Re: [PATCH 2/4] regedit: Simplify parseKeyName()

[Alexandre Julliard]

Hugh McMaster  writes:
> -
> - for (i = 0; i < ARRAY_SIZE(reg_class_keys); i++) {
> -
>    if (CompareStringW(LOCALE_USER_DEFAULT, 0, lpKeyName, len, reg_class_namesW[i], -1) == CSTR_EQUAL &&
> -
>        len == lstrlenW(reg_class_namesW[i])) {
> - num_class_keys = ARRAY_SIZE(reg_class_keys);
> - for (i = 0; i < num_class_keys; i++)
> - {
> -
>    if (!strncmpW(lpKeyName, reg_class_namesW[i], lstrlenW(reg_class_namesW[i])))
> -
>    {

You still need to check that the lengths match.

[PATCH 2/4] regedit: Simplify parseKeyName()

[Hugh McMaster]

On Tuesday, 25 April 2017 4:33 AM, Alexandre Julliard wrote:
> Hugh McMaster writes:
> > -
> >
> > -    for (i = 0; i < ARRAY_SIZE(reg_class_keys); i++) {
> > -        if (CompareStringW(LOCALE_USER_DEFAULT, 0, lpKeyName, len, reg_class_namesW[i], -1) == CSTR_EQUAL &&
> > -            len == lstrlenW(reg_class_namesW[i])) {
> > +    num_class_keys = ARRAY_SIZE(reg_class_keys);
> > +    for (i = 0; i < num_class_keys; i++)
> > +    {
> > +        if (!strncmpW(lpKeyName, reg_class_namesW[i], lstrlenW(reg_class_namesW[i])))
> > +        {
>
> You still need to check that the lengths match.

Yes, sorry about that. I'll send an updated patch.

It seems to me that it would be better to check for a backslash or null-terminator at the valid string length, 
instead of calculating the input key length. Something like the following:

for (i = 0; i < num_class_keys; i++)
    {
        int len = lstrlenW(reg_class_namesW[i]);
        WCHAR wc = lpKeyName[len];
        if (!strncmp(lpKeyName, reg_class_namesW[i], len) && (wc == 0 || wc == '\'))
        {
            *hKey = reg_class_keys[i];
            break;
        }
    }

Is this preferable? Or do you want to use pointer arithmetic?

Hugh

[PATCH 2/4] regedit: Simplify parseKeyName()

[Alexandre Julliard]

Hugh McMaster  writes:
> Yes, sorry about that. I'll send an updated patch.
>
> It seems to me that it would be better to check for a backslash or null-terminator at the valid string length, 
> instead of calculating the input key length. Something like the following:
> for (i = 0; i < num_class_keys; i++)
> {
>     int len = lstrlenW(reg_class_namesW[i]);
>     WCHAR wc = lpKeyName[len];
>     if (!strncmp(lpKeyName, reg_class_namesW[i], len) && (wc == 0 || wc == '\\'))
>     {
>         *hKey = reg_class_keys[i];
>         break;
>     }
> }
>
> Is this preferable? Or do you want to use pointer arithmetic?

You can do it that way, but you can't access lpKeyName[len] before the
strncmp since you don't know if the string is long enough.