Re: [Boost-users] [serialisation]Portable Binary Archives

From: Johan Råde (rade_at_[hidden])
Date: 2007-06-27 03:33:29

Cliff Green wrote:
>> Probably answered before, but I wondered whether there 
>> is a standard
>> implementation for portable binary archives available. 

[snip]

> If you're talking about portable binary archives for 
> Boost.Serialization, there's been talk, but I'm not sure 
> what the status is - anyone have an implementation? I'd be 
> willing to help / work with someone on it.

[snip]

> Integral byte swapping is pretty straight forward, but 
> floating point is not - besides the obvious representation 
> issues (e.g. IEEE 754 or not), there's some non-obvious 
> issues dealing with floating point normalization and 
> special values (infinity, etc). For example, I wrote one 
> template function which returned (by value) byte swapped 
> entities, but found it would silently change floating 
> point values depending on the value, platform, compiler 
> version, register usage, etc. Turns out normalization 
> would occur on the "by value" return, changing bits in the 
> byte swapped floating point number.

I'd be willing to help out with the floating point issues.

Last fall I wrote a library with portable fpclassify, isnan, signbit etc.
(It is available in the vault in the Math - Numerics folder.)
Several Boosters tested the library with more than 20 different
OS / compiler / processor combinations.
This experience taught me a lot about portable handling of floating point numbers.

--Johan Råde