internal structure of char[]

[Jarrett Billingsley]

"Bjoern" <nanali at nospam-wanadoo.fr> wrote in message 
news:fmq5d6$2p8$1 at digitalmars.com...
> Hi,
> Does somebody know the internal structure of char[]   ?
>
> Not only that I have to do a lot of converting on the DLL (D) side, I also 
> have to convert the strings on the parrent side (4GL)
>
> I hope I can use this info to simplyfy for example code like this :
>
> alias extern(Windows) void function(char* token, size_t siz = 0) 
> DisplayCallBack;
>
> export extern(Windows)
> bool TextDelimit(DisplayCallBack cb, char* source, char* delim)
> {
> char[] _source = source[0 .. strlen(source)].dup;
> char[] _delim = delim[0 .. strlen(delim)].dup;
>
> // split into an array
>     char[][] elements = Text.delimit (_source, _delim);
>     foreach (char[] element; elements)
> {
> char* s = element.ptr;
> cb(s, strlen(s));
> }
> return true;
> }
>
> Well it works fine, but I want it smarter (if possible)
> Thanks in advance, Bjoern

OK, so your function is doing probably a lot of unnecessary copying.  You 
shouldn't have to .dup those strings, just slice source[0 .. strlen(source)] 
and now that string points to the same place the source string is.  AFAIK 
Text.delimit does not modify the inputs, it just gives you an array of 
slices into it (aren't slices great?).  Lastly, doing strlen(s) in that loop 
shouldn't work (I'm surprised it does?!), since all the items of elements 
are slices, not zero-terminated strings.

Finally you shouldn't need to know anything about the internal structure of 
char[] to do this.

export extern(Windows)
bool TextDelimit(DisplayCallBack cb, char* source, char* delim)
{
    char[] _source = source[0 .. strlen(source)];
    char[] _delim = delim[0 .. strlen(delim)];

    foreach(element; Text.delimit(_source, _delim))
        cb(element.ptr, element.length);

    return true;
}