I'd like to know the lenght in seconds of a wav file.

I have found how it is recorded but i cannot interpretate it.

the structure of the file is :

RIFF format (12 bytes) 

0 - 3     "RIFF" (ASCII Characters) 

4 - 7     Total Length Of Package To Follow (Binary, little endian) 

8 - 11     "WAVE" (ASCII Characters) 
  
  
FORMAT sector (24 bytes in length total) 

0 - 3     "fmt_" (ASCII Characters) 

4 - 7     Length Of FORMAT Chunk (Binary, always 0x10) 

8 - 9     Always 0x01 

10 - 11     Channel Numbers (Always 0x01=Mono, 0x02=Stereo) 

12 - 15     Sample Rate (Binary, in Hz) 

16 - 19     Bytes Per Second 

20 - 21     Bytes Per Sample: 1=8 bit Mono, 2=8 bit Stereo or 16 bit         Mono, 4=16 bit Stereo 

22 - 23     Bits Per Sample 

so my problem is how to read binary data.
For example what should I do to have the Total Length Of Package bytes 4 to 7 of the string ?

thanks
Alessio