1 files changed, 34 insertions, 11 deletions
diff --git a/src/hash/sysvchecksum.c b/src/hash/sysvchecksum.c
index a4ce824..d22270d 100644
--- a/src/hash/sysvchecksum.c
+++ b/src/hash/sysvchecksum.c
@@ -3,25 +3,48 @@
 #include <stdint.h>
 #include <math.h>
 
-uint32_t i_sysvchecksum(uint8_t *aa, size_t len){
-    uint32_t check = 0x0;
-    
-    for(int i = 0; i != len; i++){
-        check += aa[i];
-    }
-
-    uint32_t r = check % (int)pow(2,16) + (check % (int)pow(2,32)) / (int)pow(2,16);
-    return (r % (int)pow(2,16)) + r / (int)pow(2,16);
+struct sysvchecksum_hash sysvchecksum_init(){
+  return (struct sysvchecksum_hash){.check = 0};
 }
 
+void sysvchecksum_update(uint8_t* aa, size_t len, struct sysvchecksum_hash* hash){
+  for(int i = 0; i != len; i++)
+    hash->check += aa[i];
+}
+
+uint32_t sysvchecksum_final(struct sysvchecksum_hash* hash){
+  uint32_t r = hash->check % (int)pow(2,16) + (hash->check % (int)pow(2,32)) / (int)pow(2,16);
+  return (r % (int)pow(2,16)) + r / (int)pow(2,16);
+}
+
+uint32_t sysvchecksum(uint8_t* aa, size_t len){
+  struct sysvchecksum_hash a = sysvchecksum_init();
+  sysvchecksum_update(aa, len, &a);
+  return sysvchecksum_final(&a);
+}
+
+common_hash_init_update(sysvchecksum);
+
+int l_sysvchecksum_final(lua_State* L){
+  lua_pushstring(L, "ud");
+  lua_gettable(L, 1);
+
+  struct sysvchecksum_hash* a = (struct sysvchecksum_hash*)lua_touserdata(L, -1);
+  uint32_t u = sysvchecksum_final(a);
+  char digest[32];
+  sprintf(digest,"%x",u);
+  lua_pushstring(L, digest);
+  return 1;
+}
+ 
 int l_sysvchecksum(lua_State* L){
-  
+  if(lua_gettop(L) == 0) return l_sysvchecksum_init(L);
   size_t len = 0;
   uint8_t* a = (uint8_t*)luaL_checklstring(L, 1, &len);
   
   char digest[32];
 
-  uint32_t u = i_sysvchecksum(a, len);
+  uint32_t u = sysvchecksum(a, len);
   sprintf(digest,"%x",u);
   lua_pushstring(L, digest);