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use {
crate::InsufficientWidthError,
std::{
cmp,
},
};
pub struct TblFit {
cols: Vec<ColData>,
available_sum_width: usize,
}
#[derive(Debug, Clone, Copy)]
struct ColData {
sum_widths: usize,
width: usize,
count: usize,
}
impl Default for ColData {
fn default() -> Self {
Self {
sum_widths: 0,
width: 3, count: 0, }
}
}
impl ColData {
const fn avg_width(self) -> usize {
div_ceil(self.sum_widths, self.count)
}
pub fn see_cell(&mut self, cell_width: usize) {
self.sum_widths += cell_width;
self.width = self.width.max(cell_width);
self.count += 1;
}
}
pub struct TblFitResult {
pub reduced: bool,
pub col_widths: Vec<usize>,
}
impl TblFit {
pub fn new(cols_count: usize, available_width: usize) -> Result<Self, InsufficientWidthError> {
if available_width < cols_count*4 + 1 {
return Err(InsufficientWidthError { available_width });
}
let cols = vec![ColData::default(); cols_count];
let available_sum_width = available_width - 1 - cols_count;
Ok(Self {
cols,
available_sum_width,
})
}
pub fn see_cell(&mut self, col_idx: usize, cell_width: usize) {
if let Some(col) = self.cols.get_mut(col_idx) {
col.see_cell(cell_width);
}
}
pub fn fit(&self) -> TblFitResult {
let sum_widths: usize = self.cols.iter().map(|c| c.width).sum();
if sum_widths <= self.available_sum_width {
return TblFitResult {
reduced: false,
col_widths: self.cols.iter().map(|c| c.width).collect(),
};
}
if self.cols.is_empty() {
return TblFitResult {
reduced: false,
col_widths: Vec::new(),
};
}
if self.cols.len() == 1 {
return TblFitResult {
reduced: false,
col_widths: vec![self.available_sum_width],
};
}
#[derive(Debug)]
struct ColFit {
idx: usize, std_width: usize, avg_width: usize, width: usize, }
let mut fits: Vec<ColFit> = self.cols.iter()
.enumerate()
.map(|(idx, c)| ColFit {
idx,
std_width: c.width,
avg_width: c.avg_width(),
width: c.width,
})
.collect();
if self.available_sum_width >= sum_widths {
return TblFitResult {
reduced: false,
col_widths: self.cols.iter().map(|c| c.width).collect(),
};
}
let mut excess = sum_widths - self.available_sum_width;
fits.sort_by_key(|c| cmp::Reverse(c.width));
let potential_uncut_gain_1 = fits.iter()
.filter(|c| c.width > 4 && c.width > c.avg_width + 1)
.map(|c| (c.width - c.avg_width).min(4))
.sum::<usize>();
let potential_cut_gain_1 = potential_uncut_gain_1
.min(excess);
if potential_cut_gain_1 > 0 {
for c in fits.iter_mut() {
if c.std_width > 4 && c.std_width > c.avg_width {
let gain_1 = div_ceil((c.width - c.avg_width) * potential_cut_gain_1, potential_uncut_gain_1);
let gain_1 = gain_1.min(excess).min(c.width - 4);
c.width -= gain_1;
excess -= gain_1;
if excess == 0 {
break;
}
}
}
}
if excess > 0 {
let potential_total_gain_2 = fits.iter()
.map(|c| c.width - 3)
.sum::<usize>()
.min(excess);
let excess_before_2 = excess;
for c in fits.iter_mut() {
let gain_2 = div_ceil((c.width - 3) * excess_before_2, potential_total_gain_2);
let gain_2 = gain_2.min(excess).min(c.width - 3);
c.width -= gain_2;
excess -= gain_2;
if excess == 0 {
break;
}
}
}
fits.sort_by_key(|c| c.idx);
TblFitResult {
reduced: true,
col_widths: fits.iter().map(|c| c.width).collect(),
}
}
}
const fn div_ceil(q: usize, r: usize) -> usize {
let mut res = q / r;
if q%r != 0 {
res += 1;
}
res
}