Hardened implementation(fix some seg faults, out-of-bound access) found by fuzzer.

fuzzer/runner.py

@@ -0,0 +1,20 @@
+import os, sys
+import glob
+import subprocess
+
+def main():
+    for g in glob.glob("../tests/afl/id*"):
+        print(g)
+    
+        cmd = ["../a.out", g]
+
+        proc = subprocess.Popen(cmd)
+        try:
+            outs, errs = proc.communicate(timeout=15)
+            print(outs)
+        except TimeoutExpired:
+            proc.kill()
+            outs, errs = proc.communicate()
+
+
+main()