1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
// 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);
//! ```
//!
//! # `"cjk"` feature flag
//!
//! This crate has one Cargo feature flag, `"cjk"`
//! (enabled by default).
//! It enables the [`UnicodeWidthChar::width_cjk`]
//! and [`UnicodeWidthStr::width_cjk`],
//! which perform an alternate width calculation
//! more suited to CJK contexts. The flag also unseals the
//! [`UnicodeWidthChar`] and [`UnicodeWidthStr`] traits.
//!
//! Disabling the flag (with `no_default_features` in `Cargo.toml`)
//! will reduce the amount of static data needed by the crate.
//!
//! ```rust
//! use unicode_width::UnicodeWidthStr;
//!
//! let teststr = "“𘀀”";
//! assert_eq!(teststr.width(), 4);
//!
//! #[cfg(feature = "cjk")]
//! assert_eq!(teststr.width_cjk(), 6);
//! ```
//!
//! # 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. In the following cases, the width of a string differs from the sum of the widths of its constituent characters:
//!    - The sequence `"\r\n"` has width 1.
//!    - Emoji-specific ligatures:
//!      - Well-formed, fully-qualified [emoji ZWJ sequences] have width 2.
//!      - [Emoji modifier sequences] have width 2.
//!      - [Emoji presentation sequences] have width 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.
//!    - Script-specific ligatures:
//!      - For all the following ligatures, the insertion of any number of [default-ignorable][`Default_Ignorable_Code_Point`]
//!        [combining marks] anywhere in the sequence will not change the total width. In addition, for all non-Arabic
//!        ligatures, the insertion of any number of [`'\u{200D}'` ZERO WIDTH JOINER](https://www.unicode.org/versions/Unicode15.0.0/ch23.pdf#G23126)s
//!        will not affect the width.
//!      - **[Arabic]**: A character sequence consisting of one character with [`Joining_Group`]`=Lam`,
//!        followed by any number of characters with [`Joining_Type`]`=Transparent`, followed by one character
//!        with [`Joining_Group`]`=Alef`, has total width 1. For example: `لا`‎, `لآ`‎, `ڸا`‎, `لٟٞأ`
//!      - **[Buginese]**: `"\u{1A15}\u{1A17}\u{200D}\u{1A10}"` (<a, -i> ya, `ᨕᨗ‍ᨐ`) has total width 1.
//!      - **[Hebrew]**: `"א\u{200D}ל"` (Alef-Lamed, `א‍ל`) has total width 1.
//!      - **[Khmer]**: Coeng signs consisting of `'\u{17D2}'` followed by a character in
//!        `'\u{1780}'..='\u{1782}' | '\u{1784}'..='\u{1787}' | '\u{1789}'..='\u{178C}' | '\u{178E}'..='\u{1793}' | '\u{1795}'..='\u{1798}' | '\u{179B}'..='\u{179D}' | '\u{17A0}' | '\u{17A2}'  | '\u{17A7}' | '\u{17AB}'..='\u{17AC}' | '\u{17AF}'`
//!        have width 0.
//!      - **[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. For example: `ꓹꓼ`
//!      - **[Old Turkic]**: `"\u{10C32}\u{200D}\u{10C03}"` (`𐰲‍𐰃`) has total width 1.
//!      - **[Tifinagh]**: A sequence of a Tifinagh consonant in the range `'\u{2D31}'..='\u{2D65}' | '\u{2D6F}'`, followed by either
//!        [`'\u{2D7F}'` TIFINAGH CONSONANT JOINER] or `'\u{200D}'`, followed by another Tifinangh consonant, has total width 1.
//!        For example: `ⵏ⵿ⴾ`
//!    - In an East Asian context only, `<`, `=`, or `>` have width 2 when followed by [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY].
//!      The two characters may be separated by any number of characters whose canonical decompositions consist only of characters meeting
//!      one of the following requirements:
//!      - Has [`Canonical_Combining_Class`] greater than 1, or
//!      - Is a [default-ignorable][`Default_Ignorable_Code_Point`] [combining mark][combining marks].
//! 2. In all other cases, the width of the string equals the sum of its character widths:
//!    1. [`'\u{2D7F}'` TIFINAGH CONSONANT JOINER] has width 1 (outside of the ligatures described previously).
//!    2. [`'\u{115F}'` HANGUL CHOSEONG FILLER](https://util.unicode.org/UnicodeJsps/character.jsp?a=115F) and
//!       [`'\u{17A4}'` KHMER INDEPENDENT VOWEL QAA](https://util.unicode.org/UnicodeJsps/character.jsp?a=17A4) have width 2.
//!    3. [`'\u{17D8}'` KHMER SIGN BEYYAL](https://util.unicode.org/UnicodeJsps/character.jsp?a=17D8) has width 3.
//!    4. 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).
//!       - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BGrapheme_Cluster_Break%3DPrepend%7D-%5Cp%7BPrepended_Concatenation_Mark%7D)
//!         with the [`Grapheme_Extend=Prepend`] property, that are not also [`Prepended_Concatenation_Mark`]s.
//!       - [`'\u{A8FA}'` DEVANAGARI CARET](https://util.unicode.org/UnicodeJsps/character.jsp?a=A8FA).
//!    5. [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.
//!    6. 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 `Letter` or `Modifier_Symbol`.
//!    7. All other characters have width 1.
//!
//! [`'\u{0338}'` COMBINING LONG SOLIDUS OVERLAY]: https://util.unicode.org/UnicodeJsps/character.jsp?a=0338
//! [`'\u{2D7F}'` TIFINAGH CONSONANT JOINER]: https://util.unicode.org/UnicodeJsps/character.jsp?a=2D7F
//!
//! [`Canonical_Combining_Class`]: https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G50313
//! [`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=Prepend`]: https://www.unicode.org/reports/tr29/#Prepend
//! [`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
//! [`Joining_Group`]: https://www.unicode.org/versions/Unicode14.0.0/ch09.pdf#G36862
//! [`Joining_Type`]: http://www.unicode.org/versions/Unicode15.0.0/ch09.pdf#G50009
//! [`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
//!
//! [combining marks]: https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G30602
//!
//! [emoji ZWJ sequences]: https://www.unicode.org/reports/tr51/#def_emoji_sequence
//! [Emoji modifier sequences]: https://www.unicode.org/reports/tr51/#def_emoji_modifier_sequence
//! [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
//!
//! [Arabic]: https://www.unicode.org/versions/Unicode15.0.0/ch09.pdf#G7480
//! [Buginese]: https://www.unicode.org/versions/Unicode15.0.0/ch17.pdf#G26743
//! [Hebrew]: https://www.unicode.org/versions/Unicode15.0.0/ch09.pdf#G6528
//! [Khmer]: https://www.unicode.org/versions/Unicode15.0.0/ch16.pdf#G64642
//! [Lisu]: https://www.unicode.org/versions/Unicode15.0.0/ch18.pdf#G44587
//! [Old Turkic]: https://www.unicode.org/versions/Unicode15.0.0/ch14.pdf#G41975
//! [Tifinagh]: http://www.unicode.org/versions/Unicode15.0.0/ch19.pdf#G43184
//!
//!
//! ## 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]

pub use tables::UNICODE_VERSION;

mod tables;

mod private {
    pub trait Sealed {}
    #[cfg(not(feature = "cjk"))]
    impl Sealed for char {}
    #[cfg(not(feature = "cjk"))]
    impl Sealed for str {}
    #[cfg(feature = "cjk")]
    impl<T: ?Sized> Sealed for T {}
}

/// Methods for determining displayed width of Unicode characters.
pub trait UnicodeWidthChar: private::Sealed {
    /// 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.
    #[cfg(feature = "cjk")]
    fn width_cjk(self) -> Option<usize>;
}

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

    #[cfg(feature = "cjk")]
    #[inline]
    fn width_cjk(self) -> Option<usize> {
        tables::single_char_width_cjk(self)
    }
}

/// Methods for determining displayed width of Unicode strings.
pub trait UnicodeWidthStr: private::Sealed {
    /// 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.
    #[cfg(feature = "cjk")]
    fn width_cjk(&self) -> usize;
}

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

    #[cfg(feature = "cjk")]
    #[inline]
    fn width_cjk(&self) -> usize {
        tables::str_width_cjk(self)
    }
}