| use crate::ascii; |
| use crate::borrow::{Cow, Borrow}; |
| use crate::cmp::Ordering; |
| use crate::error::Error; |
| use crate::fmt::{self, Write}; |
| use crate::io; |
| use crate::mem; |
| use crate::memchr; |
| use crate::ops; |
| use crate::os::raw::c_char; |
| use crate::ptr; |
| use crate::rc::Rc; |
| use crate::slice; |
| use crate::str::{self, Utf8Error}; |
| use crate::sync::Arc; |
| use crate::sys; |
| |
| /// 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"). |
| /// |
| /// `CString` is to [`&CStr`] as [`String`] is to [`&str`]: the former |
| /// in each pair are owned strings; the latter are borrowed |
| /// references. |
| /// |
| /// # Creating a `CString` |
| /// |
| /// A `CString` is created from either a byte slice or a byte vector, |
| /// or anything that implements [`Into`]`<`[`Vec`]`<`[`u8`]`>>` (for |
| /// example, you can build a `CString` straight out of a [`String`] or |
| /// a [`&str`], since both implement that trait). |
| /// |
| /// The [`new`] method will actually check that the provided `&[u8]` |
| /// does not have 0 bytes in the middle, and return an error if it |
| /// finds one. |
| /// |
| /// # Extracting a raw pointer to the whole C string |
| /// |
| /// `CString` implements a [`as_ptr`] method through the [`Deref`] |
| /// trait. This method will give you a `*const c_char` which you can |
| /// feed directly to extern functions that expect a nul-terminated |
| /// string, like C's `strdup()`. Notice that [`as_ptr`] returns a |
| /// read-only pointer; if the C code writes to it, that causes |
| /// undefined behavior. |
| /// |
| /// # Extracting a slice of the whole C string |
| /// |
| /// Alternatively, you can obtain a `&[`[`u8`]`]` slice from a |
| /// `CString` with the [`as_bytes`] method. Slices produced in this |
| /// way do *not* contain the trailing nul terminator. This is useful |
| /// when you will be calling an extern function that takes a `*const |
| /// u8` argument which is not necessarily nul-terminated, plus another |
| /// argument with the length of the string — like C's `strndup()`. |
| /// You can of course get the slice's length with its |
| /// [`len`][slice.len] method. |
| /// |
| /// If you need a `&[`[`u8`]`]` slice *with* the nul terminator, you |
| /// can use [`as_bytes_with_nul`] instead. |
| /// |
| /// Once you have the kind of slice you need (with or without a nul |
| /// terminator), you can call the slice's own |
| /// [`as_ptr`][slice.as_ptr] method to get a read-only raw pointer to pass to |
| /// extern functions. See the documentation for that function for a |
| /// discussion on ensuring the lifetime of the raw pointer. |
| /// |
| /// [`Into`]: ../convert/trait.Into.html |
| /// [`Vec`]: ../vec/struct.Vec.html |
| /// [`String`]: ../string/struct.String.html |
| /// [`&str`]: ../primitive.str.html |
| /// [`u8`]: ../primitive.u8.html |
| /// [`new`]: #method.new |
| /// [`as_bytes`]: #method.as_bytes |
| /// [`as_bytes_with_nul`]: #method.as_bytes_with_nul |
| /// [`as_ptr`]: #method.as_ptr |
| /// [slice.as_ptr]: ../primitive.slice.html#method.as_ptr |
| /// [slice.len]: ../primitive.slice.html#method.len |
| /// [`Deref`]: ../ops/trait.Deref.html |
| /// [`CStr`]: struct.CStr.html |
| /// [`&CStr`]: struct.CStr.html |
| /// |
| /// # Examples |
| /// |
| /// ```ignore (extern-declaration) |
| /// # fn main() { |
| /// use std::ffi::CString; |
| /// use std::os::raw::c_char; |
| /// |
| /// extern { |
| /// fn my_printer(s: *const c_char); |
| /// } |
| /// |
| /// // We are certain that our string doesn't have 0 bytes in the middle, |
| /// // so we can .expect() |
| /// let c_to_print = CString::new("Hello, world!").expect("CString::new failed"); |
| /// unsafe { |
| /// my_printer(c_to_print.as_ptr()); |
| /// } |
| /// # } |
| /// ``` |
| /// |
| /// # Safety |
| /// |
| /// `CString` is intended for working with traditional C-style strings |
| /// (a sequence of non-nul bytes terminated by a single nul byte); the |
| /// primary use case for these kinds of strings is interoperating with C-like |
| /// code. Often you will need to transfer ownership to/from that external |
| /// code. It is strongly recommended that you thoroughly read through the |
| /// documentation of `CString` before use, as improper ownership management |
| /// of `CString` instances can lead to invalid memory accesses, memory leaks, |
| /// and other memory errors. |
| |
| #[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct CString { |
| // Invariant 1: the slice ends with a zero byte and has a length of at least one. |
| // Invariant 2: the slice contains only one zero byte. |
| // Improper usage of unsafe function can break Invariant 2, but not Invariant 1. |
| inner: Box<[u8]>, |
| } |
| |
| /// Representation of a borrowed C string. |
| /// |
| /// This type represents a borrowed reference to a nul-terminated |
| /// array of bytes. It can be constructed safely from a `&[`[`u8`]`]` |
| /// slice, or unsafely from a raw `*const c_char`. It can then be |
| /// converted to a Rust [`&str`] by performing UTF-8 validation, or |
| /// into an owned [`CString`]. |
| /// |
| /// `&CStr` is to [`CString`] as [`&str`] is to [`String`]: the former |
| /// in each pair are borrowed references; the latter are owned |
| /// strings. |
| /// |
| /// Note that this structure is **not** `repr(C)` and is not recommended to be |
| /// placed in the signatures of FFI functions. Instead, safe wrappers of FFI |
| /// functions may leverage the unsafe [`from_ptr`] constructor to provide a safe |
| /// interface to other consumers. |
| /// |
| /// # Examples |
| /// |
| /// Inspecting a foreign C string: |
| /// |
| /// ```ignore (extern-declaration) |
| /// use std::ffi::CStr; |
| /// use std::os::raw::c_char; |
| /// |
| /// extern { fn my_string() -> *const c_char; } |
| /// |
| /// unsafe { |
| /// let slice = CStr::from_ptr(my_string()); |
| /// println!("string buffer size without nul terminator: {}", slice.to_bytes().len()); |
| /// } |
| /// ``` |
| /// |
| /// Passing a Rust-originating C string: |
| /// |
| /// ```ignore (extern-declaration) |
| /// use std::ffi::{CString, CStr}; |
| /// use std::os::raw::c_char; |
| /// |
| /// fn work(data: &CStr) { |
| /// extern { fn work_with(data: *const c_char); } |
| /// |
| /// unsafe { work_with(data.as_ptr()) } |
| /// } |
| /// |
| /// let s = CString::new("data data data data").expect("CString::new failed"); |
| /// work(&s); |
| /// ``` |
| /// |
| /// Converting a foreign C string into a Rust [`String`]: |
| /// |
| /// ```ignore (extern-declaration) |
| /// use std::ffi::CStr; |
| /// use std::os::raw::c_char; |
| /// |
| /// extern { fn my_string() -> *const c_char; } |
| /// |
| /// fn my_string_safe() -> String { |
| /// unsafe { |
| /// CStr::from_ptr(my_string()).to_string_lossy().into_owned() |
| /// } |
| /// } |
| /// |
| /// println!("string: {}", my_string_safe()); |
| /// ``` |
| /// |
| /// [`u8`]: ../primitive.u8.html |
| /// [`&str`]: ../primitive.str.html |
| /// [`String`]: ../string/struct.String.html |
| /// [`CString`]: struct.CString.html |
| /// [`from_ptr`]: #method.from_ptr |
| #[derive(Hash)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| // FIXME: |
| // `fn from` in `impl From<&CStr> for Box<CStr>` current implementation relies |
| // on `CStr` being layout-compatible with `[u8]`. |
| // When attribute privacy is implemented, `CStr` should be annotated as `#[repr(transparent)]`. |
| // Anyway, `CStr` representation and layout are considered implementation detail, are |
| // not documented and must not be relied upon. |
| pub struct CStr { |
| // FIXME: this should not be represented with a DST slice but rather with |
| // just a raw `c_char` along with some form of marker to make |
| // this an unsized type. Essentially `sizeof(&CStr)` should be the |
| // same as `sizeof(&c_char)` but `CStr` should be an unsized type. |
| inner: [c_char] |
| } |
| |
| /// An error indicating that an interior nul byte was found. |
| /// |
| /// While Rust strings may contain nul bytes in the middle, C strings |
| /// can't, as that byte would effectively truncate the string. |
| /// |
| /// This error is created by the [`new`][`CString::new`] method on |
| /// [`CString`]. See its documentation for more. |
| /// |
| /// [`CString`]: struct.CString.html |
| /// [`CString::new`]: struct.CString.html#method.new |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::{CString, NulError}; |
| /// |
| /// let _: NulError = CString::new(b"f\0oo".to_vec()).unwrap_err(); |
| /// ``` |
| #[derive(Clone, PartialEq, Eq, Debug)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct NulError(usize, Vec<u8>); |
| |
| /// An error indicating that a nul byte was not in the expected position. |
| /// |
| /// The slice used to create a [`CStr`] must have one and only one nul |
| /// byte at the end of the slice. |
| /// |
| /// This error is created by the |
| /// [`from_bytes_with_nul`][`CStr::from_bytes_with_nul`] method on |
| /// [`CStr`]. See its documentation for more. |
| /// |
| /// [`CStr`]: struct.CStr.html |
| /// [`CStr::from_bytes_with_nul`]: struct.CStr.html#method.from_bytes_with_nul |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::{CStr, FromBytesWithNulError}; |
| /// |
| /// let _: FromBytesWithNulError = CStr::from_bytes_with_nul(b"f\0oo").unwrap_err(); |
| /// ``` |
| #[derive(Clone, PartialEq, Eq, Debug)] |
| #[stable(feature = "cstr_from_bytes", since = "1.10.0")] |
| 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, |
| } |
| } |
| } |
| |
| /// An error indicating invalid UTF-8 when converting a [`CString`] into a [`String`]. |
| /// |
| /// `CString` is just a wrapper over a buffer of bytes with a nul |
| /// terminator; [`into_string`][`CString::into_string`] performs UTF-8 |
| /// validation on those bytes and may return this error. |
| /// |
| /// This `struct` is created by the |
| /// [`into_string`][`CString::into_string`] method on [`CString`]. See |
| /// its documentation for more. |
| /// |
| /// [`String`]: ../string/struct.String.html |
| /// [`CString`]: struct.CString.html |
| /// [`CString::into_string`]: struct.CString.html#method.into_string |
| #[derive(Clone, PartialEq, Eq, Debug)] |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| pub struct IntoStringError { |
| inner: CString, |
| error: Utf8Error, |
| } |
| |
| impl CString { |
| /// Creates a new C-compatible string from a container of bytes. |
| /// |
| /// This function will consume the provided data and use the |
| /// underlying bytes to construct a new string, ensuring that |
| /// there is a trailing 0 byte. This trailing 0 byte will be |
| /// appended by this function; the provided data should *not* |
| /// contain any 0 bytes in it. |
| /// |
| /// # Examples |
| /// |
| /// ```ignore (extern-declaration) |
| /// use std::ffi::CString; |
| /// use std::os::raw::c_char; |
| /// |
| /// extern { fn puts(s: *const c_char); } |
| /// |
| /// let to_print = CString::new("Hello!").expect("CString::new failed"); |
| /// unsafe { |
| /// puts(to_print.as_ptr()); |
| /// } |
| /// ``` |
| /// |
| /// # Errors |
| /// |
| /// This function will return an error if the supplied bytes contain an |
| /// internal 0 byte. The [`NulError`] returned will contain the bytes as well as |
| /// the position of the nul byte. |
| /// |
| /// [`NulError`]: struct.NulError.html |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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 by consuming 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. |
| /// |
| /// [`new`]: #method.new |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let raw = b"foo".to_vec(); |
| /// unsafe { |
| /// let c_string = CString::from_vec_unchecked(raw); |
| /// } |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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 via [`into_raw`]. |
| /// |
| /// 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. |
| /// |
| /// > **Note:** If you need to borrow a string that was allocated by |
| /// > foreign code, use [`CStr`]. If you need to take ownership of |
| /// > a string that was allocated by foreign code, you will need to |
| /// > make your own provisions for freeing it appropriately, likely |
| /// > with the foreign code's API to do that. |
| /// |
| /// [`into_raw`]: #method.into_raw |
| /// [`CStr`]: struct.CStr.html |
| /// |
| /// # Examples |
| /// |
| /// Creates a `CString`, pass ownership to an `extern` function (via raw pointer), then retake |
| /// ownership with `from_raw`: |
| /// |
| /// ```ignore (extern-declaration) |
| /// use std::ffi::CString; |
| /// use std::os::raw::c_char; |
| /// |
| /// extern { |
| /// fn some_extern_function(s: *mut c_char); |
| /// } |
| /// |
| /// let c_string = CString::new("Hello!").expect("CString::new failed"); |
| /// let raw = c_string.into_raw(); |
| /// unsafe { |
| /// some_extern_function(raw); |
| /// let c_string = CString::from_raw(raw); |
| /// } |
| /// ``` |
| #[stable(feature = "cstr_memory", since = "1.4.0")] |
| pub unsafe fn from_raw(ptr: *mut c_char) -> CString { |
| let len = sys::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]) } |
| } |
| |
| /// Consumes the `CString` and transfers ownership of the string to a C caller. |
| /// |
| /// The pointer which this function returns 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. |
| /// |
| /// [`from_raw`]: #method.from_raw |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let c_string = CString::new("foo").expect("CString::new failed"); |
| /// |
| /// let ptr = c_string.into_raw(); |
| /// |
| /// unsafe { |
| /// assert_eq!(b'f', *ptr as u8); |
| /// assert_eq!(b'o', *ptr.offset(1) as u8); |
| /// assert_eq!(b'o', *ptr.offset(2) as u8); |
| /// assert_eq!(b'\0', *ptr.offset(3) as u8); |
| /// |
| /// // retake pointer to free memory |
| /// let _ = CString::from_raw(ptr); |
| /// } |
| /// ``` |
| #[inline] |
| #[stable(feature = "cstr_memory", since = "1.4.0")] |
| 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 UTF-8 data. |
| /// |
| /// On failure, ownership of the original `CString` is returned. |
| /// |
| /// [`String`]: ../string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let valid_utf8 = vec![b'f', b'o', b'o']; |
| /// let cstring = CString::new(valid_utf8).expect("CString::new failed"); |
| /// assert_eq!(cstring.into_string().expect("into_string() call failed"), "foo"); |
| /// |
| /// let invalid_utf8 = vec![b'f', 0xff, b'o', b'o']; |
| /// let cstring = CString::new(invalid_utf8).expect("CString::new failed"); |
| /// let err = cstring.into_string().err().expect("into_string().err() failed"); |
| /// assert_eq!(err.utf8_error().valid_up_to(), 1); |
| /// ``` |
| |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| 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()) }, |
| }) |
| } |
| |
| /// Consumes the `CString` and returns the underlying byte buffer. |
| /// |
| /// The returned buffer does **not** contain the trailing nul |
| /// terminator, and it is guaranteed to not have any interior nul |
| /// bytes. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let c_string = CString::new("foo").expect("CString::new failed"); |
| /// let bytes = c_string.into_bytes(); |
| /// assert_eq!(bytes, vec![b'f', b'o', b'o']); |
| /// ``` |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| 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 terminator. |
| /// |
| /// [`into_bytes`]: #method.into_bytes |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let c_string = CString::new("foo").expect("CString::new failed"); |
| /// let bytes = c_string.into_bytes_with_nul(); |
| /// assert_eq!(bytes, vec![b'f', b'o', b'o', b'\0']); |
| /// ``` |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| 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 |
| /// terminator, and it is guaranteed to not have any interior nul |
| /// bytes. If you need the nul terminator, use |
| /// [`as_bytes_with_nul`] instead. |
| /// |
| /// [`as_bytes_with_nul`]: #method.as_bytes_with_nul |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let c_string = CString::new("foo").expect("CString::new failed"); |
| /// let bytes = c_string.as_bytes(); |
| /// assert_eq!(bytes, &[b'f', b'o', b'o']); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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 terminator. |
| /// |
| /// [`as_bytes`]: #method.as_bytes |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let c_string = CString::new("foo").expect("CString::new failed"); |
| /// let bytes = c_string.as_bytes_with_nul(); |
| /// assert_eq!(bytes, &[b'f', b'o', b'o', b'\0']); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn as_bytes_with_nul(&self) -> &[u8] { |
| &self.inner |
| } |
| |
| /// Extracts a [`CStr`] slice containing the entire string. |
| /// |
| /// [`CStr`]: struct.CStr.html |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::{CString, CStr}; |
| /// |
| /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed"); |
| /// let cstr = c_string.as_c_str(); |
| /// assert_eq!(cstr, |
| /// CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed")); |
| /// ``` |
| #[inline] |
| #[stable(feature = "as_c_str", since = "1.20.0")] |
| pub fn as_c_str(&self) -> &CStr { |
| &*self |
| } |
| |
| /// Converts this `CString` into a boxed [`CStr`]. |
| /// |
| /// [`CStr`]: struct.CStr.html |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::{CString, CStr}; |
| /// |
| /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed"); |
| /// let boxed = c_string.into_boxed_c_str(); |
| /// assert_eq!(&*boxed, |
| /// CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed")); |
| /// ``` |
| #[stable(feature = "into_boxed_c_str", since = "1.20.0")] |
| 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. |
| /// |
| /// [`Drop`]: ../ops/trait.Drop.html |
| fn into_inner(self) -> Box<[u8]> { |
| // Rationale: `mem::forget(self)` invalidates the previous call to `ptr::read(&self.inner)` |
| // so we use `ManuallyDrop` to ensure `self` is not dropped. |
| // Then we can return the box directly without invalidating it. |
| // See https://github.com/rust-lang/rust/issues/62553. |
| let this = mem::ManuallyDrop::new(self); |
| unsafe { ptr::read(&this.inner) } |
| } |
| } |
| |
| // 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. |
| #[stable(feature = "cstring_drop", since = "1.13.0")] |
| impl Drop for CString { |
| #[inline] |
| fn drop(&mut self) { |
| unsafe { *self.inner.get_unchecked_mut(0) = 0; } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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()) } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl fmt::Debug for CString { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| fmt::Debug::fmt(&**self, f) |
| } |
| } |
| |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| impl From<CString> for Vec<u8> { |
| /// Converts a [`CString`] into a [`Vec`]`<u8>`. |
| /// |
| /// The conversion consumes the [`CString`], and removes the terminating NUL byte. |
| /// |
| /// [`Vec`]: ../vec/struct.Vec.html |
| /// [`CString`]: ../ffi/struct.CString.html |
| #[inline] |
| fn from(s: CString) -> Vec<u8> { |
| s.into_bytes() |
| } |
| } |
| |
| #[stable(feature = "cstr_debug", since = "1.3.0")] |
| 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, "\"") |
| } |
| } |
| |
| #[stable(feature = "cstr_default", since = "1.10.0")] |
| impl Default for &CStr { |
| fn default() -> Self { |
| const SLICE: &[c_char] = &[0]; |
| unsafe { CStr::from_ptr(SLICE.as_ptr()) } |
| } |
| } |
| |
| #[stable(feature = "cstr_default", since = "1.10.0")] |
| impl Default for CString { |
| /// Creates an empty `CString`. |
| fn default() -> CString { |
| let a: &CStr = Default::default(); |
| a.to_owned() |
| } |
| } |
| |
| #[stable(feature = "cstr_borrow", since = "1.3.0")] |
| impl Borrow<CStr> for CString { |
| #[inline] |
| fn borrow(&self) -> &CStr { self } |
| } |
| |
| #[stable(feature = "cstring_from_cow_cstr", since = "1.28.0")] |
| impl<'a> From<Cow<'a, CStr>> for CString { |
| #[inline] |
| fn from(s: Cow<'a, CStr>) -> Self { |
| s.into_owned() |
| } |
| } |
| |
| #[stable(feature = "box_from_c_str", since = "1.17.0")] |
| impl From<&CStr> for Box<CStr> { |
| fn from(s: &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) } |
| } |
| } |
| |
| #[stable(feature = "c_string_from_box", since = "1.18.0")] |
| impl From<Box<CStr>> for CString { |
| /// Converts a [`Box`]`<CStr>` into a [`CString`] without copying or allocating. |
| /// |
| /// [`Box`]: ../boxed/struct.Box.html |
| /// [`CString`]: ../ffi/struct.CString.html |
| #[inline] |
| fn from(s: Box<CStr>) -> CString { |
| s.into_c_string() |
| } |
| } |
| |
| #[stable(feature = "more_box_slice_clone", since = "1.29.0")] |
| impl Clone for Box<CStr> { |
| #[inline] |
| fn clone(&self) -> Self { |
| (**self).into() |
| } |
| } |
| |
| #[stable(feature = "box_from_c_string", since = "1.20.0")] |
| impl From<CString> for Box<CStr> { |
| /// Converts a [`CString`] into a [`Box`]`<CStr>` without copying or allocating. |
| /// |
| /// [`CString`]: ../ffi/struct.CString.html |
| /// [`Box`]: ../boxed/struct.Box.html |
| #[inline] |
| fn from(s: CString) -> Box<CStr> { |
| s.into_boxed_c_str() |
| } |
| } |
| |
| #[stable(feature = "cow_from_cstr", since = "1.28.0")] |
| impl<'a> From<CString> for Cow<'a, CStr> { |
| #[inline] |
| fn from(s: CString) -> Cow<'a, CStr> { |
| Cow::Owned(s) |
| } |
| } |
| |
| #[stable(feature = "cow_from_cstr", since = "1.28.0")] |
| impl<'a> From<&'a CStr> for Cow<'a, CStr> { |
| #[inline] |
| fn from(s: &'a CStr) -> Cow<'a, CStr> { |
| Cow::Borrowed(s) |
| } |
| } |
| |
| #[stable(feature = "cow_from_cstr", since = "1.28.0")] |
| impl<'a> From<&'a CString> for Cow<'a, CStr> { |
| #[inline] |
| fn from(s: &'a CString) -> Cow<'a, CStr> { |
| Cow::Borrowed(s.as_c_str()) |
| } |
| } |
| |
| #[stable(feature = "shared_from_slice2", since = "1.24.0")] |
| impl From<CString> for Arc<CStr> { |
| /// Converts a [`CString`] into a [`Arc`]`<CStr>` without copying or allocating. |
| /// |
| /// [`CString`]: ../ffi/struct.CString.html |
| /// [`Arc`]: ../sync/struct.Arc.html |
| #[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) } |
| } |
| } |
| |
| #[stable(feature = "shared_from_slice2", since = "1.24.0")] |
| impl From<&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) } |
| } |
| } |
| |
| #[stable(feature = "shared_from_slice2", since = "1.24.0")] |
| impl From<CString> for Rc<CStr> { |
| /// Converts a [`CString`] into a [`Rc`]`<CStr>` without copying or allocating. |
| /// |
| /// [`CString`]: ../ffi/struct.CString.html |
| /// [`Rc`]: ../rc/struct.Rc.html |
| #[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) } |
| } |
| } |
| |
| #[stable(feature = "shared_from_slice2", since = "1.24.0")] |
| impl From<&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) } |
| } |
| } |
| |
| #[stable(feature = "default_box_extra", since = "1.17.0")] |
| 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 caused |
| /// [`CString::new`] to fail. |
| /// |
| /// [`CString::new`]: struct.CString.html#method.new |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let nul_error = CString::new("foo\0bar").unwrap_err(); |
| /// assert_eq!(nul_error.nul_position(), 3); |
| /// |
| /// let nul_error = CString::new("foo bar\0").unwrap_err(); |
| /// assert_eq!(nul_error.nul_position(), 7); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let nul_error = CString::new("foo\0bar").unwrap_err(); |
| /// assert_eq!(nul_error.into_vec(), b"foo\0bar"); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn into_vec(self) -> Vec<u8> { self.1 } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Error for NulError { |
| fn description(&self) -> &str { "nul byte found in data" } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl From<NulError> for io::Error { |
| /// Converts a [`NulError`] into a [`io::Error`]. |
| /// |
| /// [`NulError`]: ../ffi/struct.NulError.html |
| /// [`io::Error`]: ../io/struct.Error.html |
| fn from(_: NulError) -> io::Error { |
| io::Error::new(io::ErrorKind::InvalidInput, |
| "data provided contains a nul byte") |
| } |
| } |
| |
| #[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] |
| impl Error for FromBytesWithNulError { |
| fn description(&self) -> &str { |
| match self.kind { |
| FromBytesWithNulErrorKind::InteriorNul(..) => |
| "data provided contains an interior nul byte", |
| FromBytesWithNulErrorKind::NotNulTerminated => |
| "data provided is not nul terminated", |
| } |
| } |
| } |
| |
| #[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] |
| 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. |
| /// |
| /// [`CString`]: struct.CString.html |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| pub fn into_cstring(self) -> CString { |
| self.inner |
| } |
| |
| /// Access the underlying UTF-8 error that was the cause of this error. |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| pub fn utf8_error(&self) -> Utf8Error { |
| self.error |
| } |
| } |
| |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| impl Error for IntoStringError { |
| fn description(&self) -> &str { |
| "C string contained non-utf8 bytes" |
| } |
| |
| fn cause(&self) -> Option<&dyn Error> { |
| Some(&self.error) |
| } |
| } |
| |
| #[stable(feature = "cstring_into", since = "1.7.0")] |
| 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. The total |
| /// size of the raw C string must be smaller than `isize::MAX` **bytes** |
| /// in memory due to calling the `slice::from_raw_parts` function. |
| /// 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. |
| /// |
| /// # Examples |
| /// |
| /// ```ignore (extern-declaration) |
| /// # fn main() { |
| /// use std::ffi::CStr; |
| /// use std::os::raw::c_char; |
| /// |
| /// extern { |
| /// fn my_string() -> *const c_char; |
| /// } |
| /// |
| /// unsafe { |
| /// let slice = CStr::from_ptr(my_string()); |
| /// println!("string returned: {}", slice.to_str().unwrap()); |
| /// } |
| /// # } |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr { |
| let len = sys::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. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"hello\0"); |
| /// assert!(cstr.is_ok()); |
| /// ``` |
| /// |
| /// Creating a `CStr` without a trailing nul terminator is an error: |
| /// |
| /// ``` |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"hello"); |
| /// assert!(cstr.is_err()); |
| /// ``` |
| /// |
| /// Creating a `CStr` with an interior nul byte is an error: |
| /// |
| /// ``` |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"he\0llo\0"); |
| /// assert!(cstr.is_err()); |
| /// ``` |
| #[stable(feature = "cstr_from_bytes", since = "1.10.0")] |
| 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. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::{CStr, CString}; |
| /// |
| /// unsafe { |
| /// let cstring = CString::new("hello").expect("CString::new failed"); |
| /// let cstr = CStr::from_bytes_with_nul_unchecked(cstring.to_bytes_with_nul()); |
| /// assert_eq!(cstr, &*cstring); |
| /// } |
| /// ``` |
| #[inline] |
| #[stable(feature = "cstr_from_bytes", since = "1.10.0")] |
| #[rustc_const_unstable(feature = "const_cstr_unchecked")] |
| pub const 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. |
| /// |
| /// **WARNING** |
| /// |
| /// The returned pointer is read-only; writing to it (including passing it |
| /// to C code that writes to it) causes undefined behavior. |
| /// |
| /// It is your responsibility to make sure that the underlying memory is not |
| /// freed too early. For example, the following code will cause undefined |
| /// behavior when `ptr` is used inside the `unsafe` block: |
| /// |
| /// ```no_run |
| /// # #![allow(unused_must_use)] |
| /// use std::ffi::CString; |
| /// |
| /// let ptr = CString::new("Hello").expect("CString::new failed").as_ptr(); |
| /// unsafe { |
| /// // `ptr` is dangling |
| /// *ptr; |
| /// } |
| /// ``` |
| /// |
| /// This happens because the pointer returned by `as_ptr` does not carry any |
| /// lifetime information and the [`CString`] is deallocated immediately after |
| /// the `CString::new("Hello").expect("CString::new failed").as_ptr()` expression is evaluated. |
| /// To fix the problem, bind the `CString` to a local variable: |
| /// |
| /// ```no_run |
| /// # #![allow(unused_must_use)] |
| /// use std::ffi::CString; |
| /// |
| /// let hello = CString::new("Hello").expect("CString::new failed"); |
| /// let ptr = hello.as_ptr(); |
| /// unsafe { |
| /// // `ptr` is valid because `hello` is in scope |
| /// *ptr; |
| /// } |
| /// ``` |
| /// |
| /// This way, the lifetime of the `CString` in `hello` encompasses |
| /// the lifetime of `ptr` and the `unsafe` block. |
| /// |
| /// [`CString`]: struct.CString.html |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub const 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. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"); |
| /// assert_eq!(cstr.to_bytes(), b"foo"); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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 |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"); |
| /// assert_eq!(cstr.to_bytes_with_nul(), b"foo\0"); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| 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 |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"); |
| /// assert_eq!(cstr.to_str(), Ok("foo")); |
| /// ``` |
| #[stable(feature = "cstr_to_str", since = "1.4.0")] |
| pub fn to_str(&self) -> Result<&str, str::Utf8Error> { |
| // N.B., 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 corresponding [`&str`] slice. Otherwise, it will |
| /// replace any invalid UTF-8 sequences with |
| /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD] 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 |
| /// [`Owned`]: ../borrow/enum.Cow.html#variant.Owned |
| /// [`str`]: ../primitive.str.html |
| /// [`String`]: ../string/struct.String.html |
| /// [U+FFFD]: ../char/constant.REPLACEMENT_CHARACTER.html |
| /// |
| /// # Examples |
| /// |
| /// Calling `to_string_lossy` on a `CStr` containing valid UTF-8: |
| /// |
| /// ``` |
| /// use std::borrow::Cow; |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"Hello World\0") |
| /// .expect("CStr::from_bytes_with_nul failed"); |
| /// assert_eq!(cstr.to_string_lossy(), Cow::Borrowed("Hello World")); |
| /// ``` |
| /// |
| /// Calling `to_string_lossy` on a `CStr` containing invalid UTF-8: |
| /// |
| /// ``` |
| /// use std::borrow::Cow; |
| /// use std::ffi::CStr; |
| /// |
| /// let cstr = CStr::from_bytes_with_nul(b"Hello \xF0\x90\x80World\0") |
| /// .expect("CStr::from_bytes_with_nul failed"); |
| /// assert_eq!( |
| /// cstr.to_string_lossy(), |
| /// Cow::Owned(String::from("Hello �World")) as Cow<'_, str> |
| /// ); |
| /// ``` |
| #[stable(feature = "cstr_to_str", since = "1.4.0")] |
| 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 |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ffi::CString; |
| /// |
| /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed"); |
| /// let boxed = c_string.into_boxed_c_str(); |
| /// assert_eq!(boxed.into_c_string(), CString::new("foo").expect("CString::new failed")); |
| /// ``` |
| #[stable(feature = "into_boxed_c_str", since = "1.20.0")] |
| 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) } } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl PartialEq for CStr { |
| fn eq(&self, other: &CStr) -> bool { |
| self.to_bytes().eq(other.to_bytes()) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Eq for CStr {} |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl PartialOrd for CStr { |
| fn partial_cmp(&self, other: &CStr) -> Option<Ordering> { |
| self.to_bytes().partial_cmp(&other.to_bytes()) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Ord for CStr { |
| fn cmp(&self, other: &CStr) -> Ordering { |
| self.to_bytes().cmp(&other.to_bytes()) |
| } |
| } |
| |
| #[stable(feature = "cstr_borrow", since = "1.3.0")] |
| impl ToOwned for CStr { |
| type Owned = CString; |
| |
| fn to_owned(&self) -> CString { |
| CString { inner: self.to_bytes_with_nul().into() } |
| } |
| } |
| |
| #[stable(feature = "cstring_asref", since = "1.7.0")] |
| impl From<&CStr> for CString { |
| fn from(s: &CStr) -> CString { |
| s.to_owned() |
| } |
| } |
| |
| #[stable(feature = "cstring_asref", since = "1.7.0")] |
| impl ops::Index<ops::RangeFull> for CString { |
| type Output = CStr; |
| |
| #[inline] |
| fn index(&self, _index: ops::RangeFull) -> &CStr { |
| self |
| } |
| } |
| |
| #[stable(feature = "cstring_asref", since = "1.7.0")] |
| impl AsRef<CStr> for CStr { |
| #[inline] |
| fn as_ref(&self) -> &CStr { |
| self |
| } |
| } |
| |
| #[stable(feature = "cstring_asref", since = "1.7.0")] |
| impl AsRef<CStr> for CString { |
| #[inline] |
| fn as_ref(&self) -> &CStr { |
| self |
| } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::*; |
| use crate::os::raw::c_char; |
| use crate::borrow::Cow::{Borrowed, Owned}; |
| use crate::hash::{Hash, Hasher}; |
| use crate::collections::hash_map::DefaultHasher; |
| use crate::rc::Rc; |
| use crate::sync::Arc; |
| |
| #[test] |
| fn c_to_rust() { |
| let data = b"123\0"; |
| let ptr = data.as_ptr() as *const c_char; |
| unsafe { |
| assert_eq!(CStr::from_ptr(ptr).to_bytes(), b"123"); |
| assert_eq!(CStr::from_ptr(ptr).to_bytes_with_nul(), b"123\0"); |
| } |
| } |
| |
| #[test] |
| fn simple() { |
| let s = CString::new("1234").unwrap(); |
| assert_eq!(s.as_bytes(), b"1234"); |
| assert_eq!(s.as_bytes_with_nul(), b"1234\0"); |
| } |
| |
| #[test] |
| fn build_with_zero1() { |
| assert!(CString::new(&b"\0"[..]).is_err()); |
| } |
| #[test] |
| fn build_with_zero2() { |
| assert!(CString::new(vec![0]).is_err()); |
| } |
| |
| #[test] |
| fn build_with_zero3() { |
| unsafe { |
| let s = CString::from_vec_unchecked(vec![0]); |
| assert_eq!(s.as_bytes(), b"\0"); |
| } |
| } |
| |
| #[test] |
| fn formatted() { |
| let s = CString::new(&b"abc\x01\x02\n\xE2\x80\xA6\xFF"[..]).unwrap(); |
| assert_eq!(format!("{:?}", s), r#""abc\x01\x02\n\xe2\x80\xa6\xff""#); |
| } |
| |
| #[test] |
| fn borrowed() { |
| unsafe { |
| let s = CStr::from_ptr(b"12\0".as_ptr() as *const _); |
| assert_eq!(s.to_bytes(), b"12"); |
| assert_eq!(s.to_bytes_with_nul(), b"12\0"); |
| } |
| } |
| |
| #[test] |
| fn to_str() { |
| let data = b"123\xE2\x80\xA6\0"; |
| let ptr = data.as_ptr() as *const c_char; |
| unsafe { |
| assert_eq!(CStr::from_ptr(ptr).to_str(), Ok("123…")); |
| assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Borrowed("123…")); |
| } |
| let data = b"123\xE2\0"; |
| let ptr = data.as_ptr() as *const c_char; |
| unsafe { |
| assert!(CStr::from_ptr(ptr).to_str().is_err()); |
| assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Owned::<str>(format!("123\u{FFFD}"))); |
| } |
| } |
| |
| #[test] |
| fn to_owned() { |
| let data = b"123\0"; |
| let ptr = data.as_ptr() as *const c_char; |
| |
| let owned = unsafe { CStr::from_ptr(ptr).to_owned() }; |
| assert_eq!(owned.as_bytes_with_nul(), data); |
| } |
| |
| #[test] |
| fn equal_hash() { |
| let data = b"123\xE2\xFA\xA6\0"; |
| let ptr = data.as_ptr() as *const c_char; |
| let cstr: &'static CStr = unsafe { CStr::from_ptr(ptr) }; |
| |
| let mut s = DefaultHasher::new(); |
| cstr.hash(&mut s); |
| let cstr_hash = s.finish(); |
| let mut s = DefaultHasher::new(); |
| CString::new(&data[..data.len() - 1]).unwrap().hash(&mut s); |
| let cstring_hash = s.finish(); |
| |
| 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), Ok(&b"123"[..])); |
| let cstr = CStr::from_bytes_with_nul(data); |
| assert_eq!(cstr.map(CStr::to_bytes_with_nul), Ok(&b"123\0"[..])); |
| |
| unsafe { |
| let cstr = CStr::from_bytes_with_nul(data); |
| let cstr_unchecked = CStr::from_bytes_with_nul_unchecked(data); |
| assert_eq!(cstr, Ok(cstr_unchecked)); |
| } |
| } |
| |
| #[test] |
| fn from_bytes_with_nul_unterminated() { |
| let data = b"123"; |
| let cstr = CStr::from_bytes_with_nul(data); |
| assert!(cstr.is_err()); |
| } |
| |
| #[test] |
| fn from_bytes_with_nul_interior() { |
| let data = b"1\023\0"; |
| let cstr = CStr::from_bytes_with_nul(data); |
| assert!(cstr.is_err()); |
| } |
| |
| #[test] |
| fn into_boxed() { |
| let orig: &[u8] = b"Hello, world!\0"; |
| let cstr = CStr::from_bytes_with_nul(orig).unwrap(); |
| let boxed: Box<CStr> = Box::from(cstr); |
| let cstring = cstr.to_owned().into_boxed_c_str().into_c_string(); |
| assert_eq!(cstr, &*boxed); |
| assert_eq!(&*boxed, &*cstring); |
| assert_eq!(&*cstring, cstr); |
| } |
| |
| #[test] |
| fn boxed_default() { |
| let boxed = <Box<CStr>>::default(); |
| assert_eq!(boxed.to_bytes_with_nul(), &[0]); |
| } |
| |
| #[test] |
| fn into_rc() { |
| let orig: &[u8] = b"Hello, world!\0"; |
| let cstr = CStr::from_bytes_with_nul(orig).unwrap(); |
| let rc: Rc<CStr> = Rc::from(cstr); |
| let arc: Arc<CStr> = Arc::from(cstr); |
| |
| assert_eq!(&*rc, cstr); |
| assert_eq!(&*arc, cstr); |
| |
| let rc2: Rc<CStr> = Rc::from(cstr.to_owned()); |
| let arc2: Arc<CStr> = Arc::from(cstr.to_owned()); |
| |
| assert_eq!(&*rc2, cstr); |
| assert_eq!(&*arc2, cstr); |
| } |
| |
| #[test] |
| fn cstr_const_constructor() { |
| const CSTR: &CStr = unsafe { |
| CStr::from_bytes_with_nul_unchecked(b"Hello, world!\0") |
| }; |
| |
| assert_eq!(CSTR.to_str().unwrap(), "Hello, world!"); |
| } |
| } |