linux: vmcoreinfo API: significantly improve the performance when validating each character, from O(n) to O(1).. where n is 100 chars long

volatility3/framework/symbols/linux/__init__.py

@@ -903,7 +903,8 @@ class VMCoreInfo(interfaces.configuration.VersionableInterface):
         """Converts the input VMCoreInfo data buffer into a dictionary"""
 
         # Ensure the whole buffer is printable
-        if not all(char in string.printable.encode() for char in vmcoreinfo_data):
+        printable_bytes_set = set(string.printable.encode())
+        if not all(byte in printable_bytes_set for byte in vmcoreinfo_data):
             # Abort, we are in the wrong place
             return None