| 1 | // Copyright (C) 2016 The Qt Company Ltd. |
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| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
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| 3 | |
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| 4 | #ifndef QV4_ALLOCA_H |
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| 5 | #define QV4_ALLOCA_H |
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| 6 | |
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| 7 | // |
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| 8 | // W A R N I N G |
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| 9 | // ------------- |
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| 10 | // |
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| 11 | // This file is not part of the Qt API. It exists purely as an |
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| 12 | // implementation detail. This header file may change from version to |
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| 13 | // version without notice, or even be removed. |
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| 14 | // |
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| 15 | // We mean it. |
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| 16 | // |
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| 17 | |
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| 18 | #include <QtCore/private/qglobal_p.h> |
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| 19 | |
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| 20 | #include <stdlib.h> |
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| 21 | #if __has_include(<alloca.h>) |
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| 22 | # include <alloca.h> |
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| 23 | #endif |
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| 24 | #if __has_include(<malloc.h>) |
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| 25 | # include <malloc.h> |
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| 26 | #endif |
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| 27 | |
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| 28 | #ifdef Q_CC_MSVC |
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| 29 | // This does not matter unless compiling in strict standard mode. |
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| 30 | # define alloca _alloca |
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| 31 | #endif |
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| 32 | |
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| 33 | // Define Q_ALLOCA_VAR macro to be used instead of #ifdeffing |
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| 34 | // the occurrences of alloca() in case it's not supported. |
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| 35 | // Q_ALLOCA_DECLARE and Q_ALLOCA_ASSIGN macros separate |
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| 36 | // memory allocation from the declaration and RAII. |
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| 37 | #define Q_ALLOCA_VAR(type, name, size) \ |
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| 38 | Q_ALLOCA_DECLARE(type, name); \ |
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| 39 | Q_ALLOCA_ASSIGN(type, name, size) |
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| 40 | |
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| 41 | #ifdef alloca |
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| 42 | |
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| 43 | #define Q_ALLOCA_DECLARE(type, name) \ |
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| 44 | type *name = 0 |
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| 45 | |
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| 46 | #define Q_ALLOCA_ASSIGN(type, name, size) \ |
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| 47 | name = static_cast<type*>(alloca(size)) |
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| 48 | |
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| 49 | #else |
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| 50 | # include <memory> |
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| 51 | |
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| 52 | #define Q_ALLOCA_DECLARE(type, name) \ |
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| 53 | std::unique_ptr<char[]> _qt_alloca_##name; \ |
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| 54 | type *name = nullptr |
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| 55 | |
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| 56 | #define Q_ALLOCA_ASSIGN(type, name, size) \ |
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| 57 | do { \ |
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| 58 | _qt_alloca_##name.reset(new char[size]); \ |
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| 59 | name = reinterpret_cast<type*>(_qt_alloca_##name.get()); \ |
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| 60 | } while (false) |
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| 61 | |
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| 62 | #endif |
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| 63 | |
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| 64 | #endif |
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| 65 | |
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