ubytes to ulong problem

[John Colvin]

On Saturday, 21 December 2013 at 23:52:05 UTC, Ali Çehreli wrote:
> On 12/21/2013 03:13 PM, John Colvin wrote:
>
> > Ideally the compiler will optimise your version to be fast,
> but you may
> > find you get better performance by doing the bit
> manipulations eplicitly:
>
> Assuming that the program needs to support only big endian and 
> little endian systems (i.e. excluding systems where no D 
> compiler exists :)), the following is less wordy and should be 
> equally fast:
>
> import std.bitmanip;
> import std.system;
>
> ulong ubytesToUlong(ubyte[] block, size_t n = 0)
> in
> {
>     assert (n >= 0);
>     assert (n + 8 <= block.length);
> }
> body
> {
>     ulong value = *cast(ulong*)(block.ptr + n);
>
>     if (std.system.endian == Endian.littleEndian) {
>         return *cast(ulong*)(value.nativeToBigEndian.ptr);
>
>     } else {
>         return value;
>     }
> }
>
> Ali

Nevermind equally fast, that will be much faster. -10 brain 
points for me tonight...