function dyn_data_01=read_variables(file_name_01,var_names_01,dyn_data_01,xls_sheet,xls_range)

% function dyn_data_01=read_variables(file_name_01,var_names_01,dyn_data_01,xls_sheet,xls_range)
% Read data
%
% INPUTS
%    file_name_01:    file name
%    var_names_01:    variables name
%    dyn_data_01:     
%    xls_sheet:       Excel sheet name
%    xls_range:       Excel range specification
%
% OUTPUTS
%    dyn_data_01:
%
% SPECIAL REQUIREMENTS
% all local variables have complicated names in order to avoid name
% conflicts with possible user variable names

% Copyright (C) 2005-2011 Dynare Team
%
% This file is part of Dynare.
%
% Dynare is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
%
% Dynare 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
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with Dynare.  If not, see <http://www.gnu.org/licenses/>.


old_pwd = pwd;
[path_name_02,file_name_02,ext_name_02] = fileparts(file_name_01);
if ~isempty(path_name_02)
    file_name_01 = [file_name_02, ext_name_02];
    cd(path_name_02)
end

dyn_size_01 = size(dyn_data_01,1);
var_size_01 = size(var_names_01,1);
if exist([file_name_01 '.m'],'file')
    file_name_02 = [file_name_01 '.m'];
    dyn_instr_01 = file_name_01;
    eval(dyn_instr_01);
    for dyn_i_01=1:var_size_01
        dyn_tmp_01 = eval(var_names_01(dyn_i_01,:));
        if length(dyn_tmp_01) > dyn_size_01 && dyn_size_01 > 0
            cd(old_pwd)
            error('data size is too large')
        end
        dyn_data_01(:,dyn_i_01) = dyn_tmp_01;
    end
elseif exist([file_name_01 '.mat'],'file')
    file_name_02 = [file_name_01 '.mat'];
    s = load(file_name_01);
    for dyn_i_01=1:var_size_01
        dyn_tmp_01 = s.(deblank(var_names_01(dyn_i_01,:)));
        if length(dyn_tmp_01) > dyn_size_01 && dyn_size_01 > 0
            cd(old_pwd)
            error('data size is too large')
        end
        dyn_data_01(:,dyn_i_01) = dyn_tmp_01;
    end
elseif exist([file_name_01 '.xls'],'file')
    file_name_02 = [file_name_01 '.xls'];
    [num,txt,raw] = xlsread(file_name_01,xls_sheet,xls_range);
    for dyn_i_01=1:var_size_01
        iv = strmatch(var_names_01(dyn_i_01,:),raw(1,:),'exact');
        dyn_tmp_01 = [raw{2:end,iv}]';
        if length(dyn_tmp_01) > dyn_size_01 && dyn_size_01 > 0
            cd(old_pwd)
            error('data size is too large')
        end
        dyn_data_01(:,dyn_i_01) = dyn_tmp_01;
    end
else
    cd(old_pwd)
    error(['Can''t find datafile: ' file_name_01 ]);
end
cd(old_pwd)
disp(sprintf('Loading %d observations from %s\n',...
             size(dyn_data_01,1),file_name_02))