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#[cfg(feature = "std")]
use std::io::Write;
use crate::error::Result;
#[inline(always)]
#[cold]
pub const fn cold() {}
#[inline(always)]
#[allow(unused)]
pub const fn likely(b: bool) -> bool {
if !b {
cold();
}
b
}
#[inline(always)]
pub const fn unlikely(b: bool) -> bool {
if b {
cold();
}
b
}
pub trait Writer: Sized {
fn write_one(self, v: u8) -> Result<Self>;
fn write_many(self, v: &[u8]) -> Result<Self>;
fn capacity(&self) -> usize;
}
pub struct BytesMut<'a>(&'a mut [u8]);
impl<'a> BytesMut<'a> {
pub fn new(buf: &'a mut [u8]) -> Self {
Self(buf)
}
#[inline]
pub fn write_one(self, v: u8) -> Self {
if let Some((first, tail)) = self.0.split_first_mut() {
*first = v;
Self(tail)
} else {
unreachable!()
}
}
#[inline]
pub fn write_many(self, v: &[u8]) -> Self {
if v.len() <= self.0.len() {
let (head, tail) = self.0.split_at_mut(v.len());
head.copy_from_slice(v);
Self(tail)
} else {
unreachable!()
}
}
}
impl<'a> Writer for BytesMut<'a> {
#[inline]
fn write_one(self, v: u8) -> Result<Self> {
Ok(BytesMut::write_one(self, v))
}
#[inline]
fn write_many(self, v: &[u8]) -> Result<Self> {
Ok(BytesMut::write_many(self, v))
}
#[inline]
fn capacity(&self) -> usize {
self.0.len()
}
}
#[cfg(feature = "std")]
pub struct GenericWriter<W> {
writer: W,
n_written: usize,
}
#[cfg(feature = "std")]
impl<W: Write> GenericWriter<W> {
pub const fn new(writer: W) -> Self {
Self { writer, n_written: 0 }
}
}
#[cfg(feature = "std")]
impl<W: Write> Writer for GenericWriter<W> {
fn write_one(mut self, v: u8) -> Result<Self> {
self.n_written += 1;
self.writer.write_all(&[v]).map(|_| self).map_err(Into::into)
}
fn write_many(mut self, v: &[u8]) -> Result<Self> {
self.n_written += v.len();
self.writer.write_all(v).map(|_| self).map_err(Into::into)
}
fn capacity(&self) -> usize {
usize::MAX - self.n_written
}
}
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