diff options
Diffstat (limited to 'src/vscreen.rs')
| -rw-r--r-- | src/vscreen.rs | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/src/vscreen.rs b/src/vscreen.rs new file mode 100644 index 00000000..ea5d4da6 --- /dev/null +++ b/src/vscreen.rs @@ -0,0 +1,212 @@ +use std::fmt::{Display, Formatter}; + +// Wrapper to avoid unnecessary branching when input doesn't have ANSI escape sequences. +pub struct AnsiStyle { + attributes: Option<Attributes>, +} + +impl AnsiStyle { + pub fn new() -> Self { + AnsiStyle { attributes: None } + } + + pub fn update(&mut self, sequence: &str) -> bool { + match &mut self.attributes { + Some(a) => a.update(sequence), + None => { + self.attributes = Some(Attributes::new()); + self.attributes.as_mut().unwrap().update(sequence) + } + } + } +} + +impl Display for AnsiStyle { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + match self.attributes { + Some(ref a) => a.fmt(f), + None => Ok(()), + } + } +} + +struct Attributes { + foreground: String, + background: String, + underlined: String, + + /// The character set to use. + /// REGEX: `\^[()][AB0-3]` + charset: String, + + /// A buffer for unknown sequences. + unknown_buffer: String, + + /// ON: ^[1m + /// OFF: ^[22m + bold: String, + + /// ON: ^[2m + /// OFF: ^[22m + dim: String, + + /// ON: ^[4m + /// OFF: ^[24m + underline: String, + + /// ON: ^[3m + /// OFF: ^[23m + italic: String, + + /// ON: ^[9m + /// OFF: ^[29m + strike: String, +} + +impl Attributes { + pub fn new() -> Self { + Attributes { + foreground: "".to_owned(), + background: "".to_owned(), + underlined: "".to_owned(), + charset: "".to_owned(), + unknown_buffer: "".to_owned(), + bold: "".to_owned(), + dim: "".to_owned(), + underline: "".to_owned(), + italic: "".to_owned(), + strike: "".to_owned(), + } + } + + /// Update the attributes with an escape sequence. + /// Returns `false` if the sequence is unsupported. + pub fn update(&mut self, sequence: &str) -> bool { + let mut chars = sequence.char_indices().skip(1); + + if let Some((_, t)) = chars.next() { + match t { + '(' => self.update_with_charset('(', chars.map(|(_, c)| c)), + ')' => self.update_with_charset(')', chars.map(|(_, c)| c)), + '[' => { + if let Some((i, last)) = chars.last() { + // SAFETY: Always starts with ^[ and ends with m. + self.update_with_csi(last, &sequence[2..i]) + } else { + false + } + } + _ => self.update_with_unsupported(sequence), + } + } else { + false + } + } + + fn sgr_reset(&mut self) { + self.foreground.clear(); + self.background.clear(); + self.underlined.clear(); + self.bold.clear(); + self.dim.clear(); + self.underline.clear(); + self.italic.clear(); + self.strike.clear(); + } + + fn update_with_sgr(&mut self, parameters: &str) -> bool { + let mut iter = parameters + .split(';') + .map(|p| if p.is_empty() { "0" } else { p }) + .map(|p| p.parse::<u16>()) + .map(|p| p.unwrap_or(0)); // Treat errors as 0. + + while let Some(p) = iter.next() { + match p { + 0 => self.sgr_reset(), + 1 => self.bold = format!("\x1B[{}m", parameters), + 2 => self.dim = format!("\x1B[{}m", parameters), + 3 => self.italic = format!("\x1B[{}m", parameters), + 4 => self.underline = format!("\x1B[{}m", parameters), + 23 => self.italic.clear(), + 24 => self.underline.clear(), + 22 => { + self.bold.clear(); + self.dim.clear(); + } + 30..=39 => self.foreground = Self::parse_color(p, &mut iter), + 40..=49 => self.background = Self::parse_color(p, &mut iter), + 58..=59 => self.underlined = Self::parse_color(p, &mut iter), + 90..=97 => self.foreground = Self::parse_color(p, &mut iter), + 100..=107 => self.foreground = Self::parse_color(p, &mut iter), + _ => { + // Unsupported SGR sequence. + // Be compatible and pretend one just wasn't was provided. + } + } + } + + true + } + + fn update_with_csi(&mut self, finalizer: char, sequence: &str) -> bool { + if finalizer == 'm' { + self.update_with_sgr(sequence) + } else { + false + } + } + + fn update_with_unsupported(&mut self, sequence: &str) -> bool { + self.unknown_buffer.push_str(sequence); + false + } + + fn update_with_charset(&mut self, kind: char, set: impl Iterator<Item = char>) -> bool { + self.charset = format!("\x1B{}{}", kind, set.take(1).collect::<String>()); + true + } + + fn parse_color(color: u16, parameters: &mut dyn Iterator<Item = u16>) -> String { + match color % 10 { + 8 => match parameters.next() { + Some(5) /* 256-color */ => format!("\x1B[{};5;{}m", color, join(";", 1, parameters)), + Some(2) /* 24-bit color */ => format!("\x1B[{};2;{}m", color, join(";", 3, parameters)), + Some(c) => format!("\x1B[{};{}m", color, c), + _ => "".to_owned(), + }, + 9 => "".to_owned(), + _ => format!("\x1B[{}m", color), + } + } +} + +impl Display for Attributes { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "{}{}{}{}{}{}{}{}{}", + self.foreground, + self.background, + self.underlined, + self.charset, + self.bold, + self.dim, + self.underline, + self.italic, + self.strike, + ) + } +} + +fn join( + delimiter: &str, + limit: usize, + iterator: &mut dyn Iterator<Item = impl ToString>, +) -> String { + iterator + .take(limit) + .map(|i| i.to_string()) + .collect::<Vec<String>>() + .join(delimiter) +} |