Rewrite unpack_/1 using pattern matching to get a 30-40% speedup.

Simplify pack_* and unpack_{array,map} function clauses to get more readability and a minor speedup.

1 files changed, 133 insertions, 177 deletions

diff --git a/erlang/msgpack.erl b/erlang/msgpack.erl
index 255542b..e94262d 100644
--- a/erlang/msgpack.erl
+++ b/erlang/msgpack.erl
@@ -42,8 +42,10 @@ pack(O) when is_float(O) ->
     pack_double(O);
 pack(nil) ->
     pack_nil();
-pack(Bool) when is_atom(Bool) ->
-    pack_bool(Bool);
+pack(true) ->
+    pack_true();
+pack(false) ->
+    pack_false();
 pack(Bin) when is_binary(Bin) ->
     pack_raw(Bin);
 pack(List)  when is_list(List) ->
@@ -61,13 +63,8 @@ pack(_O) ->
 % TODO: error case for imcomplete format when short for any type formats.
 -spec unpack( binary() )->
     {msgpack_term(), binary()} | {more, non_neg_integer()} | {error, reason()}.
-unpack(Bin) when not is_binary(Bin)->
-    {error, badarg};
-unpack(Bin) when bit_size(Bin) >= 8 ->
-    << Flag:8/unsigned-integer, Payload/binary >> = Bin,
-    unpack_(Flag, Payload);
-unpack(<<>>)-> % when bit_size(Bin) < 8 ->
-    {more, 1}.
+unpack(Bin) ->
+    unpack_(Bin).
 
 -spec unpack_all( binary() ) -> [msgpack_term()].
 unpack_all(Data)->
@@ -82,56 +79,52 @@ unpack_all(Data)->
 % ===== internal APIs ===== %
 
 % positive fixnum
-pack_uint_(N) when is_integer( N ) , N < 128 ->
+pack_uint_(N) when N < 128 ->
     << 2#0:1, N:7 >>;
 % uint 8
-pack_uint_( N ) when is_integer( N ) andalso N < 256 ->
+pack_uint_(N) when N < 256 ->
     << 16#CC:8, N:8 >>;
-
 % uint 16
-pack_uint_( N ) when is_integer( N ) andalso N < 65536 ->
+pack_uint_(N) when N < 65536 ->
     << 16#CD:8, N:16/big-unsigned-integer-unit:1 >>;
-
 % uint 32
-pack_uint_( N ) when is_integer( N ) andalso N < 16#FFFFFFFF->
+pack_uint_(N) when N < 16#FFFFFFFF->
     << 16#CE:8, N:32/big-unsigned-integer-unit:1 >>;
-
 % uint 64
-pack_uint_( N ) when is_integer( N )->
+pack_uint_(N) ->
     << 16#CF:8, N:64/big-unsigned-integer-unit:1 >>.
 
 % negative fixnum
-pack_int_( N ) when is_integer( N ) , N >= -32->
+pack_int_(N) when N >= -32->
     << 2#111:3, N:5 >>;
 % int 8
-pack_int_( N ) when is_integer( N ) , N >= -256 ->
+pack_int_(N) when N >= -256 ->
     << 16#D0:8, N:8 >>;
 % int 16
-pack_int_( N ) when is_integer( N ), N >= -65536 ->
+pack_int_(N) when N >= -65536 ->
     << 16#D1:8, N:16/big-signed-integer-unit:1 >>;
 % int 32
-pack_int_( N ) when is_integer( N ), N >= -16#FFFFFFFF ->
+pack_int_(N) when N >= -16#FFFFFFFF ->
     << 16#D2:8, N:32/big-signed-integer-unit:1 >>;
 % int 64
-pack_int_( N ) when is_integer( N )->
+pack_int_(N) ->
     << 16#D3:8, N:64/big-signed-integer-unit:1 >>.
 
-% nil
-pack_nil()->    << 16#C0:8 >>.
-% pack_true / pack_false
-pack_bool(true)->    << 16#C3:8 >>;
-pack_bool(false)->   << 16#C2:8 >>.
+% nil/true/false
+pack_nil() ->  << 16#C0:8 >>.
+pack_true()->  << 16#C3:8 >>.
+pack_false()-> << 16#C2:8 >>.
 
 % float : erlang's float is always IEEE 754 64bit format.
 %pack_float(F) when is_float(F)->
 %    << 16#CA:8, F:32/big-float-unit:1 >>.
 %    pack_double(F).
 % double
-pack_double(F) when is_float(F)->
+pack_double(F) ->
     << 16#CB:8, F:64/big-float-unit:1 >>.
 
 % raw bytes
-pack_raw(Bin) when is_binary(Bin)->
+pack_raw(Bin) ->
     case byte_size(Bin) of
 	Len when Len < 6->
 	    << 2#101:3, Len:5, Bin/binary >>;
@@ -142,24 +135,22 @@ pack_raw(Bin) when is_binary(Bin)->
     end.
 
 % list / tuple
-pack_array(L) when is_list(L)->
+pack_array(L) ->
     case length(L) of
  	Len when Len < 16 ->
  	    << 2#1001:4, Len:4/integer-unit:1, (pack_array_(L, <<>>))/binary >>;
 	Len when Len < 16#10000 -> % 65536
-	    << 16#DC:8, Len:16/big-unsigned-integer-unit:1,(pack_array_(L, <<>>))/binary >>;
+	    << 16#DC:8, Len:16/big-unsigned-integer-unit:1, (pack_array_(L, <<>>))/binary >>;
 	Len ->
-	    << 16#DD:8, Len:32/big-unsigned-integer-unit:1,(pack_array_(L, <<>>))/binary >>
+	    << 16#DD:8, Len:32/big-unsigned-integer-unit:1, (pack_array_(L, <<>>))/binary >>
     end.
 pack_array_([], Acc) -> Acc;
 pack_array_([Head|Tail], Acc) ->
     pack_array_(Tail, <<Acc/binary,  (pack(Head))/binary>>).
 
 % FIXME! this should be tail-recursive and without lists:reverse/1
-unpack_array_(<<>>, 0, RetList)   -> {lists:reverse(RetList), <<>>};
-unpack_array_(Remain, 0, RetList) when is_binary(Remain)-> {lists:reverse(RetList), Remain};
-unpack_array_(<<>>, RestLen, _RetList) when RestLen > 0 ->  {more, RestLen};
-unpack_array_(Bin, RestLen, RetList) when is_binary(Bin)->
+unpack_array_(Remain, 0, RetList) -> {lists:reverse(RetList), Remain};
+unpack_array_(Bin, RestLen, RetList) ->
     case unpack(Bin) of
 	{more, Len} -> {more, Len+RestLen-1};
 	{Term, Rest}-> unpack_array_(Rest, RestLen-1, [Term|RetList])
@@ -181,10 +172,10 @@ pack_map_([{Key,Value}|Tail], Acc) ->
     pack_map_(Tail, << Acc/binary, (pack(Key))/binary, (pack(Value))/binary>>).
 
 % FIXME: write test for unpack_map/1
--spec unpack_map_(binary(), non_neg_integer(), [{term(), msgpack_term()}])->
-    {more, non_neg_integer()} | { any(), binary()}.
-unpack_map_(Bin,  0,  Acc) when is_binary(Bin) -> {{lists:reverse(Acc)}, Bin};
-unpack_map_(Bin, Len, Acc) when is_binary(Bin) and is_integer(Len) ->
+-spec unpack_map_(binary(), non_neg_integer(), [{term(), msgpack_term()}]) ->
+    {more, non_neg_integer()} | {any(), binary()}.
+unpack_map_(Bin,  0,  Acc) -> {{lists:reverse(Acc)}, Bin};
+unpack_map_(Bin, Len, Acc) ->
     case unpack(Bin) of
 	{ more, MoreLen } -> { more, MoreLen+Len-1 };
 	{ Key, Rest } ->
@@ -195,142 +186,107 @@ unpack_map_(Bin, Len, Acc) when is_binary(Bin) and is_integer(Len) ->
 	    end
     end.
 
-% {more, <remaining byte size>
--spec unpack_(Flag::integer(), Payload::binary())->
-    {more, pos_integer()} | {msgpack_term(), binary()} | {error, reason()}.
-unpack_(Flag, Payload)->
-    PayloadLen = byte_size(Payload),
-    case Flag of
-	16#C0 ->
-	    {nil, Payload};
-	16#C2 ->
-	    {false, Payload};
-	16#C3 ->
-	    {true, Payload};
-
-	16#CA when PayloadLen >= 4 -> % 32bit float
-	    << Return:32/float-unit:1, Rest/binary >> = Payload,
-	    {Return, Rest};
-	16#CA ->
-	    {more, 4-PayloadLen}; % at least more
-
-	16#CB when PayloadLen >= 8 -> % 64bit float
-	    << Return:64/float-unit:1, Rest/binary >> = Payload,
-	    {Return, Rest};
-	16#CB ->
-	    {more, 8-PayloadLen};
-
-	16#CC when PayloadLen >= 1 -> % uint 8
-	    << Int:8/unsigned-integer, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#CC ->
-	    {more, 1};
-
-	16#CD when PayloadLen >= 2 -> % uint 16
-	    << Int:16/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#CD ->
-	    {more, 2-PayloadLen};
-
-	16#CE when PayloadLen >= 4 ->
-	    << Int:32/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#CE ->
-	    {more, 4-PayloadLen}; % at least more
-
-	16#CF when PayloadLen >= 8 ->
-	    << Int:64/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#CF ->
-	    {more, 8-PayloadLen};
-
-	16#D0 when PayloadLen >= 1 -> % int 8
-	    << Int:8/big-signed-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#D0 ->
-	    {more, 1};
-
-	16#D1 when PayloadLen >= 2 -> % int 16
-	    << Int:16/big-signed-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#D1 ->
-	    {more, 2-PayloadLen};
-
-	16#D2 when PayloadLen >= 4 -> % int 32
-	    << Int:32/big-signed-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#D2 ->
-	    {more, 4-PayloadLen};
-
-	16#D3 when PayloadLen >= 8 -> % int 64
-	    << Int:64/big-signed-integer-unit:1, Rest/binary >> = Payload,
-	    {Int, Rest};
-	16#D3 ->
-	    {more, 8-PayloadLen};
-
-	16#DA when PayloadLen >= 2 -> % raw 16
-	    << Len:16/unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    << Return:Len/binary, Remain/binary >> = Rest,
-	    {Return, Remain};
-	16#DA ->
-	    {more, 16-PayloadLen};
-
-	16#DB when PayloadLen >= 4 -> % raw 32
-	    << Len:32/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    << Return:Len/binary, Remain/binary >> = Rest,
-	    {Return, Remain};
-	16#DB ->
-	    {more, 4-PayloadLen};
-
-	16#DC when PayloadLen >= 2 -> % array 16
-	    << Len:16/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    unpack_array_(Rest, Len, []);
-	16#DC ->
-	    {more, 2-PayloadLen};
-
-	16#DD when PayloadLen >= 4 -> % array 32
-	    << Len:32/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    unpack_array_(Rest, Len, []);
-	16#DD ->
-	    {more, 4-PayloadLen};
-
-	16#DE when PayloadLen >= 2 -> % map 16
-	    << Len:16/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    unpack_map_(Rest, Len, []);
-	16#DE ->
-	    {more, 2-PayloadLen};
-
-	16#DF when PayloadLen >= 4 -> % map 32
-	    << Len:32/big-unsigned-integer-unit:1, Rest/binary >> = Payload,
-	    unpack_map_(Rest, Len, []);
-
-	% positive fixnum
-	Code when Code >= 2#00000000, Code < 2#10000000->
-	    {Code, Payload};
-
-	% negative fixnum
-	Code when Code >= 2#11100000 ->
-	    {(Code - 16#100), Payload};
-
-	Code when Code >= 2#10100000 , Code < 2#11000000 ->
-%	 101XXXXX for FixRaw
-	    Len = Code rem 2#10100000,
-	    << Return:Len/binary, Remain/binary >> = Payload,
-	    {Return, Remain};
-
-	Code when Code >= 2#10010000 , Code < 2#10100000 ->
-%        1001XXXX for FixArray
-	    Len = Code rem 2#10010000,
-	    unpack_array_(Payload, Len, []);
-
-	Code when Code >= 2#10000000 , Code < 2#10010000 ->
-%        1000XXXX for FixMap
-	    Len = Code rem 2#10000000,
-	    unpack_map_(Payload, Len, []);
-
-	_Other ->
-	    {error, no_code_matches}
-    end.
+
+-spec unpack_(Payload::binary()) -> {more, pos_integer()} | {msgpack_term(), binary()} | {error, reason()}.
+unpack_(<<16#C0, Rest/binary>>) ->
+    {nil, Rest};
+unpack_(<<16#C2, Rest/binary>>) ->
+    {false, Rest};
+unpack_(<<16#C3, Rest/binary>>) ->
+    {true, Rest};
+
+unpack_(<<16#CA, Return:32/float-unit:1, Rest/binary>>) -> % 32bit float
+    {Return, Rest};
+unpack_(<<16#CA, Rest/binary>>) ->
+    {more, 4-byte_size(Rest)};
+unpack_(<<16#CB, Return:64/float-unit:1, Rest/binary>>) -> % 64bit float
+    {Return, Rest};
+unpack_(<<16#CB, Rest/binary>>) ->
+    {more, 8-byte_size(Rest)};
+
+unpack_(<<16#CC, Int:8/unsigned-integer, Rest/binary>>) -> % uint 8
+    {Int, Rest};
+unpack_(<<16#CC>>) ->
+    {more, 1};
+unpack_(<<16#CD, Int:16/big-unsigned-integer-unit:1, Rest/binary>>) -> % uint 16
+    {Int, Rest};
+unpack_(<<16#CD, Rest/binary>>) ->
+    {more, 2-byte_size(Rest)};
+unpack_(<<16#CE, Int:32/big-unsigned-integer-unit:1, Rest/binary>>) -> % uint 32
+    {Int, Rest};
+unpack_(<<16#CE, Rest/binary>>) ->
+    {more, 4-byte_size(Rest)};
+unpack_(<<16#CF, Int:64/big-unsigned-integer-unit:1, Rest/binary>>) -> % uint 64
+    {Int, Rest};
+unpack_(<<16#CF, Rest/binary>>) ->
+    {more, 8-byte_size(Rest)};
+
+unpack_(<<16#D0, Int:8/signed-integer, Rest/binary>>) -> % int 8
+    {Int, Rest};
+unpack_(<<16#D0>>) ->
+    {more, 1};
+unpack_(<<16#D1, Int:16/big-signed-integer-unit:1, Rest/binary>>) -> % int 16
+    {Int, Rest};
+unpack_(<<16#D1, Rest/binary>>) ->
+    {more, 2-byte_size(Rest)};
+unpack_(<<16#D2, Int:32/big-signed-integer-unit:1, Rest/binary>>) -> % int 32
+    {Int, Rest};
+unpack_(<<16#D2, Rest/binary>>) ->
+    {more, 4-byte_size(Rest)};
+unpack_(<<16#D3, Int:64/big-signed-integer-unit:1, Rest/binary>>) -> % int 64
+    {Int, Rest};
+unpack_(<<16#D3, Rest/binary>>) ->
+    {more, 8-byte_size(Rest)};
+
+unpack_(<<16#DA, Len:16/unsigned-integer-unit:1, Val:Len/binary, Rest/binary>>) -> % raw 16
+    {Val, Rest};
+unpack_(<<16#DA, Rest/binary>>) ->
+    {more, 16-byte_size(Rest)};
+unpack_(<<16#DB, Len:32/unsigned-integer-unit:1, Val:Len/binary, Rest/binary>>) -> % raw 32
+    {Val, Rest};
+unpack_(<<16#DB, Rest/binary>>) ->
+    {more, 32-byte_size(Rest)};
+
+unpack_(<<16#DC, Len:16/big-unsigned-integer-unit:1, Rest/binary>>) -> % array 16
+    unpack_array_(Rest, Len, []);
+unpack_(<<16#DC, Rest/binary>>) ->
+    {more, 2-byte_size(Rest)};
+unpack_(<<16#DD, Len:32/big-unsigned-integer-unit:1, Rest/binary>>) -> % array 32
+    unpack_array_(Rest, Len, []);
+unpack_(<<16#DD, Rest/binary>>) ->
+    {more, 4-byte_size(Rest)};
+
+unpack_(<<16#DE, Len:16/big-unsigned-integer-unit:1, Rest/binary>>) -> % map 16
+    unpack_map_(Rest, Len, []);
+unpack_(<<16#DE, Rest/binary>>) ->
+    {more, 2-byte_size(Rest)};
+unpack_(<<16#DF, Len:32/big-unsigned-integer-unit:1, Rest/binary>>) -> % map 32
+    unpack_map_(Rest, Len, []);
+unpack_(<<16#DF, Rest/binary>>) ->
+    {more, 4-byte_size(Rest)};
+
+unpack_(<<0:1, Value:7, Rest/binary>>) -> % positive fixnum
+    {Value, Rest};
+unpack_(<<2#111:3, Value:5, Rest/binary>>) -> % negative fixnum
+    {Value - 2#100000, Rest};
+unpack_(<<2#101:3, Len:5, Value:Len/binary, Rest/binary>>) -> % fixraw
+    {Value, Rest};
+unpack_(<<2#101:3, Len:5, Rest/binary>>) ->
+    {more, Len-byte_size(Rest)};
+unpack_(<<2#1001:4, Len:4, Rest/binary>>) -> % fixarray
+    unpack_array_(Rest, Len, []);
+unpack_(<<2#1000:4, Len:4, Rest/binary>>) -> % fixmap
+    unpack_map_(Rest, Len, []);
+
+%unpack_(<<F:8, Rest/binary>>) when F==16#C1; F==16#C4; F==16#C5; F==16#C6; F==16#C7; F==16#C8; F==16#C9; F==16#D5; F==16#D6; F==16#D7; F==16#D8; F==16#D9->
+%    {error, {badarg, <<F, Rest/binary>>}}.
+%unpack_(Other) when is_binary(Bin) ->
+%    {more, 1}.
+unpack_(<<>>) ->
+    {more, 1}.
+unpack_(Other) ->
+    {error, {badarg, Other}}.
+
 
 % ===== test codes ===== %
 -include_lib("eunit/include/eunit.hrl").
@@ -419,7 +375,7 @@ unknown_test()->
 test_([]) -> 0;
 test_([S|Rest])->
     Pack = msgpack:pack(S),
-    {S, <<>>} = msgpack:unpack( Pack ),
+    ?assertEqual({S, <<>>}, msgpack:unpack(Pack)),
     1+test_(Rest).
 
 other_test()->