btoa

btoa

   <tool, messaging, algorithm, file format> /B too A/ A {binary}
   to {ASCII} conversion utility.

   btoa is a {uuencode} or {base 64} equivalent which addresses
   some of the problems with the uuencode standard but not as
   many as the base 64 standard.  It avoids problems that some
   {hosts} have with spaces (e.g. conversion of groups of spaces
   to tabs) by not including them in its character set, but may
   still have problems on non-ASCII systems (e.g. {EBCDIC}).

   btoa is primarily used to transfer {binary files} between
   systems across connections which are not {eight-bit clean},
   e.g. {electronic mail}.

   btoa takes adjacent sets of four binary {octets} and encodes
   them as five ASCII {octets} using ASCII characters '!' through
   to 'u'.  Special characters are also used: 'x' marks the
   beginning or end of the archive; 'z' marks four consecutive
   zeros and 'y' (version 5.2) four consecutive spaces.

   Each group of four octets is processed as a 32-bit integer.
   Call this 'I'.  Let 'D' = 85^4.  Divide I by D.  Call this
   result 'R'.  Make I = I - (R * D) to avoid {overflow} on the
   next step.  Repeat, for values of D = 85^3, 85^2, 85 and 1.
   At each step, to convert R to the output character add decimal
   33 (output octet = R + ASCII value for '!').  Five output
   octets are produced.

   btoa provides some integrity checking in the form of a line
   {checksum}, and facilities for patching corrupted downloads.

   The {algorithm} used by btoa is more efficient than uuencode
   or base 64.  ASCII files are encoded to about 120% the size of
   their binary sources.  This compares with 135% for uuencode or
   base 64.

   C source (ftp://hpux.csc.liv.ac.uk/hpux/Misc/btoa-5.2/).
   (version 5.2 - ~1994).

   Pre-compiled {MS-DOS} versions are also available.

   (1997-08-08)
    

BTOA
       Binary TO ASCII (ASCII)