qglobal.cpp

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// Copyright (C) 2021 The Qt Company Ltd.
// Copyright (C) 2017 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qplatformdefs.h"
#include "qstring.h"
#include "qbytearrayview.h"
#include "qlist.h"
#include "qdir.h"
#include "qdatetime.h"
#include <private/qlocale_tools_p.h>
#include "qnativeinterface.h"
#include "qnativeinterface_p.h"
 
#ifdef Q_OS_WIN
#  include <qt_windows.h>
#endif
 
#if defined(Q_OS_VXWORKS) && defined(_WRS_KERNEL)
#  include <envLib.h>
#endif
 
#if defined(Q_OS_INTEGRITY)
extern "C" {
    // Function mmap resides in libshm_client.a. To be able to link with it one needs
    // to define symbols 'shm_area_password' and 'shm_area_name', because the library
    // is meant to allow the application that links to it to use POSIX shared memory
    // without full system POSIX.
#  pragma weak shm_area_password
#  pragma weak shm_area_name
    char shm_area_password[] = "dummy";
    char shm_area_name[] = "dummy";
}
#endif
 
QT_BEGIN_NAMESPACE
 
using namespace Qt::StringLiterals;
 
/*
    Dijkstra's bisection algorithm to find the square root of an integer.
    Deliberately not exported as part of the Qt API, but used in
    qtextdocument.cpp.
*/
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION unsigned int qt_int_sqrt(unsigned int n)
{
    // n must be in the range 0...UINT_MAX/2-1
    if (n >= (UINT_MAX >> 2)) {
        unsigned int r = 2 * qt_int_sqrt(n / 4);
        unsigned int r2 = r + 1;
        return (n >= r2 * r2) ? r2 : r;
    }
    uint h, p = 0, q = 1, r = n;
    while (q <= n)
        q <<= 2;
    while (q != 1) {
        q >>= 2;
        h = p + q;
        p >>= 1;
        if (r >= h) {
            p += q;
            r -= h;
        }
    }
    return p;
}
 
// Also specified to behave as if they call tzset():
// localtime() -- but not localtime_r(), which we use when threaded
// strftime() -- not used (except in tests)
 
struct QInternal_CallBackTable
{
    QList<QList<qInternalCallback>> callbacks;
};
 
Q_GLOBAL_STATIC(QInternal_CallBackTable, global_callback_table)
 
bool QInternal::registerCallback(Callback cb, qInternalCallback callback)
{
    if (unsigned(cb) < unsigned(QInternal::LastCallback)) {
        QInternal_CallBackTable *cbt = global_callback_table();
        cbt->callbacks.resize(cb + 1);
        cbt->callbacks[cb].append(callback);
        return true;
    }
    return false;
}
 
bool QInternal::unregisterCallback(Callback cb, qInternalCallback callback)
{
    if (unsigned(cb) < unsigned(QInternal::LastCallback)) {
        if (global_callback_table.exists()) {
            QInternal_CallBackTable *cbt = global_callback_table();
            return cbt->callbacks[cb].removeAll(callback) > 0;
        }
    }
    return false;
}
 
bool QInternal::activateCallbacks(Callback cb, void **parameters)
{
    Q_ASSERT_X(cb >= 0, "QInternal::activateCallback()", "Callback id must be a valid id");
 
    if (!global_callback_table.exists())
        return false;
 
    QInternal_CallBackTable *cbt = &(*global_callback_table);
    if (cbt && cb < cbt->callbacks.size()) {
        QList<qInternalCallback> callbacks = cbt->callbacks[cb];
        bool ret = false;
        for (int i = 0; i < callbacks.size(); ++i)
            ret |= (callbacks.at(i))(parameters);
        return ret;
    }
    return false;
}
 
namespace QtPrivate {
Q_LOGGING_CATEGORY(lcNativeInterface, "qt.nativeinterface")
}
 
QT_END_NAMESPACE