savejson.m

function json=savejson(rootname,obj,varargin)
%
% json=savejson(rootname,obj,filename)
%    or
% json=savejson(rootname,obj,opt)
% json=savejson(rootname,obj,'param1',value1,'param2',value2,...)
%
% convert a MATLAB object (cell, struct or array) into a JSON (JavaScript
% Object Notation) string
%
% author: Qianqian Fang (fangq<at> nmr.mgh.harvard.edu)
% created on 2011/09/09
%
% $Id$
%
% input:
%      rootname: the name of the root-object, when set to '', the root name
%        is ignored, however, when opt.ForceRootName is set to 1 (see below),
%        the MATLAB variable name will be used as the root name.
%      obj: a MATLAB object (array, cell, cell array, struct, struct array,
%      class instance).
%      filename: a string for the file name to save the output JSON data.
%      opt: a struct for additional options, ignore to use default values.
%        opt can have the following fields (first in [.|.] is the default)
%
%        opt.FileName [''|string]: a file name to save the output JSON data
%        opt.FloatFormat ['%.10g'|string]: format to show each numeric element
%                         of a 1D/2D array;
%        opt.ArrayIndent [1|0]: if 1, output explicit data array with
%                         precedent indentation; if 0, no indentation
%        opt.ArrayToStruct[0|1]: when set to 0, savejson outputs 1D/2D
%                         array in JSON array format; if sets to 1, an
%                         array will be shown as a struct with fields
%                         "_ArrayType_", "_ArraySize_" and "_ArrayData_"; for
%                         sparse arrays, the non-zero elements will be
%                         saved to _ArrayData_ field in triplet-format i.e.
%                         (ix,iy,val) and "_ArrayIsSparse_" will be added
%                         with a value of 1; for a complex array, the 
%                         _ArrayData_ array will include two columns 
%                         (4 for sparse) to record the real and imaginary 
%                         parts, and also "_ArrayIsComplex_":1 is added. 
%        opt.ParseLogical [0|1]: if this is set to 1, logical array elem
%                         will use true/false rather than 1/0.
%        opt.NoRowBracket [1|0]: if this is set to 1, arrays with a single
%                         numerical element will be shown without a square
%                         bracket, unless it is the root object; if 0, square
%                         brackets are forced for any numerical arrays.
%        opt.ForceRootName [0|1]: when set to 1 and rootname is empty, savejson
%                         will use the name of the passed obj variable as the 
%                         root object name; if obj is an expression and 
%                         does not have a name, 'root' will be used; if this 
%                         is set to 0 and rootname is empty, the root level 
%                         will be merged down to the lower level.
%        opt.Inf ['"$1_Inf_"'|string]: a customized regular expression pattern
%                         to represent +/-Inf. The matched pattern is '([-+]*)Inf'
%                         and $1 represents the sign. For those who want to use
%                         1e999 to represent Inf, they can set opt.Inf to '$11e999'
%        opt.NaN ['"_NaN_"'|string]: a customized regular expression pattern
%                         to represent NaN
%        opt.JSONP [''|string]: to generate a JSONP output (JSON with padding),
%                         for example, if opt.JSONP='foo', the JSON data is
%                         wrapped inside a function call as 'foo(...);'
%        opt.UnpackHex [1|0]: conver the 0x[hex code] output by loadjson 
%                         back to the string form
%        opt.SaveBinary [0|1]: 1 - save the JSON file in binary mode; 0 - text mode.
%        opt.Compact [0|1]: 1- out compact JSON format (remove all newlines and tabs)
%
%        opt can be replaced by a list of ('param',value) pairs. The param 
%        string is equivallent to a field in opt and is case sensitive.
% output:
%      json: a string in the JSON format (see http://json.org)
%
% examples:
%      jsonmesh=struct('MeshNode',[0 0 0;1 0 0;0 1 0;1 1 0;0 0 1;1 0 1;0 1 1;1 1 1],... 
%               'MeshTetra',[1 2 4 8;1 3 4 8;1 2 6 8;1 5 6 8;1 5 7 8;1 3 7 8],...
%               'MeshTri',[1 2 4;1 2 6;1 3 4;1 3 7;1 5 6;1 5 7;...
%                          2 8 4;2 8 6;3 8 4;3 8 7;5 8 6;5 8 7],...
%               'MeshCreator','FangQ','MeshTitle','T6 Cube',...
%               'SpecialData',[nan, inf, -inf]);
%      savejson('jmesh',jsonmesh)
%      savejson('',jsonmesh,'ArrayIndent',0,'FloatFormat','\t%.5g')
%
% 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(nargin==1)
   varname=inputname(1);
   obj=rootname;
   if(isempty(varname)) 
      varname='root';
   end
   rootname=varname;
else
   varname=inputname(2);
end
if(length(varargin)==1 && ischar(varargin{1}))
   opt=struct('FileName',varargin{1});
else
   opt=varargin2struct(varargin{:});
end
opt.IsOctave=exist('OCTAVE_VERSION','builtin');
rootisarray=0;
rootlevel=1;
forceroot=jsonopt('ForceRootName',0,opt);
if((isnumeric(obj) || islogical(obj) || ischar(obj) || isstruct(obj) || ...
        iscell(obj) || isobject(obj)) && isempty(rootname) && forceroot==0)
    rootisarray=1;
    rootlevel=0;
else
    if(isempty(rootname))
        rootname=varname;
    end
end
if((isstruct(obj) || iscell(obj))&& isempty(rootname) && forceroot)
    rootname='root';
end

whitespaces=struct('tab',sprintf('\t'),'newline',sprintf('\n'),'sep',sprintf(',\n'));
if(jsonopt('Compact',0,opt)==1)
    whitespaces=struct('tab','','newline','','sep',',');
end
if(~isfield(opt,'whitespaces_'))
    opt.whitespaces_=whitespaces;
end

nl=whitespaces.newline;

json=obj2json(rootname,obj,rootlevel,opt);
if(rootisarray)
    json=sprintf('%s%s',json,nl);
else
    json=sprintf('{%s%s%s}\n',nl,json,nl);
end

jsonp=jsonopt('JSONP','',opt);
if(~isempty(jsonp))
    json=sprintf('%s(%s);%s',jsonp,json,nl);
end

% save to a file if FileName is set, suggested by Patrick Rapin
if(~isempty(jsonopt('FileName','',opt)))
    if(jsonopt('SaveBinary',0,opt)==1)
	    fid = fopen(opt.FileName, 'wb');
	    fwrite(fid,json);
    else
	    fid = fopen(opt.FileName, 'wt');
	    fwrite(fid,json,'char');
    end
    fclose(fid);
end

%%-------------------------------------------------------------------------
function txt=obj2json(name,item,level,varargin)

if(iscell(item))
    txt=cell2json(name,item,level,varargin{:});
elseif(isstruct(item))
    txt=struct2json(name,item,level,varargin{:});
elseif(ischar(item))
    txt=str2json(name,item,level,varargin{:});
elseif(isobject(item)) 
    txt=matlabobject2json(name,item,level,varargin{:});
else
    txt=mat2json(name,item,level,varargin{:});
end

%%-------------------------------------------------------------------------
function txt=cell2json(name,item,level,varargin)
txt='';
if(~iscell(item))
        error('input is not a cell');
end

dim=size(item);
if(ndims(squeeze(item))>2) % for 3D or higher dimensions, flatten to 2D for now
    item=reshape(item,dim(1),numel(item)/dim(1));
    dim=size(item);
end
len=numel(item);
ws=jsonopt('whitespaces_',struct('tab',sprintf('\t'),'newline',sprintf('\n'),'sep',sprintf(',\n')),varargin{:});
padding0=repmat(ws.tab,1,level);
padding2=repmat(ws.tab,1,level+1);
nl=ws.newline;
if(len>1)
    if(~isempty(name))
        txt=sprintf('%s"%s": [%s',padding0, checkname(name,varargin{:}),nl); name=''; 
    else
        txt=sprintf('%s[%s',padding0,nl); 
    end
elseif(len==0)
    if(~isempty(name))
        txt=sprintf('%s"%s": []',padding0, checkname(name,varargin{:})); name=''; 
    else
        txt=sprintf('%s[]',padding0); 
    end
end
for j=1:dim(2)
    if(dim(1)>1)
        txt=sprintf('%s%s[%s',txt,padding2,nl);
    end
    for i=1:dim(1)
       txt=sprintf('%s%s',txt,obj2json(name,item{i,j},level+(dim(1)>1)+(len>1),varargin{:}));
       if(i<dim(1))
           txt=sprintf('%s%s',txt,sprintf(',%s',nl));
       end
    end
    if(dim(1)>1)
        txt=sprintf('%s%s%s]',txt,nl,padding2);
    end
    if(j<dim(2))
        txt=sprintf('%s%s',txt,sprintf(',%s',nl));
    end
    %if(j==dim(2)) txt=sprintf('%s%s',txt,sprintf(',%s',nl)); end
end
if(len>1)
    txt=sprintf('%s%s%s]',txt,nl,padding0);
end

%%-------------------------------------------------------------------------
function txt=struct2json(name,item,level,varargin)
txt='';
if(~isstruct(item))
	error('input is not a struct');
end
dim=size(item);
if(ndims(squeeze(item))>2) % for 3D or higher dimensions, flatten to 2D for now
    item=reshape(item,dim(1),numel(item)/dim(1));
    dim=size(item);
end
len=numel(item);
forcearray= (len>1 || (jsonopt('NoRowBracket',1,varargin{:})==0 && level>0));
ws=struct('tab',sprintf('\t'),'newline',sprintf('\n'));
ws=jsonopt('whitespaces_',ws,varargin{:});
padding0=repmat(ws.tab,1,level);
padding2=repmat(ws.tab,1,level+1);
padding1=repmat(ws.tab,1,level+(dim(1)>1)+forcearray);
nl=ws.newline;

if(isempty(item)) 
    if(~isempty(name)) 
        txt=sprintf('%s"%s": []',padding0,checkname(name,varargin{:}));
    else
        txt=sprintf('%s[]',padding0);
    end
    return;
end
if(~isempty(name)) 
    if(forcearray)
        txt=sprintf('%s"%s": [%s',padding0,checkname(name,varargin{:}),nl);
    end
else
    if(forcearray)
        txt=sprintf('%s[%s',padding0,nl);
    end
end
for j=1:dim(2)
  if(dim(1)>1)
      txt=sprintf('%s%s[%s',txt,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); 
    else
        txt=sprintf('%s%s{%s',txt,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{:}));
        if(e<length(names))
            txt=sprintf('%s%s',txt,',');
        end
        txt=sprintf('%s%s',txt,nl);
      end
    end
    txt=sprintf('%s%s}',txt,padding1);
    if(i<dim(1))
        txt=sprintf('%s%s',txt,sprintf(',%s',nl));
    end
  end
  if(dim(1)>1)
      txt=sprintf('%s%s%s]',txt,nl,padding2);
  end
  if(j<dim(2))
      txt=sprintf('%s%s',txt,sprintf(',%s',nl));
  end
end
if(forcearray)
    txt=sprintf('%s%s%s]',txt,nl,padding0);
end

%%-------------------------------------------------------------------------
function txt=str2json(name,item,level,varargin)
txt='';
if(~ischar(item))
        error('input is not a string');
end
item=reshape(item, max(size(item),[1 0]));
len=size(item,1);
ws=struct('tab',sprintf('\t'),'newline',sprintf('\n'),'sep',sprintf(',\n'));
ws=jsonopt('whitespaces_',ws,varargin{:});
padding1=repmat(ws.tab,1,level);
padding0=repmat(ws.tab,1,level+1);
nl=ws.newline;
sep=ws.sep;

if(~isempty(name)) 
    if(len>1)
        txt=sprintf('%s"%s": [%s',padding1,checkname(name,varargin{:}),nl);
    end
else
    if(len>1)
        txt=sprintf('%s[%s',padding1,nl);
    end
end
for e=1:len
    val=escapejsonstring(item(e,:));
    if(len==1)
        obj=['"' checkname(name,varargin{:}) '": ' '"',val,'"'];
        if(isempty(name))
            obj=['"',val,'"'];
        end
        txt=sprintf('%s%s%s%s',txt,padding1,obj);
    else
        txt=sprintf('%s%s%s%s',txt,padding0,['"',val,'"']);
    end
    if(e==len)
        sep='';
    end
    txt=sprintf('%s%s',txt,sep);
end
if(len>1)
    txt=sprintf('%s%s%s%s',txt,nl,padding1,']');
end

%%-------------------------------------------------------------------------
function txt=mat2json(name,item,level,varargin)
if(~isnumeric(item) && ~islogical(item))
        error('input is not an array');
end
ws=struct('tab',sprintf('\t'),'newline',sprintf('\n'),'sep',sprintf(',\n'));
ws=jsonopt('whitespaces_',ws,varargin{:});
padding1=repmat(ws.tab,1,level);
padding0=repmat(ws.tab,1,level+1);
nl=ws.newline;
sep=ws.sep;

if(length(size(item))>2 || issparse(item) || ~isreal(item) || ...
   (isempty(item) && any(size(item))) ||jsonopt('ArrayToStruct',0,varargin{:}))
    if(isempty(name))
    	txt=sprintf('%s{%s%s"_ArrayType_": "%s",%s%s"_ArraySize_": %s,%s',...
              padding1,nl,padding0,class(item),nl,padding0,regexprep(mat2str(size(item)),'\s+',','),nl);
    else
    	txt=sprintf('%s"%s": {%s%s"_ArrayType_": "%s",%s%s"_ArraySize_": %s,%s',...
              padding1,checkname(name,varargin{:}),nl,padding0,class(item),nl,padding0,regexprep(mat2str(size(item)),'\s+',','),nl);
    end
else
    if(numel(item)==1 && jsonopt('NoRowBracket',1,varargin{:})==1 && level>0)
        numtxt=regexprep(regexprep(matdata2json(item,level+1,varargin{:}),'^\[',''),']','');
    else
        numtxt=matdata2json(item,level+1,varargin{:});
    end
    if(isempty(name))
    	txt=sprintf('%s%s',padding1,numtxt);
    else
        if(numel(item)==1 && jsonopt('NoRowBracket',1,varargin{:})==1)
           	txt=sprintf('%s"%s": %s',padding1,checkname(name,varargin{:}),numtxt);
        else
    	    txt=sprintf('%s"%s": %s',padding1,checkname(name,varargin{:}),numtxt);
        end
    end
    return;
end
dataformat='%s%s%s%s%s';

if(issparse(item))
    [ix,iy]=find(item);
    data=full(item(find(item)));
    if(~isreal(item))
       data=[real(data(:)),imag(data(:))];
       if(size(item,1)==1)
           % Kludge to have data's 'transposedness' match item's.
           % (Necessary for complex row vector handling below.)
           data=data';
       end
       txt=sprintf(dataformat,txt,padding0,'"_ArrayIsComplex_": ','1', sep);
    end
    txt=sprintf(dataformat,txt,padding0,'"_ArrayIsSparse_": ','1', sep);
    if(size(item,1)==1)
        % Row vector, store only column indices.
        txt=sprintf(dataformat,txt,padding0,'"_ArrayData_": ',...
           matdata2json([iy(:),data'],level+2,varargin{:}), nl);
    elseif(size(item,2)==1)
        % Column vector, store only row indices.
        txt=sprintf(dataformat,txt,padding0,'"_ArrayData_": ',...
           matdata2json([ix,data],level+2,varargin{:}), nl);
    else
        % General case, store row and column indices.
        txt=sprintf(dataformat,txt,padding0,'"_ArrayData_": ',...
           matdata2json([ix,iy,data],level+2,varargin{:}), nl);
    end
else
    if(isreal(item))
        txt=sprintf(dataformat,txt,padding0,'"_ArrayData_": ',...
            matdata2json(item(:)',level+2,varargin{:}), nl);
    else
        txt=sprintf(dataformat,txt,padding0,'"_ArrayIsComplex_": ','1', sep);
        txt=sprintf(dataformat,txt,padding0,'"_ArrayData_": ',...
            matdata2json([real(item(:)) imag(item(:))],level+2,varargin{:}), nl);
    end
end
txt=sprintf('%s%s%s',txt,padding1,'}');

%%-------------------------------------------------------------------------
function txt=matlabobject2json(name,item,level,varargin)
if numel(item) == 0 %empty object
    st = struct();
else
    % "st = struct(item);" would produce an inmutable warning, because it
    % make the protected and private properties visible. Instead we get the
    % visible properties
    propertynames = properties(item);
    for p = 1:numel(propertynames)
        for o = numel(item):-1:1 % aray of objects
            st(o).(propertynames{p}) = item(o).(propertynames{p});
        end
    end
end
txt=struct2json(name,st,level,varargin{:});

%%-------------------------------------------------------------------------
function txt=matdata2json(mat,level,varargin)

ws=struct('tab',sprintf('\t'),'newline',sprintf('\n'),'sep',sprintf(',\n'));
ws=jsonopt('whitespaces_',ws,varargin{:});
tab=ws.tab;
nl=ws.newline;

if(size(mat,1)==1)
    pre='';
    post='';
    level=level-1;
else
    pre=sprintf('[%s',nl);
    post=sprintf('%s%s]',nl,repmat(tab,1,level-1));
end

if(isempty(mat))
    txt='null';
    return;
end
floatformat=jsonopt('FloatFormat','%.10g',varargin{:});
%if(numel(mat)>1)
    formatstr=['[' repmat([floatformat ','],1,size(mat,2)-1) [floatformat sprintf('],%s',nl)]];
%else
%    formatstr=[repmat([floatformat ','],1,size(mat,2)-1) [floatformat sprintf(',\n')]];
%end

if(nargin>=2 && size(mat,1)>1 && jsonopt('ArrayIndent',1,varargin{:})==1)
    formatstr=[repmat(tab,1,level) formatstr];
end

txt=sprintf(formatstr,mat');
txt(end-length(nl):end)=[];
if(islogical(mat) && jsonopt('ParseLogical',0,varargin{:})==1)
   txt=regexprep(txt,'1','true');
   txt=regexprep(txt,'0','false');
end
%txt=regexprep(mat2str(mat),'\s+',',');
%txt=regexprep(txt,';',sprintf('],\n['));
% if(nargin>=2 && size(mat,1)>1)
%     txt=regexprep(txt,'\[',[repmat(sprintf('\t'),1,level) '[']);
% end
txt=[pre txt post];
if(any(isinf(mat(:))))
    txt=regexprep(txt,'([-+]*)Inf',jsonopt('Inf','"$1_Inf_"',varargin{:}));
end
if(any(isnan(mat(:))))
    txt=regexprep(txt,'NaN',jsonopt('NaN','"_NaN_"',varargin{:}));
end

%%-------------------------------------------------------------------------
function newname=checkname(name,varargin)
isunpack=jsonopt('UnpackHex',1,varargin{:});
newname=name;
if(isempty(regexp(name,'0x([0-9a-fA-F]+)_','once')))
    return
end
if(isunpack)
    isoct=jsonopt('IsOctave',0,varargin{:});
    if(~isoct)
        newname=regexprep(name,'(^x|_){1}0x([0-9a-fA-F]+)_','${native2unicode(hex2dec($2))}');
    else
        pos=regexp(name,'(^x|_){1}0x([0-9a-fA-F]+)_','start');
        pend=regexp(name,'(^x|_){1}0x([0-9a-fA-F]+)_','end');
        if(isempty(pos))
            return;
        end
        str0=name;
        pos0=[0 pend(:)' length(name)];
        newname='';
        for i=1:length(pos)
            newname=[newname str0(pos0(i)+1:pos(i)-1) char(hex2dec(str0(pos(i)+3:pend(i)-1)))];
        end
        if(pos(end)~=length(name))
            newname=[newname str0(pos0(end-1)+1:pos0(end))];
        end
    end
end

%%-------------------------------------------------------------------------
function newstr=escapejsonstring(str)
newstr=str;
isoct=exist('OCTAVE_VERSION','builtin');
if(isoct)
   vv=sscanf(OCTAVE_VERSION,'%f');
   if(vv(1)>=3.8)
       isoct=0;
   end
end
if(isoct)
  escapechars={'\\','\"','\/','\a','\f','\n','\r','\t','\v'};
  for i=1:length(escapechars);
    newstr=regexprep(newstr,escapechars{i},escapechars{i});
  end
  newstr=regexprep(newstr,'\\\\(u[0-9a-fA-F]{4}[^0-9a-fA-F]*)','\$1');
else
  escapechars={'\\','\"','\/','\a','\b','\f','\n','\r','\t','\v'};
  for i=1:length(escapechars);
    newstr=regexprep(newstr,escapechars{i},regexprep(escapechars{i},'\\','\\\\'));
  end
  newstr=regexprep(newstr,'\\\\(u[0-9a-fA-F]{4}[^0-9a-fA-F]*)','\\$1');
end