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use std::ffi::{CStr, CString, NulError, FromBytesWithNulError};
use std::borrow::Cow;
use std::os::raw;
#[derive(Debug)]
pub struct NullError;
impl From<NulError> for NullError {
fn from(_: NulError) -> NullError {
NullError
}
}
impl From<FromBytesWithNulError> for NullError {
fn from(_: FromBytesWithNulError) -> NullError {
NullError
}
}
impl From<NullError> for ::std::io::Error {
fn from(e: NullError) -> ::std::io::Error {
::std::io::Error::new(::std::io::ErrorKind::Other, format!("{}", e))
}
}
impl ::std::error::Error for NullError {
fn description(&self) -> &str { "non-final null byte found" }
}
impl ::std::fmt::Display for NullError {
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, "non-final null byte found")
}
}
/// Checks for last byte and avoids allocating if it is zero.
///
/// Non-last null bytes still result in an error.
pub fn cstr_cow_from_bytes<'a>(slice: &'a [u8]) -> Result<Cow<'a, CStr>, NullError> {
static ZERO: raw::c_char = 0;
Ok(match slice.last() {
// Slice out of 0 elements
None => unsafe { Cow::Borrowed(CStr::from_ptr(&ZERO)) },
// Slice with trailing 0
Some(&0) => Cow::Borrowed(try!(CStr::from_bytes_with_nul(slice))),
// Slice with no trailing 0
Some(_) => Cow::Owned(try!(CString::new(slice))),
})
}
#[inline]
pub fn ensure_compatible_types<T, E>() {
#[cold]
#[inline(never)]
fn dopanic() {
panic!("value of requested type cannot be dynamically loaded");
}
if ::std::mem::size_of::<T>() != ::std::mem::size_of::<E>() {
dopanic()
}
}
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