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: jsonset.m
    path of file: ./repos/fieldtrip/external/jsonlab
    
    the code of the file until where you have to start completion: function json=jsonset(fname,mmap,varargin)
%
% json=jsonset(fname,mmap,'$.jsonpath1',newval1,'$.jsonpath2','newval2',...)
%
% Fast writing of JSON data records to stream or disk using memory-map 
% (mmap) returned by loadjson/loadbj and JSONPath-like keys
%
% authors:Qianqian Fang (q.fang <at> neu.edu)
% initially created on 2022/02/02
%
% input:
%      fname: a JSON/BJData/UBJSON string or stream, or a file name
%      mmap: memory-map returned by loadjson/loadbj of the same data
%            important: mmap must be produced from the same file/string,
%            otherwise calling this function may cause data corruption
%      '$.jsonpath1,2,3,...':  a series of strings in the form of JSONPath
%            as the key to each of the record to be written
%
% output:
%      json: the modified JSON string or, in the case fname is a filename,
%            the cell string made of jsonpaths that are successfully
%            written
%
% examples:
%      % create test data
%       d.arr={[1,2],'a',struct('c',2)}; d.obj=struct('k','test') 
%      % convert to json string
%       str=savejson('',d,'compact',1)
%      % parse and return mmap
%       [dat, mmap]=loadjson(str);
%      % display mmap entries
%       savejson('',mmap)
%      % replace value using mmap
%       json=jsonset(str,mmap,'$.arr.[2].c','5')
%      % save same json string to file (must set savebinary 1)
%       savejson('',d,'filename','file.json','compact',1,'savebinary',1);
%      % fast write to file
%       json=jsonset('file.json',mmap,'$.arr.[2].c','5')
%
% license:
%     BSD or GPL version 3, see LICENSE_{BSD,GPLv3}.txt files for details 
%

    
function json=jsonset(fname,mmap,varargin)
%
% json=jsonset(fname,mmap,'$.jsonpath1',newval1,'$.jsonpath2','newval2',...)
%
% Fast writing of JSON data records to stream or disk using memory-map 
% (mmap) returned by loadjson/loadbj and JSONPath-like keys
%
% authors:Qianqian Fang (q.fang <at> neu.edu)
% initially created on 2022/02/02
%
% input:
%      fname: a JSON/BJData/UBJSON string or stream, or a file name
%      mmap: memory-map returned by loadjson/loadbj of the same data
%            important: mmap must be produced from the same file/string,
%            otherwise calling this function may cause data corruption
%      '$.jsonpath1,2,3,...':  a series of strings in the form of JSONPath
%            as the key to each of the record to be written
%
% output:
%      json: the modified JSON string or, in the case fname is a filename,
%            the cell string made of jsonpaths that are successfully
%            written
%
% examples:
%      % create test data
%       d.arr={[1,2],'a',struct('c',2)}; d.obj=struct('k','test') 
%      % convert to json string
%       str=savejson('',d,'compact',1)
%      % parse and return mmap
%       [dat, mmap]=loadjson(str);
%      % display mmap entries
%       savejson('',mmap)
%      % replace value using mmap
%       json=jsonset(str,mmap,'$.arr.[2].c','5')
%      % save same json string to file (must set savebinary 1)
%       savejson('',d,'filename','file.json','compact',1,'savebinary',1);
%      % fast write to file
%       json=jsonset('file.json',mmap,'$.arr.[2].c','5')
%
% license:
%     BSD or GPL version 3, see LICENSE_{BSD,GPLv3}.txt files for details 
%
% -- this function is part of JSONLab toolbox (http://iso2mesh.sf.net/cgi-bin/index.cgi?jsonlab)
%

if(regexp(fname,'^\s*(?:\[.*\])|(?:\{.*\})\s*$','once'))
    inputstr=fname;
else
    if(~exist('memmapfile','file'))
        fid=fopen(fname,'r+b');
    end