LFWriteMetadata.m

% LFWriteMetadata - saves variables to a file in JSON format
%
% Usage:
%     LFWriteMetadata( JsonFileFname, DataToSave )
% 
% This function saves data to a JSON file.
%
% User guide: <a href="matlab:which LFToolbox.pdf; open('LFToolbox.pdf')">LFToolbox.pdf</a>
% See also: LFReadMetadata

% Copyright (c) 2013-2020 Donald G. Dansereau
% 
% Based on code from JSONlab by Qianqian Fang,
% http://www.mathworks.com.au/matlabcentral/fileexchange/33381-jsonlab-a-toolbox-to-encodedecode-json-files-in-matlaboctave
%
% Minor modifications to simplify the interface as appropriate for use in the Light Field Toolbox,
% and to tolerate the sha keys appearing at the end of some Lytro JSON files.
% 2013, Donald G. Dansereau
% 
% Enabled writing of class objects
% 2020, Nuno Monteiro

function LFWriteMetadata( JsonFileFname, DataToSave )

rootname = [];

varname=inputname(1);
opt.FileName = JsonFileFname;
opt.IsOctave=exist('OCTAVE_VERSION');
rootisarray=0;
rootlevel=1;
forceroot=jsonopt('ForceRootName',0,opt);
if((isnumeric(DataToSave) || islogical(DataToSave) || ischar(DataToSave) || isstruct(DataToSave) || iscell(DataToSave)) && isempty(rootname) && forceroot==0)
    rootisarray=1;
    rootlevel=0;
else
    if(isempty(rootname))
        rootname=varname;
    end
end
if((isstruct(DataToSave) || iscell(DataToSave))&& isempty(rootname) && forceroot)
    rootname='root';
end
json=obj2json(rootname,DataToSave,rootlevel,opt);
if(rootisarray)
    json=sprintf('%s\n',json);
else
    json=sprintf('{\n%s\n}\n',json);
end

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

% save to a file if FileName is set, suggested by Patrick Rapin
if(~isempty(jsonopt('FileName','',opt)))
    fid = fopen(opt.FileName, 'wt');
    fwrite(fid,json,'char');
    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=class2json(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);
len=numel(item); % let's handle 1D cell first
padding1=repmat(sprintf('\t'),1,level-1);
padding0=repmat(sprintf('\t'),1,level);
if(len>1) 
    if(~isempty(name))
        txt=sprintf('%s"%s": [\n',padding0, checkname(name,varargin{:})); name=''; 
    else
        txt=sprintf('%s[\n',padding0); 
    end
elseif(len==0)
    if(~isempty(name))
        txt=sprintf('%s"%s": null',padding0, checkname(name,varargin{:})); name=''; 
    else
        txt=sprintf('%snull',padding0); 
    end
end
for i=1:len
    txt=sprintf('%s%s%s',txt,padding1,obj2json(name,item{i},level+(len>1),varargin{:}));
    if(i<len) txt=sprintf('%s%s',txt,sprintf(',\n')); end
end
if(len>1) txt=sprintf('%s\n%s]',txt,padding0); end

%%-------------------------------------------------------------------------
function txt=struct2json(name,item,level,varargin)
txt = '';
if(~isstruct(item))
	error('input is not a struct');
end
txt = object2json(name,item,level,varargin{:});

%%-------------------------------------------------------------------------
function txt=class2json(name,item,level,varargin)
txt = '';
if(~isobject(item))
	error('input is not a class');
end
txt = object2json(name,item,level,varargin{:});

%%-------------------------------------------------------------------------
function txt=object2json(name,item,level,varargin)
txt='';
len=numel(item);
padding1=repmat(sprintf('\t'),1,level-1);
padding0=repmat(sprintf('\t'),1,level);
sep=',';

if(~isempty(name)) 
    if(len>1) txt=sprintf('%s"%s": [\n',padding0,checkname(name,varargin{:})); end
else
    if(len>1) txt=sprintf('%s[\n',padding0); end
end
for e=1:len
  names = fieldnames(item(e));
  if(~isempty(name) && len==1)
        txt=sprintf('%s%s"%s": {\n',txt,repmat(sprintf('\t'),1,level+(len>1)), checkname(name,varargin{:})); 
  else
        txt=sprintf('%s%s{\n',txt,repmat(sprintf('\t'),1,level+(len>1))); 
  end
  if(~isempty(names))
    for i=1:length(names)
	txt=sprintf('%s%s',txt,obj2json(names{i},getfield(item(e),...
             names{i}),level+1+(len>1),varargin{:}));
        if(i<length(names)) txt=sprintf('%s%s',txt,','); end
        txt=sprintf('%s%s',txt,sprintf('\n'));
    end
  end
  txt=sprintf('%s%s}',txt,repmat(sprintf('\t'),1,level+(len>1)));
  if(e==len) sep=''; end
  if(e<len) txt=sprintf('%s%s',txt,sprintf(',\n')); end
end
if(len>1) txt=sprintf('%s\n%s]',txt,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);
sep=sprintf(',\n');

padding1=repmat(sprintf('\t'),1,level);
padding0=repmat(sprintf('\t'),1,level+1);

if(~isempty(name)) 
    if(len>1) txt=sprintf('%s"%s": [\n',padding1,checkname(name,varargin{:})); end
else
    if(len>1) txt=sprintf('%s[\n',padding1); end
end
isoct=jsonopt('IsOctave',0,varargin{:});
for e=1:len
    if(isoct)
        val=regexprep(item(e,:),'\\','\\');
        val=regexprep(val,'"','\"');
        val=regexprep(val,'^"','\"');
    else
        val=regexprep(item(e,:),'\\','\\\\');
        val=regexprep(val,'"','\\"');
        val=regexprep(val,'^"','\\"');
    end
    if(len==1)
        DataToSave=['"' checkname(name,varargin{:}) '": ' '"',val,'"'];
	if(isempty(name)) DataToSave=['"',val,'"']; end
        txt=sprintf('%s%s%s%s',txt,repmat(sprintf('\t'),1,level),DataToSave);
    else
        txt=sprintf('%s%s%s%s',txt,repmat(sprintf('\t'),1,level+1),['"',val,'"']);
    end
    if(e==len) sep=''; end
    txt=sprintf('%s%s',txt,sep);
end
if(len>1) txt=sprintf('%s\n%s%s',txt,padding1,']'); end

%%-------------------------------------------------------------------------
function txt=mat2json(name,item,level,varargin)
if(~isnumeric(item) && ~islogical(item))
        error('input is not an array');
end

padding1=repmat(sprintf('\t'),1,level);
padding0=repmat(sprintf('\t'),1,level+1);

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

%%-------------------------------------------------------------------------
function txt=matdata2json(mat,level,varargin)
if(size(mat,1)==1)
    pre='';
    post='';
    level=level-1;
else
    pre=sprintf('[\n');
    post=sprintf('\n%s]',repmat(sprintf('\t'),1,level-1));
end
if(isempty(mat))
    txt='null';
    return;
end
floatformat=jsonopt('FloatFormat','%.10g',varargin{:});
formatstr=['[' repmat([floatformat ','],1,size(mat,2)-1) [floatformat sprintf('],\n')]];

if(nargin>=2 && size(mat,1)>1 && jsonopt('ArrayIndent',1,varargin{:})==1)
    formatstr=[repmat(sprintf('\t'),1,level) formatstr];
end
txt=sprintf(formatstr,mat');
txt(end-1: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 val=jsonopt(key,default,varargin)
val=default;
if(nargin<=2) return; end
opt=varargin{1};
if(isstruct(opt) && isfield(opt,key))
    val=getfield(opt,key);
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