AuroraMiddleware/qt5base-lts
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Optimize appending to an existing string

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Optimize the common pattern of "str += decode(data);"
and "bytearray += encode(string);"

Change-Id: I1da621fa1ad400f23c9718ecf8ae64c00d9d459c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Lars Knoll 2020-05-05 15:45:47 +02:00
parent 4d67b9dcfb
commit 4ff09cdd47
1 changed files with 22 additions and 0 deletions
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22
src/corelib/text/qstringconverter.h
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@ -327,6 +327,28 @@ struct QConcatenable<QStringEncoder::DecodedData<T>>
out = s.decoder->decodeIntoBuffer(out, s.data.data(), s.data.length());
}
};
template <typename T>
QString &operator+=(QString &a, const QStringDecoder::EncodedData<T> &b)
{
qsizetype len = a.size() + QConcatenable<QStringDecoder::EncodedData<T>>::size(b);
a.reserve(len);
QChar *it = a.data() + a.size();
QConcatenable<QStringDecoder::EncodedData<T>>::appendTo(b, it);
a.resize(qsizetype(it - a.constData())); //may be smaller than len
return a;
}
template <typename T>
QByteArray &operator+=(QByteArray &a, const QStringEncoder::DecodedData<T> &b)
{
qsizetype len = a.size() + QConcatenable<QStringEncoder::DecodedData<T>>::size(b);
a.reserve(len);
char *it = a.data() + a.size();
QConcatenable<QStringEncoder::DecodedData<T>>::appendTo(b, it);
a.resize(qsizetype(it - a.constData())); //may be smaller than len
return a;
}
#endif
QT_END_NAMESPACE