Re: Reading Float Data from a binary file into ada

[Maciej Sobczak <no.spam@no.spam.com>]

Steve wrote:

> The following snippet contains the pieces you need to do the conversion.
> 
>       TYPE aByte IS MOD 256;
> 
>       FOR aByte'SIZE USE 8;
> 
>       TYPE aByteArray IS ARRAY( Positive RANGE <> ) OF aByte;
> 
>       PRAGMA PACK( aByteArray );
> 
>       TYPE aFourBytes IS NEW aByteArray(1..4);
> 
>       FUNCTION Conv IS NEW Ada.Unchecked_Conversion( aFourBytes, float );
> 
>       ...
> 
>       a : float;
>       b : aFourBytes;
> 
>       ...
> 
>       a := Conv( b )
> 
> Use unchecked conversion to convert from a type that contains 4 bytes to the 
> float value you're looking for.

You have typed lots of lines of code to ensure that 4 bytes are treated 
as 4 bytes, but you did not provide any guarantee that Float has 4 bytes 
as well. You *can* rely on some assumptions about your compiler, but 
having these assumptions already in place anyway, is there a way to make 
the conversion simpler? Cannot you just read four bytes from the file 
directly to the Float variable using for example sequential or direct I/O?


-- 
Maciej Sobczak : http://www.msobczak.com/
Programming    : http://www.msobczak.com/prog/