🐝
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 

171 lines
4.8 KiB

/*
* meli - text_processing crate.
*
* Copyright 2017-2020 Manos Pitsidianakis
*
* This file is part of meli.
*
* meli is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* meli is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with meli. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* This is an implementation of wcwidth() and wcswidth() as defined in
* "The Single UNIX Specification, Version 2, The Open Group, 1997"
* <http://www.UNIX-systems.org/online.html>
*
* Markus Kuhn -- 2001-09-08 -- public domain
*/
// Update to Unicode 12
#[macro_export]
macro_rules! big_if_true {
($a:expr) => {
if $a {
1
} else {
0
}
};
}
type WChar = u32;
type Interval = (WChar, WChar);
pub struct CodePointsIterator<'a> {
rest: std::str::Chars<'a>,
}
/*
* UTF-8 uses a system of binary prefixes, in which the high bits of each byte mark whether it’s a single byte, the beginning of a multi-byte sequence, or a continuation byte; the remaining bits, concatenated, give the code point index. This table shows how it works:
*
* UTF-8 (binary) Code point (binary) Range
* 0xxxxxxx xxxxxxx U+0000–U+007F
* 110xxxxx 10yyyyyy xxxxxyyyyyy U+0080–U+07FF
* 1110xxxx 10yyyyyy 10zzzzzz xxxxyyyyyyzzzzzz U+0800–U+FFFF
* 11110xxx 10yyyyyy 10zzzzzz 10wwwwww xxxyyyyyyzzzzzzwwwwww U+10000–U+10FFFF
*
*/
impl<'a> Iterator for CodePointsIterator<'a> {
type Item = WChar;
fn next(&mut self) -> Option<WChar> {
self.rest.next().map(|c| c as WChar)
}
}
pub trait CodePointsIter {
fn code_points(&self) -> CodePointsIterator;
}
impl CodePointsIter for str {
fn code_points(&self) -> CodePointsIterator {
CodePointsIterator { rest: self.chars() }
}
}
impl CodePointsIter for &str {
fn code_points(&self) -> CodePointsIterator {
CodePointsIterator { rest: self.chars() }
}
}
/* auxiliary function for binary search in Interval table */
fn bisearch(ucs: WChar, table: &'static [Interval]) -> bool {
let mut min = 0;
let mut mid;
let mut max = table.len() - 1;
if ucs < table[0].0 || ucs > table[max].1 {
return false;
}
while max >= min {
mid = (min + max) / 2;
if ucs > table[mid].1 {
min = mid + 1;
} else if ucs < table[mid].0 {
max = mid - 1;
} else {
return true;
}
}
false
}
pub fn wcwidth(ucs: WChar) -> Option<usize> {
if bisearch(ucs, super::tables::ASCII) {
Some(1)
} else if bisearch(ucs, super::tables::PRIVATE) {
None
} else if bisearch(ucs, super::tables::NONPRINT) {
None
} else if bisearch(ucs, super::tables::COMBINING) {
None
} else if bisearch(ucs, super::tables::DOUBLEWIDE) {
Some(2)
} else if bisearch(ucs, super::tables::AMBIGUOUS) {
Some(1)
} else if bisearch(ucs, super::tables::UNASSIGNED) {
Some(2)
} else if bisearch(ucs, super::tables::WIDENEDIN9) {
Some(2)
} else {
Some(1)
}
}
#[test]
fn test_wcwidth() {
assert_eq!(
&"abc\0".code_points().collect::<Vec<_>>(),
&[0x61, 0x62, 0x63, 0x0]
);
assert_eq!(&"●".code_points().collect::<Vec<_>>(), &[0x25cf]);
assert_eq!(&"πŸ“Ž".code_points().collect::<Vec<_>>(), &[0x1f4ce]);
assert_eq!(
&"𐼹𐼺𐼻𐼼𐼽".code_points().collect::<Vec<_>>(),
&[0x10F39, 0x10F3A, 0x10F3B, 0x10F3C, 0x10F3D]
); // Sogdian alphabet
assert_eq!(
&"𐼹a𐼽b".code_points().collect::<Vec<_>>(),
&[0x10F39, 0x61, 0x10F3D, 0x62]
); // Sogdian alphabet
assert_eq!(
&"πŸ“Ž\u{FE0E}".code_points().collect::<Vec<_>>(),
&[0x1f4ce, 0xfe0e]
);
use crate::text_processing::grapheme_clusters::TextProcessing;
assert_eq!("●".grapheme_width(), 1);
assert_eq!("β—πŸ“Ž".grapheme_width(), 3);
assert_eq!("●\u{FE0E}πŸ“Ž\u{FE0E}".grapheme_width(), 3);
assert_eq!("πŸŽƒ".grapheme_width(), 2);
assert_eq!("πŸ‘»".grapheme_width(), 2);
}
pub fn wcswidth(mut pwcs: WChar, mut n: usize) -> Option<usize> {
let mut width = 0;
while pwcs > 0 && n > 0 {
if let Some(w) = wcwidth(pwcs) {
width += w;
} else {
return None;
}
pwcs += 1;
n -= 1;
}
Some(width)
}