On 02/19/2013 06:21 PM, Zach Brown wrote:
>> Of course, if after string_list_free() some dynamically allocated
>> strings are used then bad things could happen.
>
> Right. So let's not make that even possible by not having the code at
> all.
>
>> Sorry I don't understand the differences between {leaked, scaled,
>> raw}_string. Could you elaborate a bit ?
>
> The code I saw returned an allocated string that the caller has to worry
> about. Crummy code just ignores the problem. You added the global list
> of strings to free at some point in the future.
>
> I'm suggesting it not allocate at all so that there's nothing to free.
>
> Instead of:
>
> printf("%s", pretty(value));
>
> char *pretty(u64 value) {
> static char *units[] = { "KB", "MB", /* etc */ };
> char *str = malloc(20); /* should be 21 */
> sprintf(str, "%llu%s",
> scale(value), units[scale_index(value));
> global_list_stuff(str);
> return str;
> }
>
> Do:
>
> printf("%llu%s", scale(value), unit_string(value));
>
> char *unit(u64 value)
> {
> static char *units[] = { "KB", "MB", /* etc */ };
> return units[scale_index(value));
> }
>
> (all rough code, obviously)
>
> Then there's nothing for the caller to worry about.
Sorry but this is very dangerous and it leads to very subtle bug: what
happens if someone wrote:
printf("%d%s - %d%s\n", scale(123), unit_string(123),
scale(123), unit_string(456) );
>
> Right?
>
> - z
>
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