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

//! ANSI escape sequence related types and functions.
use crate::style::color::Rgb;

/// List of supported SGR (Select Graphics Rendition) sequences
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum Sgr {
    /// Reset all styling options
    Reset,

    /// Draw a line under the text
    Underline,

    /// Cross out the text
    CrossedOut,

    /// Disable drawing underline
    UnderlineOff,

    /// Disable crossing out
    NotCrossedOut,

    /// Change the text color
    ChangeTextColor(Rgb),

    /// Reset the text color to transparent
    DefaultTextColor,

    /// Change the background color
    ChangeBackgroundColor(Rgb),

    /// Reset the background color to transparent
    DefaultBackgroundColor,
}

fn try_parse_8b_color(v: &[u8]) -> Option<Rgb> {
    let color = *v.get(0)?;
    match color {
        //   0-  7:  standard colors (as in ESC [ 30–37 m)
        //   8- 15:  high intensity colors (as in ESC [ 90–97 m)
        0..=15 => Some(standard_to_rgb(color)),

        //  16-231:  6 × 6 × 6 cube (216 colors): 16 + 36 × r + 6 × g + b (0 ≤ r, g, b ≤ 5)
        16..=231 => {
            fn extract_ch(source: u8) -> (u8, u8) {
                let ch = (source % 6) * 51; // 5 * 51 = 255
                let remainder = source / 6;

                (ch, remainder)
            }

            let source_rgb = color - 16;
            let (b, source_rg) = extract_ch(source_rgb);
            let (g, source_r) = extract_ch(source_rg);
            let (r, _) = extract_ch(source_r);

            Some(Rgb::new(r, g, b))
        }

        // 232-255:  grayscale from black to white in 24 steps
        232..=255 => {
            let level = color - 232;
            let g = if level == 23 { 255 } else { level * 11 };
            Some(Rgb::new(g, g, g))
        }
    }
}

fn try_parse_rgb(v: &[u8]) -> Option<Rgb> {
    let r = *v.get(0)?;
    let g = *v.get(1)?;
    let b = *v.get(2)?;

    Some(Rgb::new(r, g, b))
}

fn standard_to_rgb(idx: u8) -> Rgb {
    // These colors are used in PowerShell 6 in Windows 10
    match idx {
        0 => Rgb::new(12, 12, 12),
        1 => Rgb::new(197, 15, 31),
        2 => Rgb::new(19, 161, 14),
        3 => Rgb::new(193, 156, 0),
        4 => Rgb::new(0, 55, 218),
        5 => Rgb::new(136, 23, 152),
        6 => Rgb::new(58, 150, 221),
        7 => Rgb::new(204, 204, 204),

        8 => Rgb::new(118, 118, 118),
        9 => Rgb::new(231, 72, 86),
        10 => Rgb::new(22, 198, 12),
        11 => Rgb::new(249, 241, 165),
        12 => Rgb::new(59, 120, 255),
        13 => Rgb::new(180, 0, 158),
        14 => Rgb::new(97, 214, 214),
        _ => Rgb::new(242, 242, 242),
    }
}

fn try_parse_color(v: &[u8]) -> Option<Rgb> {
    let color_type = *v.get(0)?;

    match color_type {
        2 => try_parse_rgb(&v[1..]),
        5 => try_parse_8b_color(&v[1..]),

        _ => None,
    }
}

/// Parse a set of SGR parameter numbers into a more convenient type
#[inline]
pub fn try_parse_sgr(v: &[u8]) -> Option<Sgr> {
    let code = *v.get(0)?;
    match code {
        0 => Some(Sgr::Reset),
        4 => Some(Sgr::Underline),
        9 => Some(Sgr::CrossedOut),
        24 => Some(Sgr::UnderlineOff),
        29 => Some(Sgr::NotCrossedOut),
        39 => Some(Sgr::DefaultTextColor),
        49 => Some(Sgr::DefaultBackgroundColor),
        30..=37 => Some(Sgr::ChangeTextColor(standard_to_rgb(code - 30))),
        38 => {
            let color = try_parse_color(&v[1..])?;
            Some(Sgr::ChangeTextColor(color))
        }
        90..=97 => Some(Sgr::ChangeTextColor(standard_to_rgb(code - 82))),
        40..=47 => Some(Sgr::ChangeBackgroundColor(standard_to_rgb(code - 40))),
        48 => {
            let color = try_parse_color(&v[1..])?;
            Some(Sgr::ChangeBackgroundColor(color))
        }
        100..=107 => Some(Sgr::ChangeBackgroundColor(standard_to_rgb(code - 92))),
        _ => None,
    }
}