gistfile1.rs

extern crate debug;
use std::str::CharRange;
use std::str::Chars;
use std::str::raw::slice_unchecked;

fn main() {
    let test = "¨återbesök på färöarna";
    let v: Vec<u16> = to_utf16(test).collect();
    println!("{}", v);
    println!("{}", test.to_utf16());
    assert_eq!(v, test.to_utf16());
}

struct Utf16Codeunits<'a> {
    chars: Chars<'a>,
    extra: u16
}

impl<'a> Iterator<u16> for Utf16Codeunits<'a> {
    fn next(&mut self) -> Option<u16> {
        if self.extra != 0 {
            let tmp = self.extra;
            self.extra = 0;
            return Some(tmp);
        }

        let mut buf = [0u16, ..2];
        self.chars.next().map(|ch| { 
            let n = ch.encode_utf16(buf /* as mut slice! */);
            if n == 2 { self.extra = buf[1]; }
            buf[0]
        })
    } 
}

/// Converts to a vector of `u16` encoded as UTF-16.
fn to_utf16<'a>(s: &'a str) -> Utf16Codeunits<'a> {
    Utf16Codeunits{ chars: s.chars(), extra: 0}
}