Re: [Qemu-devel] [PATCH] qemu: json: Fix parsing of integers >= 0x8000000000000000

[Anthony Liguori]

On 05/23/2011 09:29 AM, Markus Armbruster wrote:
> Anthony Liguori<address@hidden>  writes:
>
> JavaScript's implementation of JSON sets limits on the range of numbers,
> namely they need to fit into IEEE doubles.
>
> Our implementation sets different limits.  IIRC, it's something like
> "numbers with a fractional part or an exponent need to fit into IEEE
> doubles, anything else into int64_t."  Not exactly the acme of elegance,
> either.  But it works for us.

In order to be compatible with JavaScript (which I think is necessary to 
really satisfy the spec), we just need to make sure that our integers 
are represented by at least 53-bits (to enable signed integers) and 
critically, fall back to floating point representation to ensure that we 
round instead of truncate.

Regards,

Anthony Liguori

>