Re: Dubious "checksum mismatch" message on log file

[luigi scarso <luigi.scarso@gmail.com>]

On Wed, Feb 1, 2012 at 2:48 PM, Vladimir Lomov <lomov.vl@gmail.com> wrote:
>> We have
>
>> $>vftovp txr.vf
>> (VTITLE )
>> (FAMILY TXR)
>> (FACE F MRR)
>> (CODINGSCHEME TEX TEXT)
>> (DESIGNSIZE R 10.0)
>> (COMMENT DESIGNSIZE IS IN POINTS)
>> (COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)
>> (CHECKSUM O 32212676346)
>
>> while from  luatex source
>
>> source/texk/web2c/luatexdir/font/vfovf.w:
>> @ process a local font in \.{VF} file
>> @c
>> static internal_font_number
>> vf_def_font(internal_font_number f, unsigned char *vf_buffer, int *vf_cr)
>> {
>> :
>> unsigned long checksum;
>>     cs.b0 = vf_buffer[(*vf_cr)];
>>     cs.b1 = vf_buffer[(*vf_cr) + 1];
>>     cs.b2 = vf_buffer[(*vf_cr) + 2];
>>     cs.b3 = vf_buffer[(*vf_cr) + 3];
>>     (*vf_cr) += 4;
>>     checksum = (unsigned)
>>         (cs.b0 * 256 * 256 * 256 + cs.b1 * 256 * 256 + cs.b2 * 256 + cs.b3);
>> :
>
>> if (checksum != 0 && font_checksum(k) != 0
>>             && checksum != font_checksum(k))
>>             vf_local_font_warning(f, k, "checksum mismatch", (int) checksum,
>>                                   (int) font_checksum(k));
>>         if (ds != font_dsize(k))
>>             vf_local_font_warning(f, k, "design size mismatch", ds,
>>                                   font_dsize(k));
>
>> It's not related to MKIV but to luatex, and it's a warning.
>> It doesn't even matter to have --modules==all, this vf file  in the
>> standard standalone.
>> Of course you must have the pfb/afm or otf or ttf file, as usual,
>> otherwise the pdf is wrong
>
> I was not sure, that why I began this thread. I started with latex example,
> then strip it down to plain tex one and after that came to context
> minimal example.
it's also in pdftex: see
function vf_def_font
in
src/texk/web2c/pdftexdir/pdftex.web

>
> AFAIU, context suite doesn't have "plain" pdftex and luatex formats,
> therefore I compile minimal plain tex example with TeX Live 2011, and
> luatex doesn't print such message though it reads vf file.
Hm, have a look at
tex/texmf-context/tex/generic/context/luatex

>
> The problem indeed may be it luatex and how it works with vf fonts, but
> as I said, I'm not sure (don't know very well either plain tex or context).
>
> P.S. Unrelated: seems I completely lost, I read web sources, the
> quoted extract from luatex source and I don't understand how this
> number '32212676346' can be presented as
>
> cs.b0 * 256 * 256 * 256 + cs.b1 * 256 * 256 + cs.b2 * 256 + cs.b3
>
> If I don't lose my math skills the '32212676346' is
> 32212676346=7·256^{4}+128·256^{3}+6·256^{2}+110·256^{1}+250·256^{0}
IIRC, 32212676346 should be the checksum stored inside the file, ie
the font_checksum.


-- 
luigi
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