QString/QBA: add lvalue and rvalue overloads to first/last/sliced/chopped

Those ought to have been the original implementation, when they were
added in commit 38096a3d7040edac4f769270d2402ff4e39d7694, for Qt 6.0.

Because these classes are exported, we need to provide the previous only
implementations for MSVC. All other compilers would provide inline or
emit local, out-of-line copies.

Change-Id: Ifeb6206a9fa04424964bfffd178836a2ae56157d
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/corelib/tools/qarraydatapointer.h b/src/corelib/tools/qarraydatapointer.h
index 201f3e665d..2fbd6c7505 100644
--- a/src/corelib/tools/qarraydatapointer.h
+++ b/src/corelib/tools/qarraydatapointer.h
@@ -413,6 +413,26 @@ public:
         size = dst - begin();
     }
 
+    QArrayDataPointer sliced(qsizetype pos, qsizetype n) const &
+    {
+        QArrayDataPointer result(n);
+        std::uninitialized_copy_n(begin() + pos, n, result.begin());
+        result.size = n;
+        return result;
+    }
+
+    QArrayDataPointer sliced(qsizetype pos, qsizetype n) &&
+    {
+        if (needsDetach())
+            return sliced(pos, n);
+        T *newBeginning = begin() + pos;
+        std::destroy(begin(), newBeginning);
+        std::destroy(newBeginning + n, end());
+        setBegin(newBeginning);
+        size = n;
+        return std::move(*this);
+    }
+
     // forwards from QArrayData
     qsizetype allocatedCapacity() noexcept { return d ? d->allocatedCapacity() : 0; }
     qsizetype constAllocatedCapacity() const noexcept { return d ? d->constAllocatedCapacity() : 0; }