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: jnifticreate.m
    path of file: ./repos/fieldtrip/external/jnifti
    
    the code of the file until where you have to start completion: function jnii=jnifticreate(varargin)
%
%    jnii=jnifticreate
%       or
%    jnii=jnifticreate('header1', value1, 'header2', value2, ...)
%    jnii=jnifticreate(img, 'header1', value1, ...)
%
%    Create a default JNIfTI structure with default header and image volume
%
%    author: Qianqian Fang (q.fang <at> neu.edu)
%
%    input:
%        img: set the jnii.NIFTIData section
%        'header_i': the header subfield name defined in the JNIfTI
%                    specification, see https://github.com/fangq/jnifti
%        value_i: set the value for the specified JNIfTI header field
%
%    output:
%        jnii: without any input, jnii gives the default jnii header
%              if img is given, jnii also includes the NIFTIData field
%

    
function jnii=jnifticreate(varargin)
%
%    jnii=jnifticreate
%       or
%    jnii=jnifticreate('header1', value1, 'header2', value2, ...)
%    jnii=jnifticreate(img, 'header1', value1, ...)
%
%    Create a default JNIfTI structure with default header and image volume
%
%    author: Qianqian Fang (q.fang <at> neu.edu)
%
%    input:
%        img: set the jnii.NIFTIData section
%        'header_i': the header subfield name defined in the JNIfTI
%                    specification, see https://github.com/fangq/jnifti
%        value_i: set the value for the specified JNIfTI header field
%
%    output:
%        jnii: without any input, jnii gives the default jnii header
%              if img is given, jnii also includes the NIFTIData field
%
%
%    this file is part of JNIfTI specification: https://github.com/fangq/jnifti
%
%    License: Apache 2.0, see https://github.com/fangq/jnifti for details
%


jnii=struct(encodevarname('_DataInfo_'),struct(),'NIFTIHeader',struct(), 'NIFTIData', []);

% jnii.NIFTIHeader.NIIHeaderSize=  0;
% jnii.NIFTIHeader.A75DataTypeName=   'uint8';
% jnii.NIFTIHeader.A75DBName=      '';
% jnii.NIFTIHeader.A75Extend