Description

   The a64l and l64a functions are used to maintain numbers stored
   in base-64 ASCII characters as follows:

   o  a64l converts a character string to a long integer.

   o  l64a converts a long integer to a character string.

   Each character used for storing a long integer represents a
   numeric value from 0 through 63. Up to six characters can be
   used to represent a long integer.

   The characters are translated as follows:

   o  A period (.)  represents 0.

   o  A slash (/)  represents 1.

   o  The numbers 0 through 9 represent 2 through 11.

   o  Uppercase letters A through Z represent 12 through 37.

   o  Lowercase letters a through z represent 38 through 63.

   The a64l function takes a pointer to a base-64 representation,
   in which the first digit is the least significant, and returns
   a corresponding long value. If the string pointed to by the s
   parameter exceeds six characters, a64l uses only the first six
   characters.

   If the first six characters of the string contain a null
   terminator, a64l uses only characters preceding the null
   terminator.

   The a64l function translates a character string from left to
   right with the least significant number on the left, decoding
   each character as a 6-bit base-64 number.

   If s is the NULL pointer or if the string pointed to by s was
   not generated by a previous call to l64a, the behavior of a64l is
   unspecified.

   See also l64a.