Bug report: player.inv[variable]++; problem

[Scorpiorus]

I tried to use '++', '--' shortcuts with character[].inv[] variable and seems like there is a bug appeared:

if I pass inventory index as a value (returned value) then all ok:
character[EGO].inv[ 4 ]++;
or
character[EGO].inv[ GetValue() ]++;

...but if it is a variable then the messy occurs:

character[EGO].inv[index]++;

The item index is increased and the next item index+1 is set to 0.

Decreasing '--' makes the similar thing:

character[EGO].inv[index]--;

but the next item can be decreased down to -1.


'+=1' and '-=1' works fine btw.

Also I declared a struct:
struct Cchar {
int inv[10];
};

Cchar Char[10];

and it works without problems.

Chris?

P.S. Here is a testgame (inv_bug.zip)
It shows inventory array for EGO, then processes character[EGO].inv[4]--; Then show the results. There is also some other tests in. I used 2.55 but the bug appears in 2.53 too.

-Cheers

[Pumaman]

strange, I'll look into it.

[Pumaman]

Ah I see what's happened, it remembers the size of the variable when it reads it in (in this case inv[] is a short), but then that cached info gets overwritten by the size of "index" (an int) and causes it to write back 4 bytes of memory. I'll get it fixed.

[Scorpiorus]

Oh, got it. So that is why the next short is displayed as 0 if the value is greater or equal to 0 and displayed as -1 (FF:FF) if it's less. When I was declaring an array for testings I needed to type it as short or as char to discover the same thing as for inv[].

So other opposite way if an array were typed as int and index was a char, for example, then it would write back only first byte and thereby we should get a char always (so the int variable is changed within 256 different values). As result the next value isn't affected, but the current int most likely wrong.

Thanks for the explanation and tracking it down, CJ.

-Cheers

[Pumaman]

Yep, that's right.

Thanks for spotting it, this is the sort of bug which could cause headaches for ages if we couldn't work out a pattern to it