Re: gdk_pixbuf::xpm_image_save patch

[Tor Lillqvist <tml iki fi>]

 > > - As far as mkstemp goes, I think the strategy I discussed with
 > >   Tor was to add a g_mkstemp function in glib.

Umm, yes:

/**
 * g_mkstemp:
 *
 * Open a temporary file
 *
 * The parameter is a string that should match the rules for mktemp, i.e.
 * end in "XXXXXX". The X string will be modified to form the name
 * of a file that didn't exist.
 *
 * Return value: A file handle (as from open()) to the file file
 * opened for reading and writing. The file is opened in binary mode
 * on platforms where there is a difference. The file handle should be
 * closed with close(). In case of errors, -1 is returned.
 *
 * From the GNU C library.
 * Copyright (C) 1991,92,93,94,95,96,97,98,99 Free Software Foundation, Inc.
 */
int
g_mkstemp (char *tmpl)
{
#ifdef HAVE_MKSTEMP
  return mkstemp (tmpl);
#else
  int len;
  char *XXXXXX;
  int count, fd;
  static const char letters[] =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  glong value;
  GTimeVal tv;

  len = strlen (tmpl);
  if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
    return -1;

  /* This is where the Xs start.  */
  XXXXXX = &tmpl[len - 6];

  /* Get some more or less random data.  */
  g_get_current_time (&tv);
  value = tv.tv_usec ^ tv.tv_sec;

  for (count = 0; count < 100; value += 7777, ++count)
    {
      glong v = value;

      /* Fill in the random bits.  */
      XXXXXX[0] = letters[v % 62];
      v /= 62;
      XXXXXX[1] = letters[v % 62];
      v /= 62;
      XXXXXX[2] = letters[v % 62];
      v /= 62;
      XXXXXX[3] = letters[v % 62];
      v /= 62;
      XXXXXX[4] = letters[v % 62];
      v /= 62;
      XXXXXX[5] = letters[v % 62];

      fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL | O_BINARY, 0600);

      if (fd >= 0)
	return fd;
      else if (errno != EEXIST)
	/* Any other error will apply also to other names we might
	 *  try, and there are 2^32 or so of them, so give up now.
	 */
	return -1;
    }

  /* We got out of the loop because we ran out of combinations to try.  */
  return -1;
#endif
}

(Plus "#ifndef G_OS_WIN32 #define O_BINARY 0" earlier in the file.)

I'll add this to glib:gutils.c in a moment.

 > >The GIMP's XPM plugin does handle saving. It does have the same
 > >problem as mentioned above, but it at least gives the person
 > >some more flexibility in using it.

 > >So this should be a good option on win32. I'm pretty certain
 > >that some of the other image manipulation suites such as
 > >netpbm have been ported to Win32 or at least to djgpp

Except that the XPM plug-in isn't currently built on Windows, because
it uses libXpm, which uses libX11. Yes, I know that these can be built
on Windows without problems, and probably are available ready-built
somewhere. I've just been lazy.

Anyway, ImageMagick knows how to read and write Xpm. (It doesn't use
libXpm.)

--tml