Arena allocator for fast bump-pointer allocation. More...

#include <ah-arena.H>

Public Types
enum class	TemplateType { TEMPLATE }
	Tag type for dispatching to templated allocation methods. More...

Public Member Functions
	AhArenaAllocator (void *buffer, const size_t size) noexcept
	Construct arena from existing memory buffer.

	AhArenaAllocator (const char *buffer, const size_t size) noexcept
	Overload for const buffer (uses const_cast internally).

	AhArenaAllocator (const size_t size=DEFAULT_SIZE)
	Construct arena with internally allocated memory.

	~AhArenaAllocator ()
	Destructor.

	AhArenaAllocator (AhArenaAllocator &&other) noexcept
	Move constructor.

AhArenaAllocator &	operator= (AhArenaAllocator &&other) noexcept
	Move assignment operator.

	AhArenaAllocator (const AhArenaAllocator &)=delete

AhArenaAllocator &	operator= (const AhArenaAllocator &)=delete

void	reset () noexcept
	Reset arena, making all memory available again.

void *	alloc (const size_t size) noexcept
	Allocate raw memory from the arena.

void *	alloc_aligned (const size_t size, const size_t alignment) noexcept
	Allocate aligned memory from the arena.

void	dealloc (const void *addr, const size_t size) noexcept
	Deallocate memory (only effective for LIFO pattern).

template<typename T , typename... Args>
T *	alloc (TemplateType tag, Args &&... args)
	Allocate and construct an object of type T.

template<typename T >
void	dealloc (TemplateType tag, void *ptr) noexcept
	Destruct and deallocate an object.

bool	is_valid () const noexcept
	Returns true if the arena is valid (has memory).

bool	owns_memory () const noexcept
	Returns true if the arena owns its memory.

size_t	allocated_size () const noexcept
	Get total bytes currently allocated.

size_t	available_size () const noexcept
	Get remaining bytes available.

size_t	capacity () const noexcept
	Get total arena capacity.

bool	empty () const noexcept
	Returns true if the arena is empty (no allocations).

bool	full () const noexcept
	Returns true if the arena is full (no space left).

const void *	base_addr () const noexcept
	Get base address of the arena.

const void *	next_avail_addr () const noexcept
	Get next available address (current allocation pointer).

const void *	end_addr () const noexcept
	Get end address (one past last valid byte).

bool	contains (const void *ptr) const noexcept
	Check if a pointer is within this arena's range.

void *	allocate (size_t size) noexcept

void	deallocate (const void *addr, size_t size) noexcept

Static Public Attributes
static constexpr size_t	DEFAULT_SIZE = 1024 * 1024
	Default arena size (1 MB).

Private Attributes
char *	base_addr_ = nullptr

char *	curr_addr_ = nullptr

char *	end_addr_ = nullptr

bool	owns_memory_ = false

Detailed Description

Arena allocator for fast bump-pointer allocation.

AhArenaAllocator provides a simple and fast memory allocation strategy where allocations are satisfied by incrementing a pointer ("bump" allocation). Individual deallocations are only effective for LIFO (stack-like) patterns.

Performance Characteristics

Operation	Complexity
alloc()	O(1)
dealloc()	O(1)
reset()	O(1)

Memory Layout

|<------- capacity() ------->|
|<-- allocated -->|<- avail ->|
[=================[           ]
^                 ^           ^
base_addr    curr_addr    end_addr

Note: Memory is automatically freed when the arena is destroyed.; Not thread-safe. Use separate arenas per thread.

Definition at line 121 of file ah-arena.H.

Member Enumeration Documentation

◆ TemplateType

enum class Aleph::AhArenaAllocator::TemplateType

strong

Tag type for dispatching to templated allocation methods.

Enumerator
TEMPLATE

Definition at line 130 of file ah-arena.H.

Constructor & Destructor Documentation

◆ AhArenaAllocator() [1/5]

Aleph::AhArenaAllocator::AhArenaAllocator	(	void *	buffer,
		const size_t	size
	)

inlinenoexcept

Construct arena from existing memory buffer.

The arena will use the provided buffer but will NOT free it on destruction. The caller retains ownership of the buffer.

Parameters

[in]	buffer	Pointer to pre-allocated buffer.
[in]	size	Size of the buffer in bytes.

Note: The buffer must remain valid for the lifetime of the arena.; Passing a const buffer is allowed but the arena will write to it.

Definition at line 147 of file ah-arena.H.

◆ AhArenaAllocator() [2/5]

Aleph::AhArenaAllocator::AhArenaAllocator	(	const char *	buffer,
		const size_t	size
	)

inlinenoexcept

Overload for const buffer (uses const_cast internally).

Definition at line 154 of file ah-arena.H.

◆ AhArenaAllocator() [3/5]

Aleph::AhArenaAllocator::AhArenaAllocator ( const size_t size = DEFAULT_SIZE )

inlineexplicit

Construct arena with internally allocated memory.

Allocates a contiguous block of memory using malloc(). The memory is automatically freed when the arena is destroyed.

Parameters

[in] size Size of arena in bytes (default 1MB).

Exceptions

std::runtime_error If memory allocation fails.

Definition at line 169 of file ah-arena.H.

References ah_runtime_error_if, base_addr_, curr_addr_, end_addr_, owns_memory_, and Aleph::size().

◆ ~AhArenaAllocator()

Aleph::AhArenaAllocator::~AhArenaAllocator ( )

inline

Destructor.

Frees internally allocated memory if any.

Warning: Does NOT call destructors on objects allocated in the arena. The caller must ensure all objects are properly destroyed before the arena is destroyed.

Definition at line 187 of file ah-arena.H.

References base_addr_, Aleph::maps(), and owns_memory_.

◆ AhArenaAllocator() [4/5]

Aleph::AhArenaAllocator::AhArenaAllocator ( AhArenaAllocator && other )

inlinenoexcept

Move constructor.

Transfers ownership of the arena's memory. The moved-from arena becomes empty and invalid for further allocations.

Definition at line 201 of file ah-arena.H.

References Aleph::maps().

◆ AhArenaAllocator() [5/5]

Aleph::AhArenaAllocator::AhArenaAllocator ( const AhArenaAllocator & )

delete

Member Function Documentation

◆ alloc() [1/2]

void * Aleph::AhArenaAllocator::alloc ( const size_t size )

inlinenoexcept

Allocate raw memory from the arena.

Returns a pointer to at least size bytes of memory, or nullptr if insufficient space remains.

Parameters

[in] size Number of bytes to allocate.

Returns: Pointer to allocated memory, or nullptr if insufficient space.

Note: Memory is NOT zero-initialized.; Alignment is not guaranteed beyond natural alignment of char. Use alloc_aligned() for specific alignment requirements.

Definition at line 271 of file ah-arena.H.

References curr_addr_, end_addr_, and Aleph::size().

Referenced by Aleph::allocate(), allocate(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), and TEST_F().

◆ alloc() [2/2]

template<typename T , typename... Args>

T * Aleph::AhArenaAllocator::alloc	(	TemplateType	tag,
		Args &&...	args
	)

inline

Allocate and construct an object of type T.

Allocates sizeof(T) bytes and constructs T in-place using placement new with the provided arguments.

Template Parameters

T	Type to construct.
Args	Constructor argument types.

Parameters

[in]	tag	Disambiguation tag (use TemplateType::TEMPLATE) - unused parameter.
[in]	args	Constructor arguments (forwarded).

Returns: Pointer to constructed object, or nullptr if allocation fails.

Note: If allocation fails, no object is constructed and nullptr is returned.

Definition at line 353 of file ah-arena.H.

References alloc_aligned(), and Aleph::maps().

◆ alloc_aligned()

void * Aleph::AhArenaAllocator::alloc_aligned	(	const size_t	size,
		const size_t	alignment
	)

inlinenoexcept

Allocate aligned memory from the arena.

Returns a pointer to at least size bytes of memory aligned to alignment bytes, or nullptr if insufficient space.

Parameters

[in]	size	Number of bytes to allocate.
[in]	alignment	Required alignment (must be power of 2).

Returns: Pointer to aligned memory, or nullptr if insufficient space.

Definition at line 294 of file ah-arena.H.

References curr_addr_, end_addr_, Aleph::maps(), and Aleph::size().

Referenced by alloc(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), and TEST().

◆ allocate()

void * Aleph::AhArenaAllocator::allocate ( size_t size )

inlinenoexcept

Deprecated:: Use alloc() instead.

Definition at line 448 of file ah-arena.H.

References alloc(), and Aleph::size().

Referenced by TEST().

◆ allocated_size()

size_t Aleph::AhArenaAllocator::allocated_size ( ) const

inlinenoexcept

Get total bytes currently allocated.

Definition at line 395 of file ah-arena.H.

References base_addr_, and curr_addr_.

Referenced by Aleph::ArenaTreeAllocator< Node >::allocated_size(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), and TEST().

◆ available_size()

size_t Aleph::AhArenaAllocator::available_size ( ) const

inlinenoexcept

Get remaining bytes available.

Definition at line 401 of file ah-arena.H.

References curr_addr_, and end_addr_.

Referenced by Aleph::ArenaTreeAllocator< Node >::available_size(), TEST(), and TEST().

◆ base_addr()

const void * Aleph::AhArenaAllocator::base_addr ( ) const

inlinenoexcept

Get base address of the arena.

Definition at line 425 of file ah-arena.H.

References base_addr_.

◆ capacity()

size_t Aleph::AhArenaAllocator::capacity ( ) const

inlinenoexcept

Get total arena capacity.

Definition at line 407 of file ah-arena.H.

References base_addr_, and end_addr_.

Referenced by TEST(), TEST(), and TEST().

◆ contains()

bool Aleph::AhArenaAllocator::contains ( const void * ptr ) const

inlinenoexcept

Check if a pointer is within this arena's range.

Parameters

[in] ptr Pointer to check.

Returns: true if ptr is within [base_addr, end_addr).

Definition at line 439 of file ah-arena.H.

References base_addr_, end_addr_, and Aleph::maps().

◆ dealloc() [1/2]

void Aleph::AhArenaAllocator::dealloc	(	const void *	addr,
		const size_t	size
	)

inlinenoexcept

Deallocate memory (only effective for LIFO pattern).

If the address matches the most recently allocated block (and the size is correct), the memory is reclaimed. Otherwise, this is a no-op.

Parameters

[in]	addr	Address to deallocate.
[in]	size	Size of the allocation.

Note: This enables stack-like (LIFO) allocation patterns where the last allocation can be "undone".

Definition at line 326 of file ah-arena.H.

References curr_addr_, Aleph::maps(), and Aleph::size().

Referenced by dealloc(), deallocate(), TEST(), TEST(), TEST(), and TEST().

◆ dealloc() [2/2]

template<typename T >

void Aleph::AhArenaAllocator::dealloc	(	TemplateType	tag,
		void *	ptr
	)

inlinenoexcept

Destruct and deallocate an object.

Calls the destructor of T and attempts to reclaim the memory (only succeeds for LIFO deallocation pattern).

Template Parameters

T	Type of object.

Parameters

[in]	tag	Disambiguation tag (use TemplateType::TEMPLATE) - unused parameter.
[in]	ptr	Pointer to object.

Definition at line 372 of file ah-arena.H.

References dealloc().

◆ deallocate()

void Aleph::AhArenaAllocator::deallocate	(	const void *	addr,
		size_t	size
	)

inlinenoexcept

Deprecated:: Use dealloc() instead.

Definition at line 451 of file ah-arena.H.

References dealloc(), Aleph::maps(), and Aleph::size().

Referenced by TEST().

◆ empty()

bool Aleph::AhArenaAllocator::empty ( ) const

inlinenoexcept

Returns true if the arena is empty (no allocations).

Definition at line 413 of file ah-arena.H.

References base_addr_, and curr_addr_.

Referenced by TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST_F(), and TEST_F().

◆ end_addr()

const void * Aleph::AhArenaAllocator::end_addr ( ) const

inlinenoexcept

Get end address (one past last valid byte).

Definition at line 431 of file ah-arena.H.

References end_addr_.

◆ full()

bool Aleph::AhArenaAllocator::full ( ) const

inlinenoexcept

Returns true if the arena is full (no space left).

Definition at line 419 of file ah-arena.H.

References curr_addr_, and end_addr_.

Referenced by TEST(), TEST(), TEST(), TEST(), and TEST().

◆ is_valid()

bool Aleph::AhArenaAllocator::is_valid ( ) const

inlinenoexcept

Returns true if the arena is valid (has memory).

Definition at line 383 of file ah-arena.H.

References base_addr_.

Referenced by TEST(), TEST(), TEST(), TEST(), and TEST().

◆ next_avail_addr()

const void * Aleph::AhArenaAllocator::next_avail_addr ( ) const

inlinenoexcept

Get next available address (current allocation pointer).

Definition at line 428 of file ah-arena.H.

References curr_addr_.

◆ operator=() [1/2]

AhArenaAllocator & Aleph::AhArenaAllocator::operator= ( AhArenaAllocator && other )

inlinenoexcept

Move assignment operator.

Frees current memory (if owned) and takes ownership from other.

Definition at line 218 of file ah-arena.H.

References base_addr_, curr_addr_, end_addr_, Aleph::maps(), and owns_memory_.

◆ operator=() [2/2]

AhArenaAllocator & Aleph::AhArenaAllocator::operator= ( const AhArenaAllocator & )

delete

◆ owns_memory()

bool Aleph::AhArenaAllocator::owns_memory ( ) const

inlinenoexcept

Returns true if the arena owns its memory.

Definition at line 389 of file ah-arena.H.

References owns_memory_.

Referenced by TEST(), TEST(), and TEST().

◆ reset()

void Aleph::AhArenaAllocator::reset ( )

inlinenoexcept

Reset arena, making all memory available again.

After reset, the arena can be reused for new allocations. All previously returned pointers become invalid.

Warning: Does NOT call destructors on allocated objects. The caller must destroy objects manually before calling reset().

Definition at line 256 of file ah-arena.H.

References base_addr_, and curr_addr_.

Referenced by TEST(), TEST(), and TEST_F().

Member Data Documentation

◆ base_addr_

char* Aleph::AhArenaAllocator::base_addr_ = nullptr

private

Definition at line 123 of file ah-arena.H.

Referenced by AhArenaAllocator(), ~AhArenaAllocator(), allocated_size(), base_addr(), capacity(), contains(), empty(), is_valid(), operator=(), and reset().

◆ curr_addr_

char* Aleph::AhArenaAllocator::curr_addr_ = nullptr

private

Definition at line 124 of file ah-arena.H.

Referenced by AhArenaAllocator(), alloc(), alloc_aligned(), allocated_size(), available_size(), dealloc(), empty(), full(), next_avail_addr(), operator=(), and reset().

◆ DEFAULT_SIZE

constexpr size_t Aleph::AhArenaAllocator::DEFAULT_SIZE = 1024 * 1024

staticconstexpr

Default arena size (1 MB).

Definition at line 133 of file ah-arena.H.

Referenced by TEST().

◆ end_addr_

char* Aleph::AhArenaAllocator::end_addr_ = nullptr

private

Definition at line 125 of file ah-arena.H.

Referenced by AhArenaAllocator(), alloc(), alloc_aligned(), available_size(), capacity(), contains(), end_addr(), full(), and operator=().

◆ owns_memory_

bool Aleph::AhArenaAllocator::owns_memory_ = false

private

Definition at line 126 of file ah-arena.H.

Referenced by AhArenaAllocator(), ~AhArenaAllocator(), operator=(), and owns_memory().

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

ah-arena.H

Public Types

Public Member Functions

Static Public Attributes

Private Attributes

Detailed Description

Performance Characteristics

Memory Layout

Member Enumeration Documentation

◆ TemplateType

Constructor & Destructor Documentation

◆ AhArenaAllocator() [1/5]

◆ AhArenaAllocator() [2/5]

◆ AhArenaAllocator() [3/5]

◆ ~AhArenaAllocator()

◆ AhArenaAllocator() [4/5]

◆ AhArenaAllocator() [5/5]

Member Function Documentation

◆ alloc() [1/2]

◆ alloc() [2/2]

◆ alloc_aligned()

◆ allocate()

◆ allocated_size()

◆ available_size()

◆ base_addr()

◆ capacity()

◆ contains()

◆ dealloc() [1/2]

◆ dealloc() [2/2]

◆ deallocate()

◆ empty()

◆ end_addr()

◆ full()

◆ is_valid()

◆ next_avail_addr()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ owns_memory()

◆ reset()

Member Data Documentation

◆ base_addr_

◆ curr_addr_

◆ DEFAULT_SIZE

◆ end_addr_

◆ owns_memory_