String created from buffer has wrong length and strip() result is incorrect

[thedeemon via Digitalmars-d-learn]

On Friday, 17 October 2014 at 06:29:24 UTC, Lucas Burson wrote:

>    // This is where things breaks
>    {
>       ubyte[] buff = new ubyte[16];
>       buff[0..ATA_STR.length] = cast(ubyte[])(ATA_STR);
>
>       // read the string back from the buffer, stripping 
> whitespace
>       string stringFromBuffer = 
> strip(cast(string)(buff[0..16]));
>       // this shows strip() doesn't remove all whitespace
>       writefln("StrFromBuff is '%s'; length %d", 
> stringFromBuffer, stringFromBuffer.length);
>
>       // !! FAILS. stringFromBuffer is length 15, not 3.
>       assert(stringFromBuffer.length == strip(ATA_STR).length);

Unlike C, strings in D are not zero-terminated by default, they 
are just arrays, i.e. a pair of pointer and size. You create an 
array of 16 bytes and cast it to string, now you have a 16-chars 
string. You fill first few chars with data from ATA_STR but the 
rest 10 bytes of the array are still part of the string, not 
initialized with data, so having zeroes. Since this tail of 
zeroes is not whitespace (tabs or spaces etc.) 'strip' doesn't 
remove it.