From 70fb1016bc06339b9fc51bb4674c38e3190880cc Mon Sep 17 00:00:00 2001
From: ame <ameliasquires@disroot.org>
Date: Sat, 31 Aug 2024 16:32:15 -0500
Subject: fix -O3 for sysvchecksum

---
 src/hash/sysvchecksum.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

(limited to 'src/hash/sysvchecksum.c')

diff --git a/src/hash/sysvchecksum.c b/src/hash/sysvchecksum.c
index 661ee8d..107a998 100644
--- a/src/hash/sysvchecksum.c
+++ b/src/hash/sysvchecksum.c
@@ -12,12 +12,15 @@ void sysvchecksum_update(uint8_t* aa, size_t len, struct sysvchecksum_hash* hash
     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);
+uint16_t sysvchecksum_final(struct sysvchecksum_hash* hash){
+  //uint16_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));
+  //rewrote from https://github.com/cxmcc/unixsums/blob/master/sysvsum/sysvsum.go, pow breaks with clang -O3 somehow
+  uint32_t r = (hash->check & 0xffff) + (hash->check >> 16);
+  return r & 0xffff + (r >> 16);
 }
 
-uint32_t sysvchecksum(uint8_t* aa, size_t len){
+uint16_t sysvchecksum(uint8_t* aa, size_t len){
   struct sysvchecksum_hash a = sysvchecksum_init();
   sysvchecksum_update(aa, len, &a);
   return sysvchecksum_final(&a);
@@ -28,8 +31,8 @@ common_hash_init_update(sysvchecksum);
 
 int l_sysvchecksum_final(lua_State* L){
   struct sysvchecksum_hash* a = (struct sysvchecksum_hash*)lua_touserdata(L, 1);
-  uint32_t u = sysvchecksum_final(a);
-  char digest[32];
+  uint16_t u = sysvchecksum_final(a);
+  char digest[16];
   sprintf(digest,"%x",u);
   lua_pushstring(L, digest);
   return 1;
@@ -40,9 +43,9 @@ int l_sysvchecksum(lua_State* L){
   size_t len = 0;
   uint8_t* a = (uint8_t*)luaL_checklstring(L, 1, &len);
   
-  char digest[32];
+  char digest[16];
 
-  uint32_t u = sysvchecksum(a, len);
+  uint16_t u = sysvchecksum(a, len);
   sprintf(digest,"%x",u);
   lua_pushstring(L, digest);
 
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