function X = ptt2out(FileName)
% PTT2OUT   - Convert *.ptt files to *.out files

% Brian Schlining
% 21 Jan 1999

%===================================
% Get FileName if it's not supplied
%===================================
if ~nargin 
   
   [infile inpath] = uigetfile('*.ptt','Select an Eqpac Data File',0,0);
   if infile == 0 
      X = [];
      return
   end
   FileName = [inpath infile];
   
end

% Get the filename from the path and store it in the data structure
[trash, File, Ext] = fileparts(FileName);
X.Filename         = [File Ext];

fid        = fopen(FileName,'rt');    % Open the File 

Header     = fgetl(fid);              % Get the first line which contains the column descriptions
BytesInHeader = length(Header);       % Need to reposition the file pointer

%==========================================================
% Figure out roughly how many rows of data are in the file
%==========================================================
sByte       = ftell(fid);             % Get current position (in bytes)
fseek(fid,0,'eof');                   % go to the end of the file
fByte       = ftell(fid);             % Get the position in Bytes
BytesOfData = fByte - sByte;          
fseek(fid,BytesInHeader + 2,'bof');   % Rewind back to the original position + 1 line
numRows = ceil(BytesOfData/279);      % 279 is a ROUGH approx. of the number of characters per line
x = ones(numRows,31)*NaN;             % Preallocate memory

n = 0;   % Line counter
%m = 1;  % for debugging, otherwise ignore this
while ~feof(fid)
   s = fgetl(fid);
   %m = m + 1; % For debugging
   
   % Not every line is the same length, so find out where each data value
   % starts and stops by finding the spaces
   if ~isempty(s)
      y = sscanf(s,'%f %f %f/%f/%f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f');
      %fprintf(1,'%5i %3i %s\n',m,length(y),s)
      if length(y) > 30
         n = n + 1;
         x(n,:) = y(1:31,1)';
      end
      
   end
   
end

fclose(fid);

% Chop off any trailing NaN's left over from memory allocation
j = find(~isnan(x(:,1)));
x = x(j,:);


SN           = median(x(:,7));      % Easy way to get rid of bad SN values
X            = setfield(X,['SN_' num2str(SN)],ones(size(x(:,7)))*SN);
X.LU_412     = x(:,8);
X.LU_443     = x(:,9);
X.LU_490     = x(:,10);
X.LU_510     = x(:,11);
X.LU_555     = x(:,12);
X.LU_670     = x(:,13);
X.LU_683     = x(:,14);
X.ED_490     = x(:,17);
X.FLOUR_none = x(:,29);
T_w          = x(:,30);
V_BAT        = x(:,31);
Hour         = floor(x(:,2)/10000);
Minute       = floor(x(:,2)/100) - Hour;
Second       = x(:,2) - Hour - Minute;
X.TIME_TAG   = datenum(x(:,5),x(:,3),x(:,4),Hour, Minute, Second);
X.MS_TAG     = ones(size(x(:,1)))*NaN;

% Set bad values to NaN. 
% Data is bad if Lux+1/Lux < -0.1 (ex. Lu443/Lu412). Why do we consider this bad you ask?
% Peter Strutton came up with this ratio method through empirical analysis. If you have
% questions about it he's DA MAN to ask. In addition, Any LU's less than -1 are flagged too
i = (X.LU_443./X.LU_412 < -0.1 );
j = (X.LU_490./X.LU_443 < -0.1 );
k = (X.LU_510./X.LU_490 < -0.1 );
l = (X.LU_555./X.LU_510 < -0.1 );
m = (X.LU_670./X.LU_555 < -0.1 );
n = (X.LU_683./X.LU_670 < -0.1 );
i = (i|j|k|l|m|n);                     % If any of the ratios are BAD all points in that sample are flagged
X.LU_412(i) = NaN;
X.LU_443(i) = NaN;
X.LU_490(i) = NaN;
X.LU_510(i) = NaN;
X.LU_555(i) = NaN;
X.LU_670(i) = NaN;
X.LU_683(i) = NaN;
X.LU_412(i) = NaN;
i = find(X.LU_412 < -1);X.LU_412(i) = NaN;
i = find(X.LU_443 < -1);X.LU_443(i) = NaN;
i = find(X.LU_490 < -1);X.LU_490(i) = NaN;
i = find(X.LU_510 < -1);X.LU_510(i) = NaN;
i = find(X.LU_555 < -1);X.LU_555(i) = NaN;
i = find(X.LU_670 < -1);X.LU_670(i) = NaN;
i = find(X.LU_683 < -1);X.LU_683(i) = NaN;
i = find(X.ED_490 < -1);X.ED_490(i) = NaN;