diff options
Diffstat (limited to 'src/corelib/text/qstring.cpp')
-rw-r--r-- | src/corelib/text/qstring.cpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp index eed98e7c7e..32e5bb7b20 100644 --- a/src/corelib/text/qstring.cpp +++ b/src/corelib/text/qstring.cpp @@ -2504,11 +2504,12 @@ void QString::reallocData(qsizetype alloc, QArrayData::AllocationOption option) return; } - // don't use reallocate path when reducing capacity and there's free space - // at the beginning: might shift data pointer outside of allocated space - const bool cannotUseReallocate = d.freeSpaceAtBegin() > 0 && alloc < d.constAllocatedCapacity(); + // there's a case of slow reallocate path where we need to memmove the data + // before a call to ::realloc(), meaning that there's an extra "heavy" + // operation. just prefer ::malloc() branch in this case + const bool slowReallocatePath = d.freeSpaceAtBegin() > 0; - if (d->needsDetach() || cannotUseReallocate) { + if (d->needsDetach() || slowReallocatePath) { DataPointer dd(Data::allocate(alloc, option), qMin(alloc, d.size)); if (dd.size > 0) ::memcpy(dd.data(), d.data(), dd.size * sizeof(QChar)); |