| Ivan Lozano | a7e4bc0 | 2021-08-20 09:59:16 -0400 | [diff] [blame] | 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] |
| 35 | pub fn utf8_char_width(b: u8) -> usize { |
| 36 | return UTF8_CHAR_WIDTH[b as usize] as usize; |
| 37 | } |