getSacFiles(varargin)

function [varargout] = getSacFiles(varargin)
% [Sacs] = getSacFiles(varargin);
% This function returns a vector of SAC file names given information of 
% the SAC file. The input format relies on the PASSCAL/IRIS file format, 
% which is of the form:
%
% STACODE.*.*.CHAN.YYYY.*JJJ.*SAC
% 
% The file names must include a 3-spance Julian day and year in the file
% name, as well as a year.
% 
% USAGE
% [Seis] = getSacFiles('STATION','CHAN',date1,date2);
% [Seis] = getSacFiles('SAC','CHAN',date1,date2);
% [Seis] = getSacFiles('SAC','SAC',date1,date2);
% [Seis] = getSacFiles('STATION','CHAN',hour1,hour2,Julian day,year);
% [Seis] = getSacFiles('STATION','SAC',hour1,hour2,Julian day,year);
% [Seis] = getSacFiles('SAC','SAC',hour1,hour2,Julian day,year);
%
% INPUT
%
% rec:      The station string as it appears in the .SAC file name. Input
%           may be 'SAC' to specify any .SAC file
% comp:     The channel string, as it appears in the .SAC file name.  Input
%           may be 'SAC', to specify any .SAC file
% date1:    Two options: date1 may be a date-column vector, or a scalar.
%           If date1 is a scalar, it is taken to be the hours into the day.
% date2:    Same as date1.  If date1 is the start time, the date2 is the
%           end time.
% day:      The Julian day of the record.  It must be input only in the
%           case that if date1 and date2 are scalars.
% yr:       The year appearing in the SAC file name. It must input only if
%           date1 and date2 are scalars.
%
% OUTPUT
% 
% Sacs:     A cell array containing the Sac file names that match the
%           requested seismograms.
%
% EXAMPLES
%
% [Sacs] = getSacFiles('NL1','ELN',date1,date2); %get files between date1
%                                                  %and date2
% [Sacs] = getSacFiles('NL1','ELZ',2,4,204,2007); %get files from [2,4],
%                                                   %on Julian day 204, the
%                                                   %year 2007
% [Sacs] = getSacFiles('NL1','ELZ',date1,date2,2007); %year ignored

% Start function
D = dir;
I = not([D.isdir]);
D = D(I);
C = struct2cell(D);
C = {C{1,:}};

% Initialize Seis and Sacs
I       = regexp(C,'SAC');
full    = cellfun(@length,I);
I       = logical(full);
C       = C(I);
Sacs    = C(:); 
ntotal  = length(Sacs);

if(nargin==0)
    
    return;

else

    if(nargin>=1),
        rec     = varargin{1};
        if(~isempty(rec))
            I       = regexp(C,rec);
            full    = cellfun(@length,I);
            I       = logical(full);
            C       = C(I);
            Sacs    =intersect(Sacs,C(:));
        end;
    end;

    if(nargin>=2),
        comp    = varargin{2};
        if(~isempty(comp))
            I       = regexp(C,comp);
            full    = cellfun(@length,I);
            I       = logical(full);
            C       = C(I);
            Sacs    = intersect(Sacs,C(:));
        end;
    end;

    if(nargin>=3),

        date1   = (varargin{3});

        if(~isscalar(date1))
            
            %find the julian day from the date
            boy     = date1;
            boy(2:3)= 1;
            boy(4:6)= 0;
            day     = 1+floor(timediff(date1,boy)./(3600*24));
            day     = sprintf('%s.%.3i%s.','\',day,'\');
            
            %find files with same day
            I       = regexp(C,day);
            full    = cellfun(@length,I);
            I       = logical(full);
            C       = C(I);
            Sacs    = intersect(Sacs,C(:));
            
            %find files with same year
            I       = regexp(C,num2str(date1(1)));
            full    = cellfun(@length,I);
            I       = logical(full);
            C       = C(I);
            Sacs    = intersect(Sacs,C(:));
            
        end;

    end;

    if(nargin>=4),
        date2   = (varargin{4});
    end;

    if(nargin>=5),
        
        day     = sprintf('%s.%.3i%s.','\',varargin{5},'\');
        %day     = num2str(varargin{5});
        I       = regexp(C,day);
        full    = cellfun(@length,I);
        I       = logical(full);
        C       = C(I);
        Sacs    = intersect(Sacs,C(:));

    end;

    if(nargin>=6),

        yr      = num2str(varargin{6});
        I       = regexp(C,yr);
        full    = cellfun(@length,I);
        I       = logical(full);
        C       = C(I);
        Sacs    = intersect(Sacs,C(:));

    end;

end;

Sacs = unique(Sacs);
L    = size(Sacs,1);

if(L==0), disp(sprintf('\nNo files found in current directory')), end;

if(nargout>=1), varargout{1} = Sacs;    end;
if(nargout>=2), varargout{2} = ntotal;  end;