elements: improve buffer flags to string utility function

Avoid relocations and refactor so that we don't calculate
the fixed and known at compile time maximum string size
every time. Also skip the mini object flags which we are
not going to print anyway.

diff --git a/plugins/elements/gstelements_private.c b/plugins/elements/gstelements_private.c
index 2364741..f539a85 100644 (file)
--- a/plugins/elements/gstelements_private.c
+++ b/plugins/elements/gstelements_private.c
@@ -29,29 +29,33 @@
 #include "gst/gst.h"
 #include "gstelements_private.h"
 
+#define BUFFER_FLAG_SHIFT 4
+
+G_STATIC_ASSERT ((1 << BUFFER_FLAG_SHIFT) == GST_MINI_OBJECT_FLAG_LAST);
+
 /* Returns a newly allocated string describing the flags on this buffer */
 char *
 gst_buffer_get_flags_string (GstBuffer * buffer)
 {
-  static const char *const flag_list[] = {
-    "", "", "", "", "live", "decode-only", "discont", "resync", "corrupted",
-    "marker", "header", "gap", "droppable", "delta-unit", "tag-memory",
-    "FIXME"
+  static const char flag_strings[] =
+      "\000\000\000\000live\000decode-only\000discont\000resync\000corrupted\000"
+      "marker\000header\000gap\000droppable\000delta-unit\000tag-memory\000"
+      "FIXME";
+  static const guint8 flag_idx[] = { 0, 1, 2, 3, 4, 9, 21, 29, 36, 46, 53,
+    60, 64, 74, 85, 96
   };
   int i, max_bytes;
   char *flag_str, *end;
 
-  max_bytes = 1;                /* NUL */
-  for (i = 0; i < G_N_ELEMENTS (flag_list); i++) {
-    max_bytes += strlen (flag_list[i]) + 1;     /* string and space */
-  }
+  /* max size is all flag strings plus a space or terminator after each one */
+  max_bytes = sizeof (flag_strings);
   flag_str = g_malloc (max_bytes);
 
   end = flag_str;
   end[0] = '\0';
-  for (i = 0; i < G_N_ELEMENTS (flag_list); i++) {
+  for (i = BUFFER_FLAG_SHIFT; i < G_N_ELEMENTS (flag_idx); i++) {
     if (GST_MINI_OBJECT_CAST (buffer)->flags & (1 << i)) {
-      strcpy (end, flag_list[i]);
+      strcpy (end, flag_strings + flag_idx[i]);
       end += strlen (end);
       end[0] = ' ';
       end[1] = '\0';