#include <stdlib.h>
long a64l(const char *s);
char *l64a(long l);
MT-Safe
The characters used to represent ‘‘digits’’ are . for 0, / for 1, 0 through 9 for 2-11, A through Z for 12-37, and a through z for 38-63.
a64l() takes a pointer to a null-terminated base-64 representation and returns a corresponding long value. If the string pointed to by s contains more than six characters, a64l() will use the first six.
a64l() scans the character string from left to right with the least significant digit on the left, decoding each character as a 6-bit radix-64 number.
l64a() takes a long argument and returns a pointer to the corresponding base-64 representation. If the argument is 0, l64a() returns a pointer to a null string.