diff chordtools/parseinterval.m @ 1:8973548174c1 tip

adding tools to repo

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/chordtools/parseinterval.m	Mon May 06 14:43:47 2013 +0100
@@ -0,0 +1,125 @@
+%
+% PARSEINTERVAL
+% 
+% [degree, accidentals, success, errormessage] = parseinterval(interval, {verbose})
+% 
+% Parse an interval to a degree value and a number of accidentals
+% if accidentals is positive it denotes number of sharps,
+% if it is negative it denotes number of flats.
+% If the omit interval character '*' is found then present is returned as 0 
+% otherwise it is 1. 
+%
+% Success = 1 if symbols parsed correctly, 0 otherwise.
+%
+% If optional argument 'verbose' is 1, function prints any errormessage to 
+% the screen.
+% 
+% returns:  degree      (integer)
+%           accidentals (integer) 
+%           present     (boolean)
+%           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 [degree,accidentals,present,success, errormessage] = parseinterval(interval, verbose)
+
+if nargin < 2
+    verbose = 0;
+end
+
+ilength = length(interval);
+
+errormessage = '';
+accidentals = 0;
+degree = 0;
+success=1;
+present = 1;
+
+index = 1;
+ 
+% if the input string is not empty   
+if (isempty(interval) == 0)
+
+    
+    % check for omit interval '*'
+    if interval(index) == '*' 
+        present = 0;
+        index = index +1;
+    end
+
+
+    tempstring = '';
+    tempindex = 1;
+    % parse the interval string
+    while index <= ilength
+
+        switch interval(index)
+
+            case 'b' % FLAT
+                accidentals = accidentals - 1; %decrement accidental count
+                index = index + 1;
+
+            case '#' % SHARP
+                accidentals = accidentals + 1; %increment accidental count
+                index = index + 1;
+             
+            case {'1','2','3','4','5','6','7','8','9'}
+                % if neither of the above then remaining string should be
+                % an integer degree value
+                %tempstring(tempindex) = interval(index);
+                
+                %tempindex = tempindex+1;
+                %index = index+1;
+                success=1;
+                break
+                
+            otherwise
+                % unrecognised symbol
+                success=0;
+                break; %index = ilength+1;
+        end
+    end
+else
+    success=0;
+end
+
+if success
+
+% convert the degree string to an integer
+    [degree, success] = str2num(interval(index:end)); 
+
+    % check it worked and that the degree is valid
+    if isempty(degree) || (degree <= 0) 
+        success = 0; 
+    end
+end            
+
+if(success==0) % correct interval therefore return success = 1 
+    % if not an integer then the interval string is incorrect
+    errormessage = sprintf(['Error in parseinterval: Unrecognised interval "' interval '"\n']);
+    degree = 0;
+    if verbose == 1
+        fprintf(1, errormessage);
+    end
+    
+end