On 29/01/2017 4:32 AM, Nestor wrote:
On Saturday, 28 January 2017 at 14:56:03 UTC, rikki cattermole wrote:
On 29/01/2017 3:51 AM, Nestor wrote:
Hi,
One can get the length of a string easily, however since strings are
UTF-8, sometimes characters take more than one byte. I would like to
know then how many bytes does a string take, but this code didn't work
as I expected:
import std.stdio;
void main() {
string mystring1;
string mystring2 = "A string of just 48 characters for testing size.";
writeln(mystring1.sizeof);
writeln( mystring2.sizeof);
}
In both cases the size is 8, so apparently sizeof is giving me just the
default size of a string type and not the size of the variable in
memory, which is what I want.
Ideas?
A few misconceptions going on here.
A string element is not a grapheme it is a character which is one byte.
So what you want is mystring.length
Now sizeof is not telling you about the elements, its telling you how
big the reference to it is. Specifically length + pointer. It would
have been 16 if you compiled in 64bit mode for example.
If you want to know about graphemes and code points that is another
story.
For that you'll want std.uni[0] and std.utf[1].
[0] http://dlang.org/phobos/std_uni.html
[1] http://dlang.org/phobos/std_utf.html
I do not want string lenth or code points. Perhaps I didn't explain
myselft.
I want to know variable size in memory. For example, say I have an UTF-8
string of only 2 characters, but each of them takes 2 bytes. string
length would be 2, but the content of the string would take 4 bytes in
memory (excluding overhead for type size).
How can I get that?
.length
You are misunderstanding a char will always be exactly one byte in size.
Check[0] for proof.
Keep in mind here is the definition of string[1]:
alias immutable(char)[] string;
There is nothing fancy going on.
What you were asking about "characters" wise is actually graphemes as
per the unicode standard, they can be multiple bytes and codepoints in
size but not a char.
[0] http://dlang.org/spec/type.html
[1] https://github.com/dlang/druntime/blob/master/src/object.d
