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use termwiz::cell::unicode_column_width;
#[derive(Debug, Clone, Copy)]
pub enum Alignment {
Left,
Center,
Right,
}
#[derive(Debug)]
pub struct Column {
pub name: String,
pub alignment: Alignment,
}
fn emit_column<W: std::io::Write>(
text: &str,
max_width: usize,
alignment: Alignment,
output: &mut W,
) -> Result<(), std::io::Error> {
let text_width = unicode_column_width(text);
let (left_pad, right_pad) = match alignment {
Alignment::Left => (0, max_width - text_width),
Alignment::Center => {
let left_pad = (max_width - text_width) / 2;
let right_pad = max_width - (text_width + left_pad);
(left_pad, right_pad)
}
Alignment::Right => (max_width - text_width, 0),
};
for _ in 0..left_pad {
write!(output, " ")?;
}
write!(output, "{}", text)?;
for _ in 0..right_pad {
write!(output, " ")?;
}
Ok(())
}
pub fn tabulate_output<S: std::string::ToString, W: std::io::Write>(
columns: &[Column],
rows: &[Vec<S>],
output: &mut W,
) -> Result<(), std::io::Error> {
let mut col_widths: Vec<usize> = columns.iter().map(|c| c.name.len()).collect();
let mut display_rows: Vec<Vec<String>> = vec![];
for src_row in rows {
let dest_row: Vec<String> = src_row.iter().map(|col| col.to_string()).collect();
for (idx, col) in dest_row.iter().enumerate() {
let col_width = unicode_column_width(col);
if let Some(width) = col_widths.get_mut(idx) {
*width = (*width).max(col_width);
} else {
col_widths.push(col_width);
}
}
display_rows.push(dest_row);
}
for (idx, col) in columns.iter().enumerate() {
if idx > 0 {
write!(output, " ")?;
}
emit_column(&col.name, col_widths[idx], col.alignment, output)?;
}
writeln!(output)?;
for row in &display_rows {
for (idx, col) in row.iter().enumerate() {
let max_width = col_widths.get(idx).cloned().unwrap_or_else(|| col.len());
let alignment = columns
.get(idx)
.map(|c| c.alignment)
.unwrap_or(Alignment::Left);
if idx > 0 {
write!(output, " ")?;
}
emit_column(col, max_width, alignment, output)?;
}
writeln!(output)?;
}
Ok(())
}
pub fn tabulate_output_as_string<S: std::string::ToString>(
columns: &[Column],
rows: &[Vec<S>],
) -> Result<String, std::io::Error> {
let mut output: Vec<u8> = vec![];
tabulate_output(columns, rows, &mut output)?;
String::from_utf8(output)
.map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, format!("{}", e)))
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn basics() {
let cols = vec![
Column {
name: "hello".to_string(),
alignment: Alignment::Left,
},
Column {
name: "middle-of-me".to_string(),
alignment: Alignment::Center,
},
Column {
name: "world".to_string(),
alignment: Alignment::Right,
},
];
let data = vec![vec!["one", "i", "two"], vec!["longer", "boo", "again"]];
let output = tabulate_output_as_string(&cols, &data).unwrap();
eprintln!("output is:\n{}", output);
assert_eq!(
output,
"hello middle-of-me world\n\
one i two\n\
longer boo again\n"
);
}
}