AuroraMiddleware/qt5base-lts
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Remove the prepare call in QArrayData::appendInitialize()

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It's causing a performance bottleneck and is not required anymore
after changing the allocation strategy.

Take the opportunity to change the signature from using size_t to
qsizetype.

Change-Id: I74ff1637007cf7072de80e7383a23fdfe1ccd986
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Lars Knoll 2020-10-30 08:45:19 +01:00
parent b99271caa6
commit 90fadbb365
1 changed files with 10 additions and 17 deletions
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27
src/corelib/tools/qarraydataops.h
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@ -248,12 +248,12 @@ protected:
public:
typedef typename QArrayDataPointer<T>::parameter_type parameter_type;
void appendInitialize(size_t newSize)
void appendInitialize(qsizetype newSize)
{
Q_ASSERT(this->isMutable());
Q_ASSERT(!this->isShared());
Q_ASSERT(newSize > size_t(this->size));
Q_ASSERT(newSize - this->size <= size_t(this->freeSpaceAtEnd()));
Q_ASSERT(newSize > this->size);
Q_ASSERT(newSize - this->size <= this->freeSpaceAtEnd());
::memset(static_cast<void *>(this->end()), 0, (newSize - this->size) * sizeof(T));
this->size = qsizetype(newSize);
@ -491,17 +491,17 @@ protected:
public:
typedef typename QArrayDataPointer<T>::parameter_type parameter_type;
void appendInitialize(size_t newSize)
void appendInitialize(qsizetype newSize)
{
Q_ASSERT(this->isMutable());
Q_ASSERT(!this->isShared());
Q_ASSERT(newSize > size_t(this->size));
Q_ASSERT(newSize - this->size <= size_t(this->freeSpaceAtEnd()));
Q_ASSERT(newSize > this->size);
Q_ASSERT(newSize - this->size <= this->freeSpaceAtEnd());
T *const b = this->begin();
do {
new (b + this->size) T;
} while (size_t(++this->size) != newSize);
} while (++this->size != newSize);
}
void moveAppend(T *b, T *e)
@ -1342,19 +1342,12 @@ public:
// using Base::assign;
// using Base::compare;
void appendInitialize(size_t newSize)
void appendInitialize(qsizetype newSize)
{
Q_ASSERT(this->isMutable());
Q_ASSERT(!this->isShared());
Q_ASSERT(newSize > size_t(this->size));
Q_ASSERT(newSize <= size_t(this->allocatedCapacity()));
// Since this is mostly an initialization function, do not follow append
// logic of space arrangement. Instead, only prepare as much free space
// as needed for this specific operation
const size_t n = newSize - this->size;
prepareFreeSpace(GrowsForwardTag{}, n,
qMin(n, size_t(this->freeSpaceAtBegin()))); // ### perf. loss
Q_ASSERT(newSize > this->size);
Q_ASSERT(newSize - this->size <= this->freeSpaceAtEnd());
Base::appendInitialize(newSize);
}