file.rs

extern crate libc;

pub trait CharWidth {
    fn width(self) -> Option<uint>;
}

pub trait StringWidth {
    fn width(self) -> uint;
}

impl CharWidth for char {
    fn width(self) -> Option<uint> {
        width(self)
    }
}

impl<'a> StringWidth for &'a str {
    fn width(self) -> uint {
        self.chars().map(|c| c.width().unwrap_or(1)).fold(0, |a, b| a + b)
    }
}

// One might be tempted to use libc's wcwidth function here. But that would be a mistake
// since glibc's wcwidth is completely broken and doesn't even pass the test below.
pub fn width(c: char) -> Option<uint> {
    let c = c as u32;
    // Fast path for ascii
    if c >= 0x20 && c <= 0x7e {
        return Some(1);
    }
    if (c > 0x00 && c < 0x20) || (c >= 0x7f && c < 0xa0) {
        return None;
    }
    let ret = match c {
        0x00000            => 0,

        // Non-spacing characters (Mn + Me + Cf - 0x00AD)
        0x00300 .. 0x0036f => 0,
        0x00483 .. 0x00489 => 0,
        0x00591 .. 0x005bd => 0,
        0x005bf            => 0,
        0x005c1 .. 0x005c2 => 0,
        0x005c4 .. 0x005c5 => 0,
        0x005c7            => 0,
        0x00600 .. 0x00604 => 0,
        0x00610 .. 0x0061a => 0,
        0x0061c            => 0,
        0x0064b .. 0x0065f => 0,
        0x00670            => 0,
        0x006d6 .. 0x006dd => 0,
        0x006df .. 0x006e4 => 0,
        0x006e7 .. 0x006e8 => 0,
        0x006ea .. 0x006ed => 0,
        0x0070f            => 0,
        0x00711            => 0,
        0x00730 .. 0x0074a => 0,
        0x007a6 .. 0x007b0 => 0,
        0x007eb .. 0x007f3 => 0,
        0x00816 .. 0x00819 => 0,
        0x0081b .. 0x00823 => 0,
        0x00825 .. 0x00827 => 0,
        0x00829 .. 0x0082d => 0,
        0x00859 .. 0x0085b => 0,
        0x008e4 .. 0x008fe => 0,
        0x00900 .. 0x00902 => 0,
        0x0093a            => 0,
        0x0093c            => 0,
        0x00941 .. 0x00948 => 0,
        0x0094d            => 0,
        0x00951 .. 0x00957 => 0,
        0x00962 .. 0x00963 => 0,
        0x00981            => 0,
        0x009bc            => 0,
        0x009c1 .. 0x009c4 => 0,
        0x009cd            => 0,
        0x009e2 .. 0x009e3 => 0,
        0x00a01 .. 0x00a02 => 0,
        0x00a3c            => 0,
        0x00a41 .. 0x00a42 => 0,
        0x00a47 .. 0x00a48 => 0,
        0x00a4b .. 0x00a4d => 0,
        0x00a51            => 0,
        0x00a70 .. 0x00a71 => 0,
        0x00a75            => 0,
        0x00a81 .. 0x00a82 => 0,
        0x00abc            => 0,
        0x00ac1 .. 0x00ac5 => 0,
        0x00ac7 .. 0x00ac8 => 0,
        0x00acd            => 0,
        0x00ae2 .. 0x00ae3 => 0,
        0x00b01            => 0,
        0x00b3c            => 0,
        0x00b3f            => 0,
        0x00b41 .. 0x00b44 => 0,
        0x00b4d            => 0,
        0x00b56            => 0,
        0x00b62 .. 0x00b63 => 0,
        0x00b82            => 0,
        0x00bc0            => 0,
        0x00bcd            => 0,
        0x00c3e .. 0x00c40 => 0,
        0x00c46 .. 0x00c48 => 0,
        0x00c4a .. 0x00c4d => 0,
        0x00c55 .. 0x00c56 => 0,
        0x00c62 .. 0x00c63 => 0,
        0x00cbc            => 0,
        0x00cbf            => 0,
        0x00cc6            => 0,
        0x00ccc .. 0x00ccd => 0,
        0x00ce2 .. 0x00ce3 => 0,
        0x00d41 .. 0x00d44 => 0,
        0x00d4d            => 0,
        0x00d62 .. 0x00d63 => 0,
        0x00dca            => 0,
        0x00dd2 .. 0x00dd4 => 0,
        0x00dd6            => 0,
        0x00e31            => 0,
        0x00e34 .. 0x00e3a => 0,
        0x00e47 .. 0x00e4e => 0,
        0x00eb1            => 0,
        0x00eb4 .. 0x00eb9 => 0,
        0x00ebb .. 0x00ebc => 0,
        0x00ec8 .. 0x00ecd => 0,
        0x00f18 .. 0x00f19 => 0,
        0x00f35            => 0,
        0x00f37            => 0,
        0x00f39            => 0,
        0x00f71 .. 0x00f7e => 0,
        0x00f80 .. 0x00f84 => 0,
        0x00f86 .. 0x00f87 => 0,
        0x00f8d .. 0x00f97 => 0,
        0x00f99 .. 0x00fbc => 0,
        0x00fc6            => 0,
        0x0102d .. 0x01030 => 0,
        0x01032 .. 0x01037 => 0,
        0x01039 .. 0x0103a => 0,
        0x0103d .. 0x0103e => 0,
        0x01058 .. 0x01059 => 0,
        0x0105e .. 0x01060 => 0,
        0x01071 .. 0x01074 => 0,
        0x01082            => 0,
        0x01085 .. 0x01086 => 0,
        0x0108d            => 0,
        0x0109d            => 0,
        0x0135d .. 0x0135f => 0,
        0x01712 .. 0x01714 => 0,
        0x01732 .. 0x01734 => 0,
        0x01752 .. 0x01753 => 0,
        0x01772 .. 0x01773 => 0,
        0x017b4 .. 0x017b5 => 0,
        0x017b7 .. 0x017bd => 0,
        0x017c6            => 0,
        0x017c9 .. 0x017d3 => 0,
        0x017dd            => 0,
        0x0180b .. 0x0180e => 0,
        0x018a9            => 0,
        0x01920 .. 0x01922 => 0,
        0x01927 .. 0x01928 => 0,
        0x01932            => 0,
        0x01939 .. 0x0193b => 0,
        0x01a17 .. 0x01a18 => 0,
        0x01a1b            => 0,
        0x01a56            => 0,
        0x01a58 .. 0x01a5e => 0,
        0x01a60            => 0,
        0x01a62            => 0,
        0x01a65 .. 0x01a6c => 0,
        0x01a73 .. 0x01a7c => 0,
        0x01a7f            => 0,
        0x01b00 .. 0x01b03 => 0,
        0x01b34            => 0,
        0x01b36 .. 0x01b3a => 0,
        0x01b3c            => 0,
        0x01b42            => 0,
        0x01b6b .. 0x01b73 => 0,
        0x01b80 .. 0x01b81 => 0,
        0x01ba2 .. 0x01ba5 => 0,
        0x01ba8 .. 0x01ba9 => 0,
        0x01bab            => 0,
        0x01be6            => 0,
        0x01be8 .. 0x01be9 => 0,
        0x01bed            => 0,
        0x01bef .. 0x01bf1 => 0,
        0x01c2c .. 0x01c33 => 0,
        0x01c36 .. 0x01c37 => 0,
        0x01cd0 .. 0x01cd2 => 0,
        0x01cd4 .. 0x01ce0 => 0,
        0x01ce2 .. 0x01ce8 => 0,
        0x01ced            => 0,
        0x01cf4            => 0,
        0x01dc0 .. 0x01de6 => 0,
        0x01dfc .. 0x01dff => 0,
        0x0200b .. 0x0200f => 0,
        0x0202a .. 0x0202e => 0,
        0x02060 .. 0x02064 => 0,
        0x02066 .. 0x0206f => 0,
        0x020d0 .. 0x020f0 => 0,
        0x02cef .. 0x02cf1 => 0,
        0x02d7f            => 0,
        0x02de0 .. 0x02dff => 0,
        0x0302a .. 0x0302d => 0,
        0x03099 .. 0x0309a => 0,
        0x0a66f .. 0x0a672 => 0,
        0x0a674 .. 0x0a67d => 0,
        0x0a69f            => 0,
        0x0a6f0 .. 0x0a6f1 => 0,
        0x0a802            => 0,
        0x0a806            => 0,
        0x0a80b            => 0,
        0x0a825 .. 0x0a826 => 0,
        0x0a8c4            => 0,
        0x0a8e0 .. 0x0a8f1 => 0,
        0x0a926 .. 0x0a92d => 0,
        0x0a947 .. 0x0a951 => 0,
        0x0a980 .. 0x0a982 => 0,
        0x0a9b3            => 0,
        0x0a9b6 .. 0x0a9b9 => 0,
        0x0a9bc            => 0,
        0x0aa29 .. 0x0aa2e => 0,
        0x0aa31 .. 0x0aa32 => 0,
        0x0aa35 .. 0x0aa36 => 0,
        0x0aa43            => 0,
        0x0aa4c            => 0,
        0x0aab0            => 0,
        0x0aab2 .. 0x0aab4 => 0,
        0x0aab7 .. 0x0aab8 => 0,
        0x0aabe .. 0x0aabf => 0,
        0x0aac1            => 0,
        0x0aaec .. 0x0aaed => 0,
        0x0aaf6            => 0,
        0x0abe5            => 0,
        0x0abe8            => 0,
        0x0abed            => 0,
        0x0fb1e            => 0,
        0x0fe00 .. 0x0fe0f => 0,
        0x0fe20 .. 0x0fe26 => 0,
        0x0feff            => 0,
        0x0fff9 .. 0x0fffb => 0,
        0x101fd            => 0,
        0x10a01 .. 0x10a03 => 0,
        0x10a05 .. 0x10a06 => 0,
        0x10a0c .. 0x10a0f => 0,
        0x10a38 .. 0x10a3a => 0,
        0x10a3f            => 0,
        0x11001            => 0,
        0x11038 .. 0x11046 => 0,
        0x11080 .. 0x11081 => 0,
        0x110b3 .. 0x110b6 => 0,
        0x110b9 .. 0x110ba => 0,
        0x110bd            => 0,
        0x11100 .. 0x11102 => 0,
        0x11127 .. 0x1112b => 0,
        0x1112d .. 0x11134 => 0,
        0x11180 .. 0x11181 => 0,
        0x111b6 .. 0x111be => 0,
        0x116ab            => 0,
        0x116ad            => 0,
        0x116b0 .. 0x116b5 => 0,
        0x116b7            => 0,
        0x16f8f .. 0x16f92 => 0,
        0x1d167 .. 0x1d169 => 0,
        0x1d173 .. 0x1d182 => 0,
        0x1d185 .. 0x1d18b => 0,
        0x1d1aa .. 0x1d1ad => 0,
        0x1d242 .. 0x1d244 => 0,
        0xe0001            => 0,
        0xe0020 .. 0xe007f => 0,
        0xe0100 .. 0xe01ef => 0,

        // Hangul Jamo init. consonants
        0x01100 .. 0x0115f => 2,
        0x02329            => 2,
        0x0232a            => 2,
        // CJK ... Yi
        0x02e80 .. 0x0a4cf if c != 0x0303f => 2,
        // Hangul Syllables
        0x0ac00 .. 0x0d7a3 => 2,
        // CJK Compatibility Ideographs
        0x0f900 .. 0x0faff => 2,
        // Vertical forms
        0x0fe10 .. 0x0fe19 => 2,
        // CJK Compatibility Forms
        0x0fe30 .. 0x0fe6f => 2,
        // Fullwidth Forms
        0x0ff00 .. 0x0ff60 => 2,
        0x0ffe0 .. 0x0ffe6 => 2,
        0x20000 .. 0x2fffd => 2,
        0x30000 .. 0x3fffd => 2,

        _ => 1,
    };
    Some(ret)
}

#[test]
fn test_string_width() {
    assert_eq!("test".width(), 4);
    assert_eq!("你好".width(), 4);
}