diff options
Diffstat (limited to 'src/corelib/tools/qbitarray.cpp')
| -rw-r--r-- | src/corelib/tools/qbitarray.cpp | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/src/corelib/tools/qbitarray.cpp b/src/corelib/tools/qbitarray.cpp index fed2bb6bd2..cc3b8a15cf 100644 --- a/src/corelib/tools/qbitarray.cpp +++ b/src/corelib/tools/qbitarray.cpp @@ -104,12 +104,23 @@ QT_BEGIN_NAMESPACE * inline qsizetype size() const { return (d.size() << 3) - *d.constData(); } */ +static constexpr qsizetype storage_size(qsizetype size) +{ + // avoid overflow when adding 7, by doing the arithmetic in unsigned space: + return qsizetype((size_t(size) + 7) / 8); +} + +static constexpr qsizetype allocation_size(qsizetype size) +{ + return size <= 0 ? 0 : storage_size(size) + 1; +} + /*! Constructs a bit array containing \a size bits. The bits are initialized with \a value, which defaults to false (0). */ QBitArray::QBitArray(qsizetype size, bool value) - : d(size <= 0 ? 0 : 1 + (size + 7) / 8, Qt::Uninitialized) + : d(allocation_size(size), Qt::Uninitialized) { Q_ASSERT_X(size >= 0, "QBitArray::QBitArray", "Size must be greater than or equal to 0."); if (size <= 0) @@ -187,7 +198,7 @@ void QBitArray::resize(qsizetype size) d.resize(0); } else { qsizetype s = d.size(); - d.resize(1 + (size + 7) / 8); + d.resize(allocation_size(size)); uchar *c = reinterpret_cast<uchar *>(d.data()); if (size > (s << 3)) memset(c + s, 0, d.size() - s); @@ -292,7 +303,7 @@ QBitArray QBitArray::fromBits(const char *data, qsizetype size) QBitArray result; if (size == 0) return result; - qsizetype nbytes = (size + 7) / 8; + qsizetype nbytes = storage_size(size); result.d = QByteArray(nbytes + 1, Qt::Uninitialized); char *bits = result.d.data(); @@ -922,7 +933,7 @@ QDataStream &operator>>(QDataStream &in, QBitArray &ba) } const qsizetype Step = 8 * 1024 * 1024; - qsizetype totalBytes = (len + 7) / 8; + const qsizetype totalBytes = storage_size(len); qsizetype allocated = 0; while (allocated < totalBytes) { |