classdef ini < handle
  % Low-level utilities for INI files.
  properties (Access = public)
    File         % file name
    IOMode       % file opened in read-only or read-write mode?
    FileSize     % file size
    NumSection   % maximum number of datasets in this file (over all time steps)
    Verbosity    % verbose output?
  end
  %%
  properties (Access = private)
    % File info
    fileID
    fileBeg
    fileEnd
    ioflag
    tarflag
    content
  end
  %% ------------------------------------------------------------------------%%
  %%                      CONSTRUCORS/DESTRUCTORS                            %%
  %% ------------------------------------------------------------------------%%
  methods (Access = public)
    function obj = ini(varargin)
      % [obj] = ini(varargin)
      % Default contructor
      % Input 
      % ? verbosity         verbose output? (default: no)
      par = inputParser;
      addOptional(par,'verbosity',0,@isnumeric);
      parse(par,varargin{:});
      obj.resetPublicProperties();
      obj.resetPrivateProperties();
      obj.setVerbosity(par.Results.verbosity);
    end
    function delete(obj)
      % obj.delete()
      % Object destructor
      obj.close();
    end
  end
  %% ------------------------------------------------------------------------%%
  %%                     INITIALIZATION METHODS                              %%
  %% ------------------------------------------------------------------------%%
  methods(Access=public)
    function open(obj,fname)
      % obj.open()
      % Opens an INI file.
      % Input
      %   fname         file name
      obj.File    = fname;
      obj.IOMode  = 'read';
      obj.ioflag  = 'r';
      obj.tarflag = false;
      obj.fileID  = fopen(obj.File,obj.ioflag);
      obj.fileBeg = 0;
      fseek(obj.fileID,0,'eof');
      obj.fileEnd = ftell(obj.fileID);
      obj.FileSize = obj.fileEnd-obj.fileBeg;
      obj.parse();
    end
    function opentar(obj,ptr)
      % obj.opentar(ptr)
      % Opens a subfile from tar in read-only mode.
      % Input
      %   ptr             pointer: [fid,first byte,number of bytes]
      obj.File    = 'tar-mode';                      % Set generic file name
      obj.IOMode  = 'read';                          % abstract IO mode
      obj.ioflag  = 'r';                             % internal IO mode
      obj.tarflag = true;                            % reading from tar archive?
      % Set file ID to tar file ID
      obj.fileID = ptr(1);      
      if obj.fileID<0
        error('Unable to access file: %s',obj.File);
      end
      obj.fileBeg = ptr(2);
      obj.fileEnd = ptr(2)+ptr(3);
      obj.FileSize = ptr(3);
      obj.parse();
    end
  end
  methods(Access=public)
    function close(obj)
      % obj.close()
      % Closes a file.
      tarmode = obj.tarflag;
      obj.resetPublicProperties();
      obj.resetPrivateProperties();
      if obj.fileID<0 || tarmode
        return;
      end
      status = fclose(obj.fileID);
      if status<0
        warning('Error while closing: %d',status);
        return;
      end

      obj.fileID = -1;
    end
    function setVerbosity(obj,flag)
      % obj.setVerbosity(flag)
      % Sets verbosity
      % Input 
      %   flag              '1' -> verbose output
      obj.Verbosity = flag;
    end
    function [data] = getContent(obj)
      % [data] = obj.getContent()
      % Get the entire content of the INI file.
      % Output
      %   data            entire content of file as structure
      data = obj.content;
    end
    function [data] = getSection(obj,section)
      % [data] = obj.getSection(section)
      % Get the content of a single section of the INI file.
      % Input
      %   section         name of the requested section
      % Output
      %   data            content of one section of file as structure
      if isfield(obj.content,section)
        data = obj.content.(section);
      else
        error('Section not found: %s',name);
      end
    end
    function [data] = getEntry(obj,section,entry)
      % [data] = obj.getEntry(section,entry)
      % Get the value of a single entry within the INI file.
      % Input
      %   section         name of the requested section
      %   entry           name of the entry within requested section
      % Output
      %   data            value of the requested entry
      if ~isfield(obj.content,section)
        error('Section not found: %s',section);
      elseif ~isfield(obj.content.(section),entry)
        error('Entry not found: %s',entry);
      else
        data = obj.content.(section).(entry);
      end
    end
    function [data] = listSections(obj)
      % [data] = obj.listSections()
      % Get a list of section names.
      % Output
      %   data              cell array with section names
      data = fieldnames(obj.content);
    end
    function [data] = listEntries(obj,section)
      % [data] = obj.listEntries(section)
      % Get a list of entry names within a section..
      % Input
      %   section           name of the requested section
      % Output
      %   data              cell array with section names
      data = fieldnames(obj.content.(section));
    end
  end
  %% ------------------------------------------------------------------------%%
  %%                      PRIVATE STATIC METHODS                             %%
  %% ------------------------------------------------------------------------%%
  methods(Access=private)
    function parse(obj)
      fseek(obj.fileID,obj.fileBeg,'bof');
      % Construct a struct with content of file
      obj.content = [];
      curSection = '';
      while ftell(obj.fileID)<obj.fileEnd
        str = strtrim(fgetl(obj.fileID));
        % Check for empty lines and comments (; or #)
        if isempty(str)
            continue;
        end
        if (str(1)==';')
            continue;
        end
        if (str(1)=='#')
            continue;
        end
        % Check for section
        if (str(1)=='[') && (str(end)==']')
          % This is a section: create a structure
          curSection = ini.getUniqueVarname(str(2:end-1));
          obj.content.(curSection) = [];
        else
          % This is not a section: create structure entry
          [curMember,curValue] = strtok(str,'=');
          curValue  = ini.trimValue(curValue);
          curMember = ini.getUniqueVarname(curMember);
          % We now have the field name and the corresponding value as strings.
          % Convert the value to a numeric value if possible.
          [tmp,flag] = str2num(curValue);
          if flag
              curValue = tmp;
          end
          % Add this structure to the current section
          if ~isempty(curSection)
              obj.content.(curSection).(curMember) = curValue;
          else
              obj.content.(curMember) = curValue;
          end
        end
      end
      obj.NumSection = numel(fieldnames(obj.content));
    end
    function resetPublicProperties(obj)
      obj.File       = [];
      obj.FileSize   = [];
      obj.IOMode     = [];
      obj.NumSection = [];
      obj.Verbosity  = [];
    end
    function resetPrivateProperties(obj)
      obj.fileBeg = [];
      obj.fileEnd = [];
      obj.ioflag  = [];
      obj.tarflag = [];
      obj.content = [];
    end
  end
  %% ------------------------------------------------------------------------%%
  %%                      PRIVATE STATIC METHODS                             %%
  %% ------------------------------------------------------------------------%%
  methods(Access=private,Static)
    function str = trimValue(str)
        str = strtrim(str);
        if strcmpi(str(1),'=')
            str(1)=[];
        end
        str = strtrim(str);
    end
    function varname = getUniqueVarname(varname)
        %tmp = matlab.lang.makeValidName(varname);
        %varname = matlab.lang.makeUniqueStrings(tmp,who,namelengthmax);
        varname = strrep(varname,'-','_');
        varname = genvarname(varname);
    end
  end
end