#include <QtCore/QtCore>

const QByteArray BOM_UTF16_LE = "\xff\xfe";
const QByteArray BOM_UTF16_BE = "\xfe\xff";
const QByteArray BOM_UTF8 = "\xef\xbb\xbf";

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QString sFileName = "test_utf16_le.txt";
    QStringConverter::Encoding  eEncoding;
    QStringDecoder m_decoder;

    QFile file(sFileName);
    if (file.open(QIODevice::ReadOnly))
    {
      QByteArray baLine = file.readLine();
      if (baLine.startsWith(BOM_UTF8))
        eEncoding = QStringConverter::Utf8;
      else if (baLine.startsWith(BOM_UTF16_LE))
        eEncoding = QStringConverter::Utf16LE;
      else if (baLine.startsWith(BOM_UTF16_BE))
        eEncoding = QStringConverter::Utf16BE;
      else
        eEncoding = QStringConverter::System;
      m_decoder = QStringDecoder(eEncoding);
      file.reset();
    }

    // BUG INFORMATION:
    //--------------------------------------------------------------------------
    // if the encoding of the text file is Utf-16 LE (Little Endian), line breaks
    // are handled incorrectly.
    // 
    // In Utf16-LE, linefeeds are encoded as "0x0a 0x00", but "readLine" seems to cut off the second byte.
    // So the line ends with "0x0a" and the next starts with "0x00". Besides, none of them are valid UTF-16 characters.
    // See also the HINTs below.

    bool bEof = file.atEnd();
    int nCounter = 0;
    while (!bEof)
    {
      nCounter++;

      // read the next line
      // ==> the decoder automatically skips BOMs
      QByteArray baLine = file.readLine();
      // HINT:  
      //  - each row ends with a half line feed character '0x0a', the number of read bytes is odd.
      //    ==> BUG: this is invalid for UTF-16
      //  - starting with line 2, each line starts with a leading 0-byte. --> INCORRECT!

      QString sLine = m_decoder.decode(baLine);
      // HINT:  
      //  - trailing line feeds are cut off. --> INCORRECT!
      //  - starting with line 2, each line starts with a leading line feed. --> INCORRECT!

      bEof = file.atEnd();
    }


    return a.exec();
}