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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Copyright (C) 2019 Intel Corporation.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** 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-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef QARRAYDATA_H
#define QARRAYDATA_H
#include <QtCore/qpair.h>
#include <QtCore/qatomic.h>
#include <string.h>
QT_BEGIN_NAMESPACE
template <class T> struct QTypedArrayData;
struct Q_CORE_EXPORT QArrayData
{
enum ArrayOption {
/// this option is used by the allocate() function
DefaultAllocationFlags = 0,
CapacityReserved = 0x1, //!< the capacity was reserved by the user, try to keep it
GrowsForward = 0x2, //!< allocate with eyes towards growing through append()
GrowsBackwards = 0x4 //!< allocate with eyes towards growing through prepend()
};
Q_DECLARE_FLAGS(ArrayOptions, ArrayOption)
QBasicAtomicInt ref_;
uint flags;
uint alloc;
inline size_t allocatedCapacity() noexcept
{
return alloc;
}
inline size_t constAllocatedCapacity() const noexcept
{
return alloc;
}
/// Returns true if sharing took place
bool ref() noexcept
{
ref_.ref();
return true;
}
/// Returns false if deallocation is necessary
bool deref() noexcept
{
return ref_.deref();
}
bool isShared() const noexcept
{
return ref_.loadRelaxed() != 1;
}
// Returns true if a detach is necessary before modifying the data
// This method is intentionally not const: if you want to know whether
// detaching is necessary, you should be in a non-const function already
bool needsDetach() const noexcept
{
return ref_.loadRelaxed() > 1;
}
size_t detachCapacity(size_t newSize) const noexcept
{
if (flags & CapacityReserved && newSize < constAllocatedCapacity())
return constAllocatedCapacity();
return newSize;
}
ArrayOptions detachFlags() const noexcept
{
ArrayOptions result = DefaultAllocationFlags;
if (flags & CapacityReserved)
result |= CapacityReserved;
return result;
}
Q_REQUIRED_RESULT
#if defined(Q_CC_GNU)
__attribute__((__malloc__))
#endif
static void *allocate(QArrayData **pdata, size_t objectSize, size_t alignment,
size_t capacity, ArrayOptions options = DefaultAllocationFlags) noexcept;
Q_REQUIRED_RESULT static QPair<QArrayData *, void *> reallocateUnaligned(QArrayData *data, void *dataPointer,
size_t objectSize, size_t newCapacity, ArrayOptions newOptions = DefaultAllocationFlags) Q_DECL_NOTHROW;
static void deallocate(QArrayData *data, size_t objectSize,
size_t alignment) noexcept;
};
Q_DECLARE_OPERATORS_FOR_FLAGS(QArrayData::ArrayOptions)
template <class T>
struct QTypedArrayData
: QArrayData
{
typedef T* iterator;
typedef const T* const_iterator;
class AlignmentDummy { QArrayData header; T data; };
Q_REQUIRED_RESULT static QPair<QTypedArrayData *, T *> allocate(size_t capacity,
ArrayOptions options = DefaultAllocationFlags)
{
static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
QArrayData *d;
void *result = QArrayData::allocate(&d, sizeof(T), alignof(AlignmentDummy), capacity, options);
#if (defined(Q_CC_GNU) && Q_CC_GNU >= 407) || QT_HAS_BUILTIN(__builtin_assume_aligned)
result = __builtin_assume_aligned(result, Q_ALIGNOF(AlignmentDummy));
#endif
return qMakePair(static_cast<QTypedArrayData *>(d), static_cast<T *>(result));
}
static QPair<QTypedArrayData *, T *>
reallocateUnaligned(QTypedArrayData *data, T *dataPointer, size_t capacity,
ArrayOptions options = DefaultAllocationFlags)
{
static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
QPair<QArrayData *, void *> pair =
QArrayData::reallocateUnaligned(data, dataPointer, sizeof(T), capacity, options);
return qMakePair(static_cast<QTypedArrayData *>(pair.first), static_cast<T *>(pair.second));
}
static void deallocate(QArrayData *data) noexcept
{
static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
QArrayData::deallocate(data, sizeof(T), alignof(AlignmentDummy));
}
};
namespace QtPrivate {
struct Q_CORE_EXPORT QContainerImplHelper
{
enum CutResult { Null, Empty, Full, Subset };
static constexpr CutResult mid(qsizetype originalLength, qsizetype *_position, qsizetype *_length)
{
qsizetype &position = *_position;
qsizetype &length = *_length;
if (position > originalLength) {
position = 0;
length = 0;
return Null;
}
if (position < 0) {
if (length < 0 || length + position >= originalLength) {
position = 0;
length = originalLength;
return Full;
}
if (length + position <= 0) {
position = length = 0;
return Null;
}
length += position;
position = 0;
} else if (size_t(length) > size_t(originalLength - position)) {
length = originalLength - position;
}
if (position == 0 && length == originalLength)
return Full;
return length > 0 ? Subset : Empty;
}
};
}
QT_END_NAMESPACE
#endif // include guard
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