function [pp,col,stime] = read_particles_ucf(file,varargin)
    % [pp,col] = read_particles_ucf(file,varargin)
    % Reads particle data from UCF file
    % Input
    %   file              file name (if tar-mode: ustar handle)
    % ? step              timestep to be read (default: 0 [all])
    % ? format            MATLAB format (default: 'array')
    %                       'array'     plain array with dim(ncol.np,nt)
    %                       'struct'    structure array with short fieldnames
    %                       'paraview'  structure array with H5Part fieldnames
    %                       'cell'      cell array with dim(1,nt) and plain arrays with dim(ncol,np) inside
    % ? verbosity         verbose output? (default: no)
    % ? debug             debug output? (default: no)
    % ? tarmode       read from tar-file? (default: 0)
    % Output
    %   pp                particle data in specified format
    %   col               container map 'char'->'double' which maps quantity names to column index
    %   stime             simulation time with dim(1,nt)
    
    % Parse optional input arguments
    par = inputParser;
    addParameter(par,'step',0,@isnumeric);
    addParameter(par,'format','array',@ischar);
    addParameter(par,'verbosity',0,@isnumeric);
    addParameter(par,'debug',0,@isnumeric);
    addParameter(par,'tarmode',0,@isnumeric);
    parse(par,varargin{:});
    istep     = par.Results.step;
    mlformat  = par.Results.format;
    
    % Open file
    obj = ucf('verbosity',par.Results.verbosity,'debug',par.Results.debug);
    if par.Results.tarmode
      ptr = file.pointer('particles.bin');
      obj.opentar(ptr);
    else
      obj.open(file);
    end
    if ~obj.validateType('particle')
      error('read error: no particle data.'); 
    end
 
    % Get range of steps to be read
    if istep==0
      steps = uint32(1:obj.getNumTimesteps());
    else
      steps = uint32(istep);
    end
    nstepout = numel(steps);
    
    % Get simulation time
    stime = obj.getSimulationTime();
    stime = stime(steps);
    
    % Read raw data
    for istep=nstepout:-1:1
      [data,params] = obj.readSet(steps(istep),1);
      params = cast(params,'double');
      np          = params(1);
      ncol        = params(2);
      ncol_rank   = params(3);
      ncol_hybrid = params(4);
      ncol_dem    = params(5);
      ncol_scalar = params(6);
      data = reshape(data,ncol,np);
      nscal = ncol_scalar/2;
      col = colmap_from_flags(ncol_rank,ncol_hybrid,ncol_dem,nscal);
    
      % Parse data to specified format
      switch mlformat
      case 'struct'
        pp(istep) = convert_particles_array2struct(data,col);
      case 'paraview'
        col = convert_colmap_matlab2paraview(col);
        pp(istep) = convert_particles_array2struct(data,col);
      case {'cell','array'}
        pp{istep} = data;
      otherwise
        error('Unknown format: %s',mlformat);
      end
    end
    
    % Convert cell array to 3-dim array, if mlformat=='array'
    if strcmp(mlformat,'array')
      pp = cat(3,pp{:});
    end
    
    % Close file
    obj.close();
end