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use alloc::vec::Vec;
use std::mem;
use crate::endianity::Endianity;
use crate::write::{Error, Result, Writer};
/// A `Vec<u8>` with endianity metadata.
///
/// This implements the `Writer` trait, which is used for all writing of DWARF sections.
#[derive(Debug, Clone)]
pub struct EndianVec<Endian>
where
Endian: Endianity,
{
vec: Vec<u8>,
endian: Endian,
}
impl<Endian> EndianVec<Endian>
where
Endian: Endianity,
{
/// Construct an empty `EndianVec` with the given endianity.
pub fn new(endian: Endian) -> EndianVec<Endian> {
EndianVec {
vec: Vec::new(),
endian,
}
}
/// Return a reference to the raw slice.
pub fn slice(&self) -> &[u8] {
&self.vec
}
/// Convert into a `Vec<u8>`.
pub fn into_vec(self) -> Vec<u8> {
self.vec
}
/// Take any written data out of the `EndianVec`, leaving an empty `Vec` in its place.
pub fn take(&mut self) -> Vec<u8> {
let mut vec = Vec::new();
mem::swap(&mut self.vec, &mut vec);
vec
}
}
impl<Endian> Writer for EndianVec<Endian>
where
Endian: Endianity,
{
type Endian = Endian;
#[inline]
fn endian(&self) -> Self::Endian {
self.endian
}
#[inline]
fn len(&self) -> usize {
self.vec.len()
}
fn write(&mut self, bytes: &[u8]) -> Result<()> {
self.vec.extend(bytes);
Ok(())
}
fn write_at(&mut self, offset: usize, bytes: &[u8]) -> Result<()> {
if offset > self.vec.len() {
return Err(Error::OffsetOutOfBounds);
}
let to = &mut self.vec[offset..];
if bytes.len() > to.len() {
return Err(Error::LengthOutOfBounds);
}
let to = &mut to[..bytes.len()];
to.copy_from_slice(bytes);
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::LittleEndian;
#[test]
fn test_endian_vec() {
let mut w = EndianVec::new(LittleEndian);
assert_eq!(w.endian(), LittleEndian);
assert_eq!(w.len(), 0);
w.write(&[1, 2]).unwrap();
assert_eq!(w.slice(), &[1, 2]);
assert_eq!(w.len(), 2);
w.write(&[3, 4, 5]).unwrap();
assert_eq!(w.slice(), &[1, 2, 3, 4, 5]);
assert_eq!(w.len(), 5);
w.write_at(0, &[6, 7]).unwrap();
assert_eq!(w.slice(), &[6, 7, 3, 4, 5]);
assert_eq!(w.len(), 5);
w.write_at(3, &[8, 9]).unwrap();
assert_eq!(w.slice(), &[6, 7, 3, 8, 9]);
assert_eq!(w.len(), 5);
assert_eq!(w.write_at(4, &[6, 7]), Err(Error::LengthOutOfBounds));
assert_eq!(w.write_at(5, &[6, 7]), Err(Error::LengthOutOfBounds));
assert_eq!(w.write_at(6, &[6, 7]), Err(Error::OffsetOutOfBounds));
assert_eq!(w.into_vec(), vec![6, 7, 3, 8, 9]);
}
}