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