pw::allocator::LibCAllocator Class Reference

Overview

Memory allocator that uses malloc and free.

TODO: b/301930507 - aligned_alloc is not portable. As a result, this allocator has a maximum alignment of std::align_max_t.

Inheritance diagram for pw::allocator::LibCAllocator:

Static Public Attributes
static constexpr Capabilities	kCapabilities = 0

Private Member Functions
void *	DoAllocate (Layout layout) override
void	DoDeallocate (void *ptr) override
void	DoDeallocate (void *ptr, Layout) override
void *	DoReallocate (void *ptr, Layout new_layout) override

Friends
LibCAllocator &	GetLibCAllocator ()
	Returns a reference to the LibCAllocator singleton.

Additional Inherited Members
Public Types inherited from pw::Deallocator
using	Capabilities = allocator::Capabilities
using	Capability = allocator::Capability
using	Layout = allocator::Layout
Public Member Functions inherited from pw::Allocator
void *	Allocate (Layout layout)
template<typename T , int &... kExplicitGuard, typename... Args>
std::enable_if_t<!std::is_array_v< T >, T * >	New (Args &&... args)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
ElementType *	New ()
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
ElementType *	New (size_t count)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
ElementType *	New (size_t count, size_t alignment)
	Constructs an alignment-byte aligned array of count objects.
template<typename T >
T *	NewArray (size_t count)
template<typename T >
T *	NewArray (size_t count, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
UniquePtr< T >	MakeUnique (Args &&... args)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique ()
template<typename T >
UniquePtr< T[]>	MakeUniqueArray (size_t size)
template<typename T >
UniquePtr< T[]>	MakeUniqueArray (size_t size, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
SharedPtr< T >	MakeShared (Args &&... args)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared ()
bool	Resize (void *ptr, size_t new_size)
bool	Resize (void *ptr, Layout layout, size_t new_size)
void *	Reallocate (void *ptr, Layout new_layout)
void *	Reallocate (void *ptr, Layout old_layout, size_t new_size)
size_t	GetAllocated () const
Public Member Functions inherited from pw::Deallocator
constexpr const Capabilities &	capabilities () const
constexpr bool	HasCapability (Capability capability) const
	Returns whether a given capability is enabled for this object.
void	Deallocate (void *ptr)
void	Deallocate (void *ptr, Layout layout)
template<typename ElementType >
void	DeleteArray (ElementType *ptr, size_t count)
StatusWithSize	GetCapacity () const
bool	IsEqual (const Deallocator &other) const
template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0>
void	Delete (T *ptr)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_bounded_array_v< T >, int > = 0>
void	Delete (ElementType *ptr)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
void	Delete (ElementType *ptr, size_t count)
Protected Member Functions inherited from pw::Allocator
constexpr	Allocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.
constexpr	Allocator (const Capabilities &capabilities)
Protected Member Functions inherited from pw::Deallocator
constexpr	Deallocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.
constexpr	Deallocator (const Capabilities &capabilities)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	WrapUnique (ElementType *ptr, size_t size)
Static Protected Attributes inherited from pw::Deallocator
template<typename T >
static constexpr bool	is_bounded_array_v
template<typename T >
static constexpr bool	is_unbounded_array_v

Member Function Documentation

DoAllocate()

void * pw::allocator::LibCAllocator::DoAllocate ( Layout  layout )

overrideprivatevirtual

Allocates a block of memory with the specified size and alignment.

Returns nullptr if the allocation cannot be made, or the layout has a size of 0.

Parameters

[in]

layout

Describes the memory to be allocated.

Implements pw::Allocator.

DoDeallocate() [1/2]

void pw::allocator::LibCAllocator::DoDeallocate ( void *  ptr )

overrideprivate

Releases a previously-allocated block of memory.

The given pointer must have been previously provided by this memory resource; otherwise the behavior is undefined.

Parameters

[in]

ptr

Pointer to previously-allocated memory.

DoDeallocate() [2/2]

void pw::allocator::LibCAllocator::DoDeallocate ( void *  ptr, Layout    )

inlineoverrideprivate

Releases a previously-allocated block of memory.

The given pointer must have been previously provided by this memory resource; otherwise the behavior is undefined.

Parameters

[in]

ptr

Pointer to previously-allocated memory.

DoReallocate()

void * pw::allocator::LibCAllocator::DoReallocate ( void *  ptr, Layout  new_layout  )

overrideprivatevirtual

Modifies the size of a previously-allocated block of memory.

Returns pointer to the modified block of memory, or nullptr if the memory could not be modified.

The data stored by the memory being modified must be trivially copyable. If it is not, callers should themselves attempt to Resize, then Allocate, move the data, and Deallocate as needed.

If nullptr is returned, the block of memory is unchanged. In particular, if the new_layout has a size of 0, the given pointer will NOT be deallocated.

TODO(b/331290408): This error condition needs to be better communicated to module users, who may assume the pointer is freed.

Unlike Resize, providing a null pointer will return a new allocation.

If the request can be satisfied using Resize, the alignment parameter may be ignored.

Parameters

[in]	ptr	Pointer to previously-allocated memory.
[in]	new_layout	Describes the memory to be allocated.

Reimplemented from pw::Allocator.

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The documentation for this class was generated from the following file:

• pw_allocator/public/pw_allocator/libc_allocator.h