gr::digital::packet_header_default Class Reference

Default header formatter for digital packet transmission. More...

#include <gnuradio/digital/packet_header_default.h>

Inheritance diagram for gr::digital::packet_header_default:

Public Types
typedef boost::shared_ptr < packet_header_default >	sptr

Public Member Functions
	packet_header_default (long header_len, const std::string &len_tag_key="packet_len", const std::string &num_tag_key="packet_num", int bits_per_byte=1)
virtual	~packet_header_default ()
sptr	base ()
sptr	formatter ()
void	set_header_num (unsigned header_num)
long	header_len ()
pmt::pmt_t	len_tag_key ()
virtual bool	header_formatter (long packet_len, unsigned char *out, const std::vector< tag_t > &tags=std::vector< tag_t >())
	Encodes the header information in the given tags into bits and places them into out. More...
virtual bool	header_parser (const unsigned char *header, std::vector< tag_t > &tags)
	Inverse function to header_formatter(). More...

Static Public Member Functions
static sptr	make (long header_len, const std::string &len_tag_key="packet_len", const std::string &num_tag_key="packet_num", int bits_per_byte=1)

Protected Attributes
long	d_header_len
pmt::pmt_t	d_len_tag_key
pmt::pmt_t	d_num_tag_key
int	d_bits_per_byte
unsigned	d_header_number
unsigned	d_mask
boost::crc_optimal< 8, 0x07, 0xFF, 0x00, false, false >	d_crc_impl

Detailed Description

Default header formatter for digital packet transmission.

For bursty/packetized digital transmission, packets are usually prepended with a packet header, containing the number of bytes etc. This class is not a block, but a tool to create these packet header.

This is a default packet header (see header_formatter()) for a description on the header format). To create other header, derive packet header creator classes from this function.

gr::digital::packet_headergenerator_bb uses header generators derived from this class to create packet headers from data streams.

Member Typedef Documentation

typedef boost::shared_ptr<packet_header_default> gr::digital::packet_header_default::sptr

Constructor & Destructor Documentation

gr::digital::packet_header_default::packet_header_default	(	long	header_len,
		const std::string &	len_tag_key = "packet_len",
		const std::string &	num_tag_key = "packet_num",
		int	bits_per_byte = 1
	)

virtual gr::digital::packet_header_default::~packet_header_default ( )

virtual

Member Function Documentation

sptr gr::digital::packet_header_default::base ( )

inline

sptr gr::digital::packet_header_default::formatter ( )

inline

virtual bool gr::digital::packet_header_default::header_formatter ( long  packet_len, unsigned char *  out, const std::vector< tag_t > &  tags = std::vector< tag_t >()  )

virtual

Encodes the header information in the given tags into bits and places them into out.

Uses the following header format: Bits 0-11: The packet length (what was stored in the tag with key len_tag_key) Bits 12-23: The header number (counts up everytime this function is called) Bit 24-31: 8-Bit CRC All other bits: Are set to zero

If the header length is smaller than 32, bits are simply left out. For this reason, they always start with the LSB.

However, it is recommended to stay above 32 Bits, in order to have a working CRC.

Reimplemented in gr::digital::packet_header_ofdm.

long gr::digital::packet_header_default::header_len ( )

inline

virtual bool gr::digital::packet_header_default::header_parser ( const unsigned char *  header, std::vector< tag_t > &  tags  )

virtual

Inverse function to header_formatter().

Reads the bit stream in header and writes a corresponding tag into tags.

Reimplemented in gr::digital::packet_header_ofdm.

pmt::pmt_t gr::digital::packet_header_default::len_tag_key ( )

inline

static sptr gr::digital::packet_header_default::make ( long  header_len, const std::string &  len_tag_key = "packet_len", const std::string &  num_tag_key = "packet_num", int  bits_per_byte = 1  )

static

void gr::digital::packet_header_default::set_header_num ( unsigned  header_num )

inline

Member Data Documentation

int gr::digital::packet_header_default::d_bits_per_byte

protected

boost::crc_optimal<8, 0x07, 0xFF, 0x00, false, false> gr::digital::packet_header_default::d_crc_impl

protected

long gr::digital::packet_header_default::d_header_len

protected

unsigned gr::digital::packet_header_default::d_header_number

protected

pmt::pmt_t gr::digital::packet_header_default::d_len_tag_key

protected

unsigned gr::digital::packet_header_default::d_mask

protected

pmt::pmt_t gr::digital::packet_header_default::d_num_tag_key

protected

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

• packet_header_default.h