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// Copyright 2015 The Servo Project Developers. See the
// COPYRIGHT file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! This module holds deprecated assets only.
use super::*;
/// Find the level runs within a line and return them in visual order.
///
/// NOTE: This implementation is incomplete. The algorithm needs information about the text,
/// including original `BidiClass` property of each character, to be able to perform correctly.
/// Please see [`BidiInfo::visual_runs()`](../struct.BidiInfo.html#method.visual_runs) for the
/// improved implementation.
///
/// `line` is a range of bytes indices within `levels`.
///
/// <http://www.unicode.org/reports/tr9/#Reordering_Resolved_Levels>
#[deprecated(
since = "0.3.0",
note = "please use `BidiInfo::visual_runs()` instead."
)]
pub fn visual_runs(line: Range<usize>, levels: &[Level]) -> Vec<LevelRun> {
assert!(line.start <= levels.len());
assert!(line.end <= levels.len());
let mut runs = Vec::new();
// Find consecutive level runs.
let mut start = line.start;
let mut run_level = levels[start];
let mut min_level = run_level;
let mut max_level = run_level;
for (i, &new_level) in levels.iter().enumerate().take(line.end).skip(start + 1) {
if new_level != run_level {
// End of the previous run, start of a new one.
runs.push(start..i);
start = i;
run_level = new_level;
min_level = cmp::min(run_level, min_level);
max_level = cmp::max(run_level, max_level);
}
}
runs.push(start..line.end);
let run_count = runs.len();
// Re-order the odd runs.
// <http://www.unicode.org/reports/tr9/#L2>
// Stop at the lowest *odd* level.
min_level = min_level.new_lowest_ge_rtl().expect("Level error");
while max_level >= min_level {
// Look for the start of a sequence of consecutive runs of max_level or higher.
let mut seq_start = 0;
while seq_start < run_count {
if levels[runs[seq_start].start] < max_level {
seq_start += 1;
continue;
}
// Found the start of a sequence. Now find the end.
let mut seq_end = seq_start + 1;
while seq_end < run_count && levels[runs[seq_end].start] >= max_level {
seq_end += 1;
}
// Reverse the runs within this sequence.
runs[seq_start..seq_end].reverse();
seq_start = seq_end;
}
max_level
.lower(1)
.expect("Lowering embedding level below zero");
}
runs
}
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