function [seis,hdr]=segy2mat(filename,bite_order,delay,window);
%function [seis,hdr]=segy2mat(filename);
%                                              *      *    *    *
%Reads PASSCAL SEGY in file FILENAME as generated by PASSCAL 1.9 ref2segy
%SEIS is the seismic trace and HDR is a structure containing trace header (only some
%elements are returned in HDR but this is easily changed)
%
%Note that PASSCAL SEGY is non-standard. It has not reel header, and has only 1
%trace per file, and the trace header is non standard
%
%If a second argument is passed to the function,file will be opened with
%little-endian bite order

%----Check inputs & GLOBALS
hdr=[]; seis=[];
if nargin<1
  error('READPSEGY needs at least 1 input argument')
end

%----Check for the existence of the file and get its length
%string = [ 'ls -l ', filename, ' | awk ''{print $5}'''];
%[status, ans]=unix(string);

string = dir(filename);

if length(filename)>21; 
    cmp_filename = filename(length(filename)-21:length(filename)); 
else
    cmp_filename = filename;
end

%if strcmp(char(string.name),cmp_filename) == 0
if exist(filename)~=2
%  disp(['  Problems finding PASSCAL SEGY file ',filename]);
%  disp(' ')
  return
end

%----Open file
if nargin>1 & bite_order(1)=='l'
    fid=fopen(filename,'r','ieee-le');
elseif nargin>1 & bite_order(1)=='b'
    fid=fopen(filename,'r','ieee-be');
else
    fid=fopen(filename,'r');
end
if fid<0
  disp(['  Failed to open PASSCAL SEGY file ',filename]);
  disp(' ')
  return
end


%----Read trace header
[in,count(1)]=fread(fid,7,'int32');
if isempty(in);
    disp(['  File unreadable for some reason?!?'])
    return
end
[in2,count(2)]=fread(fid,4,'int16');
[in3,count(3)]=fread(fid,8,'int32');
[in4,count(4)]=fread(fid,2,'int16');
[in5,count(5)]=fread(fid,4,'int32');
[in6,count(6)]=fread(fid,46,'int16');
[c7,count(7)]=fread(fid,18,'char'); in7=[0; 0; 0];
[in8,count(8)]=fread(fid,1,'int16');
[in9,count(9)]=fread(fid,1,'int32');
[in10,count(10)]=fread(fid,8,'int16');
[in11,count(11)]=fread(fid,1,'float32');
[in12,count(12)]=fread(fid,2,'int16');
[in13,count(13)]=fread(fid,3,'int32');


in=[in; in2; in3; in4; in5; in6; in7; in8; in9; in10; in11; in12; in13];
if sum(count)~=105
  disp(['  Failed to read header - Error code ',int2str(sum(count))]);
  disp(' ')
  fclose(fid);
  return
end

%----Assign header values (add your own favorites)
hdr.year=in(60);
hdr.day=in(61);
hdr.hour=in(62);
hdr.min=in(63);
hdr.sec=in(64);
hdr.msec=in(78);
%hdr.time_basis=in(65);
%keyboard
if in(39)~=32767
  hdr.nsamp=in(39);
else
  hdr.nsamp=in(88);
  %hdr.nsamp = 360000; % this is a temporary stopgap measure for Jonathan's data
end
hdr.nsamp=in(88);
hdr.sps=1e6/in(76);
hdr.channel=in(4);
hdr.gain = in(42);
%hdr.format=in(77);
%hdr.trigyear=in(79);
%hdr.trigday=in(80);
%hdr.trighour=in(81);
%hdr.trigmin=in(82);
%hdr.trigsec=in(83);
%hdr.trigmsec=in(84);
hdr.atod=in(85);
%hdr.inst=in(86);
%hdr.bigtime=date2secnds(in(60),in(61),in(62),in(63),in(64)+in(78)/1000);
%hdr.bigtrigtime=date2secnds(in(79),in(80),in(81),in(82),in(83)+in(84)/1000);

format=in(77);

if nargin>1 & length(bite_order)>1; % first character indicates bite_order, more than one character indicates just return hdr
    return
end

if format==0
  byte_type='int16';
  bt=2;
else
  byte_type='int32';
  bt=4;
end

if nargin>2
    delay_samples = round(delay*hdr.sps)*bt;
else delay=0; delay_samples = 0;
end
fseek(fid,delay_samples,'cof');
if nargin>3
    window_samples = floor(window*hdr.sps);
else 
    window_samples = hdr.nsamp;
end
[seis,count]=fread(fid,window_samples,byte_type);
if delay_samples*hdr.sps + window_samples*hdr.sps > hdr.nsamp
    %disp(['  Window extends beyond this file ', filename]);
end
if delay~=0
    secs=double(jhms2secs(hdr.day,hdr.hour,hdr.min,hdr.sec,hdr.msec)+delay);
    [hdr.day,hdr.hour,hdr.min,hdr.sec,hdr.msec]=secs2jhms(secs);
    hdr.nsamp = count;
end

fclose(fid);
hdr.range=max(seis)-min(seis);

if count~=hdr.nsamp
  %disp(['  Failed to read all data for file ',filename]);
  disp(' ')
  return
end
%keyboard
%[seis,hdr.reduction]=normalize(seis);