Re: [Haskell-cafe] ANNOUNCE: storable-endian

On Fri, 24 Dec 2010 11:36:23 +0100, Eugene Kirpichov wrote:

Hello,

2010/12/24 Henning Thielemann :

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Maybe you succeed to find out machine endianess at compile time. Then you could use native memory access if the user requested endianess is the one of the machine. If you achieve this, you could implement peek and poke of Float and Double by just reversing the byte order into an 'alloca'd memory area and peek from and poke into this one with a native peek or poke, respectively. That is you would not need any unsafeCoerce anymore. I don't think I'd like to allocate memory in these functions - I expect them to have very predictable and very high performance. I'm using unsafeCoerce because it allows me to treat all these types in the same fashion (which is good for correctness and readability), and unsafeCoerce's semantics is identical to what is expected of this code - interpret a memory area as a value of a different type.

You're right however that some support could be added for host endianness - once I think something up, I'll do it; maybe this could be done with a couple unsafePerformIOs and runtime tests :)

You could use ADNS.Endian.endian from package hsdns in your Setup.hs to define endianness at compile time. Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html --