On Sat, Jul 16, 2011 at 6:21 AM, Christian Manning <cmanning...@gmail.com>wrote:
> Jonathan M Davis wrote: > > > On Thursday 14 July 2011 06:27:47 Andrei Alexandrescu wrote: > >> On 7/14/11 5:51 AM, Regan Heath wrote: > >> > That's my point. I need 8/16/32/64/128 bit versions and it really > would > >> > be better if there were general variants. My version are less than > >> > optimal, but do use intrinsics where possible. Someone else can do a > >> > far better job than I, and it really should be done once, by that > >> > person. Surely we have the infrastructure for someone to add this to > >> > phobos? If something this simple can't or won't be done, what hope do > >> > we have!? > >> > >> I think we should have these functions in std.bitmanip: > >> > >> T toBigEndian(T)(T val) if (isArithmetic!T || isSomeChar!T); > >> T toLittleEndian(T)(T val) if (isArithmetic!T || isSomeChar!T); > >> T bigEndianToNative(T)(T val) if (isArithmetic!T || isSomeChar!T); > >> T littleEndianToNative(T)(T val) if (isArithmetic!T || isSomeChar!T); > >> > >> That means all characters, all integers, and all floating point numbers. > >> The implementations would opportunistically use intrinsics and other > >> specialized means. > >> > >> The documentation should specify the relationship to htonl and ntohl. > >> > >> If there's a need for converting endianness of larger buffers, we might > >> add: > >> > >> ubyte[] toBigEndian(ubyte[] val); > >> ubyte[] toLittleEndian(ubyte[] val); > >> ubyte[] bigEndianToNative(ubyte[] val); > >> ubyte[] littleEndianToNative(ubyte[] val); > >> > >> They'd use std.algorithm.reverse internally as needed. > >> > >> It's a sweet piece of work. Anyone have the time to prepare a pull > >> request? > > > > I decided to take a crack at it, and it seems to be going pretty well, > > except that I can't seem to get the floating point values right. Somehow, > > when I compare a floating point value with the same value except that > it's > > had its endianness swapped twice, they return true for is but false for > > ==, which makes absolutely no sense to me. There's obviously either > > something that I don't understand about floating point values (or the > > relationship between is and ==) or a bug in dmd. It'd be one thing if I > > couldn't get the values to reverse properly, but when they're equal > > according to is but not ==, I have no idea how that could even be > > possible. > > > > - Jonathan M Davis > > I've managed to get floating points working with unions. How are you doing > it? Maybe you're triggering a bug somewhere > After you swap it, do you return the result as a double or as a long?