root/SigProc/trunk/SigProc/fec_conv.cpp @ 4153

/****************************************************************************

Copyright 2007, Virginia Polytechnic Institute and State University

This file is part of the OSSIE Signal Processing Library.

OSSIE Core Framework is free software; you can redistribute it and/or modify
it under the terms of the Lesser GNU General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

The OSSIE Signal Processing library 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
Lesser GNU General Public License for more details.

You should have received a copy of the Lesser GNU General Public License
along with OSSIE Core Framework; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

****************************************************************************/

#include "SigProc.h"

#include <math.h>

using namespace SigProc;


trellisTable::trellisTable(
unsigned int * generatorPolynomials,
unsigned short int k,
unsigned short int n,
unsigned short K)
{
    //Build trellis table
    trellisTable::k=k;
    trellisTable::n=n;
    trellisTable::K=K;

    //std::cout<<"Constructor, generatorPolynomials:";
    for (int i=0;i<n;i++){

        std::cout<<generatorPolynomials[i]<<" ";
    }
    //std::cout<<std::endl;

    //std::cout<<"Input bits:"<<k<<" Contraint Length:"<<K<<std::endl;
    trellisTable::GenerateTrellisTable(generatorPolynomials);
}

trellisTable::~trellisTable()
{
    //Deallocate memory
    for (unsigned int i = 0; i < trellisTable::numberOfTrellisStates; i++){
        delete []trellisTable::nextState[i];
    }
    delete []trellisTable::nextState;


    for (unsigned int i = 0; i < trellisTable::numberOfTrellisStates; i++){
        delete []trellisTable::output[i];
    }
    delete []trellisTable::output;
}


void trellisTable::GenerateTrellisTable(unsigned int * generatorPolynomials)
{

    numberOfTrellisStates=int(pow(2,(k*(K-1))));
    numberOfInputStates=int(pow(2,k));
    //std::cout<<"NumberOfTrellisStates="<<numberOfTrellisStates<<std::endl;
    //std::cout<<"numberOfInputStates="<<numberOfInputStates<<std::endl;

    nextState = new unsigned int *[numberOfTrellisStates];

    for (unsigned int i = 0; i < numberOfTrellisStates; i++){
        nextState[i] = new unsigned int[numberOfInputStates];
    }

    output = new unsigned int *[numberOfTrellisStates];

    for (unsigned int i = 0; i < numberOfTrellisStates; i++){
        output[i] = new unsigned int[numberOfInputStates];
    }

    unsigned int ENCregister, tempOut;

    for (unsigned int tstate=0;tstate<numberOfTrellisStates;tstate++){
        //std::cout<<tstate<<":";
        for (unsigned short int inputIdx=0;inputIdx<numberOfInputStates;inputIdx++){
            ENCregister=inputIdx*numberOfTrellisStates+tstate;
            nextState[tstate][inputIdx]=(unsigned int)floor(ENCregister/pow(2,k));
            tempOut=0;

            for (unsigned short int bitNo=0;bitNo<n;bitNo++){
                // std::cout<<"\nBitNo:"<<bitNo<<" ENCregister:"<<ENCregister<<" g:"<<generatorPolynomials[bitNo]<<" &:"<<(ENCregister&generatorPolynomials[bitNo])
                //      <<"power:"<<(unsigned short int)pow(2,n-bitNo-1)<<"tempOut:"<<tempOut<<"\n";
                // std::cout<<"Mod2add:"<<Modulo2BitWiseAdd((ENCregister&generatorPolynomials[bitNo])*(unsigned short int)pow(2,n-bitNo-1))<<"\n";
                tempOut+=Modulo2BitWiseAdd(ENCregister&generatorPolynomials[bitNo])* (unsigned short int)pow(2,n-bitNo-1);
            }
            output[tstate][inputIdx]=tempOut;
            //std::cout<<output[tstate][inputIdx]<<" ("<<nextState[tstate][inputIdx]<<") ";


        }
        //std::cout<<std::endl;
    }
}

unsigned short int trellisTable::Modulo2BitWiseAdd(unsigned short int inputNumber)
{
    //std::cout<<"IN:"<<inputNumber;
    unsigned int tempOut;
    tempOut=inputNumber % 2;
    inputNumber>>=1;
    while (inputNumber>0){
        tempOut^=inputNumber % 2;
        inputNumber>>=1;
    }
    // std::cout<<" Out:"<<tempOut<<" ";
    return tempOut;
}

void fec_conv::SetTrellisTable(trellisTable *theTrellisTableIn)
{
    theTrellisTable=theTrellisTableIn;
}

void fec_conv::Dec2Bin(unsigned int decNumber,unsigned short int * outputData,unsigned short int numberOfBits)
{
    unsigned short int i;
    for (i=numberOfBits;i>0;i--){
        outputData[i-1]=decNumber % 2;
        decNumber>>=1;
    }
}

fec_conv_encoder::fec_conv_encoder()
{
    currentState=0;
}

fec_conv_encoder::~fec_conv_encoder()
{

}

void fec_conv_encoder::ResetState()
{
    currentState=0;
}

unsigned int fec_conv_encoder::GetState()
{
    return currentState;
}

void fec_conv_encoder::Encode(unsigned short int * inputData,unsigned short int * outputData)
{
    unsigned int inbits=0,tmp=0,outbits=0;

    for (unsigned short int i=0;i<theTrellisTable->k;i++)    {
        tmp=inputData[i];
        //std::cout<<"inputData:"<<tmp<<"\n";
        tmp<<=theTrellisTable->k-i-1;
        //std::cout<<"temp"<<tmp<<"\n";
        inbits+=tmp;
    }
    //std::cout<<"state:"<<currentState<<" inbits:"<<inbits<<" outbits:"<<outbits<<"\n";
    outbits=theTrellisTable->output[currentState][inbits];

    currentState=theTrellisTable->nextState[currentState][inbits];
    Dec2Bin(outbits,outputData,theTrellisTable->n);

}

void fec_conv_decoder::SetMode(unsigned short int mode)
{
    fec_conv_decoder::mode=mode;
};

void fec_conv_decoder::SetNoOfSymbols2TraceBack(unsigned int traceBackLength){
    //std::cout<<theTrellis;
    if (theTrellis!=NULL){
        for (unsigned int i = 0; i < theTrellisTable->numberOfTrellisStates; i++){
            delete theTrellis[i];
        };
        delete []theTrellis;
        theTrellis=NULL;
    }
    //std::cout<<theTrellis;
    //int dummy;
    //std::cin>>dummy;

    fec_conv_decoder::noOfSymbols2TraceBack=traceBackLength;

    theTrellis= new TrellisEntry*[theTrellisTable->numberOfTrellisStates];
    for (unsigned int i = 0; i < theTrellisTable->numberOfTrellisStates; i++){
        theTrellis[i] =new TrellisEntry[noOfSymbols2TraceBack+1];
    };

    if (tracedBackSymbols!=NULL){
        delete []tracedBackSymbols;
        tracedBackSymbols=NULL;
    };
    tracedBackSymbols = new unsigned int [noOfSymbols2TraceBack];

    currentTrellisIndex=0;
    for (unsigned int i=0;i<theTrellisTable->numberOfTrellisStates;i++)
        for (unsigned int j=0;j<=noOfSymbols2TraceBack;j++){
            theTrellis[i][j].previousState=0;
            theTrellis[i][j].symbolNo=0;
            theTrellis[i][j].distance=(signed int)-1;
        }
    theTrellis[0][0].distance=0;

}

void fec_conv_decoder::Symbol2Decode(unsigned short int * inputData)
{

    unsigned int inbits=0,tmp=0,newState=0;
    unsigned short int symbol;
    signed int distance;

    inbits=0;
    for (unsigned short int i=0;i<theTrellisTable->n;i++){
        tmp=inputData[i];
        //std::cout<<"inputData:"<<tmp<<"\n";
        tmp<<=theTrellisTable->n-i-1;
        //std::cout<<"temp"<<tmp<<"\n";
        inbits+=tmp;
    }
    //std::cout<<"inbits:"<<inbits<<"\n";
    currentTrellisIndex++;
    //std::cout<<"currentTrellisIndex:"<<currentTrellisIndex<<"\n";
    for (unsigned int tstate=0;tstate<theTrellisTable->numberOfTrellisStates;tstate++){
        if (theTrellis[tstate][currentTrellisIndex-1].distance!=-1){
            for (unsigned short int inputBits=0;inputBits<theTrellisTable->numberOfInputStates;inputBits++){
                newState=theTrellisTable->nextState[tstate][inputBits];
                symbol=theTrellisTable->output[tstate][inputBits];

                distance=CalculateDistance(inbits,symbol)+theTrellis[tstate][currentTrellisIndex-1].distance; //Have to calculate;
                if ((theTrellis[newState][currentTrellisIndex].distance==-1)||
                        ((distance<theTrellis[newState][currentTrellisIndex].distance))||
                        (theTrellis[newState][currentTrellisIndex].distance<0)){
                    theTrellis[newState][currentTrellisIndex].distance=distance;
                    theTrellis[newState][currentTrellisIndex].previousState=tstate;
                    theTrellis[newState][currentTrellisIndex].symbolNo=inputBits;
                };
            };
        }
        else{
        };

    }

    /*
        for (unsigned int tstate=0;tstate<numberOfTrellisStates;tstate++)
        {
                    std::cout<<"["<<tstate<<"]["<<currentTrellisIndex<<"].previousState:"
                       <<theTrellis[tstate][currentTrellisIndex].previousState<<".distance:"
                        <<theTrellis[tstate][currentTrellisIndex].distance<<".symbol:"<<
                        theTrellis[tstate][currentTrellisIndex].symbolNo<<"\n";
        };
    */
};

signed int fec_conv_decoder::CalculateDistance(unsigned short int inBits, unsigned short int symbol)
{
    unsigned short int tmp;
    signed int distance=0;
    tmp=inBits^symbol;

    while (tmp>0){
        distance+=(signed int)(tmp % 2);
        tmp>>=1;
    };
    return distance;

}

void fec_conv_decoder::TraceBackTrellis(){
    //std::cout<<"cTi:"<<currentTrellisIndex<<"; cS:"<<currentState<<";";
    unsigned int currentState;
    signed int minDistance=9999;
    unsigned int minDistState=0;

    if (currentTrellisIndex==noOfSymbols2TraceBack){
        if (mode==1){
            currentState=0;
        } else{
            for (unsigned int tstate=0;tstate<theTrellisTable->numberOfTrellisStates;tstate++)
                if ((theTrellis[tstate][currentTrellisIndex].distance!=-1)
                        &&(theTrellis[tstate][currentTrellisIndex].distance<minDistance)){
                    minDistance=theTrellis[tstate][currentTrellisIndex].distance;
                    minDistState=tstate;
                };

            currentState=minDistState;
        }
       // std::cout<<"\nMinDistance:"<<minDistance<<" minDistState:"<<minDistState<<"\n";


        unsigned short int symbol;
        while (currentTrellisIndex>0)
        {
            symbol=theTrellis[currentState][currentTrellisIndex].symbolNo;
            currentState=theTrellis[currentState][currentTrellisIndex].previousState;
            currentTrellisIndex--;
            //Dec2Bin(symbol,outputData,k);
            tracedBackSymbols[currentTrellisIndex]=symbol;
            // std::cout<<"\nsymbol:"<<symbol<<"outputData"<<outputData[0]<<"\n";
        }

        decodedSymbolIndex=0;
    }
}

void fec_conv_decoder::GetDecodedSymbol(unsigned short int * outputData)
{
    if (currentTrellisIndex==0)
    {

        if (decodedSymbolIndex<noOfSymbols2TraceBack)
        {
            Dec2Bin(tracedBackSymbols[decodedSymbolIndex],outputData,theTrellisTable->k);
        }
        decodedSymbolIndex++;
    }
    else
    {
    }
}

fec_conv_decoder::fec_conv_decoder()
{
    tracedBackSymbols=NULL;
    theTrellis=NULL;
    decodedSymbolIndex=0;
    currentTrellisIndex=0;
    mode=0;
}

fec_conv_decoder::~fec_conv_decoder()
{
    if (tracedBackSymbols!=NULL) delete  []tracedBackSymbols;

    if (theTrellis!=NULL){
        for (unsigned int i = 0; i < theTrellisTable->numberOfTrellisStates; i++){
            delete theTrellis[i];
        };
        delete []theTrellis;
    }

};