1 files changed, 25 insertions, 0 deletions
diff --git a/common.h b/common.h
index 51e90ee..8be19b0 100644
--- a/common.h
+++ b/common.h
@@ -1,3 +1,5 @@
+#ifndef NERV_COMMON_H
+#define NERV_COMMON_H
 #include "lua.h"
 #include "lauxlib.h"
 #include "lualib.h"
@@ -5,6 +7,29 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+typedef struct HashNode {
+    const char *key;
+    void *val;
+    struct HashNode *next;
+} HashNode;
+
+typedef int (*HashMapCmp_t)(const char *a, const char *b);
+typedef size_t (*HashKey_t)(const char *key);
+
+typedef struct HashMap {
+    HashNode **bucket;
+    HashMapCmp_t cmp;
+    HashKey_t hfunc;
+    size_t size;
+} HashMap;
+
+HashMap *hashmap_create(size_t size, HashKey_t hfunc, HashMapCmp_t cmp);
+void *hashmap_getval(HashMap *h, const char *key);
+void hashmap_setval(HashMap *h, const char *key, void *val);
+
+size_t bkdr_hash(const char *key);
+
 int nerv_error(lua_State *L, const char *err_mesg_fmt, ...); 
 int nerv_error_method_not_implemented(lua_State *L);
 void luaN_append_methods(lua_State *L, const luaL_Reg *mlist);
+#endif