custom data

function parse_custom_data(str)
 local t={}
 if str then
  for section, section_data in string.gfind(str,"%s*%[([^%]]*)%]%s*([^%[%z]*)%s*") do
   section = trim(section)
   t[section]={}
   for line in string.gfind(trim(section_data), "([^\n]*)\n*") do
    if string.find(line,"=")~=nil then
     for k, v in string.gfind(line, "([^=]-)%s*=%s*(.*)") do
      k = trim(k)
      if k~=nil and k~='' and v~=nil then
       t[section][k]=trim(v)
      end
     end
    else
     for k, v in string.gfind(line, "(.*)") do
      k = trim(k)
      if k~=nil and k~='' then
       t[section][k]="<<no_value>>"
      end
     end
    end
   end
  end
 end
 return t
end

function gen_custom_data(tbl)
 local str=''
 for key, value in pairs(tbl) do
  str = str.."["..key.."]\n"
  for k, v in pairs(value) do
   if v~="<<no_value>>" then
    str=str..k.." = "..v.."\n"
   else
    str=str..k.."\n"
   end
  end
 end
 return str
end

function trim (s)
 return (string.gsub(s, "^%s*(.-)%s*$", "%1"))
end