src_corelib_tools_qcontiguouscache.cpp

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// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
#include <QContiguousCache>
 
class MyRecord {};
 
QContiguousCache<MyRecord> cache{100};
 
MyRecord &slowFetchRecord(int index)
{
    return cache[index];
}
 
//! [0]
MyRecord record(int row)
{
    Q_ASSERT(row >= 0 && row < cache.count());
 
    while (row > cache.lastIndex())
        cache.append(slowFetchRecord(cache.lastIndex()+1));
    while (row < cache.firstIndex())
        cache.prepend(slowFetchRecord(cache.firstIndex()-1));
 
    return cache.at(row);
}
//! [0]
 
void example()
{
    //! [1]
    QContiguousCache<int> cache(10);
    cache.insert(INT_MAX, 1); // cache contains one value and has valid indexes, INT_MAX to INT_MAX
    cache.append(2); // cache contains two values but does not have valid indexes.
    cache.normalizeIndexes(); // cache has two values, 1 and 2.  New first index will be in the range of 0 to capacity().
    //! [1]
}