[asterisk-commits] tilghman: trunk r296826 - /trunk/include/asterisk/frame.h

[SVN commits to the Asterisk project]

Author: tilghman
Date: Tue Nov 30 16:32:20 2010
New Revision: 296826

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=296826
Log:
Add a comment on why the reserved bit is reserved.

Came up when reviewing discussion on the CODEC PREFS IE in IAX2.

Modified:
    trunk/include/asterisk/frame.h

Modified: trunk/include/asterisk/frame.h
URL: http://svnview.digium.com/svn/asterisk/trunk/include/asterisk/frame.h?view=diff&rev=296826&r1=296825&r2=296826
==============================================================================
--- trunk/include/asterisk/frame.h (original)
+++ trunk/include/asterisk/frame.h Tue Nov 30 16:32:20 2010
@@ -300,7 +300,13 @@
 #define AST_FORMAT_SPEEX16    (1ULL << 33)
 /*! Raw mu-law data (G.711) */
 #define AST_FORMAT_TESTLAW    (1ULL << 47)
-/*! Reserved bit - do not use */
+/*! Reserved bit - do not use
+ * \warning We use this bit internally for iteration.  Additionally, using this
+ * bit will severely break the implementation of codec prefs within IAX2, as we
+ * rely on the equivalence of UTF-8 and ASCII.  The codec represented by this
+ * bit should use the first two-byte encoding of UTF-8, which is not presently
+ * accounted for.  Hence, we reserve this bit as unused.
+ */
 #define AST_FORMAT_RESERVED   (1ULL << 63)
 
 enum ast_control_frame_type {