Revision control
Copy as Markdown
// Copyright (C) 2016 Klaralvdalens Datakonsult AB (KDAB).
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "stringtoint_p.h"
#include <QHash>
#include <mutex>
#include <shared_mutex>
#include <vector>
QT_BEGIN_NAMESPACE
namespace Qt3DRender {
namespace Render {
namespace {
struct StringToIntCache
{
std::shared_mutex lock;
QHash<QString, int> map;
std::vector<QString> reverseMap;
static StringToIntCache& instance()
{
static StringToIntCache c;
return c;
}
};
} // anonymous
int StringToInt::lookupId(QLatin1String str)
{
// ### optimize me
return lookupId(QString(str));
}
int StringToInt::lookupId(const QString &str)
{
auto& cache = StringToIntCache::instance();
int idx;
{
std::shared_lock readLocker(cache.lock);
idx = cache.map.value(str, -1);
}
if (Q_UNLIKELY(idx < 0)) {
std::unique_lock writeLocker(cache.lock);
idx = cache.map.value(str, -1);
if (idx < 0) {
idx = int(cache.reverseMap.size());
Q_ASSERT(size_t(cache.map.size()) == cache.reverseMap.size());
cache.map.insert(str, idx);
cache.reverseMap.push_back(str);
}
}
return idx;
}
QString StringToInt::lookupString(int idx)
{
auto& cache = StringToIntCache::instance();
std::shared_lock readLocker(cache.lock);
if (Q_LIKELY(cache.reverseMap.size() > size_t(idx)))
return cache.reverseMap[idx];
return QString();
}
} // Render
} // Qt3DRender
QT_END_NAMESPACE