The Annoyance Filter.pdf - Fourmilab

§119 ANNOYANCE-FILTER FLASH TEXT EXTRACTOR 97
119. The DefineFontInfo tag is crucial to decoding Flash text strings. Text in Flash files is stored a
glyph indices within a font. The font can, in the general case, be defined by an arbitrary stroked path
outline, independent of any standard character set. For fonts which employ standard character sets, the
optional DefineFontInfo identifies the character set and provides the mapping from the glyph indices to
characters in the font’s character set. We save these in maps indexed by the font ID so we can look
them up when we encounter text in that font.
〈 Parse Flash DefineFontInfo tag 119 〉 ≡
{
#ifdef FLASH_PARSE_DEBUG
cout ≪ "DefineFontInfo" ≪ endl ;
#endif
}
unsigned short fontID = get16 ( );
unsigned int fontNameLen = get8 ( );
string fontName ;
getString (fontName , fontNameLen );
if (¬textOnly ) {
strings .push (fontName );
}
fontFlags fFlags = static cast〈fontFlags〉(get8 ( ));
map〈unsigned short, unsigned short〉::iterator fp = fontGlyphCount .find (fontID );
if (fp ≡ fontGlyphCount .end ( )) {
if (verbose ) {
cerr ≪ "DefineFontInfo␣for␣font␣ID␣" ≪ fontID ≪
"␣without␣previous␣DefineFont." ≪ endl ;
}
ignoreTag (4);
}
else {
unsigned nGlyphs = fp ⃗ second ;
vector〈unsigned short〉 ∗v = new vector〈unsigned short〉(nGlyphs );
}
fontMap.insert (make pair (fontID , v));
fontInfoBits .insert (make pair (fontID , fFlags ));
for (unsigned int g = 0; g < nGlyphs ; g++) {
if (fFlags & fontWideCodes ) {
(∗v)[g] = get16 ( );
}
else {
(∗v)[g] = get8 ( );
}
}
This code is used in section 115.