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a few speed and/or compression ratio improvements

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This commit is contained in:
Dennis Ranke
2021-11-24 22:35:24 +01:00
parent 11b43f9bc4
commit 5e82c65c18
4 changed files with 120 additions and 27 deletions
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30
src/match_finder.rs
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@@ -6,7 +6,8 @@ pub struct MatchFinder {
rev_suffixes: Vec<u32>,
lcp: Vec<u32>,
max_matches: usize,
max_queue_size: usize,
max_matches_per_length: usize,
patience: usize,
max_length_diff: usize,
}
@@ -42,8 +43,9 @@ impl MatchFinder {
suffixes,
rev_suffixes,
lcp,
max_matches: 10,
patience: 10,
max_queue_size: 100,
max_matches_per_length: 5,
patience: 100,
max_length_diff: 2,
}
}
@@ -57,8 +59,8 @@ impl MatchFinder {
left_length: usize::MAX,
right_index: index,
right_length: usize::MAX,
current_length: 0,
matches_left: self.max_matches,
current_length: usize::MAX,
matches_left: 0,
max_length: 0,
queue: BinaryHeap::new(),
};
@@ -93,15 +95,16 @@ impl<'a> Iterator for Matches<'a> {
type Item = Match;
fn next(&mut self) -> Option<Match> {
if self.queue.is_empty() {
self.current_length = self.left_length.max(self.right_length);
if self.queue.is_empty() || self.matches_left == 0 {
self.queue.clear();
self.current_length = self.current_length.saturating_sub(1).min(self.left_length.max(self.right_length));
self.max_length = self.max_length.max(self.current_length);
if self.current_length < 2
|| self.current_length + self.finder.max_length_diff < self.max_length
{
return None;
}
while self.matches_left > 0
while self.queue.len() < self.finder.max_queue_size
&& (self.left_length == self.current_length
|| self.right_length == self.current_length)
{
@@ -109,13 +112,16 @@ impl<'a> Iterator for Matches<'a> {
self.add_to_queue(self.finder.suffixes[self.left_index]);
self.move_left();
}
if self.right_length == self.current_length && self.matches_left > 0 {
if self.right_length == self.current_length {
self.add_to_queue(self.finder.suffixes[self.right_index]);
self.move_right();
}
}
self.matches_left = self.finder.max_matches_per_length;
}
self.matches_left = self.matches_left.saturating_sub(1);
self.queue.pop().map(|pos| Match {
pos,
length: self.current_length,
@@ -144,7 +150,10 @@ impl<'a> Matches<'a> {
fn move_right(&mut self) {
let mut patience = self.finder.patience;
while self.right_length > 0 && patience > 0 && self.right_index + 1 < self.finder.suffixes.len() {
while self.right_length > 0
&& patience > 0
&& self.right_index + 1 < self.finder.suffixes.len()
{
self.right_index += 1;
self.right_length = self
.right_length
@@ -162,6 +171,5 @@ impl<'a> Matches<'a> {
fn add_to_queue(&mut self, pos: i32) {
self.queue.push(pos as usize);
self.matches_left -= 1;
}
}