rtpjitterbuffer: Don't use glib format modifiers with sscanf

We do not have a way to know the format modifiers to use with string
functions provided by the system. G_GUINT64_FORMAT and other string
modifiers only work for glib string formatting functions. We cannot
use them for string functions provided by the stdlib. See:
https://developer.gnome.org/glib/stable/glib-Basic-Types.html#glib-Basic-Types.description

```
../gst/rtpmanager/gstrtpjitterbuffer.c: In function 'gst_jitter_buffer_sink_parse_caps':
../gst/rtpmanager/gstrtpjitterbuffer.c:1523:32: error: unknown conversion type character 'l' in format [-Werror=format=]
           || sscanf (mediaclk, "direct=%" G_GUINT64_FORMAT, &clock_offset) != 1)
                                ^~~~~~~~~~
In file included from /home/nirbheek/cerbero/build/dist/windows_x86/include/glib-2.0/glib/gtypes.h:32,
                 from /home/nirbheek/cerbero/build/dist/windows_x86/include/glib-2.0/glib/galloca.h:32,
                 from /home/nirbheek/cerbero/build/dist/windows_x86/include/glib-2.0/glib.h:30,
                 from /home/nirbheek/cerbero/build/dist/windows_x86/include/gstreamer-1.0/gst/gst.h:27,
                 from /home/nirbheek/cerbero/build/dist/windows_x86/include/gstreamer-1.0/gst/rtp/gstrtpbuffer.h:27,
                 from ../gst/rtpmanager/gstrtpjitterbuffer.c:108:
/home/nirbheek/cerbero/build/dist/windows_x86/lib/glib-2.0/include/glibconfig.h:69:28: note: format string is defined here
 #define G_GUINT64_FORMAT "llu"
                            ^
../gst/rtpmanager/gstrtpjitterbuffer.c:1523:32: error: too many arguments for format [-Werror=format-extra-args]
           || sscanf (mediaclk, "direct=%" G_GUINT64_FORMAT, &clock_offset) != 1)
                                ^~~~~~~~~~
```

See also: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/379

diff --git a/gst/rtpmanager/gstrtpjitterbuffer.c b/gst/rtpmanager/gstrtpjitterbuffer.c
index be7f798..770caa9 100644 (file)
--- a/gst/rtpmanager/gstrtpjitterbuffer.c
+++ b/gst/rtpmanager/gstrtpjitterbuffer.c
@@ -1372,6 +1372,24 @@ gst_rtp_jitter_buffer_getcaps (GstPad * pad, GstCaps * filter)
   return caps;
 }
 
+/* g_ascii_string_to_unsigned is available since 2.54. Get rid of this wrapper
+ * when we bump the version in 1.18 */
+#if !GLIB_CHECK_VERSION(2,54,0)
+#define g_ascii_string_to_unsigned _gst_jitter_buffer_ascii_string_to_unsigned
+static gboolean
+_gst_jitter_buffer_ascii_string_to_unsigned (const gchar * str, guint base,
+    guint64 min, guint64 max, guint64 * out_num, GError ** error)
+{
+  gchar *endptr = NULL;
+  *out_num = g_ascii_strtoull (str, &endptr, base);
+  if (errno)
+    return FALSE;
+  if (endptr == str)
+    return FALSE;
+  return TRUE;
+}
+#endif
+
 /*
  * Must be called with JBUF_LOCK held
  */
@@ -1519,8 +1537,9 @@ gst_jitter_buffer_sink_parse_caps (GstRtpJitterBuffer * jitterbuffer,
     if ((mediaclk = gst_structure_get_string (caps_struct, "a-mediaclk"))) {
       GST_DEBUG_OBJECT (jitterbuffer, "Got media clock %s", mediaclk);
 
-      if (!g_str_has_prefix (mediaclk, "direct=")
-          || sscanf (mediaclk, "direct=%" G_GUINT64_FORMAT, &clock_offset) != 1)
+      if (!g_str_has_prefix (mediaclk, "direct=") ||
+          !g_ascii_string_to_unsigned (&mediaclk[8], 10, 0, G_MAXUINT64,
+              &clock_offset, NULL))
         GST_FIXME_OBJECT (jitterbuffer, "Unsupported media clock");
       if (strstr (mediaclk, "rate=") != NULL) {
         GST_FIXME_OBJECT (jitterbuffer, "Rate property not supported");