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Diffstat (limited to 'src/corelib/kernel/qtmochelpers.h')
-rw-r--r-- | src/corelib/kernel/qtmochelpers.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/corelib/kernel/qtmochelpers.h b/src/corelib/kernel/qtmochelpers.h new file mode 100644 index 0000000000..9d75177645 --- /dev/null +++ b/src/corelib/kernel/qtmochelpers.h @@ -0,0 +1,86 @@ +// Copyright (C) 2022 Intel Corporation. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only + +#ifndef QTMOCHELPERS_H +#define QTMOCHELPERS_H + +// +// W A R N I N G +// ------------- +// +// This file is not part of the Qt API. It exists to be used by the code that +// moc generates. This file will not change quickly, but it over the long term, +// it will likely change or even be removed. +// +// We mean it. +// + +#include <QtCore/qglobal.h> + +#include <algorithm> // std::min +#include <limits> + +#if 0 +#pragma qt_no_master_include +#endif + +QT_BEGIN_NAMESPACE +namespace QtMocHelpers { +// The maximum Size of a string literal is 2 GB on 32-bit and 4 GB on 64-bit +// (but the compiler is likely to give up before you get anywhere near that much) +static constexpr size_t MaxStringSize = + (std::min)(size_t((std::numeric_limits<uint>::max)()), + size_t((std::numeric_limits<qsizetype>::max)())); + +template <uint... Nx> constexpr size_t stringDataSizeHelper(std::integer_sequence<uint, Nx...>) +{ + // same as: + // return (0 + ... + Nx); + // but not using the fold expression to avoid exceeding compiler limits + size_t total = 0; + uint sizes[] = { Nx... }; + for (uint n : sizes) + total += n; + return total; +} + +template <int Count, size_t StringSize> struct StringData +{ + static_assert(StringSize <= MaxStringSize, "Meta Object data is too big"); + uint offsetsAndSizes[Count] = {}; + char stringdata0[StringSize] = {}; + constexpr StringData() = default; +}; + +template <uint... Nx> constexpr auto stringData(const char (&...strings)[Nx]) +{ + constexpr size_t StringSize = stringDataSizeHelper<Nx...>({}); + constexpr size_t Count = 2 * sizeof...(Nx); + + StringData<Count, StringSize> result; + const char *inputs[] = { strings... }; + uint sizes[] = { Nx... }; + + uint offset = 0; + char *output = result.stringdata0; + for (size_t i = 0; i < sizeof...(Nx); ++i) { + // copy the input string, including the terminating null + uint len = sizes[i]; + for (uint j = 0; j < len; ++j) + output[offset + j] = inputs[i][j]; + result.offsetsAndSizes[2 * i] = offset + sizeof(result.offsetsAndSizes); + result.offsetsAndSizes[2 * i + 1] = len - 1; + offset += len; + } + + return result; +} + +# define QT_MOC_HAS_STRINGDATA 1 + +} // namespace QtMocHelpers +QT_END_NAMESPACE + +QT_USE_NAMESPACE + +#endif // QTMOCHELPERS_H |