The Annoyance Filter.pdf - Fourmilab

60 QUOTED-PRINTABLE MIME DECODER ANNOYANCE-FILTER §65
65. The static method decodeEscapedText decodes text in its string argument, returning a string
with escape sequences replaced by the encoded characters.
〈 Class implementations 11 〉 +≡
string quotedPrintableMIMEdecoder ::decodeEscapedText (const string s, mailFolder ∗m)
{
string r = "";
}
string ::size type p;
for (p = 0; p < s.length ( ); p++) {
bool decoded = false ;
if (s[p] ≡ ’=’) {
if (p > (s.length ( ) − 3)) {
if (verbose ) {
cerr ≪ "decodeEscapedText:␣escape␣too␣near␣end␣of␣string:␣" ≪ s ≪ endl ;
}
}
else {
int n1 = hex to nybble (s[p + 1]), n2 = hex to nybble (s[p + 2]);
if ((n1 < 0) ∨ (n2 < 0)) {
if (verbose ) {
cerr ≪ "decodeEscapedText:␣invalid␣escape␣sequence␣\"" ≪ s.substr (p,
3) ≪ "\"" ≪ endl ;
}
}
else {
r += static cast〈char〉((n1 ≪ 4) | n2 );
decoded = true ;
p += 2;
}
}
}
if (¬decoded ) {
r += s[p];
}
}
return r;