comparison chordtools/parsenote.m @ 1:8973548174c1 tip

adding tools to repo

+%
+% PARSENOTE
+% 
+% [natural, accidentals, success, errormessage] = parsenote(note, {verbose})
+% 
+% Parse a note to a natural character value and a number of accidentals
+% if accidentals is positive it denotes number of sharps,
+% if it is negative it denotes number of flats.
+%
+% Success = 1 if symbols parsed correctly, 0 otherwise.
+%
+% If optional argument 'verbose' is 1, function prints any errormessage to 
+% the screen.
+% 
+% returns:  natural     (char)
+%           accidentals (integer) 
+%           success     (boolean)
+%           errormessage (string)
+%
+% Author: Christopher Harte, March 2009
+% 
+% Copyright: Centre for Digital Music, Queen Mary University of London 2005 
+%
+% This file is part of the C4DM Chord Toolkit V2.0  
+%
+% The C4DM Chord Toolkit 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 2 of the License, or
+% (at your option) any later version.
+%
+% The C4DM Chord Toolkit 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 the C4DM Toolkit; if not, write to the Free Software
+% Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+%
+function [natural,accidentals,success, errormessage] = parsenote(note, verbose)
+
+if nargin < 2
+    verbose = 0;
+end
+
+errormessage = '';
+
+ilength = length(note);
+
+accidentals = 0;
+natural = [];
+success=1;
+
+index = 1;
+
+if (isempty(note))  % if we have been passed an empty string
+    success=0;
+
+else  % parse the note string
+  
+    switch(note(index))
+
+        case {'A','B','C','D','E','F','G'}
+
+            %first character should be a natural
+            natural = note(index);
+            index= index+1;
+
+            %remaining characters should be sharps or flats
+            while index <= ilength
+
+                switch note(index)
+
+                    case 'b' % FLAT
+                        accidentals = accidentals - 1; %decrement accidental count
+                        index = index + 1;
+
+                    case '#' % SHARP
+                        accidentals = accidentals + 1; %increment accidental count
+                        index = index + 1;
+
+                    otherwise
+                        % if neither of the above then the note is incorrect
+                        success=0;
+                        index = ilength+1;
+                end
+            end
+
+        otherwise
+            success=0;        
+    end
+end
+    
+if(success==0) % correct note therefore return success = 1 
+    % if not an integer then the note string is incorrect
+    errormessage = sprintf(['Error in parsenote: Unrecognised note "' note '"\n']); 
+    
+    if verbose ==1
+        fprintf(1,errormessage);
+    end
+end