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.

1 files changed, 49 insertions, 0 deletions

diff --git a/libctf/ctf-hash.c b/libctf/ctf-hash.c
index 03a398e..12bd6ef 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)
 {