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/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qhashedstring_p.h"
inline unsigned stringHash(const QChar* data, unsigned length)
{
return v8::String::ComputeHash((uint16_t *)data, length);
}
void QHashedString::computeHash() const
{
m_hash = stringHash(constData(), length());
}
void QHashedStringRef::computeHash() const
{
m_hash = stringHash(m_data, m_length);
}
/*
A QHash has initially around pow(2, MinNumBits) buckets. For
example, if MinNumBits is 4, it has 17 buckets.
*/
const int MinNumBits = 4;
/*
The prime_deltas array is a table of selected prime values, even
though it doesn't look like one. The primes we are using are 1,
2, 5, 11, 17, 37, 67, 131, 257, ..., i.e. primes in the immediate
surrounding of a power of two.
The primeForNumBits() function returns the prime associated to a
power of two. For example, primeForNumBits(8) returns 257.
*/
static const uchar prime_deltas[] = {
0, 0, 1, 3, 1, 5, 3, 3, 1, 9, 7, 5, 3, 9, 25, 3,
1, 21, 3, 21, 7, 15, 9, 5, 3, 29, 15, 0, 0, 0, 0, 0
};
static inline int primeForNumBits(int numBits)
{
return (1 << numBits) + prime_deltas[numBits];
}
void QStringHashData::rehash()
{
numBits = qMax(MinNumBits, numBits + 1);
numBuckets = primeForNumBits(numBits);
delete [] buckets;
buckets = new QStringHashNode *[numBuckets];
::memset(buckets, 0, sizeof(QStringHashNode *) * numBuckets);
QStringHashNode *nodeList = nodes;
while (nodeList) {
int bucket = nodeList->key.hash() % numBuckets;
nodeList->next = buckets[bucket];
buckets[bucket] = nodeList;
nodeList = nodeList->nlist;
}
}
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