#include <allocatable.h>

Inheritance diagram for pw::allocator::AllocatableBlock< Derived >:

Public Member Functions
constexpr bool	IsFree () const

constexpr bool	Used () const

constexpr StatusWithSize	CanAlloc (Layout layout) const

constexpr BlockResult< Derived >	Resize (size_t new_inner_size)

Static Public Member Functions
static constexpr BlockResult< Derived >	AllocFirst (Derived *&&block, Layout layout)

static constexpr BlockResult< Derived >	AllocLast (Derived *&&block, Layout layout)

static constexpr BlockResult< Derived >	Free (Derived *&&block)

Protected Member Functions
constexpr StatusWithSize	DoCanAlloc (Layout layout) const

constexpr BlockResult< Derived >	DoResize (size_t new_inner_size, bool shifted=false)

Static Protected Member Functions
static constexpr BlockResult< Derived >	DoAllocFirst (Derived *&&block, Layout layout)

static constexpr BlockResult< Derived >	DoAllocLast (Derived *&&block, Layout layout)

static constexpr BlockResult< Derived >	DoFree (Derived *&&block)

Friends
template<typename >
class	AlignableBlock

template<typename >
class	BlockWithLayout

Detailed Description

template<typename Derived>
class pw::allocator::AllocatableBlock< Derived >

Mix-in for blocks that can be allocated and freed.

Block mix-ins are stateless and trivially constructible. See BasicBlock for details on how mix-ins can be combined to implement blocks.

This mix-in requires its derived type also derive from ContiguousBlock and provide the following symbols:

size_t kMinOuterSize
- Size of the smallest block that can be allocated.
bool IsFreeUnchecked() const
- Returns whether the block is free or in use.
void SetFree(bool)
- Sets whether the block is free or in use.

Member Function Documentation

◆ AllocFirst()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::AllocFirst	(	Derived *&&	block,
		Layout	layout
	)

staticconstexpr

Splits an aligned block from the start of the block, and marks it as used.

If successful, block will be replaced by a block that has an inner size of at least inner_size, and whose starting address is aligned to an alignment boundary. If unsuccessful, block will be unmodified.

This method is static in order to consume the given block pointer. On success, a pointer to the new, smaller block is returned. In total, up to two additional blocks may be created: one to pad the returned block to an alignment boundary and one for the trailing space. On error, the original pointer is returned.

For larger alignments, the AllocLast method is generally preferable to this method, as this method may create an additional fragments both before and after the returned block in order to align the usable space.

Precondition: The block must not be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: The split completed successfully. The `BlockAllocType` indicates
*     how extra memory was distributed to other blocks.
* 
*     FAILED_PRECONDITION: This block is in use and cannot be split.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ AllocLast()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::AllocLast	(	Derived *&&	block,
		Layout	layout
	)

staticconstexpr

Splits an aligned block from the end of the block, and marks it as used.

If successful, block will be replaced by a block that has an inner size of at least inner_size, and whose starting address is aligned to an alignment boundary. If unsuccessful, block will be unmodified.

This method is static in order to consume the given block pointer. On success, a pointer to the new, smaller block is returned. In total, up to two additional blocks may be created: one to pad the returned block to an alignment boundary and one for the trailing space. On error, the original pointer is returned.

Precondition: The block must not be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: The split completed successfully. The `BlockAllocType` indicates
*     how extra memory was distributed to other blocks.
* 
*     FAILED_PRECONDITION: This block is in use and cannot be split.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ CanAlloc()

template<typename Derived >

constexpr StatusWithSize pw::allocator::AllocatableBlock< Derived >::CanAlloc ( Layout layout ) const

constexpr

Checks if a block could be split from the block.

On error, this method will return the same status as AllocFirst or AllocLast without performing any modifications.

Precondition: The block must not be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: Returns the number of bytes to shift this block in order to align
*     its usable space.
* 
*     FAILED_PRECONDITION: This block is in use and cannot be split.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ DoAllocFirst()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::DoAllocFirst	(	Derived *&&	block,
		Layout	layout
	)

staticconstexprprotected

Splits an aligned block from the start of the block, and marks it as used.

If successful, block will be replaced by a block that has an inner size of at least inner_size, and whose starting address is aligned to an alignment boundary. If unsuccessful, block will be unmodified.

This method is static in order to consume the given block pointer. On success, a pointer to the new, smaller block is returned. In total, up to two additional blocks may be created: one to pad the returned block to an alignment boundary and one for the trailing space. On error, the original pointer is returned.

For larger alignments, the AllocLast method is generally preferable to this method, as this method may create an additional fragments both before and after the returned block in order to align the usable space.

Precondition: The block must not be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: The split completed successfully. The `BlockAllocType` indicates
*     how extra memory was distributed to other blocks.
* 
*     FAILED_PRECONDITION: This block is in use and cannot be split.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ DoAllocLast()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::DoAllocLast	(	Derived *&&	block,
		Layout	layout
	)

staticconstexprprotected

Splits an aligned block from the end of the block, and marks it as used.

If successful, block will be replaced by a block that has an inner size of at least inner_size, and whose starting address is aligned to an alignment boundary. If unsuccessful, block will be unmodified.

This method is static in order to consume the given block pointer. On success, a pointer to the new, smaller block is returned. In total, up to two additional blocks may be created: one to pad the returned block to an alignment boundary and one for the trailing space. On error, the original pointer is returned.

Precondition: The block must not be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: The split completed successfully. The `BlockAllocType` indicates
*     how extra memory was distributed to other blocks.
* 
*     FAILED_PRECONDITION: This block is in use and cannot be split.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ DoCanAlloc()

template<typename Derived >

constexpr StatusWithSize pw::allocator::AllocatableBlock< Derived >::DoCanAlloc ( Layout layout ) const

constexprprotected

Checks if a block could be split from the block.

On error, this method will return the same status as AllocFirst or AllocLast without performing any modifications.

Precondition: The block must not be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: Returns the number of bytes to shift this block in order to align
*     its usable space.
* 
*     FAILED_PRECONDITION: This block is in use and cannot be split.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ DoFree()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::DoFree ( Derived *&& block )

staticconstexprprotected

Marks the block as free.

This method is static in order to consume the given block pointer. It returns a pointer to a freed block that is the result of merging the given block with either or both of its neighbors, if they were free.

Note: Freeing may modify the adjacent blocks if they are free. Allocators that track free blocks must be prepared to handle this merge.

◆ DoResize()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::DoResize	(	size_t	new_inner_size,
		bool	shifted = `false`
	)

constexprprotected

Grows or shrinks the block.

If successful, block may be merged with the block after it in order to provide additional memory (when growing) or to merge released memory (when shrinking). If unsuccessful, block will be unmodified.

Note: Resizing may modify the block following this one if it is free. Allocators that track free blocks based on their size must be prepared to handle this size change.

Precondition: The block must be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: The resize completed successfully.
* 
*     FAILED_PRECONDITION: This block is not in use.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ Free()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::Free ( Derived *&& block )

staticconstexpr

Marks the block as free.

This method is static in order to consume the given block pointer. It returns a pointer to a freed block that is the result of merging the given block with either or both of its neighbors, if they were free.

Note: Freeing may modify the adjacent blocks if they are free. Allocators that track free blocks must be prepared to handle this merge.

◆ IsFree()

template<typename Derived >

constexpr bool pw::allocator::AllocatableBlock< Derived >::IsFree

constexpr

Returns: whether this block is free or is in use.

◆ Resize()

template<typename Derived >

constexpr BlockResult< Derived > pw::allocator::AllocatableBlock< Derived >::Resize ( size_t new_inner_size )

constexpr

Grows or shrinks the block.

If successful, block may be merged with the block after it in order to provide additional memory (when growing) or to merge released memory (when shrinking). If unsuccessful, block will be unmodified.

Note: Resizing may modify the block following this one if it is free. Allocators that track free blocks based on their size must be prepared to handle this size change.

Precondition: The block must be in use.

Returns

embed:rst:leading-asterisk
 
* 
*  .. pw-status-codes::
* 
*     OK: The resize completed successfully.
* 
*     FAILED_PRECONDITION: This block is not in use.
* 
*     RESOURCE_EXHAUSTED: The available space is insufficient to fulfill the
*     request. This may be due to a large requested size, or insufficient
*     remaining space to fulfill the requested alignment create a valid
*     leading block, and/or create a valid trailing block.
* 
*

◆ Used()

template<typename Derived >

constexpr bool pw::allocator::AllocatableBlock< Derived >::Used ( ) const

inlineconstexpr

Indicates whether the block is in use is free.

This method will eventually be deprecated. Prefer IsFree.

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

pw_allocator/block/public/pw_allocator/block/allocatable.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Friends

Detailed Description

Member Function Documentation

◆ AllocFirst()

◆ AllocLast()

◆ CanAlloc()

◆ DoAllocFirst()

◆ DoAllocLast()

◆ DoCanAlloc()

◆ DoFree()

◆ DoResize()

◆ Free()

◆ IsFree()

◆ Resize()

◆ Used()