[PATCH v4 5/8] reg.exe: Add wchar/raw data conversion functions

[Stefan Dösinger]

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Am 2014-10-12 19:47, schrieb Jonathan Vollebregt:
> I don't free the old string. Because the function handles more than
> one type of data the caller has to free the data when it's done -
> if I don't copy the string it will end up freeing one of it's own
> parameters.
I used bad terminology here. What I meant was that wchar_get_data
could operate on the input memory instead of copying it first since
the original data is not needed after the call.

Of course further features may require that the input remains
untouched. Is this the case?

There's another ugliness though: If the input string is "0", replacing
it with a 4-byte DWORD just works because it is a WCHAR that consists
of two two bytes elements. I don't know about other data types - they
may actually grow.

> Sorry, this seems confusing without comments. The REG_MULTI_SZ
> stores multiple strings in the registry: nil separated with a
> double nil to end the array.
> 
> When reading from the registry simply replacing the nil's with ','
> seems the simplest way to do it, and that's exactly wine's
> regedit's behaviour. I'm not sure what the native behaviour is
> supposed to be though.
As I mentioned tests would be a good idea :-) .

I understood what the function was doing after enough reading. What I
meant was that there was probably a nicer way to implement the same
behavior. E.g. if you do the character replace in the existing string
you could write this as

for (i = 0; inout[i] || input[i + 1]; i++)
{
    if (!inout[i])
        inout[i] = ',';
}

Or MakeMULTISZDisplayable() from regedit. MakeMULTISZDisplayable is
probably faster because it does only one comparison per character.

But if you cannot operate on the input data that idea is moot. You
could copy first and then run a second iteratation over the string,
but I think that results in worse performance than your code.

> If the separator has been left out of the commandline, the
> separator variable here will be 0. By default reg (From everything
> I've read) interprets "\\0" as the separator - that is it takes an
> escaped nil as it's input to split the strings.
> 
> If you *do* supply a separator variable though it will split by
> that, so the following commands should have an equivalent effect:
> 
> reg add HKCU /v test /t REG_MULTI_SZ /d "string\\0morestring" reg
> add HKCU /v test /t REG_MULTI_SZ /s "#" /d "string#morestring"
You mean it uses a two-byte separator '\\','0', rather than the
one-byte separator '\0'? In this case it would be best to make the
code work on generic string separators. The default separator needs
tests as well.

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