Re: [Qemu-devel] [PATCH v2 52/60] json: Eliminate lexer state IN_WHITESPACE, pseudo-token JSON_SKIP

[Eric Blake]

On 08/17/2018 10:05 AM, Markus Armbruster wrote:
> Bonus: static json_lexer[] loses its unused elements.  It shrinks from
> 8KiB to 4.75KiB for me.
>
> Signed-off-by: Markus Armbruster <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
> ---

>           ['a' ... 'z'] = IN_KEYWORD,
> -        [' '] = IN_WHITESPACE,
> -        ['\t'] = IN_WHITESPACE,
> -        ['\r'] = IN_WHITESPACE,
> -        ['\n'] = IN_WHITESPACE,
> +        [' '] = IN_START,
> +        ['\t'] = IN_START,
> +        ['\r'] = IN_START,
> +        ['\n'] = IN_START,
>       },
>       [IN_START_INTERPOL]['%'] = IN_INTERPOL,
> +    [IN_START_INTERPOL][' '] = IN_START_INTERPOL,
> +    [IN_START_INTERPOL]['\t'] = IN_START_INTERPOL,
> +    [IN_START_INTERPOL]['\r'] = IN_START_INTERPOL,
> +    [IN_START_INTERPOL]['\n'] = IN_START_INTERPOL,

Hmm, if we did this:

[IN_START_INTERPOL] {
  ['%'] = IN_INTERPOL,
  ['\t'] = IN_START_INTERPOL,
...
}

for similarity with all our other constructs, will gcc remember that 
we've already initialized other members not listed in the clause before, 
or will it mistakenly re-0-initialize the array members not mentioned?

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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