Mauch MIREX 2010

%

% PARSEDEGREE

% 

% [interval, accidentals, success, errormessage] = parsedegree(degree, {verbose})

% 

% Parse a degree to an interval 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 degree 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:  interval    (integer)

%           accidentals (integer) 

%           present     (boolean)

%           success     (boolean)

%           errormessage (string)  

%

% Author: Christopher Harte,  August 2005

% 

% Copyright: Centre for Digital Music, Queen Mary University of London 2005 

%

% This file is part of the C4DM Chord Toolkit.  

%

% 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 [interval,accidentals,present,success, errormessage] = parsedegree(degree, verbose)

if nargin < 2

    verbose = 0;

end

ilength = length(degree);

errormessage = '';

accidentals = 0;

interval = 0;

success=1;

present = 1;

index = 1;

% if the input string is not empty   

if (isempty(degree) == 0)

    % check for omit degree '*'

    if degree(index) == '*' 

        present = 0;

        index = index +1;

    end

    tempstring = '';

    tempindex = 1;

    % parse the degree string

    while index <= ilength

        switch degree(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 interval value

                tempstring(tempindex) = degree(index);

                tempindex = tempindex+1;

                index = index+1;

            otherwise

                % unrecognised symbol

                success=0;

                index = ilength+1;

        end

    end

else

    success=0;

end

if success

% convert the interval string to an integer

    [interval, success] = str2num(tempstring); 

    % check it worked and that the interval is valid

    if isempty(interval) || (interval <= 0) 

        success = 0; 

    end

end            

if(success==0) % correct degree therefore return success = 1 

    % if not an integer then the degree string is incorrect

    errormessage = sprintf(['Error in parsedegree: Unrecognised degree "' degree '"\n']);

    interval = 0;

    if verbose == 1

        fprintf(1, errormessage);

    end

end