Move import save functionality into SaveObject

Adds a lot of metadata to be able to easily compare the new save to the
current player.

- Adds lastSaved & identifier to the PlayerObject
- Includes a hash method used to generate an identifier

src/utils/StringHelperFunctions.ts

@@ -97,4 +97,31 @@ function generateRandomString(n: number): string {
   return str;
 }
 
-export { convertTimeMsToTimeElapsedString, longestCommonStart, containsAllStrings, formatNumber, generateRandomString };
+/**
+ * Hashes the input string. This is a fast hash, so NOT good for cryptography.
+ * This has been ripped off here: https://stackoverflow.com/a/52171480
+ * @param str The string that is to be hashed
+ * @param seed A seed to randomize the result
+ * @returns An hexadecimal string representation of the hashed input
+ */
+function cyrb53(str: string, seed = 0): string {
+  let h1 = 0xdeadbeef ^ seed;
+  let h2 = 0x41c6ce57 ^ seed;
+  for (let i = 0, ch; i < str.length; i++) {
+    ch = str.charCodeAt(i);
+    h1 = Math.imul(h1 ^ ch, 2654435761);
+    h2 = Math.imul(h2 ^ ch, 1597334677);
+  }
+  h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507) ^ Math.imul(h2 ^ (h2 >>> 13), 3266489909);
+  h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507) ^ Math.imul(h1 ^ (h1 >>> 13), 3266489909);
+  return (4294967296 * (2097151 & h2) + (h1 >>> 0)).toString(16);
+}
+
+export {
+  convertTimeMsToTimeElapsedString,
+  longestCommonStart,
+  containsAllStrings,
+  formatNumber,
+  generateRandomString,
+  cyrb53,
+};