* st.c (st_keys): define st_keys(). it writes each key to buffer.

* hash.c (rb_hash_keys): use st_keys() for performance improvement
  if st_data_t and VALUE are compatible.

* st.h: define macro ST_DATA_COMPATIBLE_P() to predicate whether
  st_data_t and passed type are compatible.

* configure.in: check existence of builtin function to use in
  ST_DATA_COMPATIBLE_P().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43885 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 29 insertions, 0 deletions

diff --git a/st.c b/st.c
index c8f72c68c8..1fbf1f5e7c 100644
--- a/st.c
+++ b/st.c
@@ -1091,6 +1091,35 @@ st_foreach(st_table *table, int (*func)(ANYARGS), st_data_t arg)
     return 0;
 }
 
+st_index_t
+st_keys(st_table *table, st_data_t *keys, st_index_t size)
+{
+    st_data_t key, never = (st_data_t)Qundef;
+    st_data_t *keys_start = keys;
+
+    if (table->entries_packed) {
+	st_index_t i;
+
+	if (size > table->real_entries) size = table->real_entries;
+	for (i = 0; i < size; i++) {
+	    key = PKEY(table, i);
+	    if (key == never) continue;
+	    *keys++ = key;
+	}
+    }
+    else {
+	st_table_entry *ptr = table->head;
+	st_data_t *keys_end = keys + size;
+	while (ptr && keys < keys_end) {
+	    key = ptr->key;
+	    if (key != never) *keys++ = key;
+	    ptr = ptr->fore;
+	}
+    }
+
+    return keys - keys_start;
+}
+
 #if 0  /* unused right now */
 int
 st_reverse_foreach(st_table *table, int (*func)(ANYARGS), st_data_t arg)