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Significantly speed up insertion into QJsonObject/Array

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The code was only allocating memory for the next insertion
leading to a reallocation of the whole data for every
single insertion.

The code now reserves some space and uses a decent growth
strategy to avoid repeated reallocs.

Change-Id: I48b0feab71ba8ca73e7037f8460080f198b2f009
Reviewed-by: Jamey Hicks <jamey.hicks@nokia.com>
This commit is contained in:
Lars Knoll 2012-03-20 20:45:27 +01:00 committed by Qt by Nokia
parent 8dd18751e1
commit 349c0de091
3 changed files with 47 additions and 10 deletions
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8
src/corelib/json/qjson.cpp
View File

@ -241,14 +241,6 @@ bool Entry::operator ==(const QString &key) const
return (shallowKey() == key);
}
bool Entry::operator >=(const QString &key) const
{
if (value.latinKey)
return (shallowLatin1Key() >= key);
else
return (shallowKey() >= key);
}
bool Entry::operator ==(const Entry &other) const
{
if (value.latinKey) {

21
src/corelib/json/qjson_p.h
View File

@ -620,15 +620,24 @@ public:
bool operator ==(const QString &key) const;
inline bool operator !=(const QString &key) const { return !operator ==(key); }
bool operator >=(const QString &key) const;
inline bool operator >=(const QString &key) const;
bool operator ==(const Entry &other) const;
bool operator >=(const Entry &other) const;
};
inline bool Entry::operator >=(const QString &key) const
{
if (value.latinKey)
return (shallowLatin1Key() >= key);
else
return (shallowKey() >= key);
}
inline bool operator <(const QString &key, const Entry &e)
{ return e >= key; }
class Header {
public:
qle_uint tag; // 'qbjs'
@ -735,7 +744,15 @@ public:
Data *clone(Base *b, int reserve = 0)
{
int size = sizeof(Header) + b->size + reserve;
int size = sizeof(Header) + b->size;
if (ref.load() == 1 && alloc >= size + reserve)
return this;
if (reserve) {
if (reserve < 128)
reserve = 128;
size = qMax(size + reserve, size *2);
}
char *raw = (char *)malloc(size);
Q_CHECK_PTR(raw);
memcpy(raw + sizeof(Header), b, b->size);

28
tests/benchmarks/corelib/json/tst_bench_qtbinaryjson.cpp
View File

@ -58,8 +58,12 @@ private Q_SLOTS:
void parseNumbers();
void parseJson();
void parseJsonToVariant();
void toByteArray();
void fromByteArray();
void jsonObjectInsert();
void variantMapInsert();
};
BenchmarkQtBinaryJson::BenchmarkQtBinaryJson(QObject *parent) : QObject(parent)
@ -159,6 +163,30 @@ void BenchmarkQtBinaryJson::fromByteArray()
}
}
void BenchmarkQtBinaryJson::jsonObjectInsert()
{
QJsonObject object;
QString test(QStringLiteral("testString"));
QJsonValue value(1.5);
QBENCHMARK {
for (int i = 0; i < 1000; i++)
object.insert("testkey_" + i, value);
}
}
void BenchmarkQtBinaryJson::variantMapInsert()
{
QVariantMap object;
QString test(QStringLiteral("testString"));
QVariant variantValue(1.5);
QBENCHMARK {
for (int i = 0; i < 1000; i++)
object.insert("testkey_" + i, variantValue);
}
}
QTEST_MAIN(BenchmarkQtBinaryJson)
#include "tst_bench_qtbinaryjson.moc"