Re: "byte orders" question
Re: "byte orders" question
- Subject: Re: "byte orders" question
- From: Charles Srstka <email@hidden>
- Date: Sat, 26 Nov 2011 17:37:21 -0600
If the source code that is sending you the data in the first place is your own code, you could have that code use the CFConvertFloat32ToSwapped() before sending it, and then your client can use CFConvertFloat32SwappedToHost() to convert it back, nice and easily.
At any rate, HostToBig is not what you want in the client, since you’re swapping it *to* the host byte order, not *from* it. CFSwapInt32BigToHost() would be more correct in that case, even though the two functions will both do the same thing in practice on a little-endian machine.
Charles
On Nov 26, 2011, at 5:24 PM, Koen van der Drift wrote:
>
> On Nov 26, 2011, at 6:17 PM, Koen van der Drift wrote:
>
>> Now I need to figure out how to go from u_int_32 to float.
>
>
> I think I figured it out:
>
> for (NSInteger n = 0; n < 4; n++)
> {
> u_int32_t value;
> [base64DecodedData getBytes:&value range:NSMakeRange(n*4, sizeof(u_int32_t))];
>
> u_int32_t res = CFSwapInt32HostToBig(value);
>
> float f;
>
> memcpy(&f, &res, sizeof(f));
> NSLog(@"%f", f);
>
> }
>
> This gives the expected four float values.
>
> Does this look ok, or did I overlook something?
>
> Thanks,
>
> - Koen._______________________________________________
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