diff options
Diffstat (limited to 'src/corelib/tools/qbitarray.cpp')
| -rw-r--r-- | src/corelib/tools/qbitarray.cpp | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/src/corelib/tools/qbitarray.cpp b/src/corelib/tools/qbitarray.cpp index 2b459b2b1b..4949476f25 100644 --- a/src/corelib/tools/qbitarray.cpp +++ b/src/corelib/tools/qbitarray.cpp @@ -40,6 +40,7 @@ ****************************************************************************/ #include "qbitarray.h" +#include <qalgorithms.h> #include <qdatastream.h> #include <qdebug.h> #include <string.h> @@ -159,24 +160,18 @@ int QBitArray::count(bool on) const for (int i = 0; i < len; ++i) numBits += testBit(i); #else - // See http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel const quint8 *bits = reinterpret_cast<const quint8 *>(d.data()) + 1; while (len >= 32) { quint32 v = quint32(bits[0]) | (quint32(bits[1]) << 8) | (quint32(bits[2]) << 16) | (quint32(bits[3]) << 24); - quint32 c = ((v & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; - c += (((v & 0xfff000) >> 12) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; - c += ((v >> 24) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; len -= 32; bits += 4; - numBits += int(c); + numBits += int(qPopulationCount(v)); } while (len >= 24) { quint32 v = quint32(bits[0]) | (quint32(bits[1]) << 8) | (quint32(bits[2]) << 16); - quint32 c = ((v & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; - c += (((v & 0xfff000) >> 12) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; len -= 24; bits += 3; - numBits += int(c); + numBits += int(qPopulationCount(v)); } while (len >= 0) { if (bits[len / 8] & (1 << ((len - 1) & 7))) |