Re: [bug-gnulib] Re: base64

[Paul Eggert]

Simon Josefsson <address@hidden> writes:

>> I guesss this table assumes ASCII.  Do you want your code to be
>> portable to EBCDIC hosts?
>
> If it is easy to do without run-time computation of the table, yes.
> But I don't know how to.

One possibility is to do something like this:

  #define B64_DECODE(x) \
    ((x) == 'A' ? 0 \
     : (x) == 'B' ? 1 \
     : (x) == 'C' ? 2 \
     : ... \
     : -1)

  static const signed char b64[0x100] = {
    B64_DECODE (0),
    B64_DECODE (1),
    ...
    B64_DECODE (255)
  };

A bit crude, but the only other ways that spring to mind involve using
Autoconf.