dblockpool
["Little Useful Bits" Library]

This interface provides a dynamic facility to manage the allocation and deallocation of fixed sized blocks of memory. More...

Data Structures
struct	_lub_dblockpool
Typedefs
typedef _lub_dblockpool	lub_dblockpool_t
Functions
void	lub_dblockpool_init (lub_dblockpool_t *instance, size_t blocksize, unsigned chunksize, unsigned max_chunks)
void	lub_dblockpool_fini (lub_dblockpool_t *instance)
void *	lub_dblockpool_alloc (lub_dblockpool_t *instance)
void	lub_dblockpool_free (lub_dblockpool_t *instance, void *block)

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Detailed Description

This interface provides a dynamic facility to manage the allocation and deallocation of fixed sized blocks of memory.

It dynamically allocates chunks of memory each of which is used as a "blockpool". This dynamic memory is taken from the standard heap via "malloc()".

This type of memory manager is very fast and doesn't suffer from any memory fragmentation problems.

This allocator can reuse blocks in the order in which they are freed, this is significant for some applications where you don't want to re-use a particular freed block too soon. e.g. hardware timing limits on re-use.

Author:

Graeme McKerrell

Date:

Created On : Fri Feb 24 14:50:18 2005

Version:

TESTED

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Typedef Documentation

typedef struct _lub_dblockpool lub_dblockpool_t

This type represents a "dblockpool" instance.

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Function Documentation

void* lub_dblockpool_alloc

(

lub_dblockpool_t *

instance

)

This operation allocates a "block" of memory from a "dblockpool"

Precondition:

The dblockpool must have been initialised.

Returns:

A pointer to a "block" of memory, or NULL if there is none left for allocation.

Postcondition:

The behaviour is undefined if the "dblockpool" is uninitialised.

Parameters:

instance

the "dblockpool" instance to operate on

void lub_dblockpool_fini

(

lub_dblockpool_t *

instance

)

This operation finalises an instance of a dblockpool.

Precondition:

'instance' must have been initialised first.

Postcondition:

All the dynamic memory allocated will be released.

Parameters:

instance

the "dblockpool" instance to finalise.

void lub_dblockpool_free	(	lub_dblockpool_t *	instance,
		void *	block
	)

This operation de-allocates a "block" of memory back into a "blockpool"

Precondition:

The specified block must have been previously allocated using lub_blockpool_alloc()

Postcondition:

The de-allocated block become available for subsequent lub_blockpool_alloc() requests.

Parameters:

instance	the "blockpool" instance to invoke this operation upon
block	the "block" to release back to the pool

void lub_dblockpool_init	(	lub_dblockpool_t *	instance,
		size_t	blocksize,
		unsigned	chunksize,
		unsigned	max_chunks
	)

This operation initialises an instance of a dblockpool.

Precondition:

'blocksize' must be an multiple of 'sizeof(void *)'. (If the client declares a structure for the block this should be handled automatically by the compiler)

Postcondition:

If the size constraint is not met an assert will fire.

Following initialisation the allocation of memory can be performed.

Parameters:

instance	the "dblockpool" instance to initialise.
blocksize	The size in bytes of each block.
chunksize	The number of blocks to be managed in a chunk.
max_chunks	The maximum number of chunks to be allocated. (a value of zero means unlimited...)

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