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/* -*- c++ -*- */
/*
* Copyright 2002,2011 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_TRELLIS_FSM_H
#define INCLUDED_TRELLIS_FSM_H
#include <trellis_api.h>
#include <vector>
#include <iosfwd>
/*!
* \brief Finite State Machine Specification class.
*
* An instance of this class represents a finite state machine specification (FSMS)
* rather than the FSM itself. It particular the state of the FSM
* is not stored within an instance of this class.
*/
class TRELLIS_API fsm {
private:
// Input alphabet cardinality.
int d_I;
// Number of states.
int d_S;
// Output alphabet cardinality.
int d_O;
// NS means Next State.
// next_state = d_NS[current_state * d_I + input_symbol]
std::vector<int> d_NS;
// OS means Output Symbol.
// output_symbol = d_OS[current_state * d_I + input_symbol]
std::vector<int> d_OS;
// PS means Previous State.
std::vector< std::vector<int> > d_PS;
// PI means Previous Input Symbol.
// d_PS[current_state][k] and d_PI[current_state][k], is a pair of the form
// (previous_state, previous_input_symbol) that could have produced the
// current state.
std::vector< std::vector<int> > d_PI;
// TM means Termination matrix.
// d_TMl[s*d_S+es] is the shortest number of steps to get from state s to
// state es.
std::vector<int> d_TMl;
// d_TMi[s*d_S+es] is the input symbol required to set off on the shortest
// path from state s to es.
std::vector<int> d_TMi;
void generate_PS_PI ();
void generate_TM ();
bool find_es(int es);
public:
/*!
* \brief Constructor to create an uninitialized FSMS.
*/
fsm();
/*!
* \brief Constructor to copy an FSMS.
*/
fsm(const fsm &FSM);
/*!
* \brief Constructor to to create an FSMS.
*
* \param I The number of possible input symbols.
* \param S The number of possible FSM states.
* \param O The number of possible output symbols.
* \param NS A mapping from (current state, input symbol) to next state.
* next_state = NS[current_state * I + input_symbol]
* \param OS A mapping from (current state, input symbol) to output symbol.
* output_symbol = OS[current_state * I + input_symbol]
*
*/
fsm(int I, int S, int O, const std::vector<int> &NS, const std::vector<int> &OS);
/*!
* \brief Constructor to create an FSMS from file contents.
*
* \param name filename
*
*/
fsm(const char *name);
/*!
* \brief Creates an FSMS from the generator matrix of a (n, k) binary convolutional code.
*
* \param k ???
* \param n ???
* \param G ???
*
*/
fsm(int k, int n, const std::vector<int> &G);
/*!
* \brief Creates an FSMS describing ISI.
*
* \param mod_size modulation size
* \param ch_length channel length
*
*/
fsm(int mod_size, int ch_length);
/*!
* \brief Creates an FSMS describing the trellis for a CPM.
*
* \param P ???? h=K/P (relatively prime)
* \param M alphabet size
* \param L pulse duration
*
* This FSM is based on the paper by B. Rimoldi
* "A decomposition approach to CPM", IEEE Trans. Info Theory, March 1988
* See also my own notes at http://www.eecs.umich.edu/~anastas/docs/cpm.pdf
*/
fsm(int P, int M, int L);
/*!
* \brief Creates an FSMS describing the joint trellis of two FSMs.
*
* \param FSM1 first FSMS
* \param FSM2 second FSMS
*/
fsm(const fsm &FSM1, const fsm &FSM2);
/*!
* \brief Creates an FSMS representing n stages through the originial FSM (AKA radix-n FSM).
*
* \param FSM Original FSMs
* \param n Number of stages.
*/
fsm(const fsm &FSM, int n);
int I () const { return d_I; }
int S () const { return d_S; }
int O () const { return d_O; }
const std::vector<int> & NS () const { return d_NS; }
const std::vector<int> & OS () const { return d_OS; }
const std::vector< std::vector<int> > & PS () const { return d_PS; }
const std::vector< std::vector<int> > & PI () const { return d_PI; }
const std::vector<int> & TMi () const { return d_TMi; }
const std::vector<int> & TMl () const { return d_TMl; }
/*!
* \brief Creates an svg image of the trellis representation.
*
* \param filename filename
* \param number_stages ????
*
*/
void write_trellis_svg(std::string filename ,int number_stages);
/*!
* \brief Write the FSMS to a file.
*
* \param filename filename
*
*/
void write_fsm_txt(std::string filename);
};
#endif
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