Merged revisions 296084 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

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  r296084 | russell | 2010-11-24 14:23:46 -0600 (Wed, 24 Nov 2010) | 26 lines
  
  Merged revisions 296083 via svnmerge from 
  https://origsvn.digium.com/svn/asterisk/branches/1.6.2
  
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    r296083 | russell | 2010-11-24 14:23:11 -0600 (Wed, 24 Nov 2010) | 19 lines
    
    Merged revisions 296082 via svnmerge from 
    https://origsvn.digium.com/svn/asterisk/branches/1.4
    
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      r296082 | russell | 2010-11-24 14:22:32 -0600 (Wed, 24 Nov 2010) | 12 lines
      
      Fix false reporting of an error by set_format().
      
      In the case that the native format was able to be changed to match the
      new requested format, the code proceeded to attempt to build a translation
      path, anyway.  The result would be NULL, since no translation path is
      necessary and resulted in this function thinking an error has occurred.
      This case is now specifically caught and no attempt to build a translation
      path is attempted.
      
      Thanks to our automated tests and bamboo.asterisk.org for catching this problem
      and making a whole lot of noise when things started failing.  :-)
    ........
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@296085 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/channel.c

@@ -4994,13 +4994,23 @@ static int set_format(struct ast_channel *chan, format_t fmt, format_t *rawforma
 	if (*trans)
 		ast_translator_free_path(*trans);
 	/* Build a translation path from the raw format to the desired format */
-	if (!direction)
-		/* reading */
-		*trans = ast_translator_build_path(*format, *rawformat);
-	else
-		/* writing */
-		*trans = ast_translator_build_path(*rawformat, *format);
-	res = *trans ? 0 : -1;
+	if (*format == *rawformat) {
+		/*
+		 * If we were able to swap the native format to the format that
+		 * has been requested, then there is no need to try to build
+		 * a translation path.
+		 */
+		res = 0;
+	} else {
+		if (!direction) {
+			/* reading */
+			*trans = ast_translator_build_path(*format, *rawformat);
+		} else {
+			/* writing */
+			*trans = ast_translator_build_path(*rawformat, *format);
+		}
+		res = *trans ? 0 : -1;
+	}
 	ast_channel_unlock(chan);
 	ast_debug(1, "Set channel %s to %s format %s\n", chan->name,
 		direction ? "write" : "read", ast_getformatname(fmt));