1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at http://rust-lang.org/COPYRIGHT.
3 //
4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7 // option. This file may not be copied, modified, or distributed
8 // except according to those terms.
9
10 // (This used to be in the Rust unicode crate, which is now gone, so we'll
11 // just include it inline.)
12
13 // https://tools.ietf.org/html/rfc3629
14 static UTF8_CHAR_WIDTH: [u8; 256] = [
15 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
16 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x1F
17 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
18 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x3F
19 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
20 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x5F
21 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
22 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x7F
23 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
24 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x9F
25 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
26 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xBF
27 0,0,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
28 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xDF
29 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, // 0xEF
30 4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0, // 0xFF
31 ];
32
33 /// Given a first byte, determine how many bytes are in this UTF-8 character
34 #[inline]
utf8_char_width(b: u8) -> usize35 pub fn utf8_char_width(b: u8) -> usize {
36 return UTF8_CHAR_WIDTH[b as usize] as usize;
37 }
38