const_str/
utf16.rs

1use crate::slice::advance;
2
3pub struct CharEncodeUtf16 {
4    buf: [u16; 2],
5}
6
7impl CharEncodeUtf16 {
8    /// Copied from [char::encode_utf16](https://github.com/rust-lang/rust/blob/0273e3bce7a0ce49e96a9662163e2380cb87e0be/library/core/src/char/methods.rs#L1647-L1682)
9    pub const fn new(ch: char) -> Self {
10        let mut code = ch as u32;
11        let mut buf = [0; 2];
12        if (code & 0xFFFF) == code {
13            buf[0] = code as u16;
14        } else {
15            code -= 0x1_0000;
16            buf[0] = 0xD800 | ((code >> 10) as u16);
17            buf[1] = 0xDC00 | ((code as u16) & 0x3FF);
18        }
19        Self { buf }
20    }
21
22    pub const fn has_second(&self) -> bool {
23        self.buf[1] != 0
24    }
25
26    pub const fn first(&self) -> u16 {
27        self.buf[0]
28    }
29    pub const fn second(&self) -> u16 {
30        self.buf[1]
31    }
32}
33
34pub const fn str_len_utf16(s: &str) -> usize {
35    let mut s = s.as_bytes();
36    let mut ans = 0;
37    while let Some((ch, count)) = crate::utf8::next_char(s) {
38        s = advance(s, count);
39        ans += ch.len_utf16(); // const since 1.52
40    }
41    ans
42}
const_str/utf16.rs

const_str/
utf16.rs
