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/* -*- c++ -*- */
/* Copyright 2012 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef INCLUDED_DIGITAL_HEADER_PAYLOAD_DEMUX_H
#define INCLUDED_DIGITAL_HEADER_PAYLOAD_DEMUX_H
#include <digital/api.h>
#include <gr_block.h>
namespace gr {
namespace digital {
/*!
* \brief Header/Payload demuxer.
* \ingroup digital
*
* This block is designed to handle packets from a bursty transmission.
* Input 0 takes a continuous transmission of samples.
* If used, input 1 is a trigger signal. In this case, a 1 on input 1
* is a trigger. Otherwise, a tag with the key specified in \p trigger_tag_key
* is used as a trigger (its value is irrelevant).
*
* Until a trigger signal is detected, all samples are dropped onto the floor.
* Once a trigger is detected, a total of \p header_len items are copied to output 0.
* The block then stalls until it receives a message on the message port
* \p header_data. The message must be a PMT dictionary; all key/value pairs are
* copied as tags to the first item of the payload (which is assumed to be the
* first item after the header).
* The value corresponding to the key specified in \p length_tag_key is read
* and taken as the payload length. The payload, together with the header data
* as tags, is then copied to output 1.
*
* If specified, \p guard_interval items are discarded before every symbol.
* This is useful for demuxing bursts of OFDM signals.
*
* Any tags on the input stream are copied to the corresponding output *if* they're
* on an item that is propagated. Note that a tag on the header items is copied to the
* header stream; that means the header-parsing block must handle these tags if they
* should go on the payload.
* A special case are tags on items that make up the guard interval. These are copied
* to the first item of the following symbol.
*/
class DIGITAL_API header_payload_demux : virtual public gr_block
{
public:
typedef boost::shared_ptr<header_payload_demux> sptr;
/*!
* \param header_len Number of symbols per header
* \param items_per_symbol Number of items per symbol
* \param guard_interval Number of items between two consecutive symbols
* \param length_tag_key Key of the frame length tag
* \param trigger_tag_key Key of the trigger tag
* \param output_symbols Output symbols (true) or items (false)?
* \param itemsize Item size (bytes per item)
*/
static sptr make(
int header_len,
int items_per_symbol,
int guard_interval=0,
const std::string &length_tag_key="frame_len",
const std::string &trigger_tag_key="",
bool output_symbols=false,
size_t itemsize=sizeof(gr_complex)
);
};
} // namespace digital
} // namespace gr
#endif /* INCLUDED_DIGITAL_HEADER_PAYLOAD_DEMUX_H */
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