sgx_trts/src/c_str.rs - incubator-teaclave-sgx-sdk - Git at Google

 // Copyright (C) 2017-2018 Baidu, Inc. All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 //
 //  * Redistributions of source code must retain the above copyright
 //    notice, this list of conditions and the following disclaimer.
 //  * Redistributions in binary form must reproduce the above copyright
 //    notice, this list of conditions and the following disclaimer in
 //    the documentation and/or other materials provided with the
 //    distribution.
 //  * Neither the name of Baidu, Inc., nor the names of its
 //    contributors may be used to endorse or promote products derived
 //    from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 /// A type representing an owned, C-compatible, nul-terminated string with no nul bytes in the
 /// middle.
 ///
 /// This type serves the purpose of being able to safely generate a
 /// C-compatible string from a Rust byte slice or vector. An instance of this
 /// type is a static guarantee that the underlying bytes contain no interior 0
 /// bytes ("nul characters") and that the final byte is 0 ("nul terminator").
 ///
 use sgx_types::c_char;
 use libc;
 use memchr;
 use ascii;
 //use error::Error;
 //use io;

 use core::ops;
 use core::cmp::Ordering;
 use core::mem;
 use core::ptr;
 use core::fmt::{self, Write};
 use alloc::boxed::Box;
 use alloc::borrow::{Cow, Borrow, ToOwned};
 use alloc::vec::Vec;
 use alloc::string::String;
 use alloc::slice;
 use alloc::rc::Rc;
 use alloc::sync::Arc;

 use alloc::str::{self, Utf8Error};

 /// A type representing an owned C-compatible string
 ///
 #[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)]
 pub struct CString {
     inner: Box<[u8]>,
 }

 /// Representation of a borrowed C string.
 ///
 #[derive(Hash, Eq, PartialEq)]
 pub struct CStr {
     inner: [c_char]
 }

 /// An error returned from `CString::new` to indicate that a nul byte was found
 /// in the vector provided.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct NulError(usize, Vec<u8>);

 /// An error returned from `CStr::from_bytes_with_nul` to indicate that a nul
 /// byte was found too early in the slice provided or one wasn't found at all.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct FromBytesWithNulError {
     kind: FromBytesWithNulErrorKind,
 }

 #[derive(Clone, PartialEq, Eq, Debug)]
 enum FromBytesWithNulErrorKind {
     InteriorNul(usize),
     NotNulTerminated,
 }

 impl FromBytesWithNulError {
     fn interior_nul(pos: usize) -> FromBytesWithNulError {
         FromBytesWithNulError {
             kind: FromBytesWithNulErrorKind::InteriorNul(pos),
         }
     }
     fn not_nul_terminated() -> FromBytesWithNulError {
         FromBytesWithNulError {
             kind: FromBytesWithNulErrorKind::NotNulTerminated,
         }
     }

     pub fn __description(&self) -> &str {
         match self.kind {
             FromBytesWithNulErrorKind::InteriorNul(..) =>
                 "data provided contains an interior nul byte",
             FromBytesWithNulErrorKind::NotNulTerminated =>
                 "data provided is not nul terminated",
         }
     }
 }

 /// An error returned from `CString::into_string` to indicate that a UTF-8 error
 /// was encountered during the conversion.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct IntoStringError {
     inner: CString,
     error: Utf8Error,
 }

 impl CString {
     /// Creates a new C-compatible string from a container of bytes.
     ///
     /// This method will consume the provided data and use the underlying bytes
     /// to construct a new string, ensuring that there is a trailing 0 byte.
     ///
     /// # Errors
     ///
     /// This function will return an error if the bytes yielded contain an
     /// internal 0 byte. The error returned will contain the bytes as well as
     /// the position of the nul byte.
     pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> {
         Self::_new(t.into())
     }

     fn _new(bytes: Vec<u8>) -> Result<CString, NulError> {
         match memchr::memchr(0, &bytes) {
             Some(i) => Err(NulError(i, bytes)),
             None => Ok(unsafe { CString::from_vec_unchecked(bytes) }),
         }
     }

     /// Creates a C-compatible string from a byte vector without checking for
     /// interior 0 bytes.
     ///
     /// This method is equivalent to `new` except that no runtime assertion
     /// is made that `v` contains no 0 bytes, and it requires an actual
     /// byte vector, not anything that can be converted to one with Into.
     ///
     pub unsafe fn from_vec_unchecked(mut v: Vec<u8>) -> CString {
         v.reserve_exact(1);
         v.push(0);
         CString { inner: v.into_boxed_slice() }
     }

     /// Retakes ownership of a `CString` that was transferred to C.
     ///
     /// Additionally, the length of the string will be recalculated from the pointer.
     ///
     /// # Safety
     ///
     /// This should only ever be called with a pointer that was earlier
     /// obtained by calling `into_raw` on a `CString`. Other usage (e.g. trying to take
     /// ownership of a string that was allocated by foreign code) is likely to lead
     /// to undefined behavior or allocator corruption.
     pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
         let len = libc::strlen(ptr) + 1; // Including the NUL byte
         let slice = slice::from_raw_parts_mut(ptr, len as usize);
         CString { inner: Box::from_raw(slice as *mut [c_char] as *mut [u8]) }
     }

     /// Transfers ownership of the string to a C caller.
     ///
     /// The pointer must be returned to Rust and reconstituted using
     /// `from_raw` to be properly deallocated. Specifically, one
     /// should *not* use the standard C `free` function to deallocate
     /// this string.
     ///
     /// Failure to call `from_raw` will lead to a memory leak.
     pub fn into_raw(self) -> *mut c_char {
         Box::into_raw(self.into_inner()) as *mut c_char
     }

     /// Converts the `CString` into a `String` if it contains valid Unicode data.
     ///
     /// On failure, ownership of the original `CString` is returned.
     pub fn into_string(self) -> Result<String, IntoStringError> {
         String::from_utf8(self.into_bytes())
             .map_err(|e| IntoStringError {
                 error: e.utf8_error(),
                 inner: unsafe { CString::from_vec_unchecked(e.into_bytes()) },
             })
     }

     /// Returns the underlying byte buffer.
     ///
     /// The returned buffer does **not** contain the trailing nul separator and
     /// it is guaranteed to not have any interior nul bytes.
     pub fn into_bytes(self) -> Vec<u8> {
         let mut vec = self.into_inner().into_vec();
         let _nul = vec.pop();
         debug_assert_eq!(_nul, Some(0u8));
         vec
     }

     /// Equivalent to the `into_bytes` function except that the returned vector
     /// includes the trailing nul byte.
     pub fn into_bytes_with_nul(self) -> Vec<u8> {
         self.into_inner().into_vec()
     }

     /// Returns the contents of this `CString` as a slice of bytes.
     ///
     /// The returned slice does **not** contain the trailing nul separator and
     /// it is guaranteed to not have any interior nul bytes.
     pub fn as_bytes(&self) -> &[u8] {
         &self.inner[..self.inner.len() - 1]
     }

     /// Equivalent to the `as_bytes` function except that the returned slice
     /// includes the trailing nul byte.
     pub fn as_bytes_with_nul(&self) -> &[u8] {
         &self.inner
     }

     /// Extracts a `CStr` slice containing the entire string.
     pub fn as_c_str(&self) -> &CStr {
         &*self
     }

     /// Converts this `CString` into a boxed `CStr`.
     pub fn into_boxed_c_str(self) -> Box<CStr> {
         unsafe { Box::from_raw(Box::into_raw(self.into_inner()) as *mut CStr) }
     }

     // Bypass "move out of struct which implements `Drop` trait" restriction.
     fn into_inner(self) -> Box<[u8]> {
         unsafe {
             let result = ptr::read(&self.inner);
             mem::forget(self);
             result
         }
     }
 }

 // Turns this `CString` into an empty string to prevent
 // memory unsafe code from working by accident. Inline
 // to prevent LLVM from optimizing it away in debug builds.
 impl Drop for CString {
     #[inline]
     fn drop(&mut self) {
         unsafe { *self.inner.get_unchecked_mut(0) = 0; }
     }
 }

 impl ops::Deref for CString {
     type Target = CStr;

     #[inline]
     fn deref(&self) -> &CStr {
         unsafe { CStr::from_bytes_with_nul_unchecked(self.as_bytes_with_nul()) }
     }
 }

 impl fmt::Debug for CString {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt::Debug::fmt(&**self, f)
     }
 }

 impl From<CString> for Vec<u8> {
     #[inline]
     fn from(s: CString) -> Vec<u8> {
         s.into_bytes()
     }
 }

 impl fmt::Debug for CStr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "\"")?;
         for byte in self.to_bytes().iter().flat_map(|&b| ascii::escape_default(b)) {
             f.write_char(byte as char)?;
         }
         write!(f, "\"")
     }
 }

 impl<'a> Default for &'a CStr {
     fn default() -> &'a CStr {
         const SLICE: & [c_char] = &[0];
         unsafe { CStr::from_ptr(SLICE.as_ptr()) }
     }
 }

 impl Default for CString {
     /// Creates an empty `CString`.
     fn default() -> CString {
         let a: &CStr = Default::default();
         a.to_owned()
     }
 }

 impl Borrow<CStr> for CString {
     #[inline]
     fn borrow(&self) -> &CStr { self }
 }

 impl<'a> From<&'a CStr> for Box<CStr> {
     fn from(s: &'a CStr) -> Box<CStr> {
         let boxed: Box<[u8]> = Box::from(s.to_bytes_with_nul());
         unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) }
     }
 }

 impl From<Box<CStr>> for CString {
     #[inline]
     fn from(s: Box<CStr>) -> CString {
         s.into_c_string()
     }
 }

 impl From<CString> for Box<CStr> {
     #[inline]
     fn from(s: CString) -> Box<CStr> {
         s.into_boxed_c_str()
     }
 }

 impl From<CString> for Arc<CStr> {
     #[inline]
     fn from(s: CString) -> Arc<CStr> {
         let arc: Arc<[u8]> = Arc::from(s.into_inner());
         unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) }
     }
 }

 impl<'a> From<&'a CStr> for Arc<CStr> {
     #[inline]
     fn from(s: &CStr) -> Arc<CStr> {
         let arc: Arc<[u8]> = Arc::from(s.to_bytes_with_nul());
         unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) }
     }
 }

 impl From<CString> for Rc<CStr> {
     #[inline]
     fn from(s: CString) -> Rc<CStr> {
         let rc: Rc<[u8]> = Rc::from(s.into_inner());
         unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
     }
 }

 impl<'a> From<&'a CStr> for Rc<CStr> {
     #[inline]
     fn from(s: &CStr) -> Rc<CStr> {
         let rc: Rc<[u8]> = Rc::from(s.to_bytes_with_nul());
         unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
     }
 }

 impl Default for Box<CStr> {
     fn default() -> Box<CStr> {
         let boxed: Box<[u8]> = Box::from([0]);
         unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) }
     }
 }

 impl NulError {
     /// Returns the position of the nul byte in the slice that was provided to
     /// `CString::new`.
     ///
     pub fn nul_position(&self) -> usize { self.0 }

     /// Consumes this error, returning the underlying vector of bytes which
     /// generated the error in the first place.
     ///
     pub fn into_vec(self) -> Vec<u8> { self.1 }
 }

 impl fmt::Display for NulError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "nul byte found in provided data at position: {}", self.0)
     }
 }

 impl fmt::Display for FromBytesWithNulError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.write_str(self.__description())?;
         if let FromBytesWithNulErrorKind::InteriorNul(pos) = self.kind {
             write!(f, " at byte pos {}", pos)?;
         }
         Ok(())
     }
 }

 impl IntoStringError {
     /// Consumes this error, returning original `CString` which generated the
     /// error.
     pub fn into_cstring(self) -> CString {
         self.inner
     }

     /// Access the underlying UTF-8 error that was the cause of this error.
     pub fn utf8_error(&self) -> Utf8Error {
         self.error
     }

     pub fn __description(&self) -> &str {
         "C string contained non-utf8 bytes"
     }

     pub fn __cause(&self) -> Option<&Utf8Error> {
         Some(&self.error)
     }
 }

 impl fmt::Display for IntoStringError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.__description().fmt(f)
     }
 }

 impl CStr {
     /// Wraps a raw C string with a safe C string wrapper.
     ///
     /// This function will wrap the provided `ptr` with a `CStr` wrapper, which
     /// allows inspection and interoperation of non-owned C strings. This method
     /// is unsafe for a number of reasons:
     ///
     /// * There is no guarantee to the validity of `ptr`.
     /// * The returned lifetime is not guaranteed to be the actual lifetime of
     ///   `ptr`.
     /// * There is no guarantee that the memory pointed to by `ptr` contains a
     ///   valid nul terminator byte at the end of the string.
     /// * It is not guaranteed that the memory pointed by `ptr` won't change
     ///   before the `CStr` has been destroyed.
     ///
     /// > **Note**: This operation is intended to be a 0-cost cast but it is
     /// > currently implemented with an up-front calculation of the length of
     /// > the string. This is not guaranteed to always be the case.
     ///
     pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr {
         let len = libc::strlen(ptr);
         let ptr = ptr as *const u8;
         CStr::from_bytes_with_nul_unchecked(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 the byte slice is nul-terminated
     /// and does not contain any interior nul bytes.
     ///
     pub fn from_bytes_with_nul(bytes: &[u8])
                                -> Result<&CStr, FromBytesWithNulError> {
         let nul_pos = memchr::memchr(0, bytes);
         if let Some(nul_pos) = nul_pos {
             if nul_pos + 1 != bytes.len() {
                 return Err(FromBytesWithNulError::interior_nul(nul_pos));
             }
             Ok(unsafe { CStr::from_bytes_with_nul_unchecked(bytes) })
         } else {
             Err(FromBytesWithNulError::not_nul_terminated())
         }
     }

     /// 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 nul-terminated
     /// and not contain any interior nul bytes.
     ///
     pub unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
         &*(bytes as *const [u8] as *const CStr)
     }

     /// Returns the inner pointer to this C string.
     ///
     /// The returned pointer will be valid for as long as `self` is, and points
     /// to a contiguous region of memory terminated with a 0 byte to represent
     /// the end of the string.
     ///
     pub fn as_ptr(&self) -> *const c_char {
         self.inner.as_ptr()
     }

     /// Converts this C string to a byte slice.
     ///
     /// The returned slice will **not** contain the trailing nul terminator that this C
     /// string has.
     ///
     /// > **Note**: This method is currently implemented as a constant-time
     /// > cast, but it is planned to alter its definition in the future to
     /// > perform the length calculation whenever this method is called.
     ///
     pub fn to_bytes(&self) -> &[u8] {
         let bytes = self.to_bytes_with_nul();
         &bytes[..bytes.len() - 1]
     }

     /// Converts this C string to a byte slice containing the trailing 0 byte.
     ///
     /// This function is the equivalent of [`to_bytes`] except that it will retain
     /// the trailing nul terminator instead of chopping it off.
     ///
     /// > **Note**: This method is currently implemented as a 0-cost cast, but
     /// > it is planned to alter its definition in the future to perform the
     /// > length calculation whenever this method is called.
     ///
     /// [`to_bytes`]: #method.to_bytes
     ///
     pub fn to_bytes_with_nul(&self) -> &[u8] {
         unsafe { &*(&self.inner as *const [c_char] as *const [u8]) }
     }

     /// Yields a [`&str`] slice if the `CStr` contains valid UTF-8.
     ///
     /// If the contents of the `CStr` are valid UTF-8 data, this
     /// function will return the corresponding [`&str`] slice. Otherwise,
     /// it will return an error with details of where UTF-8 validation failed.
     ///
     /// > **Note**: This method is currently implemented to check for validity
     /// > after a constant-time cast, but it is planned to alter its definition
     /// > in the future to perform the length calculation in addition to the
     /// > UTF-8 check whenever this method is called.
     ///
     /// [`&str`]: ../primitive.str.html
     ///
     pub fn to_str(&self) -> Result<&str, str::Utf8Error> {
         // NB: When CStr is changed to perform the length check in .to_bytes()
         // instead of in from_ptr(), it may be worth considering if this should
         // be rewritten to do the UTF-8 check inline with the length calculation
         // instead of doing it afterwards.
         str::from_utf8(self.to_bytes())
     }

     /// Converts a `CStr` into a [`Cow`]`<`[`str`]`>`.
     ///
     /// If the contents of the `CStr` are valid UTF-8 data, this
     /// function will return a [`Cow`]`::`[`Borrowed`]`(`[`&str`]`)`
     /// with the the corresponding [`&str`] slice. Otherwise, it will
     /// replace any invalid UTF-8 sequences with `U+FFFD REPLACEMENT
     /// CHARACTER` and return a [`Cow`]`::`[`Owned`]`(`[`String`]`)`
     /// with the result.
     ///
     /// > **Note**: This method is currently implemented to check for validity
     /// > after a constant-time cast, but it is planned to alter its definition
     /// > in the future to perform the length calculation in addition to the
     /// > UTF-8 check whenever this method is called.
     ///
     /// [`Cow`]: ../borrow/enum.Cow.html
     /// [`Borrowed`]: ../borrow/enum.Cow.html#variant.Borrowed
     /// [`str`]: ../primitive.str.html
     /// [`String`]: ../string/struct.String.html
     ///
     pub fn to_string_lossy(&self) -> Cow<str> {
         String::from_utf8_lossy(self.to_bytes())
     }

     /// Converts a [`Box`]`<CStr>` into a [`CString`] without copying or allocating.
     ///
     /// [`Box`]: ../boxed/struct.Box.html
     /// [`CString`]: struct.CString.html
     ///
     #[allow(clippy::wrong_self_convention)]
     pub fn into_c_string(self: Box<CStr>) -> CString {
         let raw = Box::into_raw(self) as *mut [u8];
         CString { inner: unsafe { Box::from_raw(raw) } }
     }
 }

 //impl PartialEq for CStr {
 //    fn eq(&self, other: &CStr) -> bool {
 //        self.to_bytes().eq(other.to_bytes())
 //    }
 //}

 //impl Eq for CStr {}

 impl PartialOrd for CStr {
     fn partial_cmp(&self, other: &CStr) -> Option<Ordering> {
         self.to_bytes().partial_cmp(&other.to_bytes())
     }
 }

 impl Ord for CStr {
     fn cmp(&self, other: &CStr) -> Ordering {
         self.to_bytes().cmp(&other.to_bytes())
     }
 }

 impl ToOwned for CStr {
     type Owned = CString;

     fn to_owned(&self) -> CString {
         CString { inner: self.to_bytes_with_nul().into() }
     }
 }

 impl<'a> From<&'a CStr> for CString {
     fn from(s: &'a CStr) -> CString {
         s.to_owned()
     }
 }

 impl ops::Index<ops::RangeFull> for CString {
     type Output = CStr;

     #[inline]
     fn index(&self, _index: ops::RangeFull) -> &CStr {
         self
     }
 }

 impl AsRef<CStr> for CStr {
     #[inline]
     fn as_ref(&self) -> &CStr {
         self
     }
 }

 impl AsRef<CStr> for CString {
     #[inline]
     fn as_ref(&self) -> &CStr {
         self
     }
 }
	// Copyright (C) 2017-2018 Baidu, Inc. All Rights Reserved.
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions
	// are met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above copyright
	// notice, this list of conditions and the following disclaimer in
	// the documentation and/or other materials provided with the
	// distribution.
	// * Neither the name of Baidu, Inc., nor the names of its
	// contributors may be used to endorse or promote products derived
	// from this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	/// A type representing an owned, C-compatible, nul-terminated string with no nul bytes in the
	/// middle.
	///
	/// This type serves the purpose of being able to safely generate a
	/// C-compatible string from a Rust byte slice or vector. An instance of this
	/// type is a static guarantee that the underlying bytes contain no interior 0
	/// bytes ("nul characters") and that the final byte is 0 ("nul terminator").
	///
	use sgx_types::c_char;
	use libc;
	use memchr;
	use ascii;
	//use error::Error;
	//use io;

	use core::ops;
	use core::cmp::Ordering;
	use core::mem;
	use core::ptr;
	use core::fmt::{self, Write};
	use alloc::boxed::Box;
	use alloc::borrow::{Cow, Borrow, ToOwned};
	use alloc::vec::Vec;
	use alloc::string::String;
	use alloc::slice;
	use alloc::rc::Rc;
	use alloc::sync::Arc;

	use alloc::str::{self, Utf8Error};

	/// A type representing an owned C-compatible string
	///
	#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)]
	pub struct CString {
	inner: Box<[u8]>,
	}

	/// Representation of a borrowed C string.
	///
	#[derive(Hash, Eq, PartialEq)]
	pub struct CStr {
	inner: [c_char]
	}

	/// An error returned from `CString::new` to indicate that a nul byte was found
	/// in the vector provided.
	#[derive(Clone, PartialEq, Eq, Debug)]
	pub struct NulError(usize, Vec<u8>);

	/// An error returned from `CStr::from_bytes_with_nul` to indicate that a nul
	/// byte was found too early in the slice provided or one wasn't found at all.
	#[derive(Clone, PartialEq, Eq, Debug)]
	pub struct FromBytesWithNulError {
	kind: FromBytesWithNulErrorKind,
	}

	#[derive(Clone, PartialEq, Eq, Debug)]
	enum FromBytesWithNulErrorKind {
	InteriorNul(usize),
	NotNulTerminated,
	}

	impl FromBytesWithNulError {
	fn interior_nul(pos: usize) -> FromBytesWithNulError {
	FromBytesWithNulError {
	kind: FromBytesWithNulErrorKind::InteriorNul(pos),
	}
	}
	fn not_nul_terminated() -> FromBytesWithNulError {
	FromBytesWithNulError {
	kind: FromBytesWithNulErrorKind::NotNulTerminated,
	}
	}

	pub fn __description(&self) -> &str {
	match self.kind {
	FromBytesWithNulErrorKind::InteriorNul(..) =>
	"data provided contains an interior nul byte",
	FromBytesWithNulErrorKind::NotNulTerminated =>
	"data provided is not nul terminated",
	}
	}
	}

	/// An error returned from `CString::into_string` to indicate that a UTF-8 error
	/// was encountered during the conversion.
	#[derive(Clone, PartialEq, Eq, Debug)]
	pub struct IntoStringError {
	inner: CString,
	error: Utf8Error,
	}

	impl CString {
	/// Creates a new C-compatible string from a container of bytes.
	///
	/// This method will consume the provided data and use the underlying bytes
	/// to construct a new string, ensuring that there is a trailing 0 byte.
	///
	/// # Errors
	///
	/// This function will return an error if the bytes yielded contain an
	/// internal 0 byte. The error returned will contain the bytes as well as
	/// the position of the nul byte.
	pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> {
	Self::_new(t.into())
	}

	fn _new(bytes: Vec<u8>) -> Result<CString, NulError> {
	match memchr::memchr(0, &bytes) {
	Some(i) => Err(NulError(i, bytes)),
	None => Ok(unsafe { CString::from_vec_unchecked(bytes) }),
	}
	}

	/// Creates a C-compatible string from a byte vector without checking for
	/// interior 0 bytes.
	///
	/// This method is equivalent to `new` except that no runtime assertion
	/// is made that `v` contains no 0 bytes, and it requires an actual
	/// byte vector, not anything that can be converted to one with Into.
	///
	pub unsafe fn from_vec_unchecked(mut v: Vec<u8>) -> CString {
	v.reserve_exact(1);
	v.push(0);
	CString { inner: v.into_boxed_slice() }
	}

	/// Retakes ownership of a `CString` that was transferred to C.
	///
	/// Additionally, the length of the string will be recalculated from the pointer.
	///
	/// # Safety
	///
	/// This should only ever be called with a pointer that was earlier
	/// obtained by calling `into_raw` on a `CString`. Other usage (e.g. trying to take
	/// ownership of a string that was allocated by foreign code) is likely to lead
	/// to undefined behavior or allocator corruption.
	pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
	let len = libc::strlen(ptr) + 1; // Including the NUL byte
	let slice = slice::from_raw_parts_mut(ptr, len as usize);
	CString { inner: Box::from_raw(slice as mut [c_char] as mut [u8]) }
	}

	/// Transfers ownership of the string to a C caller.
	///
	/// The pointer must be returned to Rust and reconstituted using
	/// `from_raw` to be properly deallocated. Specifically, one
	/// should not use the standard C `free` function to deallocate
	/// this string.
	///
	/// Failure to call `from_raw` will lead to a memory leak.
	pub fn into_raw(self) -> *mut c_char {
	Box::into_raw(self.into_inner()) as *mut c_char
	}

	/// Converts the `CString` into a `String` if it contains valid Unicode data.
	///
	/// On failure, ownership of the original `CString` is returned.
	pub fn into_string(self) -> Result<String, IntoStringError> {
	String::from_utf8(self.into_bytes())
	.map_err(\|e\| IntoStringError {
	error: e.utf8_error(),
	inner: unsafe { CString::from_vec_unchecked(e.into_bytes()) },
	})
	}

	/// Returns the underlying byte buffer.
	///
	/// The returned buffer does not contain the trailing nul separator and
	/// it is guaranteed to not have any interior nul bytes.
	pub fn into_bytes(self) -> Vec<u8> {
	let mut vec = self.into_inner().into_vec();
	let _nul = vec.pop();
	debug_assert_eq!(_nul, Some(0u8));
	vec
	}

	/// Equivalent to the `into_bytes` function except that the returned vector
	/// includes the trailing nul byte.
	pub fn into_bytes_with_nul(self) -> Vec<u8> {
	self.into_inner().into_vec()
	}

	/// Returns the contents of this `CString` as a slice of bytes.
	///
	/// The returned slice does not contain the trailing nul separator and
	/// it is guaranteed to not have any interior nul bytes.
	pub fn as_bytes(&self) -> &[u8] {
	&self.inner[..self.inner.len() - 1]
	}

	/// Equivalent to the `as_bytes` function except that the returned slice
	/// includes the trailing nul byte.
	pub fn as_bytes_with_nul(&self) -> &[u8] {
	&self.inner
	}

	/// Extracts a `CStr` slice containing the entire string.
	pub fn as_c_str(&self) -> &CStr {
	&*self
	}

	/// Converts this `CString` into a boxed `CStr`.
	pub fn into_boxed_c_str(self) -> Box<CStr> {
	unsafe { Box::from_raw(Box::into_raw(self.into_inner()) as *mut CStr) }
	}

	// Bypass "move out of struct which implements `Drop` trait" restriction.
	fn into_inner(self) -> Box<[u8]> {
	unsafe {
	let result = ptr::read(&self.inner);
	mem::forget(self);
	result
	}
	}
	}

	// Turns this `CString` into an empty string to prevent
	// memory unsafe code from working by accident. Inline
	// to prevent LLVM from optimizing it away in debug builds.
	impl Drop for CString {
	#[inline]
	fn drop(&mut self) {
	unsafe { *self.inner.get_unchecked_mut(0) = 0; }
	}
	}

	impl ops::Deref for CString {
	type Target = CStr;

	#[inline]
	fn deref(&self) -> &CStr {
	unsafe { CStr::from_bytes_with_nul_unchecked(self.as_bytes_with_nul()) }
	}
	}

	impl fmt::Debug for CString {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	fmt::Debug::fmt(&**self, f)
	}
	}

	impl From<CString> for Vec<u8> {
	#[inline]
	fn from(s: CString) -> Vec<u8> {
	s.into_bytes()
	}
	}

	impl fmt::Debug for CStr {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	write!(f, "\"")?;
	for byte in self.to_bytes().iter().flat_map(\|&b\| ascii::escape_default(b)) {
	f.write_char(byte as char)?;
	}
	write!(f, "\"")
	}
	}

	impl<'a> Default for &'a CStr {
	fn default() -> &'a CStr {
	const SLICE: & [c_char] = &[0];
	unsafe { CStr::from_ptr(SLICE.as_ptr()) }
	}
	}

	impl Default for CString {
	/// Creates an empty `CString`.
	fn default() -> CString {
	let a: &CStr = Default::default();
	a.to_owned()
	}
	}

	impl Borrow<CStr> for CString {
	#[inline]
	fn borrow(&self) -> &CStr { self }
	}

	impl<'a> From<&'a CStr> for Box<CStr> {
	fn from(s: &'a CStr) -> Box<CStr> {
	let boxed: Box<[u8]> = Box::from(s.to_bytes_with_nul());
	unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) }
	}
	}

	impl From<Box<CStr>> for CString {
	#[inline]
	fn from(s: Box<CStr>) -> CString {
	s.into_c_string()
	}
	}

	impl From<CString> for Box<CStr> {
	#[inline]
	fn from(s: CString) -> Box<CStr> {
	s.into_boxed_c_str()
	}
	}

	impl From<CString> for Arc<CStr> {
	#[inline]
	fn from(s: CString) -> Arc<CStr> {
	let arc: Arc<[u8]> = Arc::from(s.into_inner());
	unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) }
	}
	}

	impl<'a> From<&'a CStr> for Arc<CStr> {
	#[inline]
	fn from(s: &CStr) -> Arc<CStr> {
	let arc: Arc<[u8]> = Arc::from(s.to_bytes_with_nul());
	unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) }
	}
	}

	impl From<CString> for Rc<CStr> {
	#[inline]
	fn from(s: CString) -> Rc<CStr> {
	let rc: Rc<[u8]> = Rc::from(s.into_inner());
	unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
	}
	}

	impl<'a> From<&'a CStr> for Rc<CStr> {
	#[inline]
	fn from(s: &CStr) -> Rc<CStr> {
	let rc: Rc<[u8]> = Rc::from(s.to_bytes_with_nul());
	unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
	}
	}

	impl Default for Box<CStr> {
	fn default() -> Box<CStr> {
	let boxed: Box<[u8]> = Box::from([0]);
	unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) }
	}
	}

	impl NulError {
	/// Returns the position of the nul byte in the slice that was provided to
	/// `CString::new`.
	///
	pub fn nul_position(&self) -> usize { self.0 }

	/// Consumes this error, returning the underlying vector of bytes which
	/// generated the error in the first place.
	///
	pub fn into_vec(self) -> Vec<u8> { self.1 }
	}

	impl fmt::Display for NulError {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	write!(f, "nul byte found in provided data at position: {}", self.0)
	}
	}

	impl fmt::Display for FromBytesWithNulError {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	f.write_str(self.__description())?;
	if let FromBytesWithNulErrorKind::InteriorNul(pos) = self.kind {
	write!(f, " at byte pos {}", pos)?;
	}
	Ok(())
	}
	}

	impl IntoStringError {
	/// Consumes this error, returning original `CString` which generated the
	/// error.
	pub fn into_cstring(self) -> CString {
	self.inner
	}

	/// Access the underlying UTF-8 error that was the cause of this error.
	pub fn utf8_error(&self) -> Utf8Error {
	self.error
	}

	pub fn __description(&self) -> &str {
	"C string contained non-utf8 bytes"
	}

	pub fn __cause(&self) -> Option<&Utf8Error> {
	Some(&self.error)
	}
	}

	impl fmt::Display for IntoStringError {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	self.__description().fmt(f)
	}
	}

	impl CStr {
	/// Wraps a raw C string with a safe C string wrapper.
	///
	/// This function will wrap the provided `ptr` with a `CStr` wrapper, which
	/// allows inspection and interoperation of non-owned C strings. This method
	/// is unsafe for a number of reasons:
	///
	/// * There is no guarantee to the validity of `ptr`.
	/// * The returned lifetime is not guaranteed to be the actual lifetime of
	/// `ptr`.
	/// * There is no guarantee that the memory pointed to by `ptr` contains a
	/// valid nul terminator byte at the end of the string.
	/// * It is not guaranteed that the memory pointed by `ptr` won't change
	/// before the `CStr` has been destroyed.
	///
	/// > Note: This operation is intended to be a 0-cost cast but it is
	/// > currently implemented with an up-front calculation of the length of
	/// > the string. This is not guaranteed to always be the case.
	///
	pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr {
	let len = libc::strlen(ptr);
	let ptr = ptr as *const u8;
	CStr::from_bytes_with_nul_unchecked(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 the byte slice is nul-terminated
	/// and does not contain any interior nul bytes.
	///
	pub fn from_bytes_with_nul(bytes: &[u8])
	-> Result<&CStr, FromBytesWithNulError> {
	let nul_pos = memchr::memchr(0, bytes);
	if let Some(nul_pos) = nul_pos {
	if nul_pos + 1 != bytes.len() {
	return Err(FromBytesWithNulError::interior_nul(nul_pos));
	}
	Ok(unsafe { CStr::from_bytes_with_nul_unchecked(bytes) })
	} else {
	Err(FromBytesWithNulError::not_nul_terminated())
	}
	}

	/// 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 nul-terminated
	/// and not contain any interior nul bytes.
	///
	pub unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
	&(bytes as const [u8] as *const CStr)
	}

	/// Returns the inner pointer to this C string.
	///
	/// The returned pointer will be valid for as long as `self` is, and points
	/// to a contiguous region of memory terminated with a 0 byte to represent
	/// the end of the string.
	///
	pub fn as_ptr(&self) -> *const c_char {
	self.inner.as_ptr()
	}

	/// Converts this C string to a byte slice.
	///
	/// The returned slice will not contain the trailing nul terminator that this C
	/// string has.
	///
	/// > Note: This method is currently implemented as a constant-time
	/// > cast, but it is planned to alter its definition in the future to
	/// > perform the length calculation whenever this method is called.
	///
	pub fn to_bytes(&self) -> &[u8] {
	let bytes = self.to_bytes_with_nul();
	&bytes[..bytes.len() - 1]
	}

	/// Converts this C string to a byte slice containing the trailing 0 byte.
	///
	/// This function is the equivalent of [`to_bytes`] except that it will retain
	/// the trailing nul terminator instead of chopping it off.
	///
	/// > Note: This method is currently implemented as a 0-cost cast, but
	/// > it is planned to alter its definition in the future to perform the
	/// > length calculation whenever this method is called.
	///
	/// [`to_bytes`]: #method.to_bytes
	///
	pub fn to_bytes_with_nul(&self) -> &[u8] {
	unsafe { &(&self.inner as const [c_char] as *const [u8]) }
	}

	/// Yields a [`&str`] slice if the `CStr` contains valid UTF-8.
	///
	/// If the contents of the `CStr` are valid UTF-8 data, this
	/// function will return the corresponding [`&str`] slice. Otherwise,
	/// it will return an error with details of where UTF-8 validation failed.
	///
	/// > Note: This method is currently implemented to check for validity
	/// > after a constant-time cast, but it is planned to alter its definition
	/// > in the future to perform the length calculation in addition to the
	/// > UTF-8 check whenever this method is called.
	///
	/// [`&str`]: ../primitive.str.html
	///
	pub fn to_str(&self) -> Result<&str, str::Utf8Error> {
	// NB: When CStr is changed to perform the length check in .to_bytes()
	// instead of in from_ptr(), it may be worth considering if this should
	// be rewritten to do the UTF-8 check inline with the length calculation
	// instead of doing it afterwards.
	str::from_utf8(self.to_bytes())
	}

	/// Converts a `CStr` into a [`Cow`]`<`[`str`]`>`.
	///
	/// If the contents of the `CStr` are valid UTF-8 data, this
	/// function will return a [`Cow`]`::`[`Borrowed`]`(`[`&str`]`)`
	/// with the the corresponding [`&str`] slice. Otherwise, it will
	/// replace any invalid UTF-8 sequences with `U+FFFD REPLACEMENT
	/// CHARACTER` and return a [`Cow`]`::`[`Owned`]`(`[`String`]`)`
	/// with the result.
	///
	/// > Note: This method is currently implemented to check for validity
	/// > after a constant-time cast, but it is planned to alter its definition
	/// > in the future to perform the length calculation in addition to the
	/// > UTF-8 check whenever this method is called.
	///
	/// [`Cow`]: ../borrow/enum.Cow.html
	/// [`Borrowed`]: ../borrow/enum.Cow.html#variant.Borrowed
	/// [`str`]: ../primitive.str.html
	/// [`String`]: ../string/struct.String.html
	///
	pub fn to_string_lossy(&self) -> Cow<str> {
	String::from_utf8_lossy(self.to_bytes())
	}

	/// Converts a [`Box`]`<CStr>` into a [`CString`] without copying or allocating.
	///
	/// [`Box`]: ../boxed/struct.Box.html
	/// [`CString`]: struct.CString.html
	///
	#[allow(clippy::wrong_self_convention)]
	pub fn into_c_string(self: Box<CStr>) -> CString {
	let raw = Box::into_raw(self) as *mut [u8];
	CString { inner: unsafe { Box::from_raw(raw) } }
	}
	}

	//impl PartialEq for CStr {
	// fn eq(&self, other: &CStr) -> bool {
	// self.to_bytes().eq(other.to_bytes())
	// }
	//}

	//impl Eq for CStr {}

	impl PartialOrd for CStr {
	fn partial_cmp(&self, other: &CStr) -> Option<Ordering> {
	self.to_bytes().partial_cmp(&other.to_bytes())
	}
	}

	impl Ord for CStr {
	fn cmp(&self, other: &CStr) -> Ordering {
	self.to_bytes().cmp(&other.to_bytes())
	}
	}

	impl ToOwned for CStr {
	type Owned = CString;

	fn to_owned(&self) -> CString {
	CString { inner: self.to_bytes_with_nul().into() }
	}
	}

	impl<'a> From<&'a CStr> for CString {
	fn from(s: &'a CStr) -> CString {
	s.to_owned()
	}
	}

	impl ops::Index<ops::RangeFull> for CString {
	type Output = CStr;

	#[inline]
	fn index(&self, _index: ops::RangeFull) -> &CStr {
	self
	}
	}

	impl AsRef<CStr> for CStr {
	#[inline]
	fn as_ref(&self) -> &CStr {
	self
	}
	}

	impl AsRef<CStr> for CString {
	#[inline]
	fn as_ref(&self) -> &CStr {
	self
	}
	}