GNU Radio 3.6.5.1 C++ API
gr_tagged_stream_block.h
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/* -*- c++ -*- */
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/*
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* Copyright 2013 Free Software Foundation, Inc.
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*
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* This file is part of GNU Radio
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*
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* GNU Radio is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_GR_TAGGED_STREAM_BLOCK_H
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#define INCLUDED_GR_TAGGED_STREAM_BLOCK_H
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#include <
gr_core_api.h
>
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#include <
gr_block.h
>
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/*!
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* \brief Block that operates on PDUs in form of tagged streams
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* \ingroup base_blk
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*
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* Override work to provide the signal processing implementation.
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*/
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class
GR_CORE_API
gr_tagged_stream_block
:
public
gr_block
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{
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private
:
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pmt::pmt_t
d_length_tag_key;
//!< This is the key for the tag that stores the PDU length
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gr_vector_int
d_n_input_items_reqd;
//!< How many input items do I need to process the next PDU?
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protected
:
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std::string
d_length_tag_key_str
;
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gr_tagged_stream_block
(
void
){}
//allows pure virtual interface sub-classes
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gr_tagged_stream_block
(
const
std::string &name,
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gr_io_signature_sptr
input_signature,
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gr_io_signature_sptr
output_signature,
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const
std::string &length_tag_key);
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/*!
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* \brief Parse all tags on the first sample of a PDU, return the number of items per input
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* and prune the length tags.
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*
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* In most cases, you don't need to override this, unless the number of items read
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* is not directly coded in one single tag.
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*
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* Default behaviour:
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* - Go through all input ports
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* - On every input port, search for the tag with the key specified in \p length_tag_key
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* - Copy that value as an int to the corresponding position in \p n_input_items_reqd
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* - Remove the length tag.
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*
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* \param[in] tags All the tags found on the first item of every input port.
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* \param[out] n_input_items_reqd Number of items which will be read from every input
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*/
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virtual
void
parse_length_tags(
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const
std::vector<std::vector<gr_tag_t> > &tags,
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gr_vector_int
&n_input_items_reqd
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);
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/*!
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* \brief Calculate the number of output items.
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*
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* This is basically the inverse function to forecast(): Given a number of input
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* items, it returns the maximum number of output items.
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*
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* You most likely need to override this function, unless your block is a sync
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* block or integer interpolator/decimator.
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*
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*/
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virtual
int
calculate_output_stream_length(
const
gr_vector_int
&ninput_items);
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/*!
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* \brief Set the new length tags on the output stream
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*
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* Default behaviour: Set a tag with key \p length_tag_key and
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* the number of produced items on every output port.
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*
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* For anything else, override this.
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*
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* \param n_produced Length of the new PDU
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* \param n_ports Number of output ports
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*/
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virtual
void
update_length_tags(
int
n_produced,
int
n_ports);
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public
:
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/*! \brief Don't override this.
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*/
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void
/* final */
forecast
(
int
noutput_items,
gr_vector_int
&ninput_items_required);
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/*!
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* - Reads the number of input items from the tags using parse_length_tags()
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* - Checks there's enough data on the input and output buffers
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* - If not, inform the scheduler and do nothing
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* - Calls work() with the exact number of items per PDU
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* - Updates the tags using update_length_tags()
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*/
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int
general_work
(
int
noutput_items,
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gr_vector_int
&ninput_items,
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gr_vector_const_void_star
&input_items,
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gr_vector_void_star
&output_items);
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/*!
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* \brief Just like gr_block::general_work, but makes sure the input is valid
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*
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* The user must override work to define the signal processing code.
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* Check the documentation for general_work() to see what happens here.
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*
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* Like gr_sync_block, this calls consume() for you (it consumes ninput_items[i]
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* items from the i-th port).
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*
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* A note on tag propagation: The PDU length tags are handled by other functions,
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* but all other tags are handled just as in any other \p gr_block. So, most likely,
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* you either set the tag propagation policy to TPP_DONT and handle the tag
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* propagation manually, or you propagate tags through the scheduler and don't
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* do anything here.
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*
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* \param noutput_items The size of the writable output buffer
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* \param ninput_items The exact size of the items on every input for this particular PDU.
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* These will be consumed if a length tag key is provided!
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* \param input_items See gr_block
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* \param output_items See gr_block
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*/
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virtual
int
work (
int
noutput_items,
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gr_vector_int
&ninput_items,
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gr_vector_const_void_star
&input_items,
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gr_vector_void_star
&output_items) = 0;
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};
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#endif
/* INCLUDED_GR_TAGGED_STREAM_BLOCK_H */
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gnuradio-core
src
lib
runtime
gr_tagged_stream_block.h
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