Re: [xml] Simplify XPath NaN, inf and -0 handling

On Tue, Nov 14, 2017 at 04:23:29PM +0100, Nick Wellnhofer wrote:
Here's are patch that I'd like to discuss before committing.

   Hi Nick,

  what do you really gain by this ?
Things which were known portable cross many platforms now become unclear again.
Trio might be deprecated, I would ask Daniel Stenberg first, so in copy,





Simplify XPath NaN, inf and -0 handling

Use C99 macros NAN, INFINITY, isnan, isinf. If they're not available:

- Assume that (0.0 / 0.0) generates a NaN and !(x == x) tests for NaN.
- Use C89's HUGE_VAL for INFINITY.

Remove manual handling of NaN, infinity and negative zero in functions
xmlXPathValueFlipSign and xmlXPathDivValues.

Remove xmlXPathGetSign. All the tests for negative zero can be replaced
with a test for negative or positive zero.

Simplify xmlXPathRoundFunction.

Remove Trio dependency.

This should work on IEEE 754 compliant implementations even if the C99
macros aren't available, but will likely break some ancient platforms.
If problems arise, my plan is to port the relevant trionan.c solution
to xpath.c. Note that non-compliant implementations are impossible
to fully support, anyway, since XPath requires IEEE 754.
xml mailing list, project page
xml gnome org

Daniel Veillard      | Red Hat Developers Tools
veillard redhat com  | libxml Gnome XML XSLT toolkit | virtualization library

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