character encoding scheme

character encoding
character encoding scheme

   <character> (Or "character encoding scheme") A mapping of
   {binary} values to {code positions} and back; generally a 1:1
   ({bijective}) mapping.

   In the case of {ASCII}, this is generally a f(x)=x mapping:
   code point 65 maps to the byte value 65, and vice versa.  This
   is possible because ASCII uses only code positions
   representable as single bytes, i.e., values between 0 and 255,
   at most.  ({US-ASCII} only uses values 0 to 127, in fact.)

   {Unicode} and many {CJK} {coded character sets} use many more
   than 255 positions, requiring more complex mappings: sometimes
   the characters are mapped onto pairs of bytes (see {DBCS}).
   In many cases, this breaks programs that assume a one-to-one
   mapping of bytes to characters, and so, for example, treat any
   occurrance of the byte value 13 as a {carriage return}.  To
   avoid this problem, character encodings such as {UTF-8} were
   devised.

   (1998-10-18)