On 12/21/2013 03:52 PM, 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
Will that work even when the alignment is to odd bytes? Because that's
the case I was really worried about. The ubyte array is a packed
mixture of types, some of which are isolated bytes.
--
Charles Hixson
