[PATCH:libXt 2/3] GetResources: protect against underflow when type conversion fails

[Thomas Dickey]

On Sat, 5 Feb 2011, Alan Coopersmith wrote:

> I think it used to be faster to count down and compare against zero on some
> CPU's (probably 680x0 or so), and you do see that a bit in the ancient X code.
>
> I can't see any other reason to do the counting this way here, so will look into
> turning it around.

It's more likely that the developer had observed poor optimization 
resulting in repeated reevaluation of the expression which would be in the 
loop termination clause.

> On 02/ 5/11 02:47 AM, walter harms wrote:
>>
>>
>> 	    for (i = num_typed_args - typed[j]; i > 0; i--, arg++) {
>>
>> IMHO this violates the rule of least surprise. the other way around is much more
>> common. Since i is only a counter i do not see why we need to count down.
>> (More adventures people may want to use memmove, but i did not see the rest of code)
>>
>> 		    for (i=0; i < num_typed_args - typed[j]; i++) {
>>  			*arg = *(arg+1);
>> 		        arg++;
>>   		    }
>>
>> just my 2 cents,

-- 
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net