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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QV4_ALLOCA_H
#define QV4_ALLOCA_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
#include <QtCore/private/qglobal_p.h>
#if QT_CONFIG(alloca_h)
# include <alloca.h>
#elif QT_CONFIG(alloca_malloc_h)
# include <malloc.h>
// This does not matter unless compiling in strict standard mode.
# ifdef Q_CC_MSVC
# define alloca _alloca
# endif
#else
# include <stdlib.h>
#endif
// Define Q_ALLOCA_VAR macro to be used instead of #ifdeffing
// the occurrences of alloca() in case it's not supported.
// Q_ALLOCA_DECLARE and Q_ALLOCA_ASSIGN macros separate
// memory allocation from the declaration and RAII.
#define Q_ALLOCA_VAR(type, name, size) \
Q_ALLOCA_DECLARE(type, name); \
Q_ALLOCA_ASSIGN(type, name, size)
#if QT_CONFIG(alloca)
#define Q_ALLOCA_DECLARE(type, name) \
type *name = 0
#define Q_ALLOCA_ASSIGN(type, name, size) \
name = static_cast<type*>(alloca(size))
#else
QT_BEGIN_NAMESPACE
class Qt_AllocaWrapper
{
public:
Qt_AllocaWrapper() { m_data = 0; }
~Qt_AllocaWrapper() { free(m_data); }
void *data() { return m_data; }
void allocate(int size) { m_data = malloc(size); memset(m_data, 0, size); }
private:
void *m_data;
};
QT_END_NAMESPACE
#define Q_ALLOCA_DECLARE(type, name) \
Qt_AllocaWrapper _qt_alloca_##name; \
type *name = nullptr
#define Q_ALLOCA_ASSIGN(type, name, size) \
do { \
_qt_alloca_##name.allocate(size); \
name = static_cast<type*>(_qt_alloca_##name.data()); \
} while (false)
#endif
#endif
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