alplib.m

function varargout = alplib(command, varargin)
    % function varargout = alplib(command, varargin)
    % APLIB  controls access to data base of registered ALP DLLs
    % 
    %   command  is one of these keywords: 
    %   'exist', 'delete', 'get', 'set', 'empty', 'select'
    % 
    %   varargin takes additional arguments for one of the commands above
    %
    %   varargout takes the output arguments for the given command
    %
    %   command 'exist': returns true of false depending on the existence of
    %                    a API registration data base. No additional input 
    %                    arguments.
    %
    %   command 'delete': deletes an existing API registration data base. No
    %                     additional input arguments. No output arguments.
    %
    %   command 'get': Searches for specific DB record (specified by tag name in
    %                  first additional argument) or all records (if no additional
    %                  input argument is given). Output is an structure array of
    %                  records found (which may be an empty array if no record is found).    
    %
    %   command 'set': Adds a new registration record to the data base. Additional parameters must
    %                  be pairs of field names and content. All fields must be supplied: 
    %                  'tag': tag name (must be unique in the DB)
    %                  'classname': name of the associated API class
    %                  'pseudoDLL': true if DLL loading is only simulated                  
    %                  'dllfile': full path and name to the DLL file,
    %                             for use with loadlibrary (can be empty if pseudoDLL is true)
    %                  'protofile': M-file that contains the DLL function prototypes
    %                  'protofunc': function handle calling the protofile, for use with loadlibrary
    %                  'arch': architecture, either 'win32' or 'win64'. Use to prevent loading of
    %                          wrong architecture.
    %
    %   command 'empty': returns an empty structure array of registration records. No additional
    %                    input arguments.
    %
    %   command 'select': Interactive API selection by user, prompting string can be supplied by 
    %                     additional argument. Will return selected record structure or empty if
    %                     user aborted selection.
    %
    % File information:
    %   version 1.0 (feb 2014)
    %   (c) Martin Vogel
    %   email: matlab@martin-vogel.info
    %
    % Revision history:
    %   1.0 (feb 2014) initial release version
    %

    libfilename = [fileparts(mfilename('fullpath')), '\alplib.mat'];

    switch command
        case 'exist'
            % check whether database exist
            varargout{1} = exist(libfilename, 'file');

        case 'delete'
            % delete database
            delete(libfilename);
            
        case 'get'
            % get all or specific record(s)
            if alplib('exist')
                salplibs = load(libfilename);
                if isfield(salplibs, 'alplibs')
                    alplibs = salplibs.alplibs;
                else
                    % house keeping: delete wrong db
                    alplib('delete');
                    alplibs = alplib('empty');
                end
            else
                alplibs = alplib('empty');
            end
            
            % filter for supplied tag
            if nargin>1 && ischar(varargin{1})
                si = 1;
                while si<=length(alplibs)
                    if ~strcmp(alplibs(si).tag, varargin{1})
                        alplibs(si) = [];
                    else
                        si = si+1;
                    end
                end
            end
            varargout{1} = alplibs;
        
        case 'set'
            % add new record (must have unique tag!)
            
            % fill structure 
            al = alplib('empty');
            if length(varargin)>=2
                al(end+1).(varargin{1}) = varargin{2};
            end
            for vi = 3:2:length(varargin)
                al.(varargin{vi}) = varargin{vi+1};
            end
            
            % check for unique tag
            altest = alplib('get', al.tag);
            if length(altest) > 1
                varargout{1} = false;
                return;
            end
            
            % add record to lib and save
            alplibs = alplib('get');
            alplibs(end+1) = al; %#ok<NASGU>
            save(libfilename, 'alplibs');
            varargout{1} = true;
            
        case 'empty'
            % return an empty record array
            alplibs = struct('tag', {}, ...
                             'classname', {}, ...
                             'pseudoDLL', {}, ...
                             'dllfile', {}, ...
                             'protofile', {}, ...
                             'protofunc', {}, ... 
                             'arch', {});
            varargout{1} = alplibs;
            
        case 'select'
            % interactively select one record
            alplibs = alplib('get');
            infostr = {};
            for ai = 1:length(alplibs)
                if alplibs(ai).pseudoDLL
                    infostr{end+1} = sprintf('P %s (class: %s): %s', ...
                                             alplibs(ai).tag, ...
                                             alplibs(ai).classname, alplibs(ai).dllfile);  %#ok<AGROW>
                else
                    infostr{end+1} = sprintf('  %s (class: %s): %s', ...
                                             alplibs(ai).tag, ...
                                             alplibs(ai).classname, alplibs(ai).dllfile);  %#ok<AGROW>
                end
            end
            if isempty(infostr)
                infostr{1} = 'No DLL installed';
                selection = 0;
            else
                selection = -1;
            end
            if nargin>1 
                promptstr = varargin{1};
            else
                promptstr = 'Please select API:';
            end
            [tempselection, ok] = listdlg('ListString', infostr, ...
                'SelectionMode', 'single', ...
                'Name', 'Please choose...', ...
                'PromptString', promptstr, ...
                'ListSize', [500, 150]);
            if selection == -1
                selection = tempselection;
            end
            varargout{1} = selection;
            varargout{2} = ok;
            if (ok~=0) && selection>0 && length(alplibs)>=selection
                varargout{3} = alplibs(selection);
            else
                varargout{3} = [];
            end
        
    end
    
end