rtems-rfs-bitmaps.c File Reference

RTEMS File Systems Bitmap Routines. More...

#include <stdlib.h>
#include <rtems/rfs/rtems-rfs-bitmaps.h>

Macros
#define	RTEMS_RFS_BITMAP_WARNINGS   0
#define	rtems_rfs_bitmap_check(_c, _sm)

Functions
rtems_rfs_bitmap_element	rtems_rfs_bitmap_mask (unsigned int size)
rtems_rfs_bitmap_element	rtems_rfs_bitmap_mask_section (unsigned int start, unsigned int end)
int	rtems_rfs_bitmap_map_set (rtems_rfs_bitmap_control *control, rtems_rfs_bitmap_bit bit)
int	rtems_rfs_bitmap_map_clear (rtems_rfs_bitmap_control *control, rtems_rfs_bitmap_bit bit)
int	rtems_rfs_bitmap_map_test (rtems_rfs_bitmap_control *control, rtems_rfs_bitmap_bit bit, bool *state)
int	rtems_rfs_bitmap_map_set_all (rtems_rfs_bitmap_control *control)
int	rtems_rfs_bitmap_map_clear_all (rtems_rfs_bitmap_control *control)
int	rtems_rfs_bitmap_map_alloc (rtems_rfs_bitmap_control *control, rtems_rfs_bitmap_bit seed, bool *allocated, rtems_rfs_bitmap_bit *bit)
int	rtems_rfs_bitmap_create_search (rtems_rfs_bitmap_control *control)
int	rtems_rfs_bitmap_open (rtems_rfs_bitmap_control *control, rtems_rfs_file_system *fs, rtems_rfs_buffer_handle *buffer, size_t size, rtems_rfs_buffer_block block)
int	rtems_rfs_bitmap_close (rtems_rfs_bitmap_control *control)

Detailed Description

RTEMS File Systems Bitmap Routines.

These functions manage bit maps. A bit map consists of the map of bit allocated in a block and a search map where a bit represents 32 actual bits. The search map allows for a faster search for an available bit as 32 search bits can checked in a test.

Macro Definition Documentation

rtems_rfs_bitmap_check

#define rtems_rfs_bitmap_check	(		_c,
			_sm
	)

Value:

   _Assert(_sm >= _c->search_bits && \
           _sm < (_c->search_bits + \
             rtems_rfs_bitmap_elements(rtems_rfs_bitmap_elements(_c->size))))

RTEMS_RFS_BITMAP_WARNINGS

#define RTEMS_RFS_BITMAP_WARNINGS   0

Set to 1 to enable warnings when developing.

Function Documentation

rtems_rfs_bitmap_close()

int rtems_rfs_bitmap_close

(

rtems_rfs_bitmap_control *

control

)

Close a bitmap.

Parameters

[in]

control

is the bit map control.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_create_search()

int rtems_rfs_bitmap_create_search

(

rtems_rfs_bitmap_control *

control

)

Create a search bit map from the actual bit map.

Parameters

[in]

control

is the map control.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_map_alloc()

int rtems_rfs_bitmap_map_alloc	(	rtems_rfs_bitmap_control *	control,
		rtems_rfs_bitmap_bit	seed,
		bool *	allocate,
		rtems_rfs_bitmap_bit *	bit
	)

Find a free bit searching from the seed up and down until found. The search is performing by moving up from the seed for the window distance then to search down from the seed for the window distance. This is repeated out from the seed for each window until a free bit is found. The search is performed by checking the search map to see if the map has a free bit.

Parameters

[in]	control	is the map control.
[in]	seed	is the bit to search out from.
[out]	allocate	A bit was allocated.
[out]	bit	will contain the bit found free if true is returned.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_map_clear()

int rtems_rfs_bitmap_map_clear	(	rtems_rfs_bitmap_control *	control,
		rtems_rfs_bitmap_bit	bit
	)

Clear a bit in a map and make sure the search map bit is clear so a search will find this bit available.

Parameters

[in]	control	is the control for the map.
[in]	bit	is the bit in the map to clear.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_map_clear_all()

int rtems_rfs_bitmap_map_clear_all

(

rtems_rfs_bitmap_control *

control

)

Clear all bits in the bitmap and set the dirty bit.

Parameters

[in]

control

is the bitmap control.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_map_set()

int rtems_rfs_bitmap_map_set	(	rtems_rfs_bitmap_control *	control,
		rtems_rfs_bitmap_bit	bit
	)

Set a bit in a map and if all the bits are set, set the search map bit as well.

Parameters

[in]	control	is the control for the map.
[in]	bit	is the bit in the map to set.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_map_set_all()

int rtems_rfs_bitmap_map_set_all

(

rtems_rfs_bitmap_control *

control

)

Set all bits in the bitmap and set the dirty bit.

Parameters

[in]

control

is the bitmap control.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_map_test()

int rtems_rfs_bitmap_map_test	(	rtems_rfs_bitmap_control *	control,
		rtems_rfs_bitmap_bit	bit,
		bool *	state
	)

Test a bit in the map.

Parameters

[in]	control	is the bitmap control.
[in]	bit	is the bit to test.
[in]	state	is the state of the bit if no error is returned.

Return values

0	Successful operation.
error_code	An error occurred.

rtems_rfs_bitmap_mask()

rtems_rfs_bitmap_element rtems_rfs_bitmap_mask

(

unsigned int

size

)

Create a bit mask with the specified number of bits up to an element's size. The mask is aligned to bit 0 of the element.

Parameters

[in]

size

is the number of bits in the mask.

Returns

The mask of the argument size number of bits.

rtems_rfs_bitmap_mask_section()

rtems_rfs_bitmap_element rtems_rfs_bitmap_mask_section	(	unsigned int	start,
		unsigned int	end
	)

Create a bit mask section. A mask section is a mask that is not aligned to an end of the element.

Parameters

[in]	start	is the first bit of the mask numbered from 0.
[in]	end	is the end bit of the mask numbered from 0.

Returns

Mask section as defined by the start and end arguments.

rtems_rfs_bitmap_open()

int rtems_rfs_bitmap_open	(	rtems_rfs_bitmap_control *	control,
		rtems_rfs_file_system *	fs,
		rtems_rfs_buffer_handle *	buffer,
		size_t	size,
		rtems_rfs_buffer_block	block
	)

Open a bitmap control with a map and search map.

Parameters

[in]	control	is the map control.
[in]	fs	is the file system data.
[in]	buffer	is a pointer to the buffer handle the map is stored in.
[in]	size	is the number of bits in the map.

Return values

0	Successful operation.
error_code	An error occurred.