5 files changed, 19 insertions, 12 deletions
diff --git a/src/core/kauthorized.cpp b/src/core/kauthorized.cpp
index aad23949..66a2be23 100644
--- a/src/core/kauthorized.cpp
+++ b/src/core/kauthorized.cpp
@@ -332,7 +332,7 @@ KCONFIGCORE_EXPORT void loadUrlActionRestrictions(const KConfigGroup &cg)
         const QString urlProt = rule[4];
         const QString urlHost = rule[5];
         QString urlPath = rule[6];
-        const bool bEnabled = (rule[7].toLower() == QLatin1String("true"));
+        const bool bEnabled = (rule[7].compare(QLatin1String("true"), Qt::CaseInsensitive) == 0);
 
         if (refPath.startsWith(QLatin1String("$HOME"))) {
             refPath.replace(0, 5, QDir::homePath());
diff --git a/src/core/kconfiggroup.cpp b/src/core/kconfiggroup.cpp
index be1f2b0e..24a8ccfd 100644
--- a/src/core/kconfiggroup.cpp
+++ b/src/core/kconfiggroup.cpp
@@ -26,6 +26,8 @@
 #include <QTextStream>
 #include <QUrl>
 
+#include <algorithm>
+#include <array>
 #include <math.h>
 #include <stdlib.h>
 
@@ -234,11 +236,11 @@ QVariant KConfigGroup::convertToQVariant(const char *pKey, const QByteArray &val
     case QMetaType::QByteArray:
         return value;
     case QMetaType::Bool: {
-        const QByteArray lower(value.toLower());
-        if (lower == "false" || lower == "no" || lower == "off" || lower == "0") {
-            return false;
-        }
-        return true;
+        static const std::array<const char *, 4> negatives = {"false", "no", "off", "0"};
+
+        return std::all_of(negatives.begin(), negatives.end(), [value](const char *negativeString) {
+            return value.compare(negativeString, Qt::CaseInsensitive) != 0;
+        });
     }
     case QMetaType::Double:
     case QMetaType::Float:
diff --git a/src/core/kcoreconfigskeleton.cpp b/src/core/kcoreconfigskeleton.cpp
index f8097055..030039fc 100644
--- a/src/core/kcoreconfigskeleton.cpp
+++ b/src/core/kcoreconfigskeleton.cpp
@@ -608,10 +608,10 @@ void KCoreConfigSkeleton::ItemEnum::readConfig(KConfig *config)
     } else {
         int i = 0;
         mReference = -1;
-        QString tmp = cg.readEntry(mKey, QString()).toLower();
+        const QString entryString = cg.readEntry(mKey, QString());
         for (auto it = mChoices.cbegin(); it != mChoices.cend(); ++it, ++i) {
             QString choiceName = (*it).name;
-            if (valueForChoice(choiceName).toLower() == tmp) {
+            if (valueForChoice(choiceName).compare(entryString, Qt::CaseInsensitive) == 0) {
                 mReference = i;
                 break;
             }
diff --git a/src/gui/kconfigloader.cpp b/src/gui/kconfigloader.cpp
index ac39a12f..08365f17 100644
--- a/src/gui/kconfigloader.cpp
+++ b/src/gui/kconfigloader.cpp
@@ -172,7 +172,7 @@ void ConfigLoaderHandler::addItem()
     KConfigSkeletonItem *item = nullptr;
 
     if (m_type == QLatin1String("bool")) {
-        bool defaultValue = m_default.toLower() == QLatin1String("true");
+        const bool defaultValue = caseInsensitiveCompare(m_default, QLatin1String("true"));
         item = m_config->addItemBool(m_name, *d->newBool(), defaultValue, m_key);
     } else if (m_type == QLatin1String("color")) {
         item = m_config->addItemColor(m_name, *d->newColor(), QColor(m_default), m_key);
diff --git a/src/kconf_update/kconf_update.cpp b/src/kconf_update/kconf_update.cpp
index 8cbbc3c3..0e9744a0 100644
--- a/src/kconf_update/kconf_update.cpp
+++ b/src/kconf_update/kconf_update.cpp
@@ -35,6 +35,11 @@
 // the file.
 #define qCDebugFile(CATEGORY) qCDebug(CATEGORY) << m_currentFilename << ':' << m_lineCount << ":'" << m_line << "': "
 
+static bool caseInsensitiveCompare(const QStringView &a, const QLatin1String &b)
+{
+    return a.compare(b, Qt::CaseInsensitive) == 0;
+}
+
 class KonfUpdate
 {
 public:
@@ -701,11 +706,11 @@ void KonfUpdate::gotOptions(const QString &_options)
 {
     const QStringList options = _options.split(QLatin1Char{','});
     for (const auto &opt : options) {
-        const auto normalizedOpt = opt.toLower().trimmed();
+        const auto normalizedOpt = QStringView(opt).trimmed();
 
-        if (normalizedOpt == QLatin1String("copy")) {
+        if (caseInsensitiveCompare(normalizedOpt, QLatin1String("copy"))) {
             m_bCopy = true;
-        } else if (normalizedOpt == QLatin1String("overwrite")) {
+        } else if (caseInsensitiveCompare(normalizedOpt, QLatin1String("overwrite"))) {
             m_bOverwrite = true;
         }
     }