mem::transmute(slice::from_raw_parts(ptr, len as usize + 1))
}
+ /// Creates a C string wrapper from a byte slice.
+ ///
+ /// This function will cast the provided `bytes` to a `CStr` wrapper after
+ /// ensuring that it is null terminated and does not contain any interior
+ /// nul bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # #![feature(cstr_from_bytes)]
+ /// use std::ffi::CStr;
+ ///
+ /// # fn main() {
+ /// let cstr = CStr::from_bytes_with_nul(b"hello\0");
+ /// assert!(cstr.is_some());
+ /// # }
+ /// ```
+ #[unstable(feature = "cstr_from_bytes", reason = "recently added", issue = "31190")]
+ pub fn from_bytes_with_nul(bytes: &[u8]) -> Option<&CStr> {
+ if bytes.is_empty() || memchr::memchr(0, &bytes) != Some(bytes.len() - 1) {
+ None
+ } else {
+ Some(unsafe { Self::from_bytes_with_nul_unchecked(bytes) })
+ }
+ }
+
+ /// Unsafely creates a C string wrapper from a byte slice.
+ ///
+ /// This function will cast the provided `bytes` to a `CStr` wrapper without
+ /// performing any sanity checks. The provided slice must be null terminated
+ /// and not contain any interior nul bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # #![feature(cstr_from_bytes)]
+ /// use std::ffi::{CStr, CString};
+ ///
+ /// # fn main() {
+ /// unsafe {
+ /// let cstring = CString::new("hello").unwrap();
+ /// let cstr = CStr::from_bytes_with_nul_unchecked(cstring.to_bytes_with_nul());
+ /// assert_eq!(cstr, &*cstring);
+ /// }
+ /// # }
+ /// ```
+ #[unstable(feature = "cstr_from_bytes", reason = "recently added", issue = "31190")]
+ pub unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
+ mem::transmute(bytes)
+ }
+
/// Returns the inner pointer to this C string.
///
/// The returned pointer will be valid for as long as `self` is and points
assert_eq!(cstr_hash, cstring_hash);
}
+
+ #[test]
+ fn from_bytes_with_nul() {
+ let data = b"123\0";
+ let cstr = CStr::from_bytes_with_nul(data);
+ assert_eq!(cstr.map(CStr::to_bytes), Some(&b"123"[..]));
+ assert_eq!(cstr.map(CStr::to_bytes_with_nul), Some(&b"123\0"[..]));
+
+ unsafe {
+ let cstr_unchecked = CStr::from_bytes_with_nul_unchecked(data);
+ assert_eq!(cstr, Some(cstr_unchecked));
+ }
+ }
+
+ #[test]
+ fn from_bytes_with_nul_unterminated() {
+ let data = b"123";
+ let cstr = CStr::from_bytes_with_nul(data);
+ assert!(cstr.is_none());
+ }
+
+ #[test]
+ fn from_bytes_with_nul_interior() {
+ let data = b"1\023\0";
+ let cstr = CStr::from_bytes_with_nul(data);
+ assert!(cstr.is_none());
+ }
}