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authorSverker Eriksson <[email protected]>2014-03-12 20:11:10 +0100
committerSverker Eriksson <[email protected]>2014-03-14 15:08:23 +0100
commitc543d5bff7fb23c3f44cc4817c0654117de78919 (patch)
tree2ef05bcb7ea4a167b69a2938009fe25a137cc6aa /erts
parent8fbe76d64e7d55eb41943484602b928658313a65 (diff)
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erts: Change external format for maps
to be: 116,Arity, K1,V1,K2,V2,...,Kn,Vn instead of: 116,Arity, K1,K2,...,Kn, V1,V2,....,Vn We think this will be better for future internal map structures like HAMT. Would be bad if we need to iterate twice over HAMT in term_to_binary, one for keys and one for values.
Diffstat (limited to 'erts')
-rw-r--r--erts/doc/src/erl_ext_dist.xml13
-rw-r--r--erts/emulator/beam/external.c55
-rw-r--r--erts/emulator/test/map_SUITE.erl19
3 files changed, 36 insertions, 51 deletions
diff --git a/erts/doc/src/erl_ext_dist.xml b/erts/doc/src/erl_ext_dist.xml
index 9a53f3f829..fa083db4c7 100644
--- a/erts/doc/src/erl_ext_dist.xml
+++ b/erts/doc/src/erl_ext_dist.xml
@@ -581,23 +581,20 @@
<cell align="center">1</cell>
<cell align="center">4</cell>
<cell align="center">N</cell>
- <cell align="center">M</cell>
</row>
<row>
<cell align="center">116</cell>
<cell align="center">Arity</cell>
- <cell align="center">Keys</cell>
- <cell align="center">Values</cell>
+ <cell align="center">Pairs</cell>
</row>
<tcaption></tcaption></table>
<p>
<c>MAP_EXT</c> encodes a map. The <c>Arity</c> field is an unsigned
4 byte integer in big endian format that determines the number of
- key-value pairs in the map. All key terms follow in the <c>Keys</c>
- section and then all value terms in the <c>Values</c> section. Keys
- and values are paired according to order; first key with first value
- and so on. Duplicate keys are <em>not allowed</em> within the same
- map.
+ key-value pairs in the map. Key and value pairs (<c>Ki => Vi</c>)
+ are encoded in the <c>Pairs</c> section in the following order:
+ <c>K1, V1, K2, V2,..., Kn, Vn</c>.
+ Duplicate keys are <em>not allowed</em> within the same map.
</p>
<p><em>Since: </em>OTP 17.0</p>
</section>
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 9671cde228..656de7c49a 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -2562,29 +2562,25 @@ enc_term_int(TTBEncodeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj, byte* ep,
{
map_t *mp = (map_t*)map_val(obj);
Uint size = map_get_size(mp);
- Eterm *mptr;
*ep++ = MAP_EXT;
put_int32(size, ep); ep += 4;
- /* Push values first */
if (size > 0) {
- mptr = map_get_values(mp);
+ Eterm *kptr = map_get_keys(mp);
+ Eterm *vptr = map_get_values(mp);
+
for (i = size-1; i >= 1; i--) {
WSTACK_PUSH(s, ENC_TERM);
- WSTACK_PUSH(s, (UWord) mptr[i]);
+ WSTACK_PUSH(s, (UWord) vptr[i]);
+ WSTACK_PUSH(s, ENC_TERM);
+ WSTACK_PUSH(s, (UWord) kptr[i]);
}
WSTACK_PUSH(s, ENC_TERM);
- WSTACK_PUSH(s, (UWord) mptr[0]);
-
- mptr = map_get_keys(mp);
- for (i = size-1; i >= 1; i--) {
- WSTACK_PUSH(s, ENC_TERM);
- WSTACK_PUSH(s, (UWord) mptr[i]);
- }
+ WSTACK_PUSH(s, (UWord) vptr[0]);
- obj = mptr[0];
+ obj = kptr[0];
goto L_jump_start;
}
}
@@ -3518,16 +3514,16 @@ dec_term_atom_common:
keys = make_tuple(hp);
*hp++ = make_arityval(size);
- kptr = hp;
hp += size;
+ kptr = hp - 1;
mp = (map_t*)hp;
hp += MAP_HEADER_SIZE;
- vptr = hp;
hp += size;
+ vptr = hp - 1;
- /* kptr, first word for keys
- * vptr, first word for values
+ /* kptr, last word for keys
+ * vptr, last word for values
*/
/*
@@ -3542,27 +3538,12 @@ dec_term_atom_common:
mp->keys = keys;
*objp = make_map(mp);
- /* We assume the map is wellformed, meaning:
- * - ascending key order
- * - unique keys
- */
-
- objp = vptr + size - 1;
- n = size;
-
- while (n-- > 0) {
- *objp = (Eterm) COMPRESS_POINTER(next);
- next = objp;
- objp--;
- }
-
- objp = kptr + size - 1;
- n = size;
-
- while (n-- > 0) {
- *objp = (Eterm) COMPRESS_POINTER(next);
- next = objp;
- objp--;
+ for (n = size; n; n--) {
+ *vptr = (Eterm) COMPRESS_POINTER(next);
+ *kptr = (Eterm) COMPRESS_POINTER(vptr);
+ next = kptr;
+ vptr--;
+ kptr--;
}
}
break;
diff --git a/erts/emulator/test/map_SUITE.erl b/erts/emulator/test/map_SUITE.erl
index 753d6f7727..888ed8e272 100644
--- a/erts/emulator/test/map_SUITE.erl
+++ b/erts/emulator/test/map_SUITE.erl
@@ -813,16 +813,16 @@ t_map_encode_decode(Config) when is_list(Config) ->
%% literally #{ b=>2, a=>1 } in the internal order
#{ a:=1, b:=2 } =
- erlang:binary_to_term(<<131,116,0,0,0,2,100,0,1,98,100,0,1,97,97,2,97,1>>),
+ erlang:binary_to_term(<<131,116,0,0,0,2,100,0,1,98,97,2,100,0,1,97,97,1>>),
%% literally #{ "hi" => "value", a=>33, b=>55 } in the internal order
#{ a:=33, b:=55, "hi" := "value"} = erlang:binary_to_term(<<131,116,0,0,0,3,
107,0,2,104,105, % "hi" :: list()
- 100,0,1,97, % a :: atom()
- 100,0,1,98, % b :: atom()
107,0,5,118,97,108,117,101, % "value" :: list()
+ 100,0,1,97, % a :: atom()
97,33, % 33 :: integer()
+ 100,0,1,98, % b :: atom()
97,55 % 55 :: integer()
>>),
@@ -834,11 +834,17 @@ t_map_encode_decode(Config) when is_list(Config) ->
%% uniqueness violation
%% literally #{ a=>1, "hi"=>"value", a=>2 }
{'EXIT',{badarg,[{_,_,_,_}|_]}} = (catch
- erlang:binary_to_term(<<131,116,0,0,0,3,100,0,1,97,107,0,2,104,105,100,0,1,97,97,1,107,0,5,118,97,108,117,101,97,2>>)),
+ erlang:binary_to_term(<<131,116,0,0,0,3,
+ 100,0,1,97,
+ 97,1,
+ 107,0,2,104,105,
+ 107,0,5,118,97,108,117,101,
+ 100,0,1,97,
+ 97,2>>)),
%% bad size (too large)
{'EXIT',{badarg,[{_,_,_,_}|_]}} = (catch
- erlang:binary_to_term(<<131,116,0,0,0,12,100,0,1,97,100,0,1,98,97,1,97,1>>)),
+ erlang:binary_to_term(<<131,116,0,0,0,12,100,0,1,97,97,1,100,0,1,98,97,1>>)),
%% bad size (too small) .. should fail just truncate it .. weird.
%% possibly change external format so truncated will be #{a:=1}
@@ -852,7 +858,8 @@ map_encode_decode_and_match([{K,V}|Pairs], EncodedPairs, M0) ->
B0 = erlang:term_to_binary(M1),
Ls = lists:sort(fun(A,B) -> erts_internal:cmp_term(A,B) < 0 end, [{K, erlang:term_to_binary(K), erlang:term_to_binary(V)}|EncodedPairs]),
%% sort Ks and Vs according to term spec, then match it
- ok = match_encoded_map(B0, length(Ls), [Kbin||{_,Kbin,_}<-Ls] ++ [Vbin||{_,_,Vbin}<-Ls]),
+ KVbins = lists:foldr(fun({_,Kbin,Vbin}, Acc) -> [Kbin,Vbin | Acc] end, [], Ls),
+ ok = match_encoded_map(B0, length(Ls), KVbins),
%% decode and match it
M1 = erlang:binary_to_term(B0),
map_encode_decode_and_match(Pairs,Ls,M1);