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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
****************************************************************************/
#pragma once
#include <QtGlobal>
#include <cstdint>
#pragma push_macro("constexpr")
#ifndef __cpp_constexpr
#define constexpr
#endif
#pragma push_macro("noexcept")
#ifndef __cpp_noexcept
#define noexcept
#endif
#ifdef __cpp_alignas
#define ALIGNAS_16 alignas(16)
#else
#define ALIGNAS_16
#endif
namespace Utils {
namespace Internal {
using size_type = std::size_t;
static const int smallStringLayoutByteSize = 32;
static const int maximumShortStringDataAreaSize = smallStringLayoutByteSize - 1;
struct AllocatedLayout {
struct Data {
char *pointer;
size_type size;
size_type capacity;
} data;
char dummy[maximumShortStringDataAreaSize - sizeof(Data)];
std::uint8_t shortStringSize: 6;
std::uint8_t isReadOnlyReference : 1;
std::uint8_t isReference : 1;
};
struct ReferenceLayout {
struct Data {
const char *pointer;
size_type size;
size_type capacity;
} data;
char dummy[maximumShortStringDataAreaSize - sizeof(Data)];
std::uint8_t shortStringSize: 6;
std::uint8_t isReadOnlyReference : 1;
std::uint8_t isReference : 1;
};
struct ShortStringLayout {
char string[maximumShortStringDataAreaSize];
std::uint8_t shortStringSize: 6;
std::uint8_t isReadOnlyReference : 1;
std::uint8_t isReference : 1;
};
struct ALIGNAS_16 StringDataLayout {
StringDataLayout() noexcept = default;
constexpr StringDataLayout(const char *string,
size_type size) noexcept
: reference({{string, size, 0}, {}, 0, true, true})
{
}
template<size_type Size>
constexpr StringDataLayout(const char(&string)[Size]) noexcept
#if __cpp_constexpr < 201304
: reference({{string, Size - 1, 0}, {}, 0, true, true})
#endif
{
#if __cpp_constexpr >= 201304
if (Size <= maximumShortStringDataAreaSize) {
for (size_type i = 0; i < Size; ++i)
shortString.string[i] = string[i];
#if defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Woverflow"
shortString.shortStringSize = std::uint8_t(Size) - 1;
#pragma GCC diagnostic pop
#endif
shortString.isReference = false;
shortString.isReadOnlyReference = false;
} else {
reference.data.pointer = string;
reference.data.size = Size - 1;
reference.data.capacity = 0;
reference.shortStringSize = 0;
reference.isReference = true;
reference.isReadOnlyReference = true;
}
#endif
}
union {
AllocatedLayout allocated;
ReferenceLayout reference;
ShortStringLayout shortString = {};
};
};
} // namespace Internal
} // namespace Utils
#pragma pop_macro("noexcept")
#pragma pop_macro("constexpr")
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