The Annoyance Filter.pdf - Fourmilab

§15 ANNOYANCE-FILTER DICTIONARY WORD 23
}
}
16. This method writes a binary representation of the word to an output stream. This is used to create
the binary word database used to avoid rebuilding the letter and character category counts every time. Each
entry begins with the number of characters in the word followed by its text. After this, the count and
probability fields are output in portable big-endian format. We do assume IEEE floating point compatibility
across platforms, but auto-detect floating point byte order.
〈 Class implementations 11 〉 +≡
void dictionaryWord ::exportToBinaryFile (ostream &os ){ unsigned char c;
const unsigned char ∗fp;
const double k1 = −1.0;
#define outCount (x)c = (x); os .put (c)
#define outNumber (x)os .put ((x ≫ 24) & # FF);
os .put ((x ≫ 16) & # FF);
os .put ((x ≫ 8) & # FF); os .put (x & # FF)
outCount (text .length ( ));
os .write (text .data ( ), text .length ( ));
outNumber (n mail ( ));
outNumber (n junk ( ));
fp = reinterpret cast〈const unsigned char ∗〉(&k1 );
if (fp[0] ≡ 0) {
fp = reinterpret cast〈unsigned char ∗〉(&junkProbability );
for (unsigned int i = 0; i < (sizeof junkProbability ); i++) {
outCount (fp[((sizeof junkProbability ) − 1) − i]);
}
}
else { /∗ Big-endian platform ∗/
os .write (reinterpret cast〈const char ∗〉(&junkProbability ), sizeof junkProbability );
}
#undef outCount
#undef outNumber
}