Mauch MIREX 2010

%

% INTERVAL2SEMITONE

% 

% [semitone, success, errormessage] = interval2semitone(interval, accidental, {verbose})

% 

% Convert an interval and accidentals pair to a semitone value

% 

% Success = 1 if interval converted correctly, 0 otherwise.

% 

% If optional argument 'verbose' is 1, function prints any errormessage to 

% the screen.

% 

% returns:  semitone (string)

%           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 [semitone, success, errormessage] = interval2semitone(interval, accidentals, verbose)

if nargin < 3 

    % verbose defaults 0

    verbose = 0;

end

errormessage = '';

% semitone equivalents for intervals

%           interval   1,2,3,4,5,6,7         

semitonetranslation = [0,2,4,5,7,9,11];

semitone = 0;

success = 1;

if (interval > 0) && (interval < 50)

% semitone value is the number of semitones equivalent to the interval

% added to the number of accidentals (sharps are positive, flats are

% negative) and the number of octaves above the reference note to

% account for extensions 

semitone = semitonetranslation(mod(interval,8) + fix(interval/8)) + accidentals + 12*fix(interval/8);

else

    success = 0;

    errormessage = sprintf('Error in interval2semitone: out of range interval "%d"\n', interval);

    if verbose == 1

        fprintf(1,errormessage);

    end

end