feat: vfs - path walking and dnode caching.

[lunaix-os.git] / lunaix-os / includes / lib / hash.h

diff --git a/lunaix-os/includes/lib/hash.h b/lunaix-os/includes/lib/hash.h
new file mode 100644 (file)
index 0000000..ad5e98b
--- /dev/null
+++ b/lunaix-os/includes/lib/hash.h
@@ -0,0 +1,26 @@
+#ifndef __LUNAIX_HASH_H
+#define __LUNAIX_HASH_H
+
+#include <stdint.h>
+
+#define HASH_SIZE_BITS 32
+
+uint32_t
+strhash_32(unsigned char* str, uint32_t truncate_to);
+
+/**
+ * @brief Simple generic hash function
+ *
+ * ref:
+ * https://elixir.bootlin.com/linux/v5.18.12/source/include/linux/hash.h#L60
+ *
+ * @param val
+ * @return uint32_t
+ */
+inline uint32_t
+hash_32(uint32_t val, uint32_t truncate_to)
+{
+    return (val * 0x61C88647u) >> (HASH_SIZE_BITS - truncate_to);
+}
+
+#endif /* __LUNAIX_HASH_H */