forked from mirrors/gecko-dev
b60da2612e
Differential Revision: https://phabricator.services.mozilla.com/D67246 --HG-- extra : moz-landing-system : lando
131 lines
4.3 KiB
Rust
131 lines
4.3 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Determine displayed width of `char` and `str` types according to
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//! [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
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//! rules.
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//!
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//! ```rust
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//! extern crate unicode_width;
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//!
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//! use unicode_width::UnicodeWidthStr;
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//!
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//! fn main() {
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//! let teststr = "Ｈｅｌｌｏ, ｗｏｒｌｄ!";
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//! let width = UnicodeWidthStr::width(teststr);
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//! println!("{}", teststr);
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//! println!("The above string is {} columns wide.", width);
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//! let width = teststr.width_cjk();
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//! println!("The above string is {} columns wide (CJK).", width);
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//! }
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//! ```
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//!
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//! # features
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//!
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//! unicode-width supports a `no_std` feature. This eliminates dependence
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//! on std, and instead uses equivalent functions from core.
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//!
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//! # crates.io
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//!
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//! You can use this package in your project by adding the following
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//! to your `Cargo.toml`:
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//!
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//! ```toml
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//! [dependencies]
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//! unicode-width = "0.1.5"
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//! ```
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#![deny(missing_docs, unsafe_code)]
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#![doc(html_logo_url = "https://unicode-rs.github.io/unicode-rs_sm.png",
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html_favicon_url = "https://unicode-rs.github.io/unicode-rs_sm.png")]
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#![cfg_attr(feature = "bench", feature(test))]
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#![no_std]
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#[cfg(test)]
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#[macro_use]
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extern crate std;
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#[cfg(feature = "bench")]
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extern crate test;
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use tables::charwidth as cw;
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pub use tables::UNICODE_VERSION;
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use core::ops::Add;
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mod tables;
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#[cfg(test)]
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mod tests;
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/// Methods for determining displayed width of Unicode characters.
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pub trait UnicodeWidthChar {
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/// Returns the character's displayed width in columns, or `None` if the
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/// character is a control character other than `'\x00'`.
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///
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/// This function treats characters in the Ambiguous category according
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/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
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/// as 1 column wide. This is consistent with the recommendations for non-CJK
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/// contexts, or when the context cannot be reliably determined.
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fn width(self) -> Option<usize>;
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/// Returns the character's displayed width in columns, or `None` if the
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/// character is a control character other than `'\x00'`.
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///
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/// This function treats characters in the Ambiguous category according
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/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
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/// as 2 columns wide. This is consistent with the recommendations for
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/// CJK contexts.
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fn width_cjk(self) -> Option<usize>;
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}
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impl UnicodeWidthChar for char {
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#[inline]
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fn width(self) -> Option<usize> { cw::width(self, false) }
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#[inline]
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fn width_cjk(self) -> Option<usize> { cw::width(self, true) }
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}
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/// Methods for determining displayed width of Unicode strings.
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pub trait UnicodeWidthStr {
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/// Returns the string's displayed width in columns.
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///
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/// Control characters are treated as having zero width.
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///
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/// This function treats characters in the Ambiguous category according
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/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
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/// as 1 column wide. This is consistent with the recommendations for
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/// non-CJK contexts, or when the context cannot be reliably determined.
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fn width<'a>(&'a self) -> usize;
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/// Returns the string's displayed width in columns.
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///
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/// Control characters are treated as having zero width.
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///
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/// This function treats characters in the Ambiguous category according
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/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
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/// as 2 column wide. This is consistent with the recommendations for
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/// CJK contexts.
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fn width_cjk<'a>(&'a self) -> usize;
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}
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impl UnicodeWidthStr for str {
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#[inline]
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fn width(&self) -> usize {
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self.chars().map(|c| cw::width(c, false).unwrap_or(0)).fold(0, Add::add)
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}
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#[inline]
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fn width_cjk(&self) -> usize {
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self.chars().map(|c| cw::width(c, true).unwrap_or(0)).fold(0, Add::add)
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}
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}
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