169 lines
4.5 KiB
C++
169 lines
4.5 KiB
C++
/* -*- C++ -*- */
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/*
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* Copyright 2008-2011 Steve Glass
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*
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* This file is part of OP25.
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*
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* OP25 is free software; you can redistribute it and/or modify it
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* 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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* OP25 is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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* 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 OP25; see the file COPYING. If not, write to the Free
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* Software Foundation, Inc., 51 Franklin Street, Boston, MA
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* 02110-1301, USA.
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*/
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#ifndef INCLUDED_OP25_DECODER_FF_H
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#define INCLUDED_OP25_DECODER_FF_H
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#include <boost/scoped_ptr.hpp>
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#include <data_unit.h>
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#include <data_unit_handler.h>
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#include <gr_block.h>
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#include <gr_msg_queue.h>
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#include <imbe_decoder.h>
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typedef boost::shared_ptr<class op25_decoder_ff> op25_decoder_ff_sptr;
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op25_decoder_ff_sptr op25_make_decoder_ff();
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/**
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* op25_decoder_ff is a GNU Radio block for decoding APCO P25
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* signals. This class expects its input to be a stream of dibit
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* symbols from the demodulator and produces a mono audio
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* stream.
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*/
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class op25_decoder_ff : public gr_block
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{
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public:
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/**
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* op25_decoder_ff (virtual) destructor.
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*/
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virtual ~op25_decoder_ff();
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/**
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* Estimate nof_input_items_reqd for a given nof_output_items.
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*/
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virtual void forecast(int nof_output_items, gr_vector_int &nof_input_items_reqd);
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/**
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* Process symbols into frames.
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*/
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virtual int general_work(int nof_output_items, gr_vector_int& nof_input_items, gr_vector_const_void_star& input_items, gr_vector_void_star& output_items);
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/**
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* Return a pointer to a string identifying the destination of
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* the received frames.
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*
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* \return A pointer to a NUL-terminated character string.
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*/
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const char *destination() const;
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/**
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* Accessor for the msgq attribute. Returns a pointer to the msgq
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* if it exists.
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*
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* \return A (possibly NULL) gr_msg_queue_sptr pointing to the message queue.
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*/
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gr_msg_queue_sptr get_msgq() const;
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/**
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* Accessor for the msgq attribute. Sets the msgq to point to the
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* provided message queue object.
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*
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* \return A (possibly NULL) gr_msg_queue_sptr pointing to the message queue.
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*/
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void set_msgq(gr_msg_queue_sptr msgq);
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private:
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/**
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* Expose class to public ctor. Create a new instance of
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* op25_decoder_ff and wrap it in a shared_ptr. This is effectively
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* the public constructor.
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*/
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friend op25_decoder_ff_sptr op25_make_decoder_ff();
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/**
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* op25_decoder_ff protected constructor.
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*/
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op25_decoder_ff();
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/**
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* Tests whether d_frame_header correlates with the APCO P25 frame
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* sync sequence. This method must only be called when the frame
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* header is larger than 48 bits in length (the minimum size for
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* the FS).
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*
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* \return true if the frame header correlates; otherwise false.
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*/
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bool correlated();
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/**
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* Tests whether d_frame_header identifies a known data unit and if
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* so sets d_data_unit to point to an appropriate instance and
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* returns a pointer to it. This method must only be called when
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* the frame header is larger than 114 bits in length (the minimum
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* size for a frame containing a NID).
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*
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* \return A data_unit_sptr pointing to an appropriate data_unit
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* instance or NULL if the frame header is unrecognized.
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*/
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data_unit_sptr identified();
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/**
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* Handle a received symbol.
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*
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* \param d The symbol to process.
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*/
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void receive_symbol(dibit d);
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private:
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/**
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* When d_state == READING the current data unit, otherwise null.
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*/
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data_unit_sptr d_data_unit;
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/**
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* The head of a chain of data_unit_handler instances.
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*/
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data_unit_handler_sptr d_data_unit_handler;
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/**
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* A bit_queue used to correlate the FS.
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*/
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bit_queue d_frame_hdr;
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/**
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* The IMBE decoder to use.
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*/
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imbe_decoder_sptr d_imbe;
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/**
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* Valid states for the decoder state model.
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*/
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enum { SYNCHRONIZING, IDENTIFYING, READING } d_state;
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/**
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* The p25cai (TUN/TAP) data unit handler.
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*/
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class p25cai_du_handler *d_p25cai_du_handler;
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/**
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* The snapshot data unit handler.
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*/
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class snapshot_du_handler *d_snapshot_du_handler;
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};
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#endif /* INCLUDED_OP25_DECODER_FF_H */
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