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function varargout = dspblkrandsrc2(action) 
% DSPBLKRANDSRC2 DSP Blockset Random Source Generator block helper function. 
 
% Copyright 1995-2001 The MathWorks, Inc.  
% $Revision: 1.3 $ $Date: 2001/04/05 15:48:32 $ 
 
blk = gcbh; 
 
if nargin==0, action = 'dynamic'; end 
 
RepMode = get_param(blk,'RepMode'); 
 
switch action 
 case 'icon' 
  % Plotting of icon: 
   
  % Random data: 
  x = (0:.1:.9)'; 
  y = [0.5645 
       0.3024 
       0.7520 
       0.4752 
       0.1684 
       0.5462 
       0.5798 
       0.3904 
       0.8463 
       0.1681]; 
   
  % Axes: 
  x=[x;NaN;0; 0;NaN;0;1]; 
  y=[y;NaN;1;-1;NaN;0;0]; 
   
  varargout(1:2) = {x,y}; 
  
 case 'seed' 
  % Compute (if necessary) seed value 
   
  % There is a structure in Random Source's UserData parameter 
  % that has two fields, Seed and SeedFlag.  They are used as: 
  % Seed: 
  %       This is (a string representation) of the seed value 
  %       that is actually passed into the S-fcn.  This value 
  %       is only equal to the seed in the dialog if the  
  %       repeatabilit mode is 'Specify seed'.  Its default 
  %       value is '-1'. 
  % SeedFlag:  
  %       This flag can have three values: (1) 'SaveSeed' if  
  %       the repeatability mode is 'Repeatable' and a seed 
  %       has already been calculated, (2) 'DoNotSaveSeed' if 
  %       the repeatability mode is 'Specify seed' or 'Not 
  %       repeatable' (and thus the seed field in the user  
  %       data is not the 'official' seed - it's either truly 
  %       not saved, or in the dialog seed) and (3) 'Unset' 
  %       for either a new block or an old block that was 
  %       saved before this functionality change.  The 
  %       default value is 'Unset' 
   
  ud = get_param(blk,'userdata'); 
  ud_old = ud; 
   
  % Currently, if UserData = [] and UserDataPersistent = 'off',  
  % then this is an old block -  that is, one that was saved  
  % before this functionality change. 
  % It seems that for now the userdata is NOT copied into old 
  % blocks from the library block.  Assuming this doesn't 
  % change, detecting an 'old block' is trivial - just check 
  % either field 
  % 
  % If it DOES change, then the following logic will be needed 
  % to detect old blocks: 
  % Change the default value of Seed in the library model file to 
  % '-1', and use the logic below: 
  % if (strcmp(ud.SeedFlag, 'Unset')) 
  %   if (strcmp(get_param(blk,'Seed'),'-1')) 
  %     % This is the library block 
  %     ud.Seed = '1'; 
  %     ud.SeedFlag = 'DoNotSaveSeed';  
  %     set_param(blk,'Seed','1'); 
  %   else 
  %     % This is an 'old' block 
  %     ud.Seed = get_param(blk,'Seed'); 
  %     ud.SeedFlag = 'DoNotSaveSeed';  
  %     set_param(blk,'RepMode','Specify seed'); 
  %   end 
  % end 
  % 
  % Existing R12 models need this block of code to work properly 
  % for R12.1 and possible future releases 
  % 
 
  if isempty(ud), 
    % This is an old block (before R12.1) 
    ud.Seed = get_param(blk,'Seed'); 
    ud.SeedFlag = 'DoNotSaveSeed'; 
     
    % Need to reset the RepMode 
    % (note: this is intentially done 
    %  and without the user necessarily 
    %  being aware of it...) 
    % Note: using dspsafe_set_param below 
    % because sometimes the set_param fails 
    % and we don't want this function to  
    % end here (some tests will fail when 
    % they shouldn't) 
    dspsafe_set_param(blk,'RepMode','Specify seed'); 
  else 
    % This is a new block (R12.1 or later) 
     
    % Create an initial random seed when necessary 
    % return current seed otherwise 
     
    if (strcmp(RepMode,'Specify seed')) 
      % Use seed specified by user 
      ud.Seed = get_param(blk,'Seed'); 
      ud.SeedFlag = 'DoNotSaveSeed';  
     
    elseif (strcmp(RepMode,'Repeatable')) 
      % Only need to change seed if this is a change in mode 
      % That is, if we were already in Repeatable mode, 
      % do not recalculate seed.   
      if strcmp(ud.SeedFlag,'DoNotSaveSeed'), 
        % Just changed to Repeatable mode 
        seedVal = floor(rand(1)*100000); 
        ud.Seed = num2str(seedVal); 
        ud.SeedFlag = 'SaveSeed'; 
      end 
     
    else  
      % Not repeatable: recalculate seed 
      seedVal = floor(rand(1)*100000); 
      ud.Seed = num2str(seedVal); 
      ud.SeedFlag = 'DoNotSaveSeed'; 
    end 
  end 
   
  % update the user data if it changed 
  if ~isequal(ud,ud_old), 
    % Using dspsafe_set_param for same reasons as 
    % above 
    dspsafe_set_param(blk,'userdata',ud); 
  end 
   
  % set the return arg to the seed value 
  varargout = {ud.Seed}; 
   
 case 'dynamic' 
  % Adjust mask enables 
  SrcType = get_param(blk,'SrcType'); 
  InheritMode = strcmp(get_param(blk,'Inherit'),'on'); 
  SampMode = get_param(blk,'SampMode'); 
  enables = get_param(blk,'maskenables'); 
  oldenables=enables; 
   
  % Check for distribution change 
  if strcmp(SrcType,'Gaussian') 
    enables(4:5) = {'on'}; 
    enables(2:3) = {'off'}; 
    enables(6)   = {'on'}; 
  else 
    enables(4:5) = {'off'}; 
    enables(2:3) = {'on'}; 
    enables(6)   = {'on'};	 
  end 
   
  % Check for repeatability mode change 
  if strcmp(RepMode,'Specify seed') 
    enables(7) = {'on'}; 
  else 
    enables(7) = {'off'}; 
  end 
   
  % Check for inherit mode change 
  if InheritMode, 
    enables(9:12)  = {'off'}; 
  elseif (~InheritMode & strcmp(SampMode,'Discrete')) 
    enables(9:12)  = {'on'}; 
  elseif (~InheritMode & strcmp(SampMode,'Continuous')) 
    enables(9)    = {'on'}; 
    enables(10:11) = {'off'}; 
    enables(12)   = {'on'}; 
  end 
 
  % Only reset the enables if they have changed 
  if (~isequal(enables,oldenables)) 
    set_param(blk,'maskenables',enables); 
  end 
   
 otherwise 
  error('dspblkrandsrc2: unhandled action');  
end 
 
% [EOF] dspblkrandsrc2.m