src/libstd/ffi/c_str.rs

   1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use ascii;
  12 use borrow::{Cow, ToOwned, Borrow};
  13 use boxed::Box;
  14 use convert::{Into, From};
  15 use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
  16 use error::Error;
  17 use fmt::{self, Write};
  18 use io;
  19 use iter::Iterator;
  20 use libc;
  21 use mem;
  22 use ops::Deref;
  23 use option::Option::{self, Some, None};
  24 use os::raw::c_char;
  25 use result::Result::{self, Ok, Err};
  26 use slice;
  27 use str::{self, Utf8Error};
  28 use string::String;
  29 use vec::Vec;
  30
  31 /// A type representing an owned C-compatible string
  32 ///
  33 /// This type serves the primary purpose of being able to safely generate a
  34 /// C-compatible string from a Rust byte slice or vector. An instance of this
  35 /// type is a static guarantee that the underlying bytes contain no interior 0
  36 /// bytes and the final byte is 0.
  37 ///
  38 /// A `CString` is created from either a byte slice or a byte vector. After
  39 /// being created, a `CString` predominately inherits all of its methods from
  40 /// the `Deref` implementation to `[c_char]`. Note that the underlying array
  41 /// is represented as an array of `c_char` as opposed to `u8`. A `u8` slice
  42 /// can be obtained with the `as_bytes` method.  Slices produced from a `CString`
  43 /// do *not* contain the trailing nul terminator unless otherwise specified.
  44 ///
  45 /// # Examples
  46 ///
  47 /// ```no_run
  48 /// # fn main() {
  49 /// use std::ffi::CString;
  50 /// use std::os::raw::c_char;
  51 ///
  52 /// extern {
  53 ///     fn my_printer(s: *const c_char);
  54 /// }
  55 ///
  56 /// let c_to_print = CString::new("Hello, world!").unwrap();
  57 /// unsafe {
  58 ///     my_printer(c_to_print.as_ptr());
  59 /// }
  60 /// # }
  61 /// ```
  62 #[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)]
  63 #[stable(feature = "rust1", since = "1.0.0")]
  64 pub struct CString {
  65     inner: Box<[u8]>,
  66 }
  67
  68 /// Representation of a borrowed C string.
  69 ///
  70 /// This dynamically sized type is only safely constructed via a borrowed
  71 /// version of an instance of `CString`. This type can be constructed from a raw
  72 /// C string as well and represents a C string borrowed from another location.
  73 ///
  74 /// Note that this structure is **not** `repr(C)` and is not recommended to be
  75 /// placed in the signatures of FFI functions. Instead safe wrappers of FFI
  76 /// functions may leverage the unsafe `from_ptr` constructor to provide a safe
  77 /// interface to other consumers.
  78 ///
  79 /// # Examples
  80 ///
  81 /// Inspecting a foreign C string
  82 ///
  83 /// ```no_run
  84 /// use std::ffi::CStr;
  85 /// use std::os::raw::c_char;
  86 ///
  87 /// extern { fn my_string() -> *const c_char; }
  88 ///
  89 /// fn main() {
  90 ///     unsafe {
  91 ///         let slice = CStr::from_ptr(my_string());
  92 ///         println!("string length: {}", slice.to_bytes().len());
  93 ///     }
  94 /// }
  95 /// ```
  96 ///
  97 /// Passing a Rust-originating C string
  98 ///
  99 /// ```no_run
 100 /// use std::ffi::{CString, CStr};
 101 /// use std::os::raw::c_char;
 102 ///
 103 /// fn work(data: &CStr) {
 104 ///     extern { fn work_with(data: *const c_char); }
 105 ///
 106 ///     unsafe { work_with(data.as_ptr()) }
 107 /// }
 108 ///
 109 /// fn main() {
 110 ///     let s = CString::new("data data data data").unwrap();
 111 ///     work(&s);
 112 /// }
 113 /// ```
 114 ///
 115 /// Converting a foreign C string into a Rust `String`
 116 ///
 117 /// ```no_run
 118 /// use std::ffi::CStr;
 119 /// use std::os::raw::c_char;
 120 ///
 121 /// extern { fn my_string() -> *const c_char; }
 122 ///
 123 /// fn my_string_safe() -> String {
 124 ///     unsafe {
 125 ///         CStr::from_ptr(my_string()).to_string_lossy().into_owned()
 126 ///     }
 127 /// }
 128 ///
 129 /// fn main() {
 130 ///     println!("string: {}", my_string_safe());
 131 /// }
 132 /// ```
 133 #[derive(Hash)]
 134 #[stable(feature = "rust1", since = "1.0.0")]
 135 pub struct CStr {
 136     // FIXME: this should not be represented with a DST slice but rather with
 137     //        just a raw `c_char` along with some form of marker to make
 138     //        this an unsized type. Essentially `sizeof(&CStr)` should be the
 139     //        same as `sizeof(&c_char)` but `CStr` should be an unsized type.
 140     inner: [c_char]
 141 }
 142
 143 /// An error returned from `CString::new` to indicate that a nul byte was found
 144 /// in the vector provided.
 145 #[derive(Clone, PartialEq, Debug)]
 146 #[stable(feature = "rust1", since = "1.0.0")]
 147 pub struct NulError(usize, Vec<u8>);
 148
 149 /// An error returned from `CString::into_string` to indicate that a UTF-8 error
 150 /// was encountered during the conversion.
 151 #[derive(Clone, PartialEq, Debug)]
 152 #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 153 pub struct IntoStringError {
 154     inner: CString,
 155     error: Utf8Error,
 156 }
 157
 158 impl CString {
 159     /// Creates a new C-compatible string from a container of bytes.
 160     ///
 161     /// This method will consume the provided data and use the underlying bytes
 162     /// to construct a new string, ensuring that there is a trailing 0 byte.
 163     ///
 164     /// # Examples
 165     ///
 166     /// ```no_run
 167     /// use std::ffi::CString;
 168     /// use std::os::raw::c_char;
 169     ///
 170     /// extern { fn puts(s: *const c_char); }
 171     ///
 172     /// fn main() {
 173     ///     let to_print = CString::new("Hello!").unwrap();
 174     ///     unsafe {
 175     ///         puts(to_print.as_ptr());
 176     ///     }
 177     /// }
 178     /// ```
 179     ///
 180     /// # Errors
 181     ///
 182     /// This function will return an error if the bytes yielded contain an
 183     /// internal 0 byte. The error returned will contain the bytes as well as
 184     /// the position of the nul byte.
 185     #[stable(feature = "rust1", since = "1.0.0")]
 186     pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> {
 187         Self::_new(t.into())
 188     }
 189
 190     fn _new(bytes: Vec<u8>) -> Result<CString, NulError> {
 191         match bytes.iter().position(|x| *x == 0) {
 192             Some(i) => Err(NulError(i, bytes)),
 193             None => Ok(unsafe { CString::from_vec_unchecked(bytes) }),
 194         }
 195     }
 196
 197     /// Creates a C-compatible string from a byte vector without checking for
 198     /// interior 0 bytes.
 199     ///
 200     /// This method is equivalent to `new` except that no runtime assertion
 201     /// is made that `v` contains no 0 bytes, and it requires an actual
 202     /// byte vector, not anything that can be converted to one with Into.
 203     #[stable(feature = "rust1", since = "1.0.0")]
 204     pub unsafe fn from_vec_unchecked(mut v: Vec<u8>) -> CString {
 205         v.push(0);
 206         CString { inner: v.into_boxed_slice() }
 207     }
 208
 209     /// Retakes ownership of a CString that was transferred to C.
 210     ///
 211     /// The only appropriate argument is a pointer obtained by calling
 212     /// `into_raw`. The length of the string will be recalculated
 213     /// using the pointer.
 214     #[unstable(feature = "cstr_memory2", reason = "recently added",
 215                issue = "27769")]
 216     #[rustc_deprecated(since = "1.4.0", reason = "renamed to from_raw")]
 217     pub unsafe fn from_ptr(ptr: *const c_char) -> CString {
 218         CString::from_raw(ptr as *mut _)
 219     }
 220
 221     /// Retakes ownership of a CString that was transferred to C.
 222     ///
 223     /// The only appropriate argument is a pointer obtained by calling
 224     /// `into_raw`. The length of the string will be recalculated
 225     /// using the pointer.
 226     #[stable(feature = "cstr_memory", since = "1.4.0")]
 227     pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
 228         let len = libc::strlen(ptr) + 1; // Including the NUL byte
 229         let slice = slice::from_raw_parts(ptr, len as usize);
 230         CString { inner: mem::transmute(slice) }
 231     }
 232
 233     /// Transfers ownership of the string to a C caller.
 234     ///
 235     /// The pointer must be returned to Rust and reconstituted using
 236     /// `from_raw` to be properly deallocated. Specifically, one
 237     /// should *not* use the standard C `free` function to deallocate
 238     /// this string.
 239     ///
 240     /// Failure to call `from_raw` will lead to a memory leak.
 241     #[unstable(feature = "cstr_memory2", reason = "recently added",
 242                issue = "27769")]
 243     #[rustc_deprecated(since = "1.4.0", reason = "renamed to into_raw")]
 244     pub fn into_ptr(self) -> *const c_char {
 245         self.into_raw() as *const _
 246     }
 247
 248     /// Transfers ownership of the string to a C caller.
 249     ///
 250     /// The pointer must be returned to Rust and reconstituted using
 251     /// `from_raw` to be properly deallocated. Specifically, one
 252     /// should *not* use the standard C `free` function to deallocate
 253     /// this string.
 254     ///
 255     /// Failure to call `from_raw` will lead to a memory leak.
 256     #[stable(feature = "cstr_memory", since = "1.4.0")]
 257     pub fn into_raw(self) -> *mut c_char {
 258         Box::into_raw(self.inner) as *mut c_char
 259     }
 260
 261     /// Converts the `CString` into a `String` if it contains valid Unicode data.
 262     ///
 263     /// On failure, ownership of the original `CString` is returned.
 264     #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 265     pub fn into_string(self) -> Result<String, IntoStringError> {
 266         String::from_utf8(self.into_bytes())
 267             .map_err(|e| IntoStringError {
 268                 error: e.utf8_error(),
 269                 inner: unsafe { CString::from_vec_unchecked(e.into_bytes()) },
 270             })
 271     }
 272
 273     /// Returns the underlying byte buffer.
 274     ///
 275     /// The returned buffer does **not** contain the trailing nul separator and
 276     /// it is guaranteed to not have any interior nul bytes.
 277     #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 278     pub fn into_bytes(self) -> Vec<u8> {
 279         // FIXME: Once this method becomes stable, add an `impl Into<Vec<u8>> for CString`
 280         let mut vec = self.inner.into_vec();
 281         let _nul = vec.pop();
 282         debug_assert_eq!(_nul, Some(0u8));
 283         vec
 284     }
 285
 286     /// Equivalent to the `into_bytes` function except that the returned vector
 287     /// includes the trailing nul byte.
 288     #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 289     pub fn into_bytes_with_nul(self) -> Vec<u8> {
 290         self.inner.into_vec()
 291     }
 292
 293     /// Returns the contents of this `CString` as a slice of bytes.
 294     ///
 295     /// The returned slice does **not** contain the trailing nul separator and
 296     /// it is guaranteed to not have any interior nul bytes.
 297     #[stable(feature = "rust1", since = "1.0.0")]
 298     pub fn as_bytes(&self) -> &[u8] {
 299         &self.inner[..self.inner.len() - 1]
 300     }
 301
 302     /// Equivalent to the `as_bytes` function except that the returned slice
 303     /// includes the trailing nul byte.
 304     #[stable(feature = "rust1", since = "1.0.0")]
 305     pub fn as_bytes_with_nul(&self) -> &[u8] {
 306         &self.inner
 307     }
 308 }
 309
 310 #[stable(feature = "rust1", since = "1.0.0")]
 311 impl Deref for CString {
 312     type Target = CStr;
 313
 314     fn deref(&self) -> &CStr {
 315         unsafe { mem::transmute(self.as_bytes_with_nul()) }
 316     }
 317 }
 318
 319 #[stable(feature = "rust1", since = "1.0.0")]
 320 impl fmt::Debug for CString {
 321     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 322         fmt::Debug::fmt(&**self, f)
 323     }
 324 }
 325
 326 #[stable(feature = "cstr_debug", since = "1.3.0")]
 327 impl fmt::Debug for CStr {
 328     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 329         try!(write!(f, "\""));
 330         for byte in self.to_bytes().iter().flat_map(|&b| ascii::escape_default(b)) {
 331             try!(f.write_char(byte as char));
 332         }
 333         write!(f, "\"")
 334     }
 335 }
 336
 337 #[stable(feature = "cstr_borrow", since = "1.3.0")]
 338 impl Borrow<CStr> for CString {
 339     fn borrow(&self) -> &CStr { self }
 340 }
 341
 342 impl NulError {
 343     /// Returns the position of the nul byte in the slice that was provided to
 344     /// `CString::new`.
 345     #[stable(feature = "rust1", since = "1.0.0")]
 346     pub fn nul_position(&self) -> usize { self.0 }
 347
 348     /// Consumes this error, returning the underlying vector of bytes which
 349     /// generated the error in the first place.
 350     #[stable(feature = "rust1", since = "1.0.0")]
 351     pub fn into_vec(self) -> Vec<u8> { self.1 }
 352 }
 353
 354 #[stable(feature = "rust1", since = "1.0.0")]
 355 impl Error for NulError {
 356     fn description(&self) -> &str { "nul byte found in data" }
 357 }
 358
 359 #[stable(feature = "rust1", since = "1.0.0")]
 360 impl fmt::Display for NulError {
 361     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 362         write!(f, "nul byte found in provided data at position: {}", self.0)
 363     }
 364 }
 365
 366 #[stable(feature = "rust1", since = "1.0.0")]
 367 impl From<NulError> for io::Error {
 368     fn from(_: NulError) -> io::Error {
 369         io::Error::new(io::ErrorKind::InvalidInput,
 370                        "data provided contains a nul byte")
 371     }
 372 }
 373
 374 impl IntoStringError {
 375     /// Consumes this error, returning original `CString` which generated the
 376     /// error.
 377     #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 378     pub fn into_cstring(self) -> CString {
 379         self.inner
 380     }
 381
 382     /// Access the underlying UTF-8 error that was the cause of this error.
 383     #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 384     pub fn utf8_error(&self) -> Utf8Error {
 385         self.error
 386     }
 387 }
 388
 389 #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 390 impl Error for IntoStringError {
 391     fn description(&self) -> &str {
 392         Error::description(&self.error)
 393     }
 394 }
 395
 396 #[unstable(feature = "cstring_into", reason = "recently added", issue = "29157")]
 397 impl fmt::Display for IntoStringError {
 398     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 399         fmt::Display::fmt(&self.error, f)
 400     }
 401 }
 402
 403 impl CStr {
 404     /// Casts a raw C string to a safe C string wrapper.
 405     ///
 406     /// This function will cast the provided `ptr` to the `CStr` wrapper which
 407     /// allows inspection and interoperation of non-owned C strings. This method
 408     /// is unsafe for a number of reasons:
 409     ///
 410     /// * There is no guarantee to the validity of `ptr`
 411     /// * The returned lifetime is not guaranteed to be the actual lifetime of
 412     ///   `ptr`
 413     /// * There is no guarantee that the memory pointed to by `ptr` contains a
 414     ///   valid nul terminator byte at the end of the string.
 415     ///
 416     /// > **Note**: This operation is intended to be a 0-cost cast but it is
 417     /// > currently implemented with an up-front calculation of the length of
 418     /// > the string. This is not guaranteed to always be the case.
 419     ///
 420     /// # Examples
 421     ///
 422     /// ```no_run
 423     /// # fn main() {
 424     /// use std::ffi::CStr;
 425     /// use std::os::raw::c_char;
 426     /// use std::str;
 427     ///
 428     /// extern {
 429     ///     fn my_string() -> *const c_char;
 430     /// }
 431     ///
 432     /// unsafe {
 433     ///     let slice = CStr::from_ptr(my_string());
 434     ///     println!("string returned: {}",
 435     ///              str::from_utf8(slice.to_bytes()).unwrap());
 436     /// }
 437     /// # }
 438     /// ```
 439     #[stable(feature = "rust1", since = "1.0.0")]
 440     pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr {
 441         let len = libc::strlen(ptr);
 442         mem::transmute(slice::from_raw_parts(ptr, len as usize + 1))
 443     }
 444
 445     /// Returns the inner pointer to this C string.
 446     ///
 447     /// The returned pointer will be valid for as long as `self` is and points
 448     /// to a contiguous region of memory terminated with a 0 byte to represent
 449     /// the end of the string.
 450     #[stable(feature = "rust1", since = "1.0.0")]
 451     pub fn as_ptr(&self) -> *const c_char {
 452         self.inner.as_ptr()
 453     }
 454
 455     /// Converts this C string to a byte slice.
 456     ///
 457     /// This function will calculate the length of this string (which normally
 458     /// requires a linear amount of work to be done) and then return the
 459     /// resulting slice of `u8` elements.
 460     ///
 461     /// The returned slice will **not** contain the trailing nul that this C
 462     /// string has.
 463     ///
 464     /// > **Note**: This method is currently implemented as a 0-cost cast, but
 465     /// > it is planned to alter its definition in the future to perform the
 466     /// > length calculation whenever this method is called.
 467     #[stable(feature = "rust1", since = "1.0.0")]
 468     pub fn to_bytes(&self) -> &[u8] {
 469         let bytes = self.to_bytes_with_nul();
 470         &bytes[..bytes.len() - 1]
 471     }
 472
 473     /// Converts this C string to a byte slice containing the trailing 0 byte.
 474     ///
 475     /// This function is the equivalent of `to_bytes` except that it will retain
 476     /// the trailing nul instead of chopping it off.
 477     ///
 478     /// > **Note**: This method is currently implemented as a 0-cost cast, but
 479     /// > it is planned to alter its definition in the future to perform the
 480     /// > length calculation whenever this method is called.
 481     #[stable(feature = "rust1", since = "1.0.0")]
 482     pub fn to_bytes_with_nul(&self) -> &[u8] {
 483         unsafe { mem::transmute(&self.inner) }
 484     }
 485
 486     /// Yields a `&str` slice if the `CStr` contains valid UTF-8.
 487     ///
 488     /// This function will calculate the length of this string and check for
 489     /// UTF-8 validity, and then return the `&str` if it's valid.
 490     ///
 491     /// > **Note**: This method is currently implemented to check for validity
 492     /// > after a 0-cost cast, but it is planned to alter its definition in the
 493     /// > future to perform the length calculation in addition to the UTF-8
 494     /// > check whenever this method is called.
 495     #[stable(feature = "cstr_to_str", since = "1.4.0")]
 496     pub fn to_str(&self) -> Result<&str, str::Utf8Error> {
 497         // NB: When CStr is changed to perform the length check in .to_bytes()
 498         // instead of in from_ptr(), it may be worth considering if this should
 499         // be rewritten to do the UTF-8 check inline with the length calculation
 500         // instead of doing it afterwards.
 501         str::from_utf8(self.to_bytes())
 502     }
 503
 504     /// Converts a `CStr` into a `Cow<str>`.
 505     ///
 506     /// This function will calculate the length of this string (which normally
 507     /// requires a linear amount of work to be done) and then return the
 508     /// resulting slice as a `Cow<str>`, replacing any invalid UTF-8 sequences
 509     /// with `U+FFFD REPLACEMENT CHARACTER`.
 510     ///
 511     /// > **Note**: This method is currently implemented to check for validity
 512     /// > after a 0-cost cast, but it is planned to alter its definition in the
 513     /// > future to perform the length calculation in addition to the UTF-8
 514     /// > check whenever this method is called.
 515     #[stable(feature = "cstr_to_str", since = "1.4.0")]
 516     pub fn to_string_lossy(&self) -> Cow<str> {
 517         String::from_utf8_lossy(self.to_bytes())
 518     }
 519 }
 520
 521 #[stable(feature = "rust1", since = "1.0.0")]
 522 impl PartialEq for CStr {
 523     fn eq(&self, other: &CStr) -> bool {
 524         self.to_bytes().eq(other.to_bytes())
 525     }
 526 }
 527 #[stable(feature = "rust1", since = "1.0.0")]
 528 impl Eq for CStr {}
 529 #[stable(feature = "rust1", since = "1.0.0")]
 530 impl PartialOrd for CStr {
 531     fn partial_cmp(&self, other: &CStr) -> Option<Ordering> {
 532         self.to_bytes().partial_cmp(&other.to_bytes())
 533     }
 534 }
 535 #[stable(feature = "rust1", since = "1.0.0")]
 536 impl Ord for CStr {
 537     fn cmp(&self, other: &CStr) -> Ordering {
 538         self.to_bytes().cmp(&other.to_bytes())
 539     }
 540 }
 541
 542 #[stable(feature = "cstr_borrow", since = "1.3.0")]
 543 impl ToOwned for CStr {
 544     type Owned = CString;
 545
 546     fn to_owned(&self) -> CString {
 547         unsafe { CString::from_vec_unchecked(self.to_bytes().to_vec()) }
 548     }
 549 }
 550
 551 #[cfg(test)]
 552 mod tests {
 553     use prelude::v1::*;
 554     use super::*;
 555     use os::raw::c_char;
 556     use borrow::Cow::{Borrowed, Owned};
 557     use hash::{SipHasher, Hash, Hasher};
 558
 559     #[test]
 560     fn c_to_rust() {
 561         let data = b"123\0";
 562         let ptr = data.as_ptr() as *const c_char;
 563         unsafe {
 564             assert_eq!(CStr::from_ptr(ptr).to_bytes(), b"123");
 565             assert_eq!(CStr::from_ptr(ptr).to_bytes_with_nul(), b"123\0");
 566         }
 567     }
 568
 569     #[test]
 570     fn simple() {
 571         let s = CString::new("1234").unwrap();
 572         assert_eq!(s.as_bytes(), b"1234");
 573         assert_eq!(s.as_bytes_with_nul(), b"1234\0");
 574     }
 575
 576     #[test]
 577     fn build_with_zero1() {
 578         assert!(CString::new(&b"\0"[..]).is_err());
 579     }
 580     #[test]
 581     fn build_with_zero2() {
 582         assert!(CString::new(vec![0]).is_err());
 583     }
 584
 585     #[test]
 586     fn build_with_zero3() {
 587         unsafe {
 588             let s = CString::from_vec_unchecked(vec![0]);
 589             assert_eq!(s.as_bytes(), b"\0");
 590         }
 591     }
 592
 593     #[test]
 594     fn formatted() {
 595         let s = CString::new(&b"abc\x01\x02\n\xE2\x80\xA6\xFF"[..]).unwrap();
 596         assert_eq!(format!("{:?}", s), r#""abc\x01\x02\n\xe2\x80\xa6\xff""#);
 597     }
 598
 599     #[test]
 600     fn borrowed() {
 601         unsafe {
 602             let s = CStr::from_ptr(b"12\0".as_ptr() as *const _);
 603             assert_eq!(s.to_bytes(), b"12");
 604             assert_eq!(s.to_bytes_with_nul(), b"12\0");
 605         }
 606     }
 607
 608     #[test]
 609     fn to_str() {
 610         let data = b"123\xE2\x80\xA6\0";
 611         let ptr = data.as_ptr() as *const c_char;
 612         unsafe {
 613             assert_eq!(CStr::from_ptr(ptr).to_str(), Ok("123…"));
 614             assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Borrowed("123…"));
 615         }
 616         let data = b"123\xE2\0";
 617         let ptr = data.as_ptr() as *const c_char;
 618         unsafe {
 619             assert!(CStr::from_ptr(ptr).to_str().is_err());
 620             assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Owned::<str>(format!("123\u{FFFD}")));
 621         }
 622     }
 623
 624     #[test]
 625     fn to_owned() {
 626         let data = b"123\0";
 627         let ptr = data.as_ptr() as *const c_char;
 628
 629         let owned = unsafe { CStr::from_ptr(ptr).to_owned() };
 630         assert_eq!(owned.as_bytes_with_nul(), data);
 631     }
 632
 633     #[test]
 634     fn equal_hash() {
 635         let data = b"123\xE2\xFA\xA6\0";
 636         let ptr = data.as_ptr() as *const c_char;
 637         let cstr: &'static CStr = unsafe { CStr::from_ptr(ptr) };
 638
 639         let mut s = SipHasher::new_with_keys(0, 0);
 640         cstr.hash(&mut s);
 641         let cstr_hash = s.finish();
 642         let mut s = SipHasher::new_with_keys(0, 0);
 643         CString::new(&data[..data.len() - 1]).unwrap().hash(&mut s);
 644         let cstring_hash = s.finish();
 645
 646         assert_eq!(cstr_hash, cstring_hash);
 647     }
 648 }