NS_ERROR_ILLEGAL_INPUT Error while trying to read local .txt file using xul

Question

I am trying to read a locally stored text file in windows xp using xul program below:

function read_text_file(file_path)
{
  var file = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsILocalFile); 
  file.initWithPath(file_path); 
  var data = "";   
  var fstream = Components.classes["@mozilla.org/network/file-input-stream;1"].createInstance(Components.interfaces.nsIFileInputStream);   
  var cstream = Components.classes["@mozilla.org/intl/converter-input-stream;1"].createInstance(Components.interfaces.nsIConverterInputStream);   
  fstream.init(file, -1, 0, 0);
  cstream.init(fstream, "UTF-8", 0, 0); // you can use another encoding here if you wish   

  let (str = {}) {   
  let read = 0;   
  do {
      read = cstream.readString(0xffffffff, str); // read as much as we can and put it in str.value   
      data += str.value;   
     } 
  while (read != 0);
  }
  cstream.close(); // this closes fstream
  return data;
}

But getting Error in read = cstream.readString(0xffffffff, str);:

Error: NS_ERROR_ILLEGAL_INPUT: Component returned failure code: 0x8050000e (NS_ERROR_ILLEGAL_INPUT) [nsIConverterInputStream.readString]
Source File: chrome://quicknote/content/overlay.js
Line: 168

here I found some description here, but it didn't help.

Answer 1

The most likely reason for this is that the data in that file is not in fact encoded in UTF-8, so trying to decode as UTF-8 ends up throwing.

Answer 2

here is the answer: Reading textual data