preserves/implementations/rust/preserves/src/value/iolist.rs

86 lines
2.0 KiB
Rust

use std::borrow::Cow;
use std::cell::RefCell;
use std::io;
#[derive(Eq, Debug)]
pub struct IOList {
chunks: RefCell<Vec<Vec<u8>>>,
len: usize,
}
impl IOList {
pub fn new() -> Self {
IOList {
chunks: RefCell::new(Vec::new()),
len: 0,
}
}
fn rightmost_chunk(&mut self) -> &mut Vec<u8> {
let cs = self.chunks.get_mut();
if cs.is_empty() {
cs.push(Vec::new());
}
cs.last_mut().unwrap()
}
fn consolidate(&self) {
if self.chunks.borrow().len() != 1 {
let bs = self.chunks.replace(Vec::new()).concat();
self.chunks.borrow_mut().push(bs);
}
}
pub fn len(&mut self) -> usize {
self.len
}
pub fn write(&mut self, b: u8) {
self.rightmost_chunk().push(b);
self.len += 1;
}
#[inline(always)]
pub fn write_all(&mut self, cow: Cow<'_, [u8]>) {
self.len += cow.len();
match cow {
Cow::Borrowed(bs) => self.chunks.get_mut().push(bs.to_owned()),
Cow::Owned(bs) => self.chunks.get_mut().push(bs),
}
}
pub fn append(&mut self, mut iol: IOList) {
self.len += iol.len();
self.chunks.get_mut().append(&mut iol.chunks.take());
}
pub fn write_to<W: io::Write>(self, mut w: W) -> io::Result<()> {
for chunk in self.chunks.take() {
w.write_all(&chunk)?;
}
Ok(())
}
}
impl std::cmp::PartialEq for IOList {
fn eq(&self, other: &Self) -> bool {
self.consolidate();
other.consolidate();
self.chunks.borrow().last().unwrap() == other.chunks.borrow().last().unwrap()
}
}
impl std::cmp::Ord for IOList {
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
self.consolidate();
other.consolidate();
self.chunks.borrow().last().unwrap().cmp(other.chunks.borrow().last().unwrap())
}
}
impl std::cmp::PartialOrd for IOList {
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
Some(self.cmp(other))
}
}