1 files changed, 16 insertions, 11 deletions

diff --git a/src/corelib/text/qcollator_posix.cpp b/src/corelib/text/qcollator_posix.cpp
index b409dbd96d..5ed80c1b8e 100644
--- a/src/corelib/text/qcollator_posix.cpp
+++ b/src/corelib/text/qcollator_posix.cpp
@@ -36,7 +36,7 @@ void QCollatorPrivate::cleanup()
 static void stringToWCharArray(QVarLengthArray<wchar_t> &ret, QStringView string)
 {
     ret.resize(string.length());
-    int len = string.toWCharArray(ret.data());
+    qsizetype len = string.toWCharArray(ret.data());
     ret.resize(len+1);
     ret[len] = 0;
 }
@@ -50,8 +50,8 @@ int QCollator::compare(QStringView s1, QStringView s2) const
 
     if (d->isC())
         return s1.compare(s2, caseSensitivity());
-    if (d->dirty)
-        d->init();
+
+    d->ensureInitialized();
 
     QVarLengthArray<wchar_t> array1, array2;
     stringToWCharArray(array1, s1);
@@ -61,8 +61,7 @@ int QCollator::compare(QStringView s1, QStringView s2) const
 
 QCollatorSortKey QCollator::sortKey(const QString &string) const
 {
-    if (d->dirty)
-        d->init();
+    d->ensureInitialized();
 
     QVarLengthArray<wchar_t> original;
     stringToWCharArray(original, string);
@@ -70,13 +69,19 @@ QCollatorSortKey QCollator::sortKey(const QString &string) const
     if (d->isC()) {
         std::copy(original.cbegin(), original.cend(), result.begin());
     } else {
-        size_t size = std::wcsxfrm(result.data(), original.constData(), string.size());
-        if (size > uint(result.size())) {
-            result.resize(size+1);
-            size = std::wcsxfrm(result.data(), original.constData(), string.size());
+        auto availableSizeIncludingNullTerminator = result.size();
+        size_t neededSizeExcludingNullTerminator = std::wcsxfrm(
+                result.data(), original.constData(), availableSizeIncludingNullTerminator);
+        if (neededSizeExcludingNullTerminator > size_t(availableSizeIncludingNullTerminator - 1)) {
+            result.resize(neededSizeExcludingNullTerminator + 1);
+            availableSizeIncludingNullTerminator = result.size();
+            neededSizeExcludingNullTerminator = std::wcsxfrm(result.data(), original.constData(),
+                                                             availableSizeIncludingNullTerminator);
+            Q_ASSERT(neededSizeExcludingNullTerminator
+                     == size_t(availableSizeIncludingNullTerminator - 1));
         }
-        result.resize(size+1);
-        result[size] = 0;
+        result.resize(neededSizeExcludingNullTerminator + 1);
+        result[neededSizeExcludingNullTerminator] = 0;
     }
     return QCollatorSortKey(new QCollatorSortKeyPrivate(std::move(result)));
 }