The Annoyance Filter.pdf - Fourmilab

§100 ANNOYANCE-FILTER FLASH STREAM DECODER 83
}
}
get8 ( );
void getString (string &s, int n = −1); /∗ Bit field decoding methods ∗/
void initBits (void);
unsigned int getBits (int n);
int getSignedBits (const int n);
void getRect (rect ∗ r); /∗ Read a Rectangle specification ∗/
void getMatrix (matrix ∗ mat ); /∗ Read a Matrix definition ∗/
};
101. Read the header of the Flash file into memory, validating its signature.
〈 Class implementations 11 〉 +≡
void flashStream ::readHeader (void){ sig [0] = get8 ( );
sig [1] = get8 ( );
sig [2] = get8 ( ); if (isEOF ( ) ∨ (memcmp(sig , "FWS", 3) ≠ 0)) { error = true ;
if (verbose ) {
cerr ≪ "Invalid␣signature␣in␣Flash␣animation␣file." ≪ endl ;
}
return; } version = get8 ( );
fileLength = get32 ( );
getRect (&frameSize );
frameRate = get16 ( );
frameCount = get16 ( ); }
102. Write a primate-readable description of the Flash header on the output stream argument os ,
which defaults to cout .
〈 Class implementations 11 〉 +≡
void flashStream ::describe (ostream &os )
{
os ≪ "Flash␣animation␣version␣" ≪ static cast〈unsigned int〉(version ) ≪ endl ;
os ≪ "␣␣File␣length:␣" ≪ fileLength ≪ "␣bytes." ≪ endl ;
os ≪ "␣␣Frame␣size:␣␣X:␣" ≪ frameSize .xMin ≪ "␣−␣" ≪ frameSize .xMax ≪ "␣Y:␣" ≪
frameSize .yMin ≪ "␣−␣" ≪ frameSize .yMax ≪ endl ;
os ≪ "␣␣Frame␣rate:␣" ≪ setprecision (5) ≪ (frameRate /256.0) ≪ "␣fps." ≪ endl ;
os ≪ "␣␣Frame␣count:␣" ≪ frameCount ≪ endl ;
}