replacing string concatenation by str cells to gain 2x speed in savejson

savejson.m

@@ -150,12 +150,13 @@
 end
 
 % save to a file if FileName is set, suggested by Patrick Rapin
-if(~isempty(jsonopt('FileName','',opt)))
+filename=jsonopt('FileName','',opt);
+if(~isempty(filename))
  if(jsonopt('SaveBinary',0,opt)==1)
- fid = fopen(opt.filename, 'wb');
+ fid = fopen(filename, 'wb');
  fwrite(fid,json);
  else
- fid = fopen(opt.filename, 'wt');
+ fid = fopen(filename, 'wt');
  fwrite(fid,json,'char');
  end
  fclose(fid);
@@ -178,7 +179,7 @@
 
 %%-------------------------------------------------------------------------
 function txt=cell2json(name,item,level,varargin)
-txt='';
+txt={};
 if(~iscell(item))
  error('input is not a cell');
 end
@@ -196,42 +197,43 @@
 bracketlevel=~jsonopt('singletcell',1,varargin{:});
 if(len>bracketlevel)
  if(~isempty(name))
- txt=sprintf('%s"%s": [%s',padding0, checkname(name,varargin{:}),nl); name=''; 
+ txt={padding0, '"', checkname(name,varargin{:}),'": [', nl}; name=''; 
  else
- txt=sprintf('%s[%s',padding0,nl); 
+ txt={padding0, '[', nl};
  end
 elseif(len==0)
  if(~isempty(name))
- txt=sprintf('%s"%s": []',padding0, checkname(name,varargin{:})); name=''; 
+ txt={padding0, '"' checkname(name,varargin{:}) '": []'}; name=''; 
  else
- txt=sprintf('%s[]',padding0); 
+ txt={padding0, '[]'};
  end
 end
 for i=1:dim(1)
  if(dim(1)>1)
- txt=sprintf('%s%s[%s',txt,padding2,nl);
+ txt(end+1:end+3)={padding2,'[',nl};
  end
  for j=1:dim(2)
- txt=sprintf('%s%s',txt,obj2json(name,item{i,j},level+(dim(1)>1)+(len>bracketlevel),varargin{:}));
+ txt{end+1}=obj2json(name,item{i,j},level+(dim(1)>1)+(len>bracketlevel),varargin{:});
  if(j<dim(2))
- txt=sprintf('%s%s',txt,sprintf(',%s',nl));
+ txt(end+1:end+2)={',' nl};
  end
  end
  if(dim(1)>1)
- txt=sprintf('%s%s%s]',txt,nl,padding2);
+ txt(end+1:end+3)={nl,padding2,']'};
  end
  if(i<dim(1))
- txt=sprintf('%s%s',txt,sprintf(',%s',nl));
+ txt(end+1:end+2)={',' nl};
  end
  %if(j==dim(2)) txt=sprintf('%s%s',txt,sprintf(',%s',nl)); end
 end
 if(len>bracketlevel)
- txt=sprintf('%s%s%s]',txt,nl,padding0);
+ txt(end+1:end+3)={nl,padding0,']'};
 end
+txt = sprintf('%s',txt{:});
 
 %%-------------------------------------------------------------------------
 function txt=struct2json(name,item,level,varargin)
-txt='';
+txt={};
 if(~isstruct(item))
  error('input is not a struct');
 end
@@ -251,61 +253,62 @@
 
 if(isempty(item)) 
  if(~isempty(name)) 
- txt=sprintf('%s"%s": []',padding0,checkname(name,varargin{:}));
+ txt={padding0, '"', checkname(name,varargin{:}),'": []'};
  else
- txt=sprintf('%s[]',padding0);
+ txt={padding0, '[]'};
  end
  return;
 end
 if(~isempty(name)) 
  if(forcearray)
- txt=sprintf('%s"%s": [%s',padding0,checkname(name,varargin{:}),nl);
+ txt={padding0, '"', checkname(name,varargin{:}),'": [', nl};
  end
 else
  if(forcearray)
- txt=sprintf('%s[%s',padding0,nl);
+ txt={padding0, '[', nl};
  end
 end
 for j=1:dim(2)
  if(dim(1)>1)
- txt=sprintf('%s%s[%s',txt,padding2,nl);
+ txt(end+1:end+3)={padding2,'[',nl};
  end
  for i=1:dim(1)
  names = fieldnames(item(i,j));
  if(~isempty(name) && len==1 && ~forcearray)
- txt=sprintf('%s%s"%s": {%s',txt,padding1, checkname(name,varargin{:}),nl); 
+ txt(end+1:end+5)={padding1, '"', checkname(name,varargin{:}),'": {', nl};
  else
- txt=sprintf('%s%s{%s',txt,padding1,nl); 
+ txt(end+1:end+3)={padding1, '{', nl};
  end
  if(~isempty(names))
  for e=1:length(names)
- txt=sprintf('%s%s',txt,obj2json(names{e},item(i,j).(names{e}),...
- level+(dim(1)>1)+1+forcearray,varargin{:}));
+ txt{end+1}=obj2json(names{e},item(i,j).(names{e}),...
+ level+(dim(1)>1)+1+forcearray,varargin{:});
  if(e<length(names))
- txt=sprintf('%s%s',txt,',');
+ txt{end+1}=',';
  end
- txt=sprintf('%s%s',txt,nl);
+ txt{end+1}=nl;
  end
  end
- txt=sprintf('%s%s}',txt,padding1);
+ txt(end+1:end+2)={padding1,'}'};
  if(i<dim(1))
- txt=sprintf('%s%s',txt,sprintf(',%s',nl));
+ txt(end+1:end+2)={',' nl};
  end
  end
  if(dim(1)>1)
- txt=sprintf('%s%s%s]',txt,nl,padding2);
+ txt(end+1:end+3)={nl,padding2,']'};
  end
  if(j<dim(2))
- txt=sprintf('%s%s',txt,sprintf(',%s',nl));
+ txt(end+1:end+2)={',' nl};
  end
 end
 if(forcearray)
- txt=sprintf('%s%s%s]',txt,nl,padding0);
+ txt(end+1:end+3)={nl,padding0,']'};
 end
+txt = sprintf('%s',txt{:});
 
 %%-------------------------------------------------------------------------
 function txt=str2json(name,item,level,varargin)
-txt='';
+txt={};
 if(~ischar(item))
  error('input is not a string');
 end
@@ -320,11 +323,11 @@
 
 if(~isempty(name)) 
  if(len>1)
- txt=sprintf('%s"%s": [%s',padding1,checkname(name,varargin{:}),nl);
+ txt={padding1, '"', checkname(name,varargin{:}),'": [', nl};
  end
 else
  if(len>1)
- txt=sprintf('%s[%s',padding1,nl);
+ txt={padding1, '[', nl};
  end
 end
 for e=1:len
@@ -334,18 +337,19 @@
  if(isempty(name))
  obj=['"',val,'"'];
  end
- txt=sprintf('%s%s%s%s',txt,padding1,obj);
+ txt(end+1:end+2)={padding1, obj};
  else
- txt=sprintf('%s%s%s%s',txt,padding0,['"',val,'"']);
+ txt(end+1:end+4)={padding0,'"',val,'"'};
  end
  if(e==len)
  sep='';
  end
- txt=sprintf('%s%s',txt,sep);
+ txt{end+1}=sep;
 end
 if(len>1)
- txt=sprintf('%s%s%s%s',txt,nl,padding1,']');
+ txt(end+1:end+3)={nl,padding1,']'};
 end
+txt = sprintf('%s',txt{:});
 
 %%-------------------------------------------------------------------------
 function txt=mat2json(name,item,level,varargin)

saveubjson.m

@@ -125,8 +125,9 @@
 end
 
 % save to a file if FileName is set, suggested by Patrick Rapin
-if(~isempty(jsonopt('FileName','',opt)))
- fid = fopen(opt.filename, 'wb');
+filename=jsonopt('FileName','',opt);
+if(~isempty(filename))
+ fid = fopen(filename, 'wb');
  fwrite(fid,json);
  fclose(fid);
 end