use std::{borrow::Cow, fmt::Debug, io::Read};
use byteorder::ReadBytesExt;
use crate::Error;
pub trait Reader<'de>: ReadBytesExt {
fn buffered_read_bytes(&mut self, length: usize) -> Result<Cow<'de, [u8]>, Error>;
}
#[allow(clippy::module_name_repetitions)]
pub struct SliceReader<'a> {
pub(crate) data: &'a [u8],
}
impl<'a> Debug for SliceReader<'a> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("SliceReader")
.field(
"preview",
&format!("{:0x?}", &self.data[..8.min(self.data.len())]),
)
.finish()
}
}
impl<'a> From<&'a [u8]> for SliceReader<'a> {
fn from(data: &'a [u8]) -> Self {
Self { data }
}
}
impl<'de> Reader<'de> for SliceReader<'de> {
fn buffered_read_bytes(&mut self, length: usize) -> Result<Cow<'de, [u8]>, Error> {
if length > self.data.len() {
self.data = &self.data[self.data.len()..];
Err(Error::Eof)
} else {
let (start, remaining) = self.data.split_at(length);
self.data = remaining;
Ok(Cow::Borrowed(start))
}
}
}
impl<'a> Read for SliceReader<'a> {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
let remaining_length = self.data.len();
let (to_copy, remaining) = self.data.split_at(remaining_length.min(buf.len()));
buf[..to_copy.len()].copy_from_slice(to_copy);
self.data = remaining;
Ok(to_copy.len())
}
fn read_exact(&mut self, buf: &mut [u8]) -> std::io::Result<()> {
self.read(buf).map(|_| ())
}
}
#[allow(clippy::module_name_repetitions)]
pub struct IoReader<R: ReadBytesExt> {
pub(crate) reader: R,
}
impl<'de, R: ReadBytesExt> IoReader<R> {
pub(crate) fn new(reader: R) -> Self {
Self { reader }
}
}
impl<'de, R: ReadBytesExt> Reader<'de> for IoReader<R> {
fn buffered_read_bytes(&mut self, length: usize) -> Result<Cow<'de, [u8]>, Error> {
let mut buffer = vec![0; length];
self.reader.read_exact(&mut buffer)?;
Ok(Cow::Owned(buffer))
}
}
impl<'de, R: ReadBytesExt> Read for IoReader<R> {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
self.reader.read(buf)
}
fn read_vectored(&mut self, bufs: &mut [std::io::IoSliceMut<'_>]) -> std::io::Result<usize> {
self.reader.read_vectored(bufs)
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> std::io::Result<usize> {
self.reader.read_to_end(buf)
}
fn read_to_string(&mut self, buf: &mut String) -> std::io::Result<usize> {
self.reader.read_to_string(buf)
}
fn read_exact(&mut self, buf: &mut [u8]) -> std::io::Result<()> {
self.reader.read_exact(buf)
}
}