Hi,
Bogdan wrote:
> W dniu 04.06.2012 22:04, Jean-Pierre André wrote:
>
>> Hi,
>>
>> Bogdan wrote:
>>
>>> Hello everybody.
>>>
>>> I've prepared a small patch for utils.c and ntfswipe.c:
>>> - in utils.c, checking for allocated blocks is fixed to pre-fetch
>>> data on the first run,
>>>
>>>
>> - if ((lcn< bmplcn)
>> + if ((bmplcn< 0) || (lcn< bmplcn)
>> || (lcn>= (long long)(bmplcn + (sizeof(buffer)<< 3)))) {
>>
>> Can you explain this one ?
>>
>> AFAIK lcn is always>= 0 there, and bmplcn can only be
>> negative when it is == -(sizeof(buffer)<< 3), so the last
>> condition is true when bmplcn is negative.
>> So the change does nothing.
>>
> There are 2 issues here. The clue issue is the "(bmplcn< 0)"
> condition, which makes us fill the buffer on the first run.
>
Which the third condition is expected to do.
> The second issue is the second condition (the one you're talking
> about). Yes, "-(sizeof(buffer)<< 3)" makes bmplcn negative, so it
> looks like this condition will always be the same as "lcn => 0". But
>
I see no relation between the two conditions.
> there is one small detail that makes the change: bmplcn is STATIC. It
> holds its value between calls. The second condition checks if "lcn"
> doesn't fall beyond the current buffer.
>
Maybe youPlease exhibit a circumstance where the original condition
and the new one lead to different behavior.
> [...]
>
>
>>> Additionally, a small correction is added to the layout.h file
>>> (change from floating-point constant to long long), so that there
>>> are no warnings when ntfsck.c is being compiled. You can make this
>>> conditional, there are autoconf tests that check for support of the
>>> "long long" type in the C compiler.
>>>
>>>
>> Hmm, this patch is wrong :
>>
>> -#define magicNTFS const_cpu_to_le64(0x202020205346544e) /*
>> "NTFS " */
>> +#define magicNTFS const_cpu_to_le64(0x202020205346544ll) /*
>> "NTFS " */
>>
> Why do you think it's wrong? I change a floating point value to a
> long long.
>
The final 'e' is not a floating-point indication, but a part
of the encoding of the character 'N'. So you changed the
value, without making it more portable.
Regards
Jean-Pierre
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