Tweak the handling of the frame list inside of ast_answer().

This does not change any behavior, but moves the frames from the local frame
list back to the channel read queue using an O(n) algorithm instead of O(n^2).


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@182553 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/channel.c

@@ -1801,7 +1801,7 @@ int __ast_answer(struct ast_channel *chan, unsigned int delay, int cdr_answer)
 					ast_frfree(cur);
 				}
 
-				AST_LIST_INSERT_TAIL(&frames, new, frame_list);
+				AST_LIST_INSERT_HEAD(&frames, new, frame_list);
 
 				/* if a specific delay period was requested, continue
 				 * until that delay has passed. don't stop just because
@@ -1837,8 +1837,7 @@ int __ast_answer(struct ast_channel *chan, unsigned int delay, int cdr_answer)
 
 			if (res == 0) {
 				ast_channel_lock(chan);
-				while ((cur = AST_LIST_LAST(&frames))) {
-					AST_LIST_REMOVE(&frames, cur, frame_list);
+				while ((cur = AST_LIST_REMOVE_HEAD(&frames, frame_list))) {
 					ast_queue_frame_head(chan, cur);
 					ast_frfree(cur);
 				}