RTEMS File Systems Block Position and Size Management. More...

#include <rtems/rfs/rtems-rfs-file-system.h>
#include <rtems/rfs/rtems-rfs-inode.h>

Include dependency graph for rtems-rfs-block-pos.h:

Data Structures
struct	rtems_rfs_block_pos_s
	A block position is a block number times the block size plus the offset. More...

struct	rtems_rfs_block_size_s
	A block size is the number of blocks less one plus the offset where the offset must be less than the block size. More...

Macros
#define	rtems_rfs_block_copy_bpos(_lhs, _rhs)
	Copy a block position. More...

#define	rtems_rfs_block_copy_size(_lhs, _rhs)
	Copy a block size. More...

#define	rtems_rfs_block_pos_last_block(_p, _s) ((((_p)->bno == 0) && ((_s)->count == 0)) \|\| ((_p)->bno == ((_s)->count - 1)))
	Last block ?

#define	rtems_rfs_block_pos_past_end(_p, _s)
	Last block ? More...

#define	rtems_rfs_block_pos_block_past_end(_p, _s) (((_p)->bno && ((_s)->count == 0)) \|\| ((_p)->bno >= (_s)->count))
	Is the block position past the end.

#define	rtems_rfs_block_size_get_bpos(_s, _b)
	Copy the size to the block position. More...

#define	rtems_rfs_block_size_equal(_lhs, _rhs) (((_lhs)->count == (_rhs)->count) && ((_lhs)->offset == (_rhs)->offset))
	Do the sizes match ?

Typedefs
typedef rtems_rfs_inode_block	rtems_rfs_block_no
	The block number is the same type as the inode block number. More...

typedef uint32_t	rtems_rfs_block_off
	The offset into a block.

typedef struct rtems_rfs_block_pos_s	rtems_rfs_block_pos
	A block position is a block number times the block size plus the offset. More...

typedef struct rtems_rfs_block_size_s	rtems_rfs_block_size
	A block size is the number of blocks less one plus the offset where the offset must be less than the block size.

Functions
void	rtems_rfs_block_get_bpos (rtems_rfs_file_system fs, rtems_rfs_pos pos, rtems_rfs_block_pos bpos)
	Given a position compute the block number and block offset. More...

rtems_rfs_pos	rtems_rfs_block_get_pos (rtems_rfs_file_system fs, rtems_rfs_block_pos bpos)
	Given a block position compute the absolute offset. More...

void	rtems_rfs_block_get_block_size (rtems_rfs_file_system fs, rtems_rfs_pos pos, rtems_rfs_block_size size)
	Set the size given a position. More...

rtems_rfs_pos	rtems_rfs_block_get_size (rtems_rfs_file_system fs, rtems_rfs_block_size size)
	Calculate the position given the number of blocks and the offset. More...

Detailed Description

RTEMS File Systems Block Position and Size Management.

These functions manage the position in a block map as well as a size of data held in a block map. The position is the block count plus the offset into the last block where a block position of 0 and an offset of 0 is the start of a map. The size has a block count plus an offset, but the offset into the last block gives the actual size of the data in the map. This means a size will always have a block count greater than 0 when the file is not empty. A size offset of 0 and a non-zero block count means the length if aligned to the end of the block. For this reason there are 2 similar types so we know which set of rules are in use and the reason for this file.

Macro Definition Documentation

◆ rtems_rfs_block_copy_bpos

#define rtems_rfs_block_copy_bpos	(	_lhs,
		_rhs
	)

Value:

do { (_lhs)->bno = (_rhs)->bno; \
       (_lhs)->boff = (_rhs)->boff; \
       (_lhs)->block = (_rhs)->block; } while (0)

Copy a block position.

Parameters

[in]	_lhs	is the left hand side.
[in]	_rhs	is the right hand side.

◆ rtems_rfs_block_copy_size

#define rtems_rfs_block_copy_size	(	_lhs,
		_rhs
	)

Value:

do { (_lhs)->count = (_rhs)->count; \

(_lhs)->offset = (_rhs)->offset; } while (0)

Copy a block size.

Parameters

[in]	_lhs	is the left hand side.
[in]	_rhs	is the right hand side.

◆ rtems_rfs_block_pos_past_end

#define rtems_rfs_block_pos_past_end	(	_p,
		_s
	)

Value:

(((_p)->bno && ((_s)->count == 0)) || \
   ((_p)->bno >= (_s)->count) || \
   (((_p)->bno == ((_s)->count - 1)) && ((_p)->boff > (_s)->offset)))

Last block ?

◆ rtems_rfs_block_size_get_bpos

#define rtems_rfs_block_size_get_bpos	(	_s,
		_b
	)

Value:

do { (_b)->bno = (_s)->count; \
       (_b)->boff = (_s)->offset; \
       (_b)->block = 0; \
       if ((_b)->boff) --(_b)->bno; } while (0)

Copy the size to the block position.

Note the block position and the size have different block counts.

Typedef Documentation

◆ rtems_rfs_block_no

typedef rtems_rfs_inode_block rtems_rfs_block_no

The block number is the same type as the inode block number.

This makes sure the sizes of the types match.

◆ rtems_rfs_block_pos

typedef struct rtems_rfs_block_pos_s rtems_rfs_block_pos

A block position is a block number times the block size plus the offset.

The block field can be used hold a block number for the position as a look up cache.

Function Documentation

◆ rtems_rfs_block_get_block_size()

void rtems_rfs_block_get_block_size	(	rtems_rfs_file_system *	fs,
		rtems_rfs_pos	pos,
		rtems_rfs_block_size *	size
	)

Set the size given a position.

Parameters

[in]	fs	is the file system data.
[in]	pos	is the position as an absolute offset from the start.
[out]	size	is a pointer to the block size to fill in.

◆ rtems_rfs_block_get_bpos()

void rtems_rfs_block_get_bpos	(	rtems_rfs_file_system *	fs,
		rtems_rfs_pos	pos,
		rtems_rfs_block_pos *	bpos
	)

Given a position compute the block number and block offset.

Parameters

[in]	fs	is the file system data.
[in]	pos	is the position as an absolute offset from the start.
[out]	bpos	is a pointer to the block position to fill in.

◆ rtems_rfs_block_get_pos()

rtems_rfs_pos rtems_rfs_block_get_pos	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_pos *	bpos
	)

Given a block position compute the absolute offset.

Parameters

[in]	fs	is the file system data.
[out]	bpos	is a pointer to the block position to fill in.

Return values

offset The absolute offset.

◆ rtems_rfs_block_get_size()

rtems_rfs_pos rtems_rfs_block_get_size	(	rtems_rfs_file_system *	fs,
		rtems_rfs_block_size *	size
	)

Calculate the position given the number of blocks and the offset.

If the block count is 0 the size is 0. If the block is greater than 0 and the offset is 0 the size is number of blocks multipled by the block size and if the offset is not 0 it is the offset into the last block. For example if blocks is 1 and offset is 0 the size is the block size. If the block count is 1 and size is 100 the size is 100.

Parameters

[in]	fs	is the file system data.
[in]	size	The size in blocks and offset.

Return values

size	The size in bytes.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ rtems_rfs_block_copy_bpos

◆ rtems_rfs_block_copy_size

◆ rtems_rfs_block_pos_past_end

◆ rtems_rfs_block_size_get_bpos

Typedef Documentation

◆ rtems_rfs_block_no

◆ rtems_rfs_block_pos

Function Documentation

◆ rtems_rfs_block_get_block_size()

◆ rtems_rfs_block_get_bpos()

◆ rtems_rfs_block_get_pos()

◆ rtems_rfs_block_get_size()