diff options
| -rw-r--r-- | erts/emulator/beam/bif.tab | 1 | ||||
| -rw-r--r-- | erts/emulator/beam/erl_map.c | 66 | ||||
| -rw-r--r-- | erts/preloaded/src/erts_internal.erl | 12 |
3 files changed, 71 insertions, 8 deletions
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab index a6510ace81..ce2cffa498 100644 --- a/erts/emulator/beam/bif.tab +++ b/erts/emulator/beam/bif.tab @@ -671,3 +671,4 @@ bif math:floor/1 bif math:ceil/1 bif math:fmod/2 bif os:set_signal/2 +bif erts_internal:maps_to_list/2 diff --git a/erts/emulator/beam/erl_map.c b/erts/emulator/beam/erl_map.c index 9062e44b10..a80f5d6a16 100644 --- a/erts/emulator/beam/erl_map.c +++ b/erts/emulator/beam/erl_map.c @@ -91,7 +91,7 @@ static BIF_RETTYPE hashmap_merge(Process *p, Eterm nodeA, Eterm nodeB, int swap_ static Export hashmap_merge_trap_export; static BIF_RETTYPE maps_merge_trap_1(BIF_ALIST_1); static Uint hashmap_subtree_size(Eterm node); -static Eterm hashmap_to_list(Process *p, Eterm map); +static Eterm hashmap_to_list(Process *p, Eterm map, Sint n); static Eterm hashmap_keys(Process *p, Eterm map); static Eterm hashmap_values(Process *p, Eterm map); static Eterm hashmap_delete(Process *p, Uint32 hx, Eterm key, Eterm node, Eterm *value); @@ -161,13 +161,58 @@ BIF_RETTYPE maps_to_list_1(BIF_ALIST_1) { BIF_RET(res); } else if (is_hashmap(BIF_ARG_1)) { - return hashmap_to_list(BIF_P, BIF_ARG_1); + return hashmap_to_list(BIF_P, BIF_ARG_1, -1); } BIF_P->fvalue = BIF_ARG_1; BIF_ERROR(BIF_P, BADMAP); } +/* erts_internal:maps_to_list/2 + * + * This function should be removed once iterators are in place. + * Never document it. + * Never encourage its usage. + * + * A negative value in ARG 2 means the entire map. + */ + +BIF_RETTYPE erts_internal_maps_to_list_2(BIF_ALIST_2) { + Sint m; + if (term_to_Sint(BIF_ARG_2, &m)) { + if (is_flatmap(BIF_ARG_1)) { + Uint n; + Eterm* hp; + Eterm *ks,*vs, res, tup; + flatmap_t *mp = (flatmap_t*)flatmap_val(BIF_ARG_1); + + ks = flatmap_get_keys(mp); + vs = flatmap_get_values(mp); + n = flatmap_get_size(mp); + + if (m >= 0) { + n = m < n ? m : n; + } + + hp = HAlloc(BIF_P, (2 + 3) * n); + res = NIL; + + while(n--) { + tup = TUPLE2(hp, ks[n], vs[n]); hp += 3; + res = CONS(hp, tup, res); hp += 2; + } + + BIF_RET(res); + } else if (is_hashmap(BIF_ARG_1)) { + return hashmap_to_list(BIF_P, BIF_ARG_1, m); + } + BIF_P->fvalue = BIF_ARG_1; + BIF_ERROR(BIF_P, BADMAP); + } + BIF_ERROR(BIF_P, BADARG); +} + + /* maps:find/2 * return value if key *matches* a key in the map */ @@ -1917,15 +1962,22 @@ BIF_RETTYPE maps_values_1(BIF_ALIST_1) { BIF_ERROR(BIF_P, BADMAP); } -static Eterm hashmap_to_list(Process *p, Eterm node) { +static Eterm hashmap_to_list(Process *p, Eterm node, Sint m) { DECLARE_WSTACK(stack); Eterm *hp, *kv; - Eterm res = NIL; + Eterm tup, res = NIL; + Uint n = hashmap_size(node); - hp = HAlloc(p, hashmap_size(node) * (2 + 3)); + if (m >= 0) { + n = m < n ? m : n; + } + + hp = HAlloc(p, n * (2 + 3)); hashmap_iterator_init(&stack, node, 0); - while ((kv=hashmap_iterator_next(&stack)) != NULL) { - Eterm tup = TUPLE2(hp, CAR(kv), CDR(kv)); + while (n--) { + kv = hashmap_iterator_next(&stack); + ASSERT(kv != NULL); + tup = TUPLE2(hp, CAR(kv), CDR(kv)); hp += 3; res = CONS(hp, tup, res); hp += 2; diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl index a27cb2ba38..bcc779e6f6 100644 --- a/erts/preloaded/src/erts_internal.erl +++ b/erts/preloaded/src/erts_internal.erl @@ -31,7 +31,8 @@ -export([await_port_send_result/3]). -export([cmp_term/2]). --export([map_to_tuple_keys/1, term_type/1, map_hashmap_children/1]). +-export([map_to_tuple_keys/1, term_type/1, map_hashmap_children/1, + maps_to_list/2]). -export([open_port/2, port_command/3, port_connect/2, port_close/1, port_control/3, port_call/3, port_info/1, port_info/2]). @@ -369,6 +370,15 @@ map_hashmap_children(_M) -> Multi :: boolean(), Res :: term(). +%% return a list of key value pairs, at most of length N +-spec maps_to_list(M,N) -> Pairs when + M :: map(), + N :: integer(), + Pairs :: list(). + +maps_to_list(_M, _N) -> + erlang:nif_error(undefined). + %% erlang:demonitor(Ref, [flush]) traps to %% erts_internal:flush_monitor_messages(Ref, Res) when %% it needs to flush monitor messages. |