feat: vfs - path walking and dnode caching.

[lunaix-os.git] / lunaix-os / includes / lunaix / ds / hashtable.h

diff --git a/lunaix-os/includes/lunaix/ds/hashtable.h b/lunaix-os/includes/lunaix/ds/hashtable.h
new file mode 100644 (file)
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+++ b/lunaix-os/includes/lunaix/ds/hashtable.h
@@ -0,0 +1,49 @@
+/**
+ * @file hashtable.h Simple hash table implementation.
+ * Based on
+ * https://elixir.bootlin.com/linux/v5.18.12/source/include/linux/hashtable.h
+ * @author Lunaixsky (zelong56@gmail.com)
+ * @brief
+ * @version 0.1
+ * @date 2022-07-20
+ *
+ * @copyright Copyright (c) 2022
+ *
+ */
+#ifndef __LUNAIX_HASHTABLE_H
+#define __LUNAIX_HASHTABLE_H
+
+#include <lib/hash.h>
+#include <lunaix/ds/llist.h>
+
+struct hbucket
+{
+    struct hlist_node* head;
+};
+
+#define __hashkey(table, hash) (hash % (sizeof(table) / sizeof(table[0])))
+
+#define DECLARE_HASHTABLE(name, bucket_num) struct hbucket name[bucket_num];
+
+#define hashtable_bucket_foreach(bucket, pos, n, member)                       \
+    for (pos = list_entry((bucket)->head, typeof(*pos), member);               \
+         pos && ({                                                             \
+             n = list_entry(pos->member.next, typeof(*pos), member);           \
+             1;                                                                \
+         });                                                                   \
+         pos = n)
+
+#define hashtable_hash_foreach(table, hash, pos, n, member)                    \
+    hashtable_bucket_foreach(&table[__hashkey(table, hash)], pos, n, member)
+
+#define hashtable_init(table)                                                  \
+    {                                                                          \
+        for (int i = 0; i < (sizeof(table) / sizeof(table[0])); i++) {         \
+            table[i].head = 0;                                                 \
+        }                                                                      \
+    }
+
+#define hashtable_hash_in(table, list_node, hash)                              \
+    hlist_add(&table[__hashkey(table, hash)].head, list_node)
+
+#endif /* __LUNAIX_HASHTABLE_H */