[PATCH] vbscript: Implemented String

[Shuai Meng]

Thanks for commenting.

2014-10-21 0:20 GMT+08:00 Nikolay Sivov <bunglehead at gmail.com>:

>  On 10/20/2014 19:58, Shuai Meng wrote:
>
> Thank you very much for commenting on this patch.
>
> 2014-10-20 0:06 GMT+08:00 Nikolay Sivov <bunglehead at gmail.com>:
>
>>  +    str = SysAllocStringLen(NULL, 1023);
>>> +    newstr = SysAllocStringLen(NULL, 1023);
>>>
>> Where this length comes from?
>> Well, I tested String on windows xp, and found that 1023 was the limit,
>> when given a number bigger than that, the output kept the length of 1023.
>>
>   Can you add this too as a test? In some compact way if possible.
>
I tried again and I found that maybe you were right. The number of 1023 was
got like this: I wrote vbscript with a common text editor on xp, and save
it as xx.vbs, then double clicked it. I used this method and found that
MsgBox String(1024, 65) only printed "a...(the length is 1023)....a".
Tragedy is today I write MsgBox Len(String(1024, 65)), and it prints 1024!
It's the same with the other numbers greater than 1023!   So I  was cheated
yesterday. The true limit may be 32768 * 16384 * 1.25， but I am not sure. I
need to know the exact limit of the length of the string subtype, however
experiments show difference with the documents of microsoft which claims
the limit is about 2 billion.

>
>    +    switch(V_VT(arg + 1)) {
>>> +    case VT_NULL:
>>> +        return MAKE_VBSERROR(VBSE_ILLEGAL_NULL_USE);
>>> +    case VT_BSTR:
>>> +        str = V_BSTR(arg + 1);
>>> +        break;
>>> +    case  VT_ARRAY|VT_BYREF|VT_VARIANT:
>>> +        return DISP_E_TYPEMISMATCH;
>>> +    default:
>>> +        hres = to_short(arg + 1, &tmp);
>>> +        if(FAILED(hres))
>>> +            return hres;
>>> +        str[0] = (char)tmp;
>>> +        break;
>>> +    }
>>>
>> You only need first character, right? Then why do you need a full BSTR
>> pointer in VT_BSTR case? And assigning it
>> to 'str' you leak a previously allocated buffer.
>
> So how do I get the first character of (arg + 1)?  How about this: str[0]
> = * V_BSTR(arg + 1)
> In fact I don't quite understand how SysAllocStringLen work, but I see it
> is used in the former function, so I think maybe it is necessary.
>
> What I don't get is why do you allocate 'str' at all, it should be just
> 'WCHAR ch;' variable.
>
Yes, you are right.

>
>   Why cast to (char)tmp?
>>
> I think the type of str[0] is WCHAR, and tmp is an integer, shouldn't we
> make a cast?
>
> WCHAR is 'unsigned short'. And it feels like it needs more tests for other
> variant types.
>
Yes, such as VT_DATE, but problem is it can't be tested. Until now, '#' is
still not supported in wine.

>
>
>>  +    else if(len == 0)
>>> +        newstr = '\0';
>>>
>> Same way you're losing pointer to allocated buffer.
>>
>>
>>
>
>
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