feat: adding protobuf decoder for parse of google auth migrations

lib/protobuf-decoder/varintUtils.js

@@ -0,0 +1,24 @@
+"use bigint"
+export function decodeVarint(buffer, offset) {
+  let res = BigInt(0);
+  let shift = 0;
+  let byte = 0;
+
+  do {
+    if (offset >= buffer.length) {
+      throw new RangeError("Index out of bound decoding varint");
+    }
+
+    byte = buffer[offset++];
+
+    const multiplier = exponentiate(BigInt(2), BigInt(shift));
+    const thisByteValue = multiply(BigInt(byte & 0x7f), multiplier);
+    shift += 7;
+    res = add(res, thisByteValue);
+  } while (byte >= 0x80);
+
+  return {
+    value: res,
+    length: shift / 7
+  };
+}