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Trailing cells in right and center alignment mode #30

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Trailing cells in right and center alignment mode #30

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5033f0f
a trailing-cell in right and center alignment mode
alex-ozdemir Mar 11, 2020
8bc709b
Larger tests, skirting and then applying rustfmt
alex-ozdemir Mar 11, 2020
4716300
Not sure why my formatter and the CI one differ..
alex-ozdemir Mar 11, 2020
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44 changes: 34 additions & 10 deletions src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -101,7 +101,7 @@ pub struct TabWriter<W> {
}

/// `Alignment` represents how a `TabWriter` should align text within its cell.
#[derive(Debug)]
#[derive(Debug, PartialEq, Eq)]
pub enum Alignment {
/// Text should be aligned with the left edge of the cell
Left,
Expand Down Expand Up @@ -257,7 +257,11 @@ impl<W: io::Write> io::Write for TabWriter<W> {
if self.curcell.size > 0 {
self.term_curcell();
}
let widths = cell_widths(&self.lines, self.minwidth);
let widths = cell_widths(
&self.lines,
self.minwidth,
self.alignment != Alignment::Left,
);

// This is a trick to avoid allocating padding for every cell.
// Just allocate the most we'll ever need and borrow from it.
Expand All @@ -280,7 +284,7 @@ impl<W: io::Write> io::Write for TabWriter<W> {
let bytes =
&self.buf.get_ref()[cell.start..cell.start + cell.size];
if i >= widths.len() {
// There is no width for the last column
// There may be no width for the last column
assert_eq!(i, line.len() - 1);
self.w.write_all(bytes)?;
} else {
Expand All @@ -295,9 +299,15 @@ impl<W: io::Write> io::Write for TabWriter<W> {
}
};
right_spaces += self.padding;
write!(&mut self.w, "{}", &padding[0..left_spaces])?;
// Omit initial padding if this is the last cell and its empty
if !(bytes.len() == 0 && i + 1 == line.len()) {
write!(&mut self.w, "{}", &padding[0..left_spaces])?;
}
self.w.write_all(bytes)?;
write!(&mut self.w, "{}", &padding[0..right_spaces])?;
// Omit final padding if this is the last cell.
if i + 1 < line.len() {
write!(&mut self.w, "{}", &padding[0..right_spaces])?;
}
}
}
}
Expand Down Expand Up @@ -347,7 +357,13 @@ impl<W: ::std::any::Any> error::Error for IntoInnerError<W> {
}
}

fn cell_widths(lines: &Vec<Vec<Cell>>, minwidth: usize) -> Vec<Vec<usize>> {
/// Compute the widths of all cells.
/// If `trailing_cell` is set, then a cell is placed to the right of the final tab on each line.
fn cell_widths(
lines: &Vec<Vec<Cell>>,
minwidth: usize,
trailing_cell: bool,
) -> Vec<Vec<usize>> {
// Naively, this algorithm looks like it could be O(n^2m) where `n` is
// the number of lines and `m` is the number of contiguous columns.
//
Expand All @@ -358,13 +374,21 @@ fn cell_widths(lines: &Vec<Vec<Cell>>, minwidth: usize) -> Vec<Vec<usize>> {
if iline.is_empty() {
continue;
}
for col in ws[i].len()..(iline.len() - 1) {
let n_cols = iline.len() - 1 + trailing_cell as usize;
for col in ws[i].len()..n_cols {
let mut width = minwidth;
let mut contig_count = 0;
for line in lines[i..].iter() {
if col + 1 >= line.len() {
// ignores last column
break;
if trailing_cell {
if col >= line.len() {
// does not ignore last column
break;
}
} else {
if col + 1 >= line.len() {
// ignores last column
break;
}
}
contig_count += 1;
width = cmp::max(width, line[col].width);
Expand Down
75 changes: 66 additions & 9 deletions src/test.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -90,16 +90,16 @@ fn test_one_cell() {
}

#[test]
fn test_one_cell_right() {
fn test_one_tab_right() {
iseq(
tabw().padding(2).minwidth(2).alignment(Alignment::Right),
"a\tb\nxx\tyy",
" a b\nxx yy",
" a b\nxx yy",
);
}

#[test]
fn test_one_cell_center() {
fn test_one_tab_center() {
iseq(
tabw().padding(2).minwidth(2).alignment(Alignment::Center),
"a\tb\nxx\tyy",
Expand Down Expand Up @@ -156,18 +156,75 @@ fn test_table_center() {
fn test_contiguous_columns_right() {
iseq(
tabw().padding(1).minwidth(0).alignment(Alignment::Right),
"x\tfoo\tx\nx\tfoofoo\tx\n\nx\tfoofoofoo\tx",
"x foo x\nx foofoo x\n\nx foofoofoo x",
);
concat!(
"x\tfoo\tx\n",
"x\tfoofoo\tx\n",
"\n",
"x\tfoofoofoo\tx\n",
"\n",
"x\tfoo\tx\n",
"x\tfoofoo\tx\n",
),
concat!(
"x foo x\n",
"x foofoo x\n",
"\n",
"x foofoofoo x\n",
"\n",
"x foo x\n",
"x foofoo x\n",
),
)
}

#[test]
fn test_empty_cell_right() {
iseq(
tabw().padding(1).minwidth(0).alignment(Alignment::Right),
concat!(
"x\tfoo\tx\n",
"x\tfoofoo\tx\n",
"\t\n",
"x\tfoofoofoo\tx\n",
"\t\n",
"x\tfoo\tx\n",
"x\tfoofoo\tx\n",
),
concat!(
"x foo x\n",
"x foofoo x\n",
" \n",
"x foofoofoo x\n",
" \n",
"x foo x\n",
"x foofoo x\n",
),
)
}

#[test]
fn test_contiguous_columns_center() {
iseq(
tabw().padding(1).minwidth(0).alignment(Alignment::Center),
"x\tfoo\tx\nx\tfoofoo\tx\n\nx\tfoofoofoo\tx",
"x foo x\nx foofoo x\n\nx foofoofoo x",
);
concat!(
"x\tfoo\txyx\n",
"x\tfoofoo\tx\n",
"\n",
"x\tfoofoofoo\tx\n",
"\n",
"x\tfoo\txyx\n",
"x\tfoofoo\tx\n",
),
concat!(
"x foo xyx\n",
"x foofoo x\n",
"\n",
"x foofoofoo x\n",
"\n",
"x foo xyx\n",
"x foofoo x\n",
),
)
}

#[test]
Expand Down