digital_crc32_bb Class Reference

Byte-stream CRC block. More...

#include <digital_crc32_bb.h>

Inheritance diagram for digital_crc32_bb:

List of all members.

Public Member Functions
	~digital_crc32_bb ()
int	calculate_output_stream_length (const std::vector< int > &ninput_items)
	Calculate the number of output items.
int	work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
	Just like gr_block::general_work, but makes sure the input is valid.
Friends
DIGITAL_API digital_crc32_bb_sptr	digital_make_crc32_bb (bool check, const std::string &lengthtagname)

---

Detailed Description

Byte-stream CRC block.

Input: stream of bytes, which form a packet. The first byte of the packet has a tag with key "length" and the value being the number of bytes in the packet.

Output: The same bytes as incoming, but trailing a CRC32 of the packet. The tag is re-set to the new length.

---

Constructor & Destructor Documentation

digital_crc32_bb::~digital_crc32_bb

(

)

---

Member Function Documentation

int digital_crc32_bb::calculate_output_stream_length

(

const std::vector< int > &

ninput_items

)

[virtual]

Calculate the number of output items.

This is basically the inverse function to forecast(): Given a number of input items, it returns the maximum number of output items.

You most likely need to override this function, unless your block is a sync block or integer interpolator/decimator.

Reimplemented from gr_tagged_stream_block.

int digital_crc32_bb::work	(	int	noutput_items,
		gr_vector_int &	ninput_items,
		gr_vector_const_void_star &	input_items,
		gr_vector_void_star &	output_items
	)		[virtual]

Just like gr_block::general_work, but makes sure the input is valid.

The user must override work to define the signal processing code. Check the documentation for general_work() to see what happens here.

Like gr_sync_block, this calls consume() for you (it consumes ninput_items[i] items from the i-th port).

A note on tag propagation: The PDU length tags are handled by other functions, but all other tags are handled just as in any other gr_block. So, most likely, you either set the tag propagation policy to TPP_DONT and handle the tag propagation manually, or you propagate tags through the scheduler and don't do anything here.

Parameters:

noutput_items	The size of the writable output buffer
ninput_items	The exact size of the items on every input for this particular PDU. These will be consumed if a length tag key is provided!
input_items	See gr_block
output_items	See gr_block

Implements gr_tagged_stream_block.

---

Friends And Related Function Documentation

DIGITAL_API digital_crc32_bb_sptr digital_make_crc32_bb	(	bool	check,
		const std::string &	lengthtagname
	)		[friend]

---

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

• digital_crc32_bb.h