Revision control
++ // Copyright (C) 2020 The Qt Company Ltd.
++ // Copyright (C) 2019 Intel Corporation.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
++ // Qt-Security score:significant reason:default
++
++ #ifndef QARRAYDATA_H
++ #define QARRAYDATA_H
++
++ #include <QtCore/qpair.h>
++ #include <QtCore/qatomic.h>
++ #include <QtCore/qflags.h>
++ #include <QtCore/qcontainerfwd.h>
++ #include <string.h>
++
++ QT_BEGIN_NAMESPACE
++
++ #if __has_cpp_attribute(gnu::malloc)
++ # define Q_DECL_MALLOCLIKE [[nodiscard, gnu::malloc]]
++ #elif Q_CC_MSVC_ONLY
++ # define Q_DECL_MALLOCLIKE [[nodiscard]] __declspec(allocator) __declspec(restrict)
++ #else
++ # define Q_DECL_MALLOCLIKE [[nodiscard]]
++ #endif
++
++ template <class T> struct QTypedArrayData;
++
++ template <class T>
++ struct QTypedArrayAllocationResult
++ {
++ QTypedArrayData<T> *header;
++ T *ptr;
++
++ [[deprecated]]
++ operator std::pair<QTypedArrayData<T>*, T*>() const noexcept { return {header, ptr}; }
++ };
++
++ struct QArrayData
++ {
++ enum AllocationOption {
++ Grow,
++ KeepSize
++ };
++
++ enum GrowthPosition {
++ GrowsAtEnd,
++ GrowsAtBeginning
++ };
++
++ enum ArrayOption {
++ ArrayOptionDefault = 0,
++ CapacityReserved = 0x1 //!< the capacity was reserved by the user, try to keep it
++ };
++ Q_DECLARE_FLAGS(ArrayOptions, ArrayOption)
++
++ QBasicAtomicInt ref_;
++ ArrayOptions flags;
++ qsizetype alloc;
++
++ qsizetype allocatedCapacity() noexcept
++ {
++ qsizetype a = alloc;
++ Q_PRESUME(a > 0);
++ return a;
++ }
++
++ qsizetype constAllocatedCapacity() const noexcept
++ {
++ qsizetype a = alloc;
++ Q_PRESUME(a > 0);
++ return a;
++ }
++
++ /// Returns true if sharing took place
++ bool ref() noexcept
++ {
++ ref_.refRelaxed(); // suffices for ref-counting
++ 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() noexcept
++ {
++ return ref_.loadRelaxed() > 1;
++ }
++
++ qsizetype detachCapacity(qsizetype newSize) const noexcept
++ {
++ if (flags & CapacityReserved && newSize < constAllocatedCapacity())
++ return constAllocatedCapacity();
++ return newSize;
++ }
++
++ Q_DECL_MALLOCLIKE
++ static Q_CORE_EXPORT void *allocate(QArrayData **pdata, qsizetype objectSize, qsizetype alignment,
++ qsizetype capacity, AllocationOption option = QArrayData::KeepSize) noexcept;
++ Q_DECL_MALLOCLIKE
++ static Q_CORE_EXPORT void *allocate1(QArrayData **pdata, qsizetype capacity,
++ AllocationOption option = QArrayData::KeepSize) noexcept;
++ Q_DECL_MALLOCLIKE
++ static Q_CORE_EXPORT void *allocate2(QArrayData **pdata, qsizetype capacity,
++ AllocationOption option = QArrayData::KeepSize) noexcept;
++
++ [[nodiscard]] static Q_CORE_EXPORT std::pair<QArrayData *, void *> reallocateUnaligned(QArrayData *data, void *dataPointer,
++ qsizetype objectSize, qsizetype newCapacity, AllocationOption option) noexcept;
++ static Q_CORE_EXPORT void deallocate(QArrayData *data, qsizetype objectSize,
++ qsizetype alignment) noexcept;
++ };
++
++ Q_DECLARE_OPERATORS_FOR_FLAGS(QArrayData::ArrayOptions)
++
++ namespace QtPrivate {
++ // QArrayData with strictest alignment requirements supported by malloc()
++ #if defined(Q_PROCESSOR_X86_32) && defined(Q_CC_GNU)
++ // GCC's definition is incorrect since GCC 8 (commit r240248 in SVN; commit
++ // 63012d9a57edc950c5f30242d1e19318b5708060 in Git). This is applied to all
++ // GCC-like compilers in case they decide to follow GCC's lead in being wrong.
++ constexpr size_t MaxPrimitiveAlignment = 2 * sizeof(void *);
++ #else
++ constexpr size_t MaxPrimitiveAlignment = alignof(std::max_align_t);
++ #endif
++
++ struct alignas(MaxPrimitiveAlignment) AlignedQArrayData : QArrayData
++ {
++ };
++ }
++
++ template <class T>
++ struct QTypedArrayData
++ : QArrayData
++ {
++ struct AlignmentDummy { QtPrivate::AlignedQArrayData header; T data; };
++
++ [[nodiscard]] static QTypedArrayAllocationResult<T>
++ allocate(qsizetype capacity, AllocationOption option = QArrayData::KeepSize)
++ {
++ static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
++ Q_DECL_UNINITIALIZED
++ QArrayData *d;
++ void *result;
++ if constexpr (sizeof(T) == 1) {
++ // necessarily, alignof(T) == 1
++ result = allocate1(&d, capacity, option);
++ } else if constexpr (sizeof(T) == 2) {
++ // alignof(T) may be 1, but that makes no difference
++ result = allocate2(&d, capacity, option);
++ } else {
++ result = QArrayData::allocate(&d, sizeof(T), alignof(AlignmentDummy), capacity, option);
++ }
++ #if __has_builtin(__builtin_assume_aligned)
++ // and yet we do offer results that have stricter alignment
++ result = __builtin_assume_aligned(result, Q_ALIGNOF(AlignmentDummy));
++ #endif
++ return {static_cast<QTypedArrayData *>(d), static_cast<T *>(result)};
++ }
++
++ static QTypedArrayAllocationResult<T>
++ reallocateUnaligned(QTypedArrayData *data, T *dataPointer, qsizetype capacity, AllocationOption option)
++ {
++ static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
++ std::pair<QArrayData *, void *> pair =
++ QArrayData::reallocateUnaligned(data, dataPointer, sizeof(T), capacity, option);
++ return {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));
++ }
++
++ static T *dataStart(QArrayData *data, qsizetype alignment) noexcept
++ {
++ // Alignment is a power of two
++ Q_ASSERT(alignment >= qsizetype(alignof(QArrayData)) && !(alignment & (alignment - 1)));
++ void *start = reinterpret_cast<void *>((quintptr(data) + sizeof(QArrayData) + alignment - 1)
++ & ~quintptr(alignment - 1));
++ return static_cast<T *>(start);
++ }
++
++ constexpr static qsizetype maxSize() noexcept
++ {
++ // -1 to deal with the pointer one-past-the-end
++ return (QtPrivate::MaxAllocSize - sizeof(QtPrivate::AlignedQArrayData) - 1) / sizeof(T);
++ }
++ constexpr static qsizetype max_size() noexcept
++ {
++ return maxSize();
++ }
++ };
++
++ 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;
++ }
++ };
++ }
++
++ #undef Q_DECL_MALLOCLIKE
++
++ QT_END_NAMESPACE
++
++ #endif // include guard