Field Specification (FSPEC)

ASTERIX Field Specification (FSPEC) processing. More...

Collaboration diagram for Field Specification (FSPEC):

Data Structures
struct	ast_fspec_t
	Field Specification (FSPEC). More...

Functions
ast_fspec_t	ast_fspec_decode (const unsigned char *const buffer, const size_t bufsize)
	FSPEC decode function.
ast_fspec_t	ast_fspec_copy (unsigned char *const buffer, const size_t bufsize, const ast_fspec_t src)
	FSPEC copy function.
bool	ast_fspec_is_set (const ast_fspec_t *fspec, const unsigned int frn)
	Test whether a data item is present.
bool	ast_fspec_set (unsigned char *const buffer, const size_t bufsize, const unsigned int frn, const bool set)
	Set or clear the presence bit of a data item.

Detailed Description

ASTERIX Field Specification (FSPEC) processing.

Description:

The Field Specification (FSPEC) prefixes a data record and indicates, by one bit per Field Reference Number (FRN), which data items of the UAP are present in the record. The last bit of each FSPEC octet (FX) extends the FSPEC to a following octet.

Function Documentation

ast_fspec_copy()

ast_fspec_t ast_fspec_copy	(	unsigned char *const	buffer,
		const size_t	bufsize,
		const ast_fspec_t	src )

FSPEC copy function.

Parameters

buffer	Buffer to write destination FSPEC data
bufsize	Buffer size
src	Original FSPEC, must be valid

Returns

Copied FSPEC

This function copies the original FSPEC to the specified buffer. If the FSPEC has been successfully copied, the returned FSPEC will be marked as "valid". If any error occurs, the returned FSPEC will be marked as "invalid".

ast_fspec_decode()

ast_fspec_t ast_fspec_decode	(	const unsigned char *const	buffer,
		const size_t	bufsize )

FSPEC decode function.

Parameters

buffer	Buffer to read FSPEC data
bufsize	Buffer size

Returns

Decoded FSPEC

This function reads the FSPEC octets (FX extension included) from buffer and counts the data items present. If the FSPEC can be successfully decoded, the returned FSPEC will be marked as "valid". If any error occurs, the returned FSPEC will be marked as "invalid".

ast_fspec_is_set()

bool ast_fspec_is_set	(	const ast_fspec_t *	fspec,
		const unsigned int	frn )

Test whether a data item is present.

Parameters

fspec	FSPEC to check
frn	Field Reference Number (FRN) of the data item

Returns

true, if the data item with the given FRN is present

ast_fspec_set()

bool ast_fspec_set	(	unsigned char *const	buffer,
		const size_t	bufsize,
		const unsigned int	frn,
		const bool	set )

Set or clear the presence bit of a data item.

Parameters

buffer	Buffer holding the FSPEC data to modify
bufsize	Buffer size
frn	Field Reference Number (FRN) of the data item
set	true to set the bit, false to clear it

Returns

true, if the bit has been successfully modified

This function modifies the FSPEC octets in buffer directly; the FX extension bits are not changed.