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use std::borrow::Cow;
use std::ffi::{CStr, CString};
use std::os::raw;
use crate::Error;
/// Checks for the last byte and avoids allocating if it is zero.
///
/// Non-last null bytes still result in an error.
pub(crate) fn cstr_cow_from_bytes(slice: &[u8]) -> Result<Cow<'_, CStr>, Error> {
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(
CStr::from_bytes_with_nul(slice)
.map_err(|source| Error::CreateCStringWithTrailing { source })?,
),
// Slice with no trailing 0
Some(_) => {
Cow::Owned(CString::new(slice).map_err(|source| Error::CreateCString { source })?)
}
})
}
#[inline]
pub(crate) fn ensure_compatible_types<T, E>() -> Result<(), Error> {
if ::std::mem::size_of::<T>() != ::std::mem::size_of::<E>() {
Err(Error::IncompatibleSize)
} else {
Ok(())
}
}