Fix extracting 0 bytes from queue

2 files changed, 9 insertions, 4 deletions

diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl
index fbbe0a49c8..af9f0cbf3a 100644
--- a/lib/ssl/src/ssl_connection.erl
+++ b/lib/ssl/src/ssl_connection.erl
@@ -670,6 +670,8 @@ read_application_dist_data(DHandle, Front0, BufferSize, Rear0, Bin0) ->
             end
     end.
 
+iovec_from_front(0, Front, Rear, Acc) ->
+    {lists:reverse(Acc),Front,Rear};
 iovec_from_front(Size, [], Rear, Acc) ->
     iovec_from_front(Size, lists:reverse(Rear), [], Acc);
 iovec_from_front(Size, [Bin|Front], Rear, Acc) ->
diff --git a/lib/ssl/src/tls_record.erl b/lib/ssl/src/tls_record.erl
index 38022030ee..afbf95948d 100644
--- a/lib/ssl/src/tls_record.erl
+++ b/lib/ssl/src/tls_record.erl
@@ -489,16 +489,19 @@ validate_tls_record_length(Versions, {_,Size0,_} = Q0, Acc, Type, Version, Lengt
     end.
 
 
-binary_from_front(SplitSize, {Front,Size,Rear}) ->
+binary_from_front(0, Q) ->
+    {<<>>, Q};
+binary_from_front(SplitSize, {Front,Size,Rear}) when SplitSize =< Size ->
     binary_from_front(SplitSize, Front, Size, Rear, []).
 %%
+%% SplitSize > 0 and there is at least SplitSize bytes buffered in Front and Rear
 binary_from_front(SplitSize, [], Size, [_] = Rear, Acc) ->
-    %% Optimize a simple case
+    %% Optimize a simple case - avoid lists:reverse/1
     binary_from_front(SplitSize, Rear, Size, [], Acc);
-binary_from_front(SplitSize, [], Size, Rear, Acc) ->
+binary_from_front(SplitSize, [], Size, [_|_] = Rear, Acc) ->
     binary_from_front(SplitSize, lists:reverse(Rear), Size, [], Acc);
 binary_from_front(SplitSize, [Bin|Front], Size, Rear, []) ->
-    %% Optimize a frequent case
+    %% Optimize the frequent case when the accumulator is empty
     BinSize = byte_size(Bin),
     if
         SplitSize < BinSize ->