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Use casts instead of transmute #43

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Use casts instead of transmute #43

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6 changes: 2 additions & 4 deletions src/abomonated.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,4 @@

use std::mem::transmute;
use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};

Expand All @@ -8,7 +7,7 @@ use super::{Abomonation, decode};
/// A type wrapping owned decoded abomonated data.
///
/// This type ensures that decoding and pointer correction has already happened,
/// and implements `Deref<Target=T>` using a pointer cast (transmute).
/// and implements `Deref<Target=T>` using a pointer cast.
///
/// #Safety
///
Expand Down Expand Up @@ -121,7 +120,6 @@ impl<T, S: DerefMut<Target=[u8]>> Deref for Abomonated<T, S> {
type Target = T;
#[inline]
fn deref(&self) -> &T {
let result: &T = unsafe { transmute(self.decoded.get_unchecked(0)) };
result
unsafe { &*(self.decoded.as_ptr() as *const T) }
}
}
15 changes: 7 additions & 8 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -72,8 +72,7 @@ pub mod abomonated;
///
#[inline]
pub unsafe fn encode<T: Abomonation, W: Write>(typed: &T, write: &mut W) -> IOResult<()> {
let slice = std::slice::from_raw_parts(mem::transmute(typed), mem::size_of::<T>());
write.write_all(slice)?;
write.write_all(typed_to_bytes(typed))?;
typed.entomb(write)?;
Ok(())
}
Expand Down Expand Up @@ -124,7 +123,7 @@ pub unsafe fn decode<T: Abomonation>(bytes: &mut [u8]) -> Option<(&T, &mut [u8])
if bytes.len() < mem::size_of::<T>() { None }
else {
let (split1, split2) = bytes.split_at_mut(mem::size_of::<T>());
let result: &mut T = mem::transmute(split1.get_unchecked_mut(0));
let result: &mut T = &mut *(split1.as_mut_ptr() as *mut T);
if let Some(remaining) = result.exhume(split2) {
Some((result, remaining))
}
Expand Down Expand Up @@ -468,7 +467,7 @@ impl Abomonation for String {
if self.len() > bytes.len() { None }
else {
let (mine, rest) = bytes.split_at_mut(self.len());
std::ptr::write(self, String::from_raw_parts(mem::transmute(mine.as_ptr()), self.len(), self.len()));
std::ptr::write(self, String::from_raw_parts(mine.as_mut_ptr(), self.len(), self.len()));
Some(rest)
}
}
Expand Down Expand Up @@ -514,7 +513,7 @@ impl<T: Abomonation> Abomonation for Vec<T> {
impl<T: Abomonation> Abomonation for Box<T> {
#[inline]
unsafe fn entomb<W: Write>(&self, bytes: &mut W) -> IOResult<()> {
bytes.write_all(std::slice::from_raw_parts(mem::transmute(&**self), mem::size_of::<T>()))?;
bytes.write_all(typed_to_bytes::<T>(&**self))?;
(**self).entomb(bytes)?;
Ok(())
}
Expand All @@ -524,7 +523,7 @@ impl<T: Abomonation> Abomonation for Box<T> {
if binary_len > bytes.len() { None }
else {
let (mine, mut rest) = bytes.split_at_mut(binary_len);
std::ptr::write(self, mem::transmute(mine.as_mut_ptr() as *mut T));
std::ptr::write(self, Box::from_raw(mine.as_mut_ptr() as *mut T));
let temp = rest; rest = (**self).exhume(temp)?;
Some(rest)
}
Expand All @@ -535,8 +534,8 @@ impl<T: Abomonation> Abomonation for Box<T> {
}

// This method currently enables undefined behavior, by exposing padding bytes.
#[inline] unsafe fn typed_to_bytes<T>(slice: &[T]) -> &[u8] {
std::slice::from_raw_parts(slice.as_ptr() as *const u8, slice.len() * mem::size_of::<T>())
#[inline] unsafe fn typed_to_bytes<T: ?Sized>(typed: &T) -> &[u8] {
std::slice::from_raw_parts(typed as *const T as *const u8, mem::size_of_val(typed))
}

mod network {
Expand Down