From 3fdd4046c4306256233984e289898f24324273f9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Tue, 10 Mar 2015 09:04:56 +0100
Subject: erts: Add hashmap_iterator_prev to maps
---
erts/emulator/beam/erl_map.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
erts/emulator/beam/erl_map.h | 1 +
2 files changed, 46 insertions(+)
(limited to 'erts')
diff --git a/erts/emulator/beam/erl_map.c b/erts/emulator/beam/erl_map.c
index 5eafa69b06..65a31d3680 100644
--- a/erts/emulator/beam/erl_map.c
+++ b/erts/emulator/beam/erl_map.c
@@ -1758,6 +1758,51 @@ Eterm* hashmap_iterator_next(ErtsWStack* s) {
}
}
+Eterm* hashmap_iterator_prev(ErtsWStack* s) {
+ Eterm node, *ptr, hdr;
+ Uint32 sz,i;
+
+ for (;;) {
+ ASSERT(!WSTACK_ISEMPTY((*s)));
+ node = (Eterm) WSTACK_POP((*s));
+ if (is_non_value(node)) {
+ return NULL;
+ }
+ switch (primary_tag(node)) {
+ case TAG_PRIMARY_LIST:
+ return list_val(node);
+
+ case TAG_PRIMARY_BOXED:
+ ptr = boxed_val(node);
+ hdr = *ptr;
+ ASSERT(is_header(hdr));
+ switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
+ case HAMT_SUBTAG_HEAD_ARRAY:
+ ptr++;
+ case HAMT_SUBTAG_NODE_ARRAY:
+ ptr++;
+ i = 0;
+ while(i < 16) { WSTACK_PUSH((*s), (UWord)ptr[i++]); }
+ break;
+ case HAMT_SUBTAG_HEAD_BITMAP:
+ ptr++;
+ case HAMT_SUBTAG_NODE_BITMAP:
+ sz = hashmap_bitcount(MAP_HEADER_VAL(hdr));
+ ASSERT(sz < 17);
+ i = 0;
+ ptr++;
+ while(i < sz) { WSTACK_PUSH((*s), (UWord)ptr[i++]); }
+ break;
+ default:
+ erl_exit(1, "bad header");
+ }
+ break;
+
+ default:
+ erl_exit(1, "bad hamt node");
+ }
+ }
+}
const Eterm *erts_hashmap_get(Uint32 hx, Eterm key, Eterm node) {
Eterm *ptr, hdr;
Eterm th[2];
diff --git a/erts/emulator/beam/erl_map.h b/erts/emulator/beam/erl_map.h
index 659295184d..db22d461ce 100644
--- a/erts/emulator/beam/erl_map.h
+++ b/erts/emulator/beam/erl_map.h
@@ -102,6 +102,7 @@ int erts_validate_and_sort_map(map_t* map);
Uint hashmap_over_estimated_heap_size(Uint n);
void hashmap_iterator_init(struct ErtsWStack_* s, Eterm node);
Eterm* hashmap_iterator_next(struct ErtsWStack_* s);
+Eterm* hashmap_iterator_prev(struct ErtsWStack_* s);
int hashmap_key_hash_cmp(Eterm* ap, Eterm* bp);
Eterm erts_hashmap_from_array(ErtsHeapFactory*, Eterm *leafs, Uint n, int reject_dupkeys);
const Eterm *erts_hashmap_get(Uint32 hx, Eterm key, Eterm map);
--
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