On Friday, 17 October 2014 at 08:31:04 UTC, spir via
Digitalmars-d-learn wrote:
On 17/10/14 09:29, thedeemon via Digitalmars-d-learn wrote:
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.
Side-note: since your string has those zeroes at the end, strip
only removes the space at start (thus, final size=15), instead
of at both ends.
d
Okay things are becoming more clear. The cast to string is
nothing like the C++ string ctor, I made a bad assumption.
So given the below buffer would I use fromStringz (is this in the
stdlib?) to cast it from a null-terminated buffer to a good
string? Shouldn't the compiler give a warning about casting a
buffer to a string without using fromStringz?
Buffer = [ 0x20, 0x41, 0x54, 0x41, 0x20, 0x00, 0x00, ...]?
