sub ValidateInputFile{

my($line,
   $llen,
   $LineNo,
   $ErrChar,
   $ErrCount,
   $mtch_junk,
   $tncount,
   @check,
   $SOF_fh);

$tncount=0;
$ErrCount=0;
$SOF_fh=OpenFile($fqd_sof, "READ");
$SOFV_fh=OpenFile($fqd_sof.'validated', "WRITE");
$SOFR_fh=OpenFile($fqd_sof.'removed', "WRITE");

@HeaderGarbage = ('^LD 20',
                  '^PT0000 ',
                  '^REQ\: PRT',
                  '^TYPE\: TNB',
                  '^TN   $',
                  '^CDEN ',
                  '^CUST ',
                  '^DATE ',
                  '^PAGE ',
                  '^DES  ');
    
    foreach $RegEx (@HeaderGarbage){
        $CHRegex = qr/($RegEx\n)/;
        push @HeaderRegExes, $CHRegex;
    }
    
    @ErrCodes = ('(^\*.*\n)',
                 '(ADMIN VSID.*)',
                 '(BUG.*\n)',
                 '(?<![A-Z])(AUD.*)',
                 '(SCH.*\n)',
                 '(MAINT.*\n)',
                 '(OPRDATA.*\n)',
                 '(TIM000.*\n)',
                 '(DTC103.*)',
                 '(DTC001.*)',
                 '(DSL.*TIME.*\n)',
                 '(FIR110.*\n)',
                 '(FIR103.*\n)',
                 '(^ERR.*\n)',
                 '(DCH:.*)',
                 '(^VAS008.*\n)',
                 '(^INDEX.*VTN.*\n)',
                 '(^IND.*\n)',
                 '(^  NET  56  P.*\n)',
                 '(00A1491A 00000C16 00000000 000014F0 00000000 00000000 00000000 128)',
                 '(0000 00000000 0  00000000 00000000 00000000 00000000 00000000 00000000)');

    foreach $RegEx (@ErrCodes){
        $CBRegex = qr/$RegEx/;
        push @BodyRegExes, $CBRegex;
    }    

while ($line = ($SOF_fh->getline)){
    $LineNo++;
    $llen=length($line);
    #Remove the DOS line endings
    $line=~s/\r\n/\n/;
    # Following code removes spurious switch codes that cant be suppressed
    # First lets strip the first 20 lines of the TNB file of garbage
    if ($LineNo < 30){
        #print $LineNo."\n";
        #print $line;
        foreach $ErrChar (@HeaderRegExes){
            undef $mtch_junk;
            #print "Checking ".$ErrChar."\n";
            if ($line=~/$ErrChar/){
                    $ErrCount++;
                    #print " Found ".$ErrChar."\n";
                    $line=~s/$ErrChar//;
                    $mtch_junk = $1;
                        
                if ($LineNo != $LastInvLine){
                    # Only print the line the first time we go over it
                    # Because $1 isn't reset if a subsequent attempt to match fails
                        if ($mtch_junk){
                            $LastInvLine = $LineNo;
                            $SOFR_fh->write("$LineNo($ErrChar)->$mtch_junk\n");
                        }
                    }
                
            }
            
        }
    }
    # Now attempt to remove spurious codes
    foreach $ErrChar (@BodyRegExes){
        undef $mtch_junk;
        # Need to ensure this doesn't match BAUD just AUD
        if ($line=~/$ErrChar/){
                $ErrCount++;
                $line=~s/$ErrChar//;
                $mtch_junk = $1;
                if ($LineNo != $LastInvLine){
                    # Only print the line the first time we go over it
                    # Because $1 isn't reset if a subsequent attempt to match fails
                    if ($mtch_junk){
                    $LastInvLine = $LineNo;
                    $SOFR_fh->write("$LineNo($ErrChar)->$mtch_junk\n");
                    }
                }
        }
        
    }
      
    if ($line =~ /^(TN\s+\d+\s+\d+)/) {
            $tncount++;
            #$LOG_fh->write(msg("INFO","Found $1","FORMAT"),8);
            #print $1."\n";
    }
    $SOFV_fh->write($line);
}
$LOG_fh->write(msg("INFO","Removed $ErrCount occurrences of non TN data","FORMAT"),4);
msg("INFO","Removed $ErrCount occurrences of non TN data","PRINT");
$LOG_fh->write(msg("INFO","Found $tncount occurrences of TN at beginning of line","FORMAT"),4);
msg("INFO","Found $tncount occurrences of TN at beginning of line","PRINT");
$SwitchCount{$switch_id}{'REMOVED'} = $ErrCount;
$SwitchCount{$switch_id}{'TN_COUNT'} = $tncount;


$SOF_fh->close or throw TNBCriticalException("Cannot close switch output file");
undef $SOF_fh;
undef $SOFV_fh;
undef $SOFR_fh;
return $tncount;
}