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Re: Inconsistent...

From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c
Subject Re: Inconsistent...
Date 2023-11-01 00:39 +0000
Organization A noiseless patient Spider
Message-ID <87a5ryqpc5.fsf@bsb.me.uk> (permalink)
References (2 earlier) <uhpndq$3c4tj$1@i2pn2.org> <87lebjqb6g.fsf@bsb.me.uk> <uhr28e$3dnb9$1@i2pn2.org> <87fs1qrcns.fsf@bsb.me.uk> <uhrhdm$3edkt$1@i2pn2.org>

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bart <bc@freeuk.com> writes:

> [Another repost as i2pn2 not always sending my messges]
>
> On 31/10/2023 16:15, Ben Bacarisse wrote:
>> bart <bc@freeuk.com> writes:
>>
>>> [Reposting as the original reply seems to have vanished, but it may
>>> reappear]
>>>
>>> On 31/10/2023 11:32, Ben Bacarisse wrote:
>>>> bart <bc@freeuk.com> writes:
>>>>
>>>>> On 30/10/2023 23:22, bart wrote:
>>>>>> On 30/10/2023 21:01, Chris M. Thomasson wrote:
>>>>
>>>>>> I tweaked the source code (used explicit assignment to fields of some
>>>>>> structs) to be able to use my compilers.
>>>>>> Then I tried these compilers:
>>>>>> gcc 13.2.0 - this worked. (I assume it is supposed to show some
>>>>>> plaintext, encrypted text starting "fog.IiQ' U'?zDjP))v$oN)?z<xT
>>>>>> CAPNKUfB...", then the identical plaintext)
>>>>>> tcc - failed. The encrypted text started
>>>>>> "xy,$}lu~@NM*a%^z1YA+'N@9yrV]E...", and the decrypted was:
>>>>>>
>>>
>    "dEjtkuXVjq5*uzqpWXE6tkzXVjq5czuqpWXE!t9zX\j35czu30/XE!tkuX\!qocuu3pWXEjtkzXVj3oczuq4WXE!0
>>>>>> kz.Vjqocuu3p/TEj0ku.Vj31cuz3pWXEjtkzXVj3o*uzq4W."
>>>>>
>>>>> Regarding tcc, a few things differ internally, but I think one clue is
>>>    here:
>>>>>
>>>>>      #define CT_MBROT_ABET_LOOKUP(mp_char) \
>>>>>       ((strchr(CT_MBROT_ABET, (mp_char))) - CT_MBROT_ABET)
>>>>>
>>>>> This is effectively doing the following (to get an offset into the
>>>     string?):
>>>>>
>>>>>       str("ABC", c) - "ABC";
>>>>>
>>>>> It is assuming that both string literals have the same address.
>>>>
>>>> This is an unwarranted assumption.
>>>>
>>>> But the result is also undefined when mp_char does not occur in the
>>>> string which can happen for two printable ASCII characters.
>>>>
>>>> Chris, you should test your code more thoroughly.
>>>>
>>>>> If I move that string into a variable, then Tcc starts to work. So does
>>>>> bcc.
>>>>
>>>> Saying that tcc starts to work when you fix the bug suggests that tcc
>>>> was not working before, but it's the code that was not working.  tcc
>>>> (and presumably bcc) were working fine all along.
>>>>
>>>>> lccwin32 still has a problem.
>>>>
>>>> What's the problem?  Are you sure it's lccwin32 and not the source code
>>>> that has the problem?
>>>
>>> When I say that compiler X has a problem, obviously I mean that the
>    program
>>> built with X shows an error.
>>
>> That's a very odd way of putting it.  My guess is that the
>> program has multiple meanings (and in some cases none).  The compiler is
>> (probably) correctly picking one of them.
>>
>>> That is, the results are incorrect.
>>
>> Ah, then you know more that I.  What are the correct results?
>
> No spec is given. But I would say one requirement is that encrypting and
> then decrypting a piece of plain text should produce the original
> text.

I think we've ended up talking about different things.  I've not seen
such a run.  The OP posted two runs that both re-created the original
text, but which had different intermediate data.

-- 
Ben.

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Thread

Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-30 14:01 -0700
  Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-30 14:11 -0700
  Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-30 14:30 -0700
    Re: Inconsistent... Richard Harnden <richard.nospam@gmail.invalid> - 2023-10-30 22:01 +0000
      Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-30 15:09 -0700
  Re: Inconsistent... bart <bc@freeuk.com> - 2023-10-30 23:22 +0000
    Re: Inconsistent... bart <bc@freeuk.com> - 2023-10-30 23:44 +0000
    Re: Inconsistent... bart <bc@freeuk.com> - 2023-10-31 02:05 +0000
      Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-31 11:32 +0000
        Re: Inconsistent... bart <bc@freeuk.com> - 2023-10-31 14:16 +0000
          Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-31 16:15 +0000
            Re: Inconsistent... bart <bc@freeuk.com> - 2023-10-31 18:35 +0000
              Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-31 14:05 -0700
                Re: Inconsistent... bart <bc@freeuk.com> - 2023-10-31 22:29 +0000
              Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 00:39 +0000
                Re: Inconsistent... bart <bc@freeuk.com> - 2023-11-01 10:35 +0000
                Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 13:29 +0000
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 12:52 -0700
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 14:30 -0700
        Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-31 13:37 -0700
          Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 00:44 +0000
            Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-31 20:26 -0700
              Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 11:05 +0000
            Re: Inconsistent... bart <bc@freeuk.com> - 2023-11-01 10:59 +0000
              Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-01 13:01 +0100
                Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 13:52 +0000
                Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-01 20:12 +0100
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 12:52 -0700
                Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-02 10:04 +0100
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-02 10:51 -0700
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-02 11:02 -0700
                Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-02 20:02 +0100
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-02 12:03 -0700
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-03 23:57 -0700
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-04 00:11 -0700
                Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-02 20:28 +0000
                Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-03 10:23 +0100
                [OT] Encryption (Was: Inconsistent...) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-03 10:10 +0000
                Re: [OT] Encryption (Was: Inconsistent...) David Brown <david.brown@hesbynett.no> - 2023-11-03 15:01 +0100
                Re: [OT] Encryption (Was: Inconsistent...) scott@slp53.sl.home (Scott Lurndal) - 2023-11-03 16:52 +0000
                Re: [OT] Encryption (Was: Inconsistent...) "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-03 15:12 -0700
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-03 15:11 -0700
              Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 13:43 +0000
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 12:53 -0700
                Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 20:08 +0000
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 13:12 -0700
                Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 21:12 +0000
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 14:16 -0700
                Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 21:43 +0000
                Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-01 16:02 -0700
                Re: Inconsistent... bart <bc@freeuk.com> - 2023-11-01 22:59 +0000
  Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-30 23:52 +0000
    Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-31 13:45 -0700
    Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-10-31 14:29 -0700
    Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-02 10:10 +0100
      Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-02 09:52 +0000
        Re: Inconsistent... bart <bc@freeuk.com> - 2023-11-02 11:31 +0000
          Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-02 13:52 +0100
            Re: Inconsistent... bart <bc@freeuk.com> - 2023-11-02 14:07 +0000
              Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-02 16:53 +0100
                Re: Inconsistent... bart <bc@freeuk.com> - 2023-11-02 19:15 +0000
                Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-03 10:33 +0100
          Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-02 20:43 +0000
            Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-02 13:47 -0700
        Re: Inconsistent... David Brown <david.brown@hesbynett.no> - 2023-11-02 13:34 +0100
  Re: Inconsistent... Richard Harnden <richard.nospam@gmail.invalid> - 2023-11-01 20:32 +0000
    Re: Inconsistent... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-11-01 21:36 +0000
      Re: Inconsistent... Richard Harnden <richard.nospam@gmail.invalid> - 2023-11-01 21:54 +0000
      Re: Inconsistent... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-11-09 15:54 -0800
  Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-09 01:16 -0800
  Re: Inconsistent... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-11-10 21:02 -0800

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