You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gifti.m
    path of file: ./repos/CBIG/external_packages/matlab/non_default_packages/palm/palm-alpha109/fileio/@gifti
    
    the code of the file until where you have to start completion: function this = gifti(varargin)
% GIfTI Geometry file format class
% Geometry format under the Neuroimaging Informatics Technology Initiative
% (NIfTI):
%                 http://www.nitrc.org/projects/gifti/
%                      http://nifti.nimh.nih.gov/
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% Guillaume Flandin
% $Id: gifti.m 6347 2015-02-24 17:59:16Z guillaume $

switch nargin
    
    case 0
        this = giftistruct;
        this = class(this,'gifti');
        
    case 1
        if isa(varargin{1},'gifti')
            this = varargin{1};
            

    
function this = gifti(varargin)
% GIfTI Geometry file format class
% Geometry format under the Neuroimaging Informatics Technology Initiative
% (NIfTI):
%                 http://www.nitrc.org/projects/gifti/
%                      http://nifti.nimh.nih.gov/
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% Guillaume Flandin
% $Id: gifti.m 6347 2015-02-24 17:59:16Z guillaume $

switch nargin
    
    case 0
        this = giftistruct;
        this = class(this,'gifti');
        
    case 1
        if isa(varargin{1},'gifti')
            this = varargin{1};
            
        elseif isstruct(varargin{1})
            f       = {'faces', 'face', 'tri' 'vertices', 'vert', 'pnt', 'cdata', 'indices'};
            ff      = {'faces', 'faces', 'faces', 'vertices', 'vertices', 'vertices', 'cdata', 'indices'};
            [c, ia] = intersect(f,fieldnames(varargin{1}));
            if ~isempty(c)
                this = gifti;
                for i=1:length(c)
                    this = subsasgn(this,...
                        struct('type','.','subs',ff{ia(i)}),...
                        varargin{1}.(c{i}));
                end