title: hash that maps strings to integers
body: <p>Looking for some hash function to make string to int mapping with following restrictions.</p>
  
  <p>restrictions: 
                Same strings go to same number.
                Different strings go to different numbers.
                During one run of application I am getting strings from same length, only in            the runtime I know the length.</p>
  
  <p>Any suggestions how to create the hash function ?</p>