Bitwise on String Operations: Define user permissions with bitwise operations

This class can define user permissions with bitwise operations.

It can define several types of user permissions as numbers that have one bit set like User, NormalAdmin, SysAdmin, Reading, Writing, ToAuthorize, Management, ContentManagement, Operator, SubOperator and Accounting.

The class can perform bitwise operations with different sets of permissions like and, or, xor, not and minus.