -> bool {
             return ch == ' ' || ch == '\t';
@@ -70,7 +70,7 @@ static bool read_xbm_header(QIODevice *device, int& w, int& h)
         int index = defineLen;
         while (buf[index] && isAsciiSpace(buf[index]))
             ++index;
-        while (buf[index] && isAsciiLetterOrNumber(buf[index]))
+        while (buf[index] && checkChar(buf[index]))
             ++index;
         while (buf[index] && isAsciiSpace(buf[index]))
             ++index;

src/gui/image/qxpmhandler.cpp

@@ -15,12 +15,15 @@
 
 #include <private/qcolor_p.h>
 #include <private/qduplicatetracker_p.h> // for easier std::pmr detection
+#include <private/qtools_p.h>
 
 #include <algorithm>
 #include <array>
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 Q_DECLARE_LOGGING_CATEGORY(lcImageIo)
 
 static quint64 xpmHash(const QString &str)
@@ -736,15 +739,13 @@ static QString fbname(const QString &fileName) // get file basename (sort of)
         int i = qMax(s.lastIndexOf(u'/'), s.lastIndexOf(u'\\'));
         if (i < 0)
             i = 0;
-        auto isAsciiLetterOrNumber = [](QChar ch) -> bool {
+        auto checkChar = [](QChar ch) -> bool {
-            return (ch.unicode() >= '0' && ch.unicode() <= '9') ||
+            uchar uc = ch.unicode();
-                    (ch.unicode() >= 'A' && ch.unicode() <= 'Z') ||
+            return isAsciiLetterOrNumber(uc) || uc == '_';
-                    (ch.unicode() >= 'a' && ch.unicode() <= 'z') ||
-                    ch.unicode() == '_';
         };
         int start = -1;
         for (; i < s.size(); ++i) {
-            if (isAsciiLetterOrNumber(s.at(i))) {
+            if (checkChar(s.at(i))) {
                 start = i;
             } else if (start > 0)
                 break;

src/network/access/qnetworkreplyhttpimpl.cpp

@@ -21,6 +21,7 @@
 #include "QtCore/qcoreapplication.h"
 
 #include <QtCore/private/qthread_p.h>
+#include <QtCore/private/qtools_p.h>
 
 #include "qnetworkcookiejar.h"
 #include "qnetconmonitor_p.h"
@@ -32,6 +33,7 @@
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtMiscUtils;
 
 class QNetworkProxy;
 
@@ -1720,8 +1722,8 @@ QNetworkCacheMetaData QNetworkReplyHttpImplPrivate::fetchCacheMetaData(const QNe
             QByteArray v = q->rawHeader(header);
             if (v.size() == 3
                 && v[0] == '1'
-                && v[1] >= '0' && v[1] <= '9'
+                && isAsciiDigit(v[1])
-                && v[2] >= '0' && v[2] <= '9')
+                && isAsciiDigit(v[2]))
                 continue;
         }
 

src/plugins/tls/shared/qasn1element.cpp

@@ -8,11 +8,14 @@
 #include <QtCore/qdatetime.h>
 #include <QtCore/qlist.h>
 #include <QDebug>
+#include <private/qtools_p.h>
 
 #include <limits>
 
 QT_BEGIN_NAMESPACE
 
+using namespace QtMiscUtils;
+
 typedef QMap<QByteArray, QByteArray> OidNameMap;
 static OidNameMap createOidMap()
 {
@@ -213,11 +216,6 @@ QDateTime QAsn1Element::toDateTime() const
 
     // QDateTime::fromString is lenient and accepts +- signs in front
     // of the year; but ASN.1 doesn't allow them.
-    const auto isAsciiDigit = [](char c)
-    {
-        return c >= '0' && c <= '9';
-    };
-
     if (!isAsciiDigit(mValue[0]))
         return result;