The Annoyance Filter.pdf - Fourmilab

§79 ANNOYANCE-FILTER SHIFT-JIS DECODER 69
79. The four additional characters added by the Macintosh are # 80 (backslash), # FD (copyright
symbol), # FE (trademark symbol), and # FF (ellipsis). We check for them and translate them into
plausible ISO 8859 replacements, expanding as necessary into multiple character sequences via the
pending string mechanism.
〈 Check for Macintosh-specific single byte characters and translate 79 〉 ≡
switch (c1 ) {
case # 80:
c1 = ’\\’; /∗ Macintosh backslash ∗/
break;
case # FD:
c1 = # A9; /∗ ISO 8859 c○ symbol ∗/
break;
case # FE: c1 = ’T’; /∗ Trademark ( TM ) symbol ∗/
pending = "M";
break;
case # FF: /∗ Ellipsis (“. . .”) ∗/
c1 = ’.’;
pending = "..";
break;
}
This code is used in section 76.
80. Unicode decoders.
The Unicode character set (itself a subset of the 32 bit ISO 10646 character set), uses a variety of
encoding schemes. The Unicode MBCSdecoder is the parent class for all specific Unicode decoders and
provides common services for them.
〈 Class definitions 10 〉 +≡
class Unicode MBCSdecoder : public MBCSdecoder {
public:
virtual string name (void)
{
return "Unicode";
}
virtual int getNextDecodedChar (void) = 0; /∗ Get next decoded byte ∗/
};