4 files changed, 80 insertions, 3 deletions

diff --git a/src/core/idhash.c b/src/core/idhash.c
index 67ae67ea..306c751f 100644
--- a/src/core/idhash.c
+++ b/src/core/idhash.c
@@ -1,5 +1,5 @@
 //
-// Copyright 2023 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2024 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -366,4 +366,26 @@ nni_id_alloc32(nni_id_map *m, uint32_t *idp, void *val)
 	NNI_ASSERT(id < (1ULL << 32));
 	*idp = (uint32_t) id;
 	return (rv);
-}
\ No newline at end of file
+}
+
+bool
+nni_id_visit(nni_id_map *m, uint64_t *keyp, void **valp, uint32_t *cursor)
+{
+	// cursor is just a cursor into the table
+	uint32_t index = *cursor;
+	while (index < m->id_cap) {
+		if (m->id_entries[index].val != NULL) {
+			if (valp != NULL) {
+				*valp = m->id_entries[index].val;
+			}
+			if (keyp != NULL) {
+				*keyp = m->id_entries[index].key;
+			}
+			*cursor = index + 1;
+			return true;
+		}
+		index++;
+	}
+	*cursor = index;
+	return (false);
+}
diff --git a/src/core/idhash.h b/src/core/idhash.h
index b2c07062..11cc7a08 100644
--- a/src/core/idhash.h
+++ b/src/core/idhash.h
@@ -1,5 +1,5 @@
 //
-// Copyright 2023 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2024 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -54,6 +54,7 @@ extern int   nni_id_alloc(nni_id_map *, uint64_t *, void *);
 extern int   nni_id_alloc32(nni_id_map *, uint32_t *, void *);
 extern int   nni_id_remove(nni_id_map *, uint64_t);
 extern void  nni_id_map_sys_fini(void);
+extern bool  nni_id_visit(nni_id_map *, uint64_t *, void **, uint32_t *);
 
 #define NNI_ID_MAP_INITIALIZER(min, max, flags)            \
 	{                                                  \
diff --git a/src/supplemental/util/idhash.c b/src/supplemental/util/idhash.c
index cf48df3e..4ededa31 100644
--- a/src/supplemental/util/idhash.c
+++ b/src/supplemental/util/idhash.c
@@ -60,3 +60,9 @@ nng_id_alloc(nng_id_map *map, uint64_t *id, void *val)
 {
 	return (nni_id_alloc(&map->m, id, val));
 }
+
+bool
+nng_id_visit(nng_id_map *map, uint64_t *id, void **valp, uint32_t *cursor)
+{
+	return (nni_id_visit(&map->m, id, valp, cursor));
+}
diff --git a/src/supplemental/util/idhash_test.c b/src/supplemental/util/idhash_test.c
index 5bbdc4fb..e0d472a0 100644
--- a/src/supplemental/util/idhash_test.c
+++ b/src/supplemental/util/idhash_test.c
@@ -182,6 +182,52 @@ test_id_set_out_of_range(void)
 	nng_id_map_free(m);
 }
 
+void
+test_id_visit(void)
+{
+	nng_id_map *m;
+	int         x, y;
+	uint64_t    id1;
+	uint64_t    id2;
+	int        *v1;
+	int        *v2;
+	uint32_t    cursor = 0;
+
+	NUTS_PASS(nng_id_map_alloc(&m, 10, 13, 0));
+
+	// We can insert outside the range forcibly.
+	NUTS_PASS(nng_id_set(m, 1, &x));
+	NUTS_PASS(nng_id_set(m, 100, &y));
+	NUTS_TRUE(nng_id_visit(m, &id1, (void **) &v1, &cursor));
+	NUTS_ASSERT(id1 == 1 || id1 == 100);
+	NUTS_ASSERT(v1 == &x || v1 == &y);
+	NUTS_TRUE(nng_id_visit(m, &id2, (void **) &v2, &cursor));
+	NUTS_ASSERT(id2 == 1 || id2 == 100);
+	NUTS_ASSERT(v2 == &x || v2 == &y);
+	NUTS_ASSERT(id1 != id2);
+	NUTS_ASSERT(v1 != v2);
+	NUTS_TRUE(!nng_id_visit(m, &id2, (void **) &v2, &cursor));
+	nng_id_map_free(m);
+}
+
+void
+test_id_visit_out_of_range(void)
+{
+	nng_id_map *m;
+	int         x, y;
+	uint64_t    id1;
+	int        *v1;
+	uint32_t    cursor = 1000;
+
+	NUTS_PASS(nng_id_map_alloc(&m, 10, 13, 0));
+
+	// We can insert outside the range forcibly.
+	NUTS_PASS(nng_id_set(m, 1, &x));
+	NUTS_PASS(nng_id_set(m, 100, &y));
+	NUTS_TRUE(!nng_id_visit(m, &id1, (void **) &v1, &cursor));
+	nng_id_map_free(m);
+}
+
 #define STRESS_LOAD 50000
 #define NUM_VALUES 1000
 
@@ -303,6 +349,8 @@ NUTS_TESTS = {
 	{ "id resize", test_id_resize },
 	{ "id dynamic", test_id_dynamic },
 	{ "id set out of range", test_id_set_out_of_range },
+	{ "id visit", test_id_visit },
+	{ "id visit out of range", test_id_visit_out_of_range },
 	{ "id stress", test_id_stress },
 	{ "id alloc long long", test_id_alloc_long_long },
 	{ NULL, NULL },