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-rw-r--r--erts/emulator/beam/bif.tab1
-rw-r--r--erts/emulator/beam/erl_map.c66
2 files changed, 60 insertions, 7 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;