matthiasm@8: %
matthiasm@8: %PARSECHORD parse chord symbol to its constituent string elements
matthiasm@8: % 
matthiasm@8: % [rootnote, shorthand, degreelist,
matthiasm@8: %              bass, success, errormessage] = parsechord(chord, {verbose})
matthiasm@8: % 	
matthiasm@8: % Parses the chord symbol string "chord" into its separate string elements. 
matthiasm@8: % 
matthiasm@8: % NOTE: This function does not check validity of the chord elements, it
matthiasm@8: % merely separates them according to the chord syntax. 
matthiasm@8: % To obtain chord elements with included validity check use GETCHORDINFO.
matthiasm@8: %
matthiasm@8: % Success = 1 if symbols parsed correctly, 0 otherwise.
matthiasm@8: %
matthiasm@8: % If optional argument 'verbose' is 1, function prints any errormessage to 
matthiasm@8: % the screen.
matthiasm@8: % 	
matthiasm@8: % returns:  rootnote        (note string)
matthiasm@8: %           shorthand       (shorthand string)
matthiasm@8: %           degreelist      (degree-list string)
matthiasm@8: %           bass            (degree string)
matthiasm@8: %           success         (boolean)
matthiasm@8: %           errormessage    (string)
matthiasm@8: %
matthiasm@8: % See also: getchordinfo                     
matthiasm@8: %
matthiasm@8: % Author: Christopher Harte,  August 2005
matthiasm@8: % 
matthiasm@8: % Copyright: Centre for Digital Music, Queen Mary University of London 2005 
matthiasm@8: %
matthiasm@8: % This file is part of the C4DM Chord Toolkit.  
matthiasm@8: %
matthiasm@8: % The C4DM Chord Toolkit is free software; you can redistribute it and/or 
matthiasm@8: % modify it under the terms of the GNU General Public License as published 
matthiasm@8: % by the Free Software Foundation; either version 2 of the License, or
matthiasm@8: % (at your option) any later version.
matthiasm@8: %
matthiasm@8: % The C4DM Chord Toolkit is distributed in the hope that it will be useful,
matthiasm@8: % but WITHOUT ANY WARRANTY; without even the implied warranty of
matthiasm@8: % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
matthiasm@8: % GNU General Public License for more details.
matthiasm@8: %
matthiasm@8: % You should have received a copy of the GNU General Public License
matthiasm@8: % along with the C4DM Toolkit; if not, write to the Free Software
matthiasm@8: % Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
matthiasm@8: 
matthiasm@8: %		
matthiasm@8: function  [rootnote, shorthand, degrees, bass, success, errormessage] = parsechord(chord, verbose)
matthiasm@8: 	
matthiasm@8: % set verbose default to 0
matthiasm@8: if nargin <2
matthiasm@8:     verbose = 0;
matthiasm@8: end
matthiasm@8: 
matthiasm@8: ilength = length(chord);
matthiasm@8: 
matthiasm@8: % initialise variables
matthiasm@8: errormessage = '';
matthiasm@8: rootnote = '';
matthiasm@8: shorthand = '';
matthiasm@8: degrees = '';
matthiasm@8: bass = '';
matthiasm@8: 
matthiasm@8: success = 1;
matthiasm@8: index = 1;
matthiasm@8: 
matthiasm@8: 
matthiasm@8: % check for 'no chord' symbol
matthiasm@8: if chord(index) == 'N'
matthiasm@8:     rootnote = chord(index);
matthiasm@8:     index = index +1;
matthiasm@8:     % check to see there are no further characters
matthiasm@8:     if(index<=ilength)
matthiasm@8:         errormessage = sprintf(['Error in parsechord: \nExtra characters after "no chord" symbol "' chord '"\n']); 
matthiasm@8:         success = 0;
matthiasm@8:     end
matthiasm@8: else
matthiasm@8: % parse thechord symbol
matthiasm@8: 
matthiasm@8:     % the first part of the symbol before a switch character should be the root note
matthiasm@8:     while ((index <=ilength ))
matthiasm@8:     
matthiasm@8:         if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
matthiasm@8:            (chord(index) ==  '(') || (chord(index) ==  ')')
matthiasm@8:             
matthiasm@8:             break
matthiasm@8:         end
matthiasm@8: 
matthiasm@8:         rootnote(index) = chord(index);
matthiasm@8:         index = index+1;
matthiasm@8:     
matthiasm@8:         if(index > ilength) || (chord(index) == '/')
matthiasm@8:             % if chord is a rootnote on its own or with just a bass note 
matthiasm@8:             % then it is a major chord therefore set shorthand to 'maj'
matthiasm@8:             shorthand = 'maj';
matthiasm@8:         end
matthiasm@8:     end
matthiasm@8:     
matthiasm@8:     % initialise booleans to record which switch characters we have found
matthiasm@8:     colon = 0;
matthiasm@8:     openbracket = 0;
matthiasm@8:     closebracket = 0;
matthiasm@8:     slash = 0;
matthiasm@8:     
matthiasm@8:     % parse the rest of the chord symbol
matthiasm@8:     while(index <= ilength)
matthiasm@8:         
matthiasm@8:         % reset temporary index 
matthiasm@8:         tempindex = 1;
matthiasm@8:         
matthiasm@8:        switch(chord(index))
matthiasm@8:        
matthiasm@8:            case ':'  
matthiasm@8:                         
matthiasm@8:                % if we find a colon after any switch characters have 
matthiasm@8:                % already occured then the symbol is incorrect 
matthiasm@8:                if (colon || openbracket || closebracket || slash)
matthiasm@8:                     errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
matthiasm@8:                     success = 0;
matthiasm@8:                     index = ilength+1;
matthiasm@8:                else
matthiasm@8:                 
matthiasm@8:                    % found the first instance of a colon character
matthiasm@8:                    colon = 1;
matthiasm@8:                    
matthiasm@8:                    index = index +1;
matthiasm@8:                    
matthiasm@8:                    if(index > ilength)
matthiasm@8:                         errormessage = sprintf(['Error in parsechord: \nFound ":" at end of chord string "' chord '"\n']); 
matthiasm@8:                         success = 0; 
matthiasm@8:                    end
matthiasm@8:                    % colon should be followed by a shorthand string or
matthiasm@8:                    % a degree list contained in brackets
matthiasm@8:                    while (index <= ilength)
matthiasm@8:                        
matthiasm@8:                        if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
matthiasm@8:                           (chord(index) ==  '(') || (chord(index) ==  ')')
matthiasm@8: 
matthiasm@8:                            break
matthiasm@8:                        end
matthiasm@8: 
matthiasm@8:                        % copy character into shorthand
matthiasm@8:                        shorthand(tempindex) = chord(index);
matthiasm@8:                        index = index +1;
matthiasm@8:                        tempindex = tempindex +1;
matthiasm@8: 
matthiasm@8:                    end
matthiasm@8:                
matthiasm@8:                end
matthiasm@8:                
matthiasm@8:            case '('
matthiasm@8:                
matthiasm@8:                % if we have had a colon but no other switch charaters then
matthiasm@8:                % an open bracket signifies the start of the degree list
matthiasm@8:                if (colon && ~slash && ~closebracket && ~openbracket) 
matthiasm@8:                    
matthiasm@8:                    openbracket = 1;
matthiasm@8:                    
matthiasm@8:                    index = index +1;
matthiasm@8:                    
matthiasm@8:                    while (index <= ilength)
matthiasm@8: 
matthiasm@8:                        if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
matthiasm@8:                           (chord(index) ==  '(') || (chord(index) ==  ')')
matthiasm@8: 
matthiasm@8:                            break
matthiasm@8:                        end
matthiasm@8:                        
matthiasm@8:                        % copy character into degrees
matthiasm@8:                        degrees(tempindex) = chord(index);
matthiasm@8:                        index = index +1;
matthiasm@8:                        tempindex = tempindex +1;
matthiasm@8: 
matthiasm@8:                    end
matthiasm@8:                    
matthiasm@8:                    if(index > ilength)
matthiasm@8:                         errormessage = sprintf(['Error in parsechord: \nDegree list brackets not closed in chord "' chord '"\n']); 
matthiasm@8:                         success = 0; 
matthiasm@8:                    end
matthiasm@8:                    
matthiasm@8:                else
matthiasm@8:                    errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
matthiasm@8:                    success = 0;
matthiasm@8:                    index = ilength +1;
matthiasm@8:                end
matthiasm@8:                
matthiasm@8:            case ')'
matthiasm@8:                
matthiasm@8:                
matthiasm@8:                % if we find a closing bracket then we should either be at
matthiasm@8:                % the end of the symbol or there should be a slash to follow
matthiasm@8:                if (colon && openbracket && ~slash && ~closebracket) 
matthiasm@8:                    
matthiasm@8:                    closebracket = 1;
matthiasm@8:                    index = index +1;
matthiasm@8:                    
matthiasm@8:                else
matthiasm@8:                    errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
matthiasm@8:                    success = 0;
matthiasm@8:                    index = ilength +1;
matthiasm@8:                end
matthiasm@8:                
matthiasm@8:                % check to see that the brackets contained something
matthiasm@8:                if isempty(degrees)
matthiasm@8:                    errormessage = sprintf(['Error in parsechord: \nBrackets contain no degrees in chord "' chord '"\n']); 
matthiasm@8:                    success = 0;
matthiasm@8:                    index = ilength +1;
matthiasm@8:                end
matthiasm@8:                
matthiasm@8:                
matthiasm@8:            case '/'
matthiasm@8:                % forward slash should be followed by a degree string
matthiasm@8:               
matthiasm@8:                    slash = 1;
matthiasm@8: 
matthiasm@8:                    % move on to next character to process the expected bass degree
matthiasm@8:                    index = index +1;
matthiasm@8:                                      
matthiasm@8:                    % check that we haven't overun the end of the symbol string
matthiasm@8:                    if(index > ilength)
matthiasm@8:                         errormessage = sprintf(['Error in parsechord: \nNo bass degree "/" at end of chord "' chord '"\n']); 
matthiasm@8:                         success = 0; 
matthiasm@8:                    end
matthiasm@8:                    
matthiasm@8:                    % check that if we have had an open bracket that it also
matthiasm@8:                    % had a closed bracket
matthiasm@8:                    if(xor(openbracket,closebracket))
matthiasm@8:                         errormessage = sprintf(['Error in parsechord: \nFound "/" before closing bracket in chord "' chord '"\n']); 
matthiasm@8:                         success = 0; 
matthiasm@8:                         index = ilength +1;
matthiasm@8:                    end
matthiasm@8: 
matthiasm@8:                    % check that the previous character was not a ':'
matthiasm@8:                    if(chord(index-2) == ':')
matthiasm@8:                         errormessage = sprintf(['Error in parsechord: \nFound "/" directly after ":" in chord "' chord '"\n']); 
matthiasm@8:                         success = 0; 
matthiasm@8:                         index = ilength +1;
matthiasm@8:                    end
matthiasm@8: 
matthiasm@8:                    
matthiasm@8:                    while( index <= ilength )
matthiasm@8:                        
matthiasm@8:                        % if we find a switch character after a slash then
matthiasm@8:                        % the symbol is incorrect
matthiasm@8:                        if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
matthiasm@8:                           (chord(index) ==  '(') || (chord(index) ==  ')')
matthiasm@8:          
matthiasm@8:                            errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
matthiasm@8:                            success = 0;
matthiasm@8:                            index = ilength +1;
matthiasm@8:                        
matthiasm@8:                        else
matthiasm@8: 
matthiasm@8:                            % copy remaining characters into bass
matthiasm@8:                            bass(tempindex) = chord(index);
matthiasm@8:                            index = index +1;
matthiasm@8:                            tempindex = tempindex +1;
matthiasm@8:                        end
matthiasm@8:                    end
matthiasm@8:                             
matthiasm@8:            otherwise
matthiasm@8:                 errormessage = sprintf(['Error in parsechord: \nUnrecognised chord "' chord '"\n']); 
matthiasm@8:                 success = 0;
matthiasm@8:                 index = ilength + 1;
matthiasm@8:        end
matthiasm@8:             
matthiasm@8:     end
matthiasm@8: end            
matthiasm@8:             
matthiasm@8: if (verbose == 1) && (success == 0)
matthiasm@8:     fprintf(1,errormessage);
matthiasm@8: end
matthiasm@8:         
matthiasm@8: