YASQ - Proper way to convert byte[] <--> string

Frits van Bommel fvbommel at REMwOVExCAPSs.nl
Thu Jul 12 01:42:25 PDT 2007


Steve Teale wrote:
> Frits van Bommel Wrote:
> 
>> ---
>> A[n .. n+s.length] = cast(byte[]) s;
>> ---
> 
> Can I use n+s.length?  In my experimentation i noticed that a UTF8 string containing a character using a two-byte representation definitely had an s.length of the number of characters, which was one less than the number of bytes.

You noticed wrong...
char[]s in D aren't very special, they're just specific array types that 
happen to be handled specially by some functions (such as writef*)[1]. 
The .length is the number of elements, and each element is a fixed size. 
A char is just a type representing a byte from UTF-8 text.
---
import std.stdio;

void main() {
	auto s = "\u0100";
	writefln(s);
	writefln(s.length);
	writefln((cast(byte[])s).length);
}
---
Outputs a weird character (an A with a - on top) and two times the number 2.


[1]: and by foreach statements as well; they can automagically extract 
char/wchar/dchar elements from char[]/wchar[]dchar[], in any combination.



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