vendor/unicode-width-0.1.13/src/lib.rs - toolchain/rustc - Git at Google

 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.

 //! Determine displayed width of `char` and `str` types according to
 //! [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
 //! and other portions of the Unicode standard.
 //! See the [Rules for determining width](#rules-for-determining-width) section
 //! for the exact rules.
 //!
 //! This crate is `#![no_std]`.
 //!
 //! ```rust
 //! use unicode_width::UnicodeWidthStr;
 //!
 //! let teststr = "Ｈｅｌｌｏ, ｗｏｒｌｄ!";
 //! let width = UnicodeWidthStr::width(teststr);
 //! println!("{}", teststr);
 //! println!("The above string is {} columns wide.", width);
 //! let width = teststr.width_cjk();
 //! println!("The above string is {} columns wide (CJK).", width);
 //! ```
 //!
 //! # Rules for determining width
 //!
 //! This crate currently uses the following rules to determine the width of a
 //! character or string, in order of decreasing precedence. These may be tweaked in the future.
 //!
 //! 1. [Emoji presentation sequences] have width 2.
 //! 2. Outside of an East Asian context, [text presentation sequences] have width 1
 //!    if their base character:
 //!    - Has the [`Emoji_Presentation`] property, and
 //!    - Is not in the [Enclosed Ideographic Supplement] block.
 //! 3. The sequence `"\r\n"` has width 1.
 //! 4. [Lisu tone letter] combinations consisting of a character in the range `'\u{A4F8}'..='\u{A4FB}'`
 //!    followed by a character in the range `'\u{A4FC}'..='\u{A4FD}'` have width 1.
 //! 5. In an East Asian context only, `<`, `=`, or `>` have width 2 when followed by [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY].
 //! 6. [`'\u{115F}'` HANGUL CHOSEONG FILLER](https://util.unicode.org/UnicodeJsps/character.jsp?a=115F) has width 2.
 //! 7. The following have width 0:
 //!    - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BDefault_Ignorable_Code_Point%7D)
 //!       with the [`Default_Ignorable_Code_Point`] property.
 //!    - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BGrapheme_Extend%7D)
 //!       with the [`Grapheme_Extend`] property.
 //!    - The following 8 characters, all of which have NFD decompositions consisting of two [`Grapheme_Extend`] characters:
 //!      - [`'\u{0CC0}'` KANNADA VOWEL SIGN II](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CC0),
 //!      - [`'\u{0CC7}'` KANNADA VOWEL SIGN EE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CC7),
 //!      - [`'\u{0CC8}'` KANNADA VOWEL SIGN AI](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CC8),
 //!      - [`'\u{0CCA}'` KANNADA VOWEL SIGN O](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CCA),
 //!      - [`'\u{0CCB}'` KANNADA VOWEL SIGN OO](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CCB),
 //!      - [`'\u{1B3B}'` BALINESE VOWEL SIGN RA REPA TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B3B),
 //!      - [`'\u{1B3D}'` BALINESE VOWEL SIGN LA LENGA TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B3D), and
 //!      - [`'\u{1B43}'` BALINESE VOWEL SIGN PEPET TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B43).
 //!    - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BHangul_Syllable_Type%3DV%7D%5Cp%7BHangul_Syllable_Type%3DT%7D)
 //!       with a [`Hangul_Syllable_Type`] of `Vowel_Jamo` (`V`) or `Trailing_Jamo` (`T`).
 //!    - The following [`Prepended_Concatenation_Mark`]s:
 //!      - [`'\u{0605}'` NUMBER MARK ABOVE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0605),
 //!      - [`'\u{070F}'` SYRIAC ABBREVIATION MARK](https://util.unicode.org/UnicodeJsps/character.jsp?a=070F),
 //!      - [`'\u{0890}'` POUND MARK ABOVE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0890),
 //!      - [`'\u{0891}'` PIASTRE MARK ABOVE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0891), and
 //!      - [`'\u{08E2}'` DISPUTED END OF AYAH](https://util.unicode.org/UnicodeJsps/character.jsp?a=08E2).
 //!    - [`'\u{A8FA}'` DEVANAGARI CARET](https://util.unicode.org/UnicodeJsps/character.jsp?a=A8FA).
 //! 8. [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BEast_Asian_Width%3DF%7D%5Cp%7BEast_Asian_Width%3DW%7D)
 //!    with an [`East_Asian_Width`] of [`Fullwidth`] or [`Wide`] have width 2.
 //! 9. Characters fulfilling all of the following conditions have width 2 in an East Asian context, and width 1 otherwise:
 //!    - Has an [`East_Asian_Width`] of [`Ambiguous`], or
 //!      has a canonical decomposition to an [`Ambiguous`] character followed by [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY], or
 //!      is [`'\u{0387}'` GREEK ANO TELEIA](https://util.unicode.org/UnicodeJsps/character.jsp?a=0387), and
 //!    - Does not have a [`General_Category`] of `Modifier_Symbol`, and
 //!    - Does not have a [`Script`] of `Latin`, `Greek`, or `Cyrillic`, or is a Roman numeral in the range `'\u{2160}'..='\u{217F}'`.
 //! 10. All other characters have width 1.
 //!
 //! [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY]: https://util.unicode.org/UnicodeJsps/character.jsp?a=0338
 //!
 //! [`Default_Ignorable_Code_Point`]: https://www.unicode.org/versions/Unicode15.0.0/ch05.pdf#G40095
 //! [`East_Asian_Width`]: https://www.unicode.org/reports/tr11/#ED1
 //! [`Emoji_Presentation`]: https://unicode.org/reports/tr51/#def_emoji_presentation
 //! [`General_Category`]: https://www.unicode.org/versions/Unicode15.0.0/ch04.pdf#G124142
 //! [`Grapheme_Extend`]: https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G52443
 //! [`Hangul_Syllable_Type`]: https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G45593
 //! [`Prepended_Concatenation_Mark`]: https://www.unicode.org/versions/Unicode15.0.0/ch23.pdf#G37908
 //! [`Script`]: https://www.unicode.org/reports/tr24/#Script
 //!
 //! [`Fullwidth`]: https://www.unicode.org/reports/tr11/#ED2
 //! [`Wide`]: https://www.unicode.org/reports/tr11/#ED4
 //! [`Ambiguous`]: https://www.unicode.org/reports/tr11/#ED6
 //!
 //! [Emoji presentation sequences]: https://unicode.org/reports/tr51/#def_emoji_presentation_sequence
 //! [text presentation sequences]: https://unicode.org/reports/tr51/#def_text_presentation_sequence
 //!
 //! [Enclosed Ideographic Supplement]: https://unicode.org/charts/nameslist/n_1F200.html
 //!
 //! [Lisu tone letter]: https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G42078
 //!
 //! ## Canonical equivalence
 //!
 //! Canonically equivalent strings are assigned the same width (CJK and non-CJK).

 #![forbid(unsafe_code)]
 #![deny(missing_docs)]
 #![doc(
     html_logo_url = "https://unicode-rs.github.io/unicode-rs_sm.png",
     html_favicon_url = "https://unicode-rs.github.io/unicode-rs_sm.png"
 )]
 #![no_std]

 use tables::charwidth as cw;
 pub use tables::UNICODE_VERSION;

 mod tables;

 /// Methods for determining displayed width of Unicode characters.
 pub trait UnicodeWidthChar {
     /// Returns the character's displayed width in columns, or `None` if the
     /// character is a control character.
     ///
     /// This function treats characters in the Ambiguous category according
     /// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
     /// as 1 column wide. This is consistent with the recommendations for non-CJK
     /// contexts, or when the context cannot be reliably determined.
     fn width(self) -> Option<usize>;

     /// Returns the character's displayed width in columns, or `None` if the
     /// character is a control character.
     ///
     /// This function treats characters in the Ambiguous category according
     /// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
     /// as 2 columns wide. This is consistent with the recommendations for
     /// CJK contexts.
     fn width_cjk(self) -> Option<usize>;
 }

 impl UnicodeWidthChar for char {
     #[inline]
     fn width(self) -> Option<usize> {
         single_char_width(self, false)
     }

     #[inline]
     fn width_cjk(self) -> Option<usize> {
         single_char_width(self, true)
     }
 }

 /// Returns the [UAX #11](https://www.unicode.org/reports/tr11/) based width of `c`, or
 /// `None` if `c` is a control character.
 /// If `is_cjk == true`, ambiguous width characters are treated as double width; otherwise,
 /// they're treated as single width.
 #[inline]
 fn single_char_width(c: char, is_cjk: bool) -> Option<usize> {
     if c < '\u{7F}' {
         if c >= '\u{20}' {
             // U+0020 to U+007F (exclusive) are single-width ASCII codepoints
             Some(1)
         } else {
             // U+0001 to U+0020 (exclusive) are control codes
             None
         }
     } else if c >= '\u{A0}' {
         // No characters >= U+00A0 are control codes, so we can consult the lookup tables
         Some(cw::lookup_width(c, is_cjk))
     } else {
         // U+007F to U+00A0 (exclusive) are control codes
         None
     }
 }

 /// Methods for determining displayed width of Unicode strings.
 pub trait UnicodeWidthStr {
     /// Returns the string's displayed width in columns.
     ///
     /// This function treats characters in the Ambiguous category according
     /// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
     /// as 1 column wide. This is consistent with the recommendations for
     /// non-CJK contexts, or when the context cannot be reliably determined.
     fn width(&self) -> usize;

     /// Returns the string's displayed width in columns.
     ///
     /// This function treats characters in the Ambiguous category according
     /// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
     /// as 2 column wide. This is consistent with the recommendations for
     /// CJK contexts.
     fn width_cjk(&self) -> usize;
 }

 impl UnicodeWidthStr for str {
     #[inline]
     fn width(&self) -> usize {
         str_width(self, false)
     }

     #[inline]
     fn width_cjk(&self) -> usize {
         str_width(self, true)
     }
 }

 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
 enum NextCharInfo {
     #[default]
     Default,
     /// `'\n'`
     LineFeed,
     /// '\u{0338}'
     /// For preserving canonical equivalence with CJK
     CombiningLongSolidusOverlay,
     /// `'\u{A4FC}'..='\u{A4FD}'`
     /// <https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G42078>
     TrailingLisuToneLetter,
     /// `'\u{FE0E}'`
     Vs15,
     /// `'\u{FE0F}'`
     Vs16,
 }

 fn str_width(s: &str, is_cjk: bool) -> usize {
     s.chars()
         .rfold((0, NextCharInfo::Default), |(sum, next_info), c| {
             let (add, info) = width_in_str(c, is_cjk, next_info);
             (sum + add, info)
         })
         .0
 }

 /// Returns the [UAX #11](https://www.unicode.org/reports/tr11/) based width of `c`.
 /// If `is_cjk == true`, ambiguous width characters are treated as double width; otherwise,
 /// they're treated as single width.
 #[inline]
 fn width_in_str(c: char, is_cjk: bool, next_info: NextCharInfo) -> (usize, NextCharInfo) {
     if (is_cjk
         && next_info == NextCharInfo::CombiningLongSolidusOverlay
         && matches!(c, '<' | '=' | '>'))
         || (next_info == NextCharInfo::Vs16 && cw::starts_emoji_presentation_seq(c))
     {
         (2, NextCharInfo::Default)
     } else if c <= '\u{A0}' {
         match c {
             '\n' => (1, NextCharInfo::LineFeed),
             '\r' if next_info == NextCharInfo::LineFeed => (0, NextCharInfo::Default),
             _ => (1, NextCharInfo::Default),
         }
     } else {
         match (c, next_info) {
             ('\u{A4F8}'..='\u{A4FB}', NextCharInfo::TrailingLisuToneLetter) => {
                 (0, NextCharInfo::Default)
             }
             ('\u{0338}', _) => (0, NextCharInfo::CombiningLongSolidusOverlay),
             ('\u{A4FC}'..='\u{A4FD}', _) => (1, NextCharInfo::TrailingLisuToneLetter),
             ('\u{FE0E}', _) => (0, NextCharInfo::Vs15),
             ('\u{FE0F}', _) => (0, NextCharInfo::Vs16),
             (_, NextCharInfo::Vs15)
                 if !is_cjk && cw::starts_non_ideographic_text_presentation_seq(c) =>
             {
                 (1, NextCharInfo::Default)
             }
             _ => (cw::lookup_width(c, is_cjk), NextCharInfo::Default),
         }
     }
 }
	// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
	// file at the top-level directory of this distribution and at
	// http://rust-lang.org/COPYRIGHT.
	//
	// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
	// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
	// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
	// option. This file may not be copied, modified, or distributed
	// except according to those terms.

	//! Determine displayed width of `char` and `str` types according to
	//! [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
	//! and other portions of the Unicode standard.
	//! See the [Rules for determining width](#rules-for-determining-width) section
	//! for the exact rules.
	//!
	//! This crate is `#![no_std]`.
	//!
	//! ```rust
	//! use unicode_width::UnicodeWidthStr;
	//!
	//! let teststr = "Ｈｅｌｌｏ, ｗｏｒｌｄ!";
	//! let width = UnicodeWidthStr::width(teststr);
	//! println!("{}", teststr);
	//! println!("The above string is {} columns wide.", width);
	//! let width = teststr.width_cjk();
	//! println!("The above string is {} columns wide (CJK).", width);
	//! ```
	//!
	//! # Rules for determining width
	//!
	//! This crate currently uses the following rules to determine the width of a
	//! character or string, in order of decreasing precedence. These may be tweaked in the future.
	//!
	//! 1. [Emoji presentation sequences] have width 2.
	//! 2. Outside of an East Asian context, [text presentation sequences] have width 1
	//! if their base character:
	//! - Has the [`Emoji_Presentation`] property, and
	//! - Is not in the [Enclosed Ideographic Supplement] block.
	//! 3. The sequence `"\r\n"` has width 1.
	//! 4. [Lisu tone letter] combinations consisting of a character in the range `'\u{A4F8}'..='\u{A4FB}'`
	//! followed by a character in the range `'\u{A4FC}'..='\u{A4FD}'` have width 1.
	//! 5. In an East Asian context only, `<`, `=`, or `>` have width 2 when followed by [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY].
	//! 6. [`'\u{115F}'` HANGUL CHOSEONG FILLER](https://util.unicode.org/UnicodeJsps/character.jsp?a=115F) has width 2.
	//! 7. The following have width 0:
	//! - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BDefault_Ignorable_Code_Point%7D)
	//! with the [`Default_Ignorable_Code_Point`] property.
	//! - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BGrapheme_Extend%7D)
	//! with the [`Grapheme_Extend`] property.
	//! - The following 8 characters, all of which have NFD decompositions consisting of two [`Grapheme_Extend`] characters:
	//! - [`'\u{0CC0}'` KANNADA VOWEL SIGN II](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CC0),
	//! - [`'\u{0CC7}'` KANNADA VOWEL SIGN EE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CC7),
	//! - [`'\u{0CC8}'` KANNADA VOWEL SIGN AI](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CC8),
	//! - [`'\u{0CCA}'` KANNADA VOWEL SIGN O](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CCA),
	//! - [`'\u{0CCB}'` KANNADA VOWEL SIGN OO](https://util.unicode.org/UnicodeJsps/character.jsp?a=0CCB),
	//! - [`'\u{1B3B}'` BALINESE VOWEL SIGN RA REPA TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B3B),
	//! - [`'\u{1B3D}'` BALINESE VOWEL SIGN LA LENGA TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B3D), and
	//! - [`'\u{1B43}'` BALINESE VOWEL SIGN PEPET TEDUNG](https://util.unicode.org/UnicodeJsps/character.jsp?a=1B43).
	//! - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BHangul_Syllable_Type%3DV%7D%5Cp%7BHangul_Syllable_Type%3DT%7D)
	//! with a [`Hangul_Syllable_Type`] of `Vowel_Jamo` (`V`) or `Trailing_Jamo` (`T`).
	//! - The following [`Prepended_Concatenation_Mark`]s:
	//! - [`'\u{0605}'` NUMBER MARK ABOVE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0605),
	//! - [`'\u{070F}'` SYRIAC ABBREVIATION MARK](https://util.unicode.org/UnicodeJsps/character.jsp?a=070F),
	//! - [`'\u{0890}'` POUND MARK ABOVE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0890),
	//! - [`'\u{0891}'` PIASTRE MARK ABOVE](https://util.unicode.org/UnicodeJsps/character.jsp?a=0891), and
	//! - [`'\u{08E2}'` DISPUTED END OF AYAH](https://util.unicode.org/UnicodeJsps/character.jsp?a=08E2).
	//! - [`'\u{A8FA}'` DEVANAGARI CARET](https://util.unicode.org/UnicodeJsps/character.jsp?a=A8FA).
	//! 8. [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BEast_Asian_Width%3DF%7D%5Cp%7BEast_Asian_Width%3DW%7D)
	//! with an [`East_Asian_Width`] of [`Fullwidth`] or [`Wide`] have width 2.
	//! 9. Characters fulfilling all of the following conditions have width 2 in an East Asian context, and width 1 otherwise:
	//! - Has an [`East_Asian_Width`] of [`Ambiguous`], or
	//! has a canonical decomposition to an [`Ambiguous`] character followed by [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY], or
	//! is [`'\u{0387}'` GREEK ANO TELEIA](https://util.unicode.org/UnicodeJsps/character.jsp?a=0387), and
	//! - Does not have a [`General_Category`] of `Modifier_Symbol`, and
	//! - Does not have a [`Script`] of `Latin`, `Greek`, or `Cyrillic`, or is a Roman numeral in the range `'\u{2160}'..='\u{217F}'`.
	//! 10. All other characters have width 1.
	//!
	//! [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY]: https://util.unicode.org/UnicodeJsps/character.jsp?a=0338
	//!
	//! [`Default_Ignorable_Code_Point`]: https://www.unicode.org/versions/Unicode15.0.0/ch05.pdf#G40095
	//! [`East_Asian_Width`]: https://www.unicode.org/reports/tr11/#ED1
	//! [`Emoji_Presentation`]: https://unicode.org/reports/tr51/#def_emoji_presentation
	//! [`General_Category`]: https://www.unicode.org/versions/Unicode15.0.0/ch04.pdf#G124142
	//! [`Grapheme_Extend`]: https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G52443
	//! [`Hangul_Syllable_Type`]: https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G45593
	//! [`Prepended_Concatenation_Mark`]: https://www.unicode.org/versions/Unicode15.0.0/ch23.pdf#G37908
	//! [`Script`]: https://www.unicode.org/reports/tr24/#Script
	//!
	//! [`Fullwidth`]: https://www.unicode.org/reports/tr11/#ED2
	//! [`Wide`]: https://www.unicode.org/reports/tr11/#ED4
	//! [`Ambiguous`]: https://www.unicode.org/reports/tr11/#ED6
	//!
	//! [Emoji presentation sequences]: https://unicode.org/reports/tr51/#def_emoji_presentation_sequence
	//! [text presentation sequences]: https://unicode.org/reports/tr51/#def_text_presentation_sequence
	//!
	//! [Enclosed Ideographic Supplement]: https://unicode.org/charts/nameslist/n_1F200.html
	//!
	//! [Lisu tone letter]: https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G42078
	//!
	//! ## Canonical equivalence
	//!
	//! Canonically equivalent strings are assigned the same width (CJK and non-CJK).

	#![forbid(unsafe_code)]
	#![deny(missing_docs)]
	#![doc(
	html_logo_url = "https://unicode-rs.github.io/unicode-rs_sm.png",
	html_favicon_url = "https://unicode-rs.github.io/unicode-rs_sm.png"
	)]
	#![no_std]

	use tables::charwidth as cw;
	pub use tables::UNICODE_VERSION;

	mod tables;

	/// Methods for determining displayed width of Unicode characters.
	pub trait UnicodeWidthChar {
	/// Returns the character's displayed width in columns, or `None` if the
	/// character is a control character.
	///
	/// This function treats characters in the Ambiguous category according
	/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
	/// as 1 column wide. This is consistent with the recommendations for non-CJK
	/// contexts, or when the context cannot be reliably determined.
	fn width(self) -> Option<usize>;

	/// Returns the character's displayed width in columns, or `None` if the
	/// character is a control character.
	///
	/// This function treats characters in the Ambiguous category according
	/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
	/// as 2 columns wide. This is consistent with the recommendations for
	/// CJK contexts.
	fn width_cjk(self) -> Option<usize>;
	}

	impl UnicodeWidthChar for char {
	#[inline]
	fn width(self) -> Option<usize> {
	single_char_width(self, false)
	}

	#[inline]
	fn width_cjk(self) -> Option<usize> {
	single_char_width(self, true)
	}
	}

	/// Returns the [UAX #11](https://www.unicode.org/reports/tr11/) based width of `c`, or
	/// `None` if `c` is a control character.
	/// If `is_cjk == true`, ambiguous width characters are treated as double width; otherwise,
	/// they're treated as single width.
	#[inline]
	fn single_char_width(c: char, is_cjk: bool) -> Option<usize> {
	if c < '\u{7F}' {
	if c >= '\u{20}' {
	// U+0020 to U+007F (exclusive) are single-width ASCII codepoints
	Some(1)
	} else {
	// U+0001 to U+0020 (exclusive) are control codes
	None
	}
	} else if c >= '\u{A0}' {
	// No characters >= U+00A0 are control codes, so we can consult the lookup tables
	Some(cw::lookup_width(c, is_cjk))
	} else {
	// U+007F to U+00A0 (exclusive) are control codes
	None
	}
	}

	/// Methods for determining displayed width of Unicode strings.
	pub trait UnicodeWidthStr {
	/// Returns the string's displayed width in columns.
	///
	/// This function treats characters in the Ambiguous category according
	/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
	/// as 1 column wide. This is consistent with the recommendations for
	/// non-CJK contexts, or when the context cannot be reliably determined.
	fn width(&self) -> usize;

	/// Returns the string's displayed width in columns.
	///
	/// This function treats characters in the Ambiguous category according
	/// to [Unicode Standard Annex #11](http://www.unicode.org/reports/tr11/)
	/// as 2 column wide. This is consistent with the recommendations for
	/// CJK contexts.
	fn width_cjk(&self) -> usize;
	}

	impl UnicodeWidthStr for str {
	#[inline]
	fn width(&self) -> usize {
	str_width(self, false)
	}

	#[inline]
	fn width_cjk(&self) -> usize {
	str_width(self, true)
	}
	}

	#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
	enum NextCharInfo {
	#[default]
	Default,
	/// `'\n'`
	LineFeed,
	/// '\u{0338}'
	/// For preserving canonical equivalence with CJK
	CombiningLongSolidusOverlay,
	/// `'\u{A4FC}'..='\u{A4FD}'`
	/// <https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G42078>
	TrailingLisuToneLetter,
	/// `'\u{FE0E}'`
	Vs15,
	/// `'\u{FE0F}'`
	Vs16,
	}

	fn str_width(s: &str, is_cjk: bool) -> usize {
	s.chars()
	.rfold((0, NextCharInfo::Default), \|(sum, next_info), c\| {
	let (add, info) = width_in_str(c, is_cjk, next_info);
	(sum + add, info)
	})
	.0
	}

	/// Returns the [UAX #11](https://www.unicode.org/reports/tr11/) based width of `c`.
	/// If `is_cjk == true`, ambiguous width characters are treated as double width; otherwise,
	/// they're treated as single width.
	#[inline]
	fn width_in_str(c: char, is_cjk: bool, next_info: NextCharInfo) -> (usize, NextCharInfo) {
	if (is_cjk
	&& next_info == NextCharInfo::CombiningLongSolidusOverlay
	&& matches!(c, '<' \| '=' \| '>'))
	\|\| (next_info == NextCharInfo::Vs16 && cw::starts_emoji_presentation_seq(c))
	{
	(2, NextCharInfo::Default)
	} else if c <= '\u{A0}' {
	match c {
	'\n' => (1, NextCharInfo::LineFeed),
	'\r' if next_info == NextCharInfo::LineFeed => (0, NextCharInfo::Default),
	_ => (1, NextCharInfo::Default),
	}
	} else {
	match (c, next_info) {
	('\u{A4F8}'..='\u{A4FB}', NextCharInfo::TrailingLisuToneLetter) => {
	(0, NextCharInfo::Default)
	}
	('\u{0338}', _) => (0, NextCharInfo::CombiningLongSolidusOverlay),
	('\u{A4FC}'..='\u{A4FD}', _) => (1, NextCharInfo::TrailingLisuToneLetter),
	('\u{FE0E}', _) => (0, NextCharInfo::Vs15),
	('\u{FE0F}', _) => (0, NextCharInfo::Vs16),
	(_, NextCharInfo::Vs15)
	if !is_cjk && cw::starts_non_ideographic_text_presentation_seq(c) =>
	{
	(1, NextCharInfo::Default)
	}
	_ => (cw::lookup_width(c, is_cjk), NextCharInfo::Default),
	}
	}
	}