libctf: add hash traversal helpers

There are two, ctf_dynhash_iter and ctf_dynhash_iter_remove: the latter
lets you return a nonzero value to remove the element being iterated
over.

Used in the next commit.

libctf/
	* ctf-impl.h (ctf_hash_iter_f): New.
	(ctf_dynhash_iter): New declaration.
	(ctf_dynhash_iter_remove): New declaration.
	* ctf-hash.c (ctf_dynhash_iter): Define.
	(ctf_dynhash_iter_remove): Likewise.
	(ctf_hashtab_traverse): New.
	(ctf_hashtab_traverse_remove): Likewise.
	(struct ctf_traverse_cb_arg): Likewise.
	(struct ctf_traverse_remove_cb_arg): Likewise.

3 files changed, 67 insertions, 0 deletions

diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index dd3113b316c..21b62e1db3f 100644
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,5 +1,17 @@
 2019-06-28  Nick Alcock <nick.alcock@oracle.com>
 
+	* ctf-impl.h (ctf_hash_iter_f): New.
+	(ctf_dynhash_iter): New declaration.
+	(ctf_dynhash_iter_remove): New declaration.
+	* ctf-hash.c (ctf_dynhash_iter): Define.
+	(ctf_dynhash_iter_remove): Likewise.
+	(ctf_hashtab_traverse): New.
+	(ctf_hashtab_traverse_remove): Likewise.
+	(struct ctf_traverse_cb_arg): Likewise.
+	(struct ctf_traverse_remove_cb_arg): Likewise.
+
+2019-06-28  Nick Alcock <nick.alcock@oracle.com>
+
 	* ctf-hash.c (ctf_dynhash_remove): Call with a mocked-up element.
 
 2019-06-28  Nick Alcock <nick.alcock@oracle.com>
diff --git a/libctf/ctf-hash.c b/libctf/ctf-hash.c
index 03a398e06c9..12bd6ef9b92 100644
--- a/libctf/ctf-hash.c
+++ b/libctf/ctf-hash.c
@@ -193,6 +193,55 @@ ctf_dynhash_lookup (ctf_dynhash_t *hp, const void *key)
   return NULL;
 }
 
+typedef struct ctf_traverse_cb_arg
+{
+  ctf_hash_iter_f fun;
+  void *arg;
+} ctf_traverse_cb_arg_t;
+
+static int
+ctf_hashtab_traverse (void **slot, void *arg_)
+{
+  ctf_helem_t *helem = *((ctf_helem_t **) slot);
+  ctf_traverse_cb_arg_t *arg = (ctf_traverse_cb_arg_t *) arg_;
+
+  arg->fun (helem->key, helem->value, arg->arg);
+  return 1;
+}
+
+void
+ctf_dynhash_iter (ctf_dynhash_t *hp, ctf_hash_iter_f fun, void *arg_)
+{
+  ctf_traverse_cb_arg_t arg = { fun, arg_ };
+  htab_traverse (hp->htab, ctf_hashtab_traverse, &arg);
+}
+
+typedef struct ctf_traverse_remove_cb_arg
+{
+  struct htab *htab;
+  ctf_hash_iter_remove_f fun;
+  void *arg;
+} ctf_traverse_remove_cb_arg_t;
+
+static int
+ctf_hashtab_traverse_remove (void **slot, void *arg_)
+{
+  ctf_helem_t *helem = *((ctf_helem_t **) slot);
+  ctf_traverse_remove_cb_arg_t *arg = (ctf_traverse_remove_cb_arg_t *) arg_;
+
+  if (arg->fun (helem->key, helem->value, arg->arg))
+    htab_clear_slot (arg->htab, slot);
+  return 1;
+}
+
+void
+ctf_dynhash_iter_remove (ctf_dynhash_t *hp, ctf_hash_iter_remove_f fun,
+                         void *arg_)
+{
+  ctf_traverse_remove_cb_arg_t arg = { hp->htab, fun, arg_ };
+  htab_traverse (hp->htab, ctf_hashtab_traverse_remove, &arg);
+}
+
 void
 ctf_dynhash_destroy (ctf_dynhash_t *hp)
 {
diff --git a/libctf/ctf-impl.h b/libctf/ctf-impl.h
index 44f049316f5..2601e1b082b 100644
--- a/libctf/ctf-impl.h
+++ b/libctf/ctf-impl.h
@@ -295,6 +295,9 @@ extern int ctf_hash_eq_string (const void *, const void *);
 
 typedef void (*ctf_hash_free_fun) (void *);
 
+typedef void (*ctf_hash_iter_f) (void *key, void *value, void *arg);
+typedef int (*ctf_hash_iter_remove_f) (void *key, void *value, void *arg);
+
 extern ctf_hash_t *ctf_hash_create (unsigned long, ctf_hash_fun, ctf_hash_eq_fun);
 extern int ctf_hash_insert_type (ctf_hash_t *, ctf_file_t *, uint32_t, uint32_t);
 extern int ctf_hash_define_type (ctf_hash_t *, ctf_file_t *, uint32_t, uint32_t);
@@ -308,6 +311,9 @@ extern int ctf_dynhash_insert (ctf_dynhash_t *, void *, void *);
 extern void ctf_dynhash_remove (ctf_dynhash_t *, const void *);
 extern void *ctf_dynhash_lookup (ctf_dynhash_t *, const void *);
 extern void ctf_dynhash_destroy (ctf_dynhash_t *);
+extern void ctf_dynhash_iter (ctf_dynhash_t *, ctf_hash_iter_f, void *);
+extern void ctf_dynhash_iter_remove (ctf_dynhash_t *, ctf_hash_iter_remove_f,
+				     void *);
 
 #define	ctf_list_prev(elem)	((void *)(((ctf_list_t *)(elem))->l_prev))
 #define	ctf_list_next(elem)	((void *)(((ctf_list_t *)(elem))->l_next))