GNU Radio 3.6.5 C++ API

digital_crc32_bb Class Reference

Byte-stream CRC block. More...

#include <digital_crc32_bb.h>

Inheritance diagram for digital_crc32_bb:
gr_tagged_stream_block gr_block gr_basic_block gr_msg_accepter gruel::msg_accepter

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_itemsThe size of the writable output buffer
ninput_itemsThe exact size of the items on every input for this particular PDU. These will be consumed if a length tag key is provided!
input_itemsSee gr_block
output_itemsSee 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: