Fix issue 18632 - enable use of fromStringz with char[n]

[dkorpel]

No description provided.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	18632	enhancement	enable use of fromStringz with char[n]

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + phobos#8164"

[RazvanN7]

LGTM

[RazvanN7]

One observation is that fromStringz was originally designed to convert a C string (null terminated char*) to a D string (char[]). Since a static array is already a D string, it can be argued that allowing the case that this PR enables is pointless. However, I think this enables the use of fromStringz in generic code where it is not obvious whether the string is a C string or a D string. As such, I don't have anything against this addition, however, I'll wait for others to weight in.

[dkorpel]

Since a static array is already a D string, it can be argued that allowing the case that this PR enables is pointless.

The use case I have in mind is C api's using structures with fixed size strings, e.g:

struct WIN32_FIND_DATAW {
    DWORD           dwFileAttributes;
    FILETIME        ftCreationTime;
    // (...)
    WCHAR[MAX_PATH] cFileName = 0;
}

With the new overload, you can safely extract cFileName.fromStringz instead of cFileName.ptr.fromStringz.

[Geod24]

Additionally, some C API accept a pointer and a length and will write to that. E.g. getcwd. In which case, one might want to use a static array to avoid GC allocations.