Minor translation performance improvement (bug #2987, not that patch though)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4393 65c4cc65-6c06-0410-ace0-fbb531ad65f3

translate.c

@@ -3,9 +3,9 @@
  *
  * Translate via the use of pseudo channels
  * 
- * Copyright (C) 1999, Mark Spencer
+ * Copyright (C) 1999-2004, Digium, Inc.
  *
- * Mark Spencer <markster@linux-support.net>
+ * Mark Spencer <markster@digium.com>
  *
  * This program is free software, distributed under the terms of
  * the GNU General Public License
@@ -442,15 +442,21 @@ int ast_translator_best_choice(int *dst, int *srcs)
 	int bestdst=0;
 	int cur = 1;
 	int besttime=999999999;
-	ast_mutex_lock(&list_lock);
+	if ((*dst) & (*srcs)) {
+		/* We have a format in common */
 		for (y=0;y<MAX_FORMAT;y++) {
 			if ((cur & *dst) && (cur & *srcs)) {
 				/* This is a common format to both.  Pick it if we don't have one already */
 				besttime=0;
 				bestdst = cur;
 				best = cur;
-			break;
 			}
+			cur = cur << 1;
+		}
+	} else {
+		/* We will need to translate */
+		ast_mutex_lock(&list_lock);
+		for (y=0;y<MAX_FORMAT;y++) {
 			if (cur & *dst)
 				for (x=0;x<MAX_FORMAT;x++) {
 					if (tr_matrix[x][y].step &&	/* There's a step */
@@ -464,11 +470,12 @@ int ast_translator_best_choice(int *dst, int *srcs)
 				}
 			cur = cur << 1;
 		}
+		ast_mutex_unlock(&list_lock);
+	}
 	if (best > -1) {
 		*srcs = best;
 		*dst = bestdst;
 		best = 0;
 	}
-	ast_mutex_unlock(&list_lock);
 	return best;
 }