From 5cd20516567da82c60b5513c732e23db6918a4b6 Mon Sep 17 00:00:00 2001
From: ame <grantsquires@disroot.org>
Date: Fri, 3 Nov 2023 19:45:15 -0500
Subject: tons of checksums (i had fun:3)

---
 src/hash/fletcher.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 src/hash/fletcher.c

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

diff --git a/src/hash/fletcher.c b/src/hash/fletcher.c
new file mode 100644
index 0000000..2ed7e42
--- /dev/null
+++ b/src/hash/fletcher.c
@@ -0,0 +1,75 @@
+#include "../crypto.h"
+#include <stdio.h>
+#include <stdint.h>
+
+uint8_t i_fletcher8(uint8_t *aa, size_t len){
+    uint8_t s1 = 0, s2 = 0;
+
+    for(int i = 0; i != len; i++){
+        s1 = (s1 + aa[i]) % 15;
+        s2 = (s2 + s1) % 15;
+    }
+    return (s2 << 4) | s1;
+}
+
+uint16_t i_fletcher16(uint8_t *aa, size_t len){
+    uint16_t s1 = 0, s2 = 0;
+
+    for(int i = 0; i != len; i++){
+        s1 = (s1 + aa[i]) % 255;
+        s2 = (s2 + s1) % 255;
+    }
+    return (s2 << 8) | s1;
+}
+
+uint32_t i_fletcher32(uint8_t *aa, size_t len){
+    uint32_t s1 = 0, s2 = 0;
+
+    for(int i = 0; i != len; i++){
+        s1 = (s1 + aa[i]) % 65535;
+        s2 = (s2 + s1) % 65535;
+    }
+    return (s2 << 16) | s1;
+}
+
+int l_fletcher32(lua_State* L){
+  
+  size_t len = 0;
+  uint8_t* a = (uint8_t*)luaL_checklstring(L, 1, &len);
+  
+  char digest[32];
+
+  uint32_t u = i_fletcher32(a, len);
+  sprintf(digest,"%x",u);
+  lua_pushstring(L, digest);
+
+  return 1;
+}
+
+int l_fletcher16(lua_State* L){
+  
+  size_t len = 0;
+  uint8_t* a = (uint8_t*)luaL_checklstring(L, 1, &len);
+  
+  char digest[16];
+
+  uint16_t u = i_fletcher16(a, len);
+  sprintf(digest,"%x",u);
+  lua_pushstring(L, digest);
+
+  return 1;
+}
+
+int l_fletcher8(lua_State* L){
+  
+  size_t len = 0;
+  uint8_t* a = (uint8_t*)luaL_checklstring(L, 1, &len);
+  
+  char digest[8];
+
+  uint8_t u = i_fletcher8(a, len);
+  sprintf(digest,"%x",u);
+  lua_pushstring(L, digest);
+
+  return 1;
+}
-- 
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