diff options
| author | Thiago Macieira <thiago.macieira@intel.com> | 2013-08-28 18:37:00 -0700 |
|---|---|---|
| committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-08-31 23:03:03 +0200 |
| commit | 260a983052d0e42ccedaf49832e8dfecaa5ed1d7 (patch) | |
| tree | 00867375b3a088fd81497bb3a91c9131fe90815b /src/corelib/tools/qbitarray.cpp | |
| parent | e13e90fb55149833aa96e46087f47e4dd9ca0a75 (diff) | |
Improve QBitArray's construction performance a little
Ask for an uninitialized byte array, since we're about to memset(3) it
anyway. And don't overwrite the initial byte either.
Change-Id: I2caa2ef395ad5684416e6cd336c0444de7787b5d
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Diffstat (limited to 'src/corelib/tools/qbitarray.cpp')
| -rw-r--r-- | src/corelib/tools/qbitarray.cpp | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/src/corelib/tools/qbitarray.cpp b/src/corelib/tools/qbitarray.cpp index cae8267772..fb60534495 100644 --- a/src/corelib/tools/qbitarray.cpp +++ b/src/corelib/tools/qbitarray.cpp @@ -136,15 +136,14 @@ QT_BEGIN_NAMESPACE initialized with \a value, which defaults to false (0). */ QBitArray::QBitArray(int size, bool value) + : d(size <= 0 ? 0 : 1 + (size + 7)/8, Qt::Uninitialized) { Q_ASSERT_X(size >= 0, "QBitArray::QBitArray", "Size must be greater than or equal to 0."); - if (size <= 0) { - d.resize(0); + if (size <= 0) return; - } - d.resize(1 + (size+7)/8); + uchar* c = reinterpret_cast<uchar*>(d.data()); - memset(c, value ? 0xff : 0, d.size()); + memset(c + 1, value ? 0xff : 0, d.size() - 1); *c = d.size()*8 - size; if (value && size && size % 8) *(c+1+size/8) &= (1 << (size%8)) - 1; |