Re: gc-pbkdf2-sha1

[Simon Josefsson]

Paul Eggert <address@hidden> writes:

> Simon Josefsson <address@hidden> writes:
>
>> Bruno Haible <address@hidden> writes:
>>
>>> Simon Josefsson wrote:
>>>
>>>> +  l = dkLen / hLen;
>>>> +  if (dkLen % hLen)
>>>> +    l++;
>>>
>>> An equivalent but faster code is:
>>>
>>>      l = ((dkLen - 1) / hLen) + 1;
>>
>> Perhaps for clarity we could change it into:
>>
>> #define CEIL_DIV(a,b) (((a) - 1) / (b)) + 1
>>   l = CEIL_DIV (dkLen, hLen);
>>
>> What do you think?
>
> That implementation of CEIL_DIV doesn't work in general, e.g., if
> dkLen has the minimum value for its type.  So I wouldn't use it, at
> least not without a comment saying that it's not safe in general.
>
> Bruno's rewrite is safe because dkLen cannot possibly be zero here.

Right, I have installed Bruno's version.  Thanks!