struct text_options_t
{
  ~text_options_t ()
  {
    g_free (text_before);
    g_free (text_after);
    g_free (text);
    g_free (text_file);
    if (gs)
      g_string_free (gs, true);
    if (fp && fp != stdin)
      fclose (fp);
  }

  void add_options (option_parser_t *parser);

  void post_parse (GError **error G_GNUC_UNUSED)
  {
    if (text && text_file)
      g_set_error (error,
		   G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
		   "Only one of text and text-file can be set");
  }

  const char *get_line (unsigned int *len);

  char *text_before = nullptr;
  char *text_after = nullptr;

  int text_len = -1;
  char *text = nullptr;
  char *text_file = nullptr;

  private:
  FILE *fp = nullptr;
  GString *gs = nullptr;
};


static gboolean
parse_text (const char *name G_GNUC_UNUSED,
	    const char *arg,
	    gpointer    data,
	    GError    **error G_GNUC_UNUSED)
{
  text_options_t *text_opts = (text_options_t *) data;

  if (text_opts->text)
  {
    g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
		 "Either --text or --unicodes can be provided but not both");
    return false;
  }

  text_opts->text_len = -1;
  text_opts->text = g_strdup (arg);
  return true;
}


static gboolean
parse_unicodes (const char *name G_GNUC_UNUSED,
		const char *arg,
		gpointer    data,
		GError    **error G_GNUC_UNUSED)
{
  text_options_t *text_opts = (text_options_t *) data;

  if (text_opts->text)
  {
    g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
		 "Either --text or --unicodes can be provided but not both");
    return false;
  }

  GString *gs = g_string_new (nullptr);
  if (0 == strcmp (arg, "*"))
  {
    g_string_append_c (gs, '*');
  }
  else
  {

    char *s = (char *) arg;
    char *p;

    while (s && *s)
    {
#define DELIMITERS "<+>{},;&#\\xXuUnNiI\n\t\v\f\r "

      while (*s && strchr (DELIMITERS, *s))
	s++;
      if (!*s)
	break;

      errno = 0;
      hb_codepoint_t u = strtoul (s, &p, 16);
      if (errno || s == p)
      {
	g_string_free (gs, TRUE);
	g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
		     "Failed parsing Unicode values at: '%s'", s);
	return false;
      }

      g_string_append_unichar (gs, u);

      s = p;
    }
  }

  text_opts->text_len = gs->len;
  text_opts->text = g_string_free (gs, FALSE);
  return true;
}

const char *
text_options_t::get_line (unsigned int *len)
{
  if (text)
  {
    if (text_len == -2)
    {
      *len = 0;
      return nullptr;
    }

    if (text_len == -1)
      text_len = strlen (text);

    *len = text_len;
    text_len = -2;
    return text;
  }

  if (!fp)
  {
    if (!text_file)
      fail (true, "At least one of text or text-file must be set");

    if (0 != strcmp (text_file, "-"))
      fp = fopen (text_file, "r");
    else
      fp = stdin;

    if (!fp)
      fail (false, "Failed opening text file `%s': %s",
	    text_file, strerror (errno));

    gs = g_string_new (nullptr);
  }

  g_string_set_size (gs, 0);
  char buf[BUFSIZ];
  while (fgets (buf, sizeof (buf), fp))
  {
    unsigned bytes = strlen (buf);
    if (bytes && buf[bytes - 1] == '\n')
    {
      bytes--;
      g_string_append_len (gs, buf, bytes);
      break;
    }
    g_string_append_len (gs, buf, bytes);
  }
  if (ferror (fp))
    fail (false, "Failed reading text: %s", strerror (errno));
  *len = gs->len;
  return !*len && feof (fp) ? nullptr : gs->str;
}

void
text_options_t::add_options (option_parser_t *parser)
{
  GOptionEntry entries[] =
  {
    {"text",		0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_text,		"Set input text",			"string"},
    {"text-file",	0, 0, G_OPTION_ARG_STRING,	&this->text_file,		"Set input text file-name",		"filename"},
    {"unicodes",      'u', 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_unicodes,	"Set input Unicode codepoints\n\n    If no text is provided, standard input is used for input.\n",		"list of hex numbers"},
    {"text-before",	0, 0, G_OPTION_ARG_STRING,	&this->text_before,		"Set text context before each line",	"string"},
    {"text-after",	0, 0, G_OPTION_ARG_STRING,	&this->text_after,		"Set text context after each line",	"string"},
    {nullptr}
  };
  parser->add_group (entries,
		     "text",
		     "Text options:",
		     "Options for the input text",
		     this);
}