1007 lines
32 KiB
Rust
1007 lines
32 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use ascii;
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use borrow::{Cow, Borrow};
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use cmp::Ordering;
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use error::Error;
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use fmt::{self, Write};
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use io;
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use libc;
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use mem;
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use memchr;
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use ops;
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use os::raw::c_char;
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use ptr;
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use slice;
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use str::{self, Utf8Error};
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/// A type representing an owned C-compatible string.
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///
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/// This type serves the primary purpose of being able to safely generate a
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/// C-compatible string from a Rust byte slice or vector. An instance of this
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/// type is a static guarantee that the underlying bytes contain no interior 0
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/// bytes and the final byte is 0.
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///
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/// A `CString` is created from either a byte slice or a byte vector. A [`u8`]
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/// slice can be obtained with the `as_bytes` method. Slices produced from a
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/// `CString` do *not* contain the trailing nul terminator unless otherwise
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/// specified.
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///
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/// [`u8`]: ../primitive.u8.html
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///
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/// # Examples
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///
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/// ```no_run
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/// # fn main() {
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/// use std::ffi::CString;
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/// use std::os::raw::c_char;
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///
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/// extern {
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/// fn my_printer(s: *const c_char);
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/// }
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///
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/// let c_to_print = CString::new("Hello, world!").unwrap();
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/// unsafe {
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/// my_printer(c_to_print.as_ptr());
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/// }
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/// # }
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/// ```
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///
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/// # Safety
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///
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/// `CString` is intended for working with traditional C-style strings
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/// (a sequence of non-null bytes terminated by a single null byte); the
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/// primary use case for these kinds of strings is interoperating with C-like
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/// code. Often you will need to transfer ownership to/from that external
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/// code. It is strongly recommended that you thoroughly read through the
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/// documentation of `CString` before use, as improper ownership management
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/// of `CString` instances can lead to invalid memory accesses, memory leaks,
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/// and other memory errors.
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#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct CString {
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// Invariant 1: the slice ends with a zero byte and has a length of at least one.
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// Invariant 2: the slice contains only one zero byte.
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// Improper usage of unsafe function can break Invariant 2, but not Invariant 1.
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inner: Box<[u8]>,
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}
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/// Representation of a borrowed C string.
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///
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/// This dynamically sized type is only safely constructed via a borrowed
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/// version of an instance of `CString`. This type can be constructed from a raw
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/// C string as well and represents a C string borrowed from another location.
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///
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/// Note that this structure is **not** `repr(C)` and is not recommended to be
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/// placed in the signatures of FFI functions. Instead safe wrappers of FFI
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/// functions may leverage the unsafe [`from_ptr`] constructor to provide a safe
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/// interface to other consumers.
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///
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/// [`from_ptr`]: #method.from_ptr
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///
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/// # Examples
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///
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/// Inspecting a foreign C string:
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///
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/// ```no_run
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/// use std::ffi::CStr;
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/// use std::os::raw::c_char;
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///
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/// extern { fn my_string() -> *const c_char; }
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///
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/// unsafe {
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/// let slice = CStr::from_ptr(my_string());
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/// println!("string length: {}", slice.to_bytes().len());
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/// }
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/// ```
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///
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/// Passing a Rust-originating C string:
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///
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/// ```no_run
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/// use std::ffi::{CString, CStr};
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/// use std::os::raw::c_char;
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///
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/// fn work(data: &CStr) {
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/// extern { fn work_with(data: *const c_char); }
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///
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/// unsafe { work_with(data.as_ptr()) }
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/// }
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///
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/// let s = CString::new("data data data data").unwrap();
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/// work(&s);
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/// ```
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///
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/// Converting a foreign C string into a Rust [`String`]:
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///
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/// [`String`]: ../string/struct.String.html
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///
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/// ```no_run
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/// use std::ffi::CStr;
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/// use std::os::raw::c_char;
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///
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/// extern { fn my_string() -> *const c_char; }
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///
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/// fn my_string_safe() -> String {
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/// unsafe {
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/// CStr::from_ptr(my_string()).to_string_lossy().into_owned()
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/// }
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/// }
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///
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/// println!("string: {}", my_string_safe());
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/// ```
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#[derive(Hash)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct CStr {
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// FIXME: this should not be represented with a DST slice but rather with
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// just a raw `c_char` along with some form of marker to make
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// this an unsized type. Essentially `sizeof(&CStr)` should be the
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// same as `sizeof(&c_char)` but `CStr` should be an unsized type.
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inner: [c_char]
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}
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/// An error returned from [`CString::new`] to indicate that a nul byte was found
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/// in the vector provided.
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///
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/// [`CString::new`]: struct.CString.html#method.new
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#[derive(Clone, PartialEq, Eq, Debug)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct NulError(usize, Vec<u8>);
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/// An error returned from [`CStr::from_bytes_with_nul`] to indicate that a nul
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/// byte was found too early in the slice provided or one wasn't found at all.
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///
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/// [`CStr::from_bytes_with_nul`]: struct.CStr.html#method.from_bytes_with_nul
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#[derive(Clone, PartialEq, Eq, Debug)]
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#[stable(feature = "cstr_from_bytes", since = "1.10.0")]
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pub struct FromBytesWithNulError {
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kind: FromBytesWithNulErrorKind,
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}
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#[derive(Clone, PartialEq, Eq, Debug)]
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enum FromBytesWithNulErrorKind {
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InteriorNul(usize),
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NotNulTerminated,
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}
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impl FromBytesWithNulError {
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fn interior_nul(pos: usize) -> FromBytesWithNulError {
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FromBytesWithNulError {
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kind: FromBytesWithNulErrorKind::InteriorNul(pos),
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}
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}
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fn not_nul_terminated() -> FromBytesWithNulError {
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FromBytesWithNulError {
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kind: FromBytesWithNulErrorKind::NotNulTerminated,
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}
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}
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}
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/// An error returned from [`CString::into_string`] to indicate that a UTF-8 error
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/// was encountered during the conversion.
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///
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/// [`CString::into_string`]: struct.CString.html#method.into_string
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#[derive(Clone, PartialEq, Eq, Debug)]
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#[stable(feature = "cstring_into", since = "1.7.0")]
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pub struct IntoStringError {
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inner: CString,
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error: Utf8Error,
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}
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impl CString {
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/// Creates a new C-compatible string from a container of bytes.
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///
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/// This method will consume the provided data and use the underlying bytes
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/// to construct a new string, ensuring that there is a trailing 0 byte.
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///
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/// # Examples
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///
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/// ```no_run
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/// use std::ffi::CString;
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/// use std::os::raw::c_char;
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///
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/// extern { fn puts(s: *const c_char); }
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///
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/// let to_print = CString::new("Hello!").unwrap();
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/// unsafe {
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/// puts(to_print.as_ptr());
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/// }
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/// ```
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///
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/// # Errors
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///
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/// This function will return an error if the bytes yielded contain an
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/// internal 0 byte. The error returned will contain the bytes as well as
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/// the position of the nul byte.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> {
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Self::_new(t.into())
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}
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fn _new(bytes: Vec<u8>) -> Result<CString, NulError> {
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match memchr::memchr(0, &bytes) {
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Some(i) => Err(NulError(i, bytes)),
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None => Ok(unsafe { CString::from_vec_unchecked(bytes) }),
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}
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}
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/// Creates a C-compatible string from a byte vector without checking for
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/// interior 0 bytes.
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///
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/// This method is equivalent to [`new`] except that no runtime assertion
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/// is made that `v` contains no 0 bytes, and it requires an actual
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/// byte vector, not anything that can be converted to one with Into.
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///
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/// [`new`]: #method.new
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///
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/// # Examples
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///
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/// ```
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/// use std::ffi::CString;
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///
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/// let raw = b"foo".to_vec();
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/// unsafe {
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/// let c_string = CString::from_vec_unchecked(raw);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub unsafe fn from_vec_unchecked(mut v: Vec<u8>) -> CString {
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v.reserve_exact(1);
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v.push(0);
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CString { inner: v.into_boxed_slice() }
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}
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/// Retakes ownership of a `CString` that was transferred to C.
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///
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/// Additionally, the length of the string will be recalculated from the pointer.
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///
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/// # Safety
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///
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/// This should only ever be called with a pointer that was earlier
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/// obtained by calling [`into_raw`] on a `CString`. Other usage (e.g. trying to take
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/// ownership of a string that was allocated by foreign code) is likely to lead
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/// to undefined behavior or allocator corruption.
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///
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/// [`into_raw`]: #method.into_raw
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#[stable(feature = "cstr_memory", since = "1.4.0")]
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pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
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let len = libc::strlen(ptr) + 1; // Including the NUL byte
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let slice = slice::from_raw_parts(ptr, len as usize);
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CString { inner: mem::transmute(slice) }
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}
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/// Transfers ownership of the string to a C caller.
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///
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/// The pointer must be returned to Rust and reconstituted using
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/// [`from_raw`] to be properly deallocated. Specifically, one
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/// should *not* use the standard C `free` function to deallocate
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/// this string.
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///
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/// Failure to call [`from_raw`] will lead to a memory leak.
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///
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/// [`from_raw`]: #method.from_raw
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#[stable(feature = "cstr_memory", since = "1.4.0")]
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pub fn into_raw(self) -> *mut c_char {
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Box::into_raw(self.into_inner()) as *mut c_char
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}
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/// Converts the `CString` into a [`String`] if it contains valid Unicode data.
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///
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/// On failure, ownership of the original `CString` is returned.
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///
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/// [`String`]: ../string/struct.String.html
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#[stable(feature = "cstring_into", since = "1.7.0")]
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pub fn into_string(self) -> Result<String, IntoStringError> {
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String::from_utf8(self.into_bytes())
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.map_err(|e| IntoStringError {
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error: e.utf8_error(),
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inner: unsafe { CString::from_vec_unchecked(e.into_bytes()) },
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})
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}
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/// Returns the underlying byte buffer.
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///
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/// The returned buffer does **not** contain the trailing nul separator and
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/// it is guaranteed to not have any interior nul bytes.
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#[stable(feature = "cstring_into", since = "1.7.0")]
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pub fn into_bytes(self) -> Vec<u8> {
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let mut vec = self.into_inner().into_vec();
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let _nul = vec.pop();
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debug_assert_eq!(_nul, Some(0u8));
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vec
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}
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/// Equivalent to the [`into_bytes`] function except that the returned vector
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/// includes the trailing nul byte.
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///
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/// [`into_bytes`]: #method.into_bytes
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#[stable(feature = "cstring_into", since = "1.7.0")]
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pub fn into_bytes_with_nul(self) -> Vec<u8> {
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self.into_inner().into_vec()
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}
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/// Returns the contents of this `CString` as a slice of bytes.
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///
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/// The returned slice does **not** contain the trailing nul separator and
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/// it is guaranteed to not have any interior nul bytes.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn as_bytes(&self) -> &[u8] {
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&self.inner[..self.inner.len() - 1]
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}
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/// Equivalent to the [`as_bytes`] function except that the returned slice
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/// includes the trailing nul byte.
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///
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/// [`as_bytes`]: #method.as_bytes
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn as_bytes_with_nul(&self) -> &[u8] {
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&self.inner
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}
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/// Extracts a [`CStr`] slice containing the entire string.
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///
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/// [`CStr`]: struct.CStr.html
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#[unstable(feature = "as_c_str", issue = "40380")]
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pub fn as_c_str(&self) -> &CStr {
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&*self
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}
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/// Converts this `CString` into a boxed [`CStr`].
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///
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/// [`CStr`]: struct.CStr.html
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#[unstable(feature = "into_boxed_c_str", issue = "40380")]
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pub fn into_boxed_c_str(self) -> Box<CStr> {
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unsafe { mem::transmute(self.into_inner()) }
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}
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// Bypass "move out of struct which implements [`Drop`] trait" restriction.
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///
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/// [`Drop`]: ../ops/trait.Drop.html
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fn into_inner(self) -> Box<[u8]> {
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unsafe {
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let result = ptr::read(&self.inner);
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mem::forget(self);
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result
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}
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}
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}
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// Turns this `CString` into an empty string to prevent
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// memory unsafe code from working by accident. Inline
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// to prevent LLVM from optimizing it away in debug builds.
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#[stable(feature = "cstring_drop", since = "1.13.0")]
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impl Drop for CString {
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#[inline]
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fn drop(&mut self) {
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unsafe { *self.inner.get_unchecked_mut(0) = 0; }
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl ops::Deref for CString {
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type Target = CStr;
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fn deref(&self) -> &CStr {
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unsafe { CStr::from_bytes_with_nul_unchecked(self.as_bytes_with_nul()) }
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl fmt::Debug for CString {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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fmt::Debug::fmt(&**self, f)
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}
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}
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#[stable(feature = "cstring_into", since = "1.7.0")]
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impl From<CString> for Vec<u8> {
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fn from(s: CString) -> Vec<u8> {
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s.into_bytes()
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}
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}
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#[stable(feature = "cstr_debug", since = "1.3.0")]
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impl fmt::Debug for CStr {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "\"")?;
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for byte in self.to_bytes().iter().flat_map(|&b| ascii::escape_default(b)) {
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f.write_char(byte as char)?;
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}
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write!(f, "\"")
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}
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}
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#[stable(feature = "cstr_default", since = "1.10.0")]
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impl<'a> Default for &'a CStr {
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fn default() -> &'a CStr {
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static SLICE: &'static [c_char] = &[0];
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unsafe { CStr::from_ptr(SLICE.as_ptr()) }
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}
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}
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#[stable(feature = "cstr_default", since = "1.10.0")]
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impl Default for CString {
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/// Creates an empty `CString`.
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fn default() -> CString {
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let a: &CStr = Default::default();
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a.to_owned()
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}
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}
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#[stable(feature = "cstr_borrow", since = "1.3.0")]
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impl Borrow<CStr> for CString {
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fn borrow(&self) -> &CStr { self }
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}
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#[stable(feature = "box_from_c_str", since = "1.17.0")]
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impl<'a> From<&'a CStr> for Box<CStr> {
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fn from(s: &'a CStr) -> Box<CStr> {
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let boxed: Box<[u8]> = Box::from(s.to_bytes_with_nul());
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unsafe { mem::transmute(boxed) }
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}
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}
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#[stable(feature = "c_string_from_box", since = "1.18.0")]
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impl From<Box<CStr>> for CString {
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fn from(s: Box<CStr>) -> CString {
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s.into_c_string()
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}
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}
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#[stable(feature = "box_from_c_string", since = "1.18.0")]
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impl Into<Box<CStr>> for CString {
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fn into(self) -> Box<CStr> {
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self.into_boxed_c_str()
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}
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}
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#[stable(feature = "default_box_extra", since = "1.17.0")]
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impl Default for Box<CStr> {
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fn default() -> Box<CStr> {
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let boxed: Box<[u8]> = Box::from([0]);
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unsafe { mem::transmute(boxed) }
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}
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}
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impl NulError {
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/// Returns the position of the nul byte in the slice that was provided to
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/// [`CString::new`].
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///
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/// [`CString::new`]: struct.CString.html#method.new
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///
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/// # Examples
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///
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/// ```
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/// use std::ffi::CString;
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///
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/// 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 {
|
|
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<&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 {
|
|
/// Casts a raw C string to a safe C string wrapper.
|
|
///
|
|
/// This function will cast the provided `ptr` to the `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.
|
|
///
|
|
/// > **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
|
|
///
|
|
/// ```no_run
|
|
/// # 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 = 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 it is null 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());
|
|
/// ```
|
|
#[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 null terminated
|
|
/// and not contain any interior nul bytes.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::ffi::{CStr, CString};
|
|
///
|
|
/// unsafe {
|
|
/// let cstring = CString::new("hello").unwrap();
|
|
/// let cstr = CStr::from_bytes_with_nul_unchecked(cstring.to_bytes_with_nul());
|
|
/// assert_eq!(cstr, &*cstring);
|
|
/// }
|
|
/// ```
|
|
#[stable(feature = "cstr_from_bytes", since = "1.10.0")]
|
|
pub unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
|
|
mem::transmute(bytes)
|
|
}
|
|
|
|
/// Returns the inner pointer to this C string.
|
|
///
|
|
/// The returned pointer will be valid for as long as `self` is and points
|
|
/// to a contiguous region of memory terminated with a 0 byte to represent
|
|
/// the end of the string.
|
|
///
|
|
/// **WARNING**
|
|
///
|
|
/// It is your responsibility to make sure that the underlying memory is not
|
|
/// freed too early. For example, the following code will cause undefined
|
|
/// behaviour when `ptr` is used inside the `unsafe` block:
|
|
///
|
|
/// ```no_run
|
|
/// use std::ffi::{CString};
|
|
///
|
|
/// let ptr = CString::new("Hello").unwrap().as_ptr();
|
|
/// unsafe {
|
|
/// // `ptr` is dangling
|
|
/// *ptr;
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// This happens because the pointer returned by `as_ptr` does not carry any
|
|
/// lifetime information and the string is deallocated immediately after
|
|
/// the `CString::new("Hello").unwrap().as_ptr()` expression is evaluated.
|
|
/// To fix the problem, bind the string to a local variable:
|
|
///
|
|
/// ```no_run
|
|
/// use std::ffi::{CString};
|
|
///
|
|
/// let hello = CString::new("Hello").unwrap();
|
|
/// let ptr = hello.as_ptr();
|
|
/// unsafe {
|
|
/// // `ptr` is valid because `hello` is in scope
|
|
/// *ptr;
|
|
/// }
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn as_ptr(&self) -> *const c_char {
|
|
self.inner.as_ptr()
|
|
}
|
|
|
|
/// Converts this C string to a byte slice.
|
|
///
|
|
/// This function will calculate the length of this string (which normally
|
|
/// requires a linear amount of work to be done) and then return the
|
|
/// resulting slice of `u8` elements.
|
|
///
|
|
/// The returned slice will **not** contain the trailing nul that this C
|
|
/// string has.
|
|
///
|
|
/// > **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.
|
|
#[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 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
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn to_bytes_with_nul(&self) -> &[u8] {
|
|
unsafe { mem::transmute(&self.inner) }
|
|
}
|
|
|
|
/// Yields a [`&str`] slice if the `CStr` contains valid UTF-8.
|
|
///
|
|
/// This function will calculate the length of this string and check for
|
|
/// UTF-8 validity, and then return the [`&str`] if it's valid.
|
|
///
|
|
/// > **Note**: This method is currently implemented to check for validity
|
|
/// > after a 0-cost 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
|
|
#[stable(feature = "cstr_to_str", since = "1.4.0")]
|
|
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`]`>`.
|
|
///
|
|
/// This function will calculate the length of this string (which normally
|
|
/// requires a linear amount of work to be done) and then return the
|
|
/// resulting slice as a [`Cow`]`<`[`str`]`>`, replacing any invalid UTF-8 sequences
|
|
/// with `U+FFFD REPLACEMENT CHARACTER`.
|
|
///
|
|
/// > **Note**: This method is currently implemented to check for validity
|
|
/// > after a 0-cost 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
|
|
/// [`str`]: ../primitive.str.html
|
|
#[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
|
|
#[unstable(feature = "into_boxed_c_str", issue = "40380")]
|
|
pub fn into_c_string(self: Box<CStr>) -> CString {
|
|
unsafe { mem::transmute(self) }
|
|
}
|
|
}
|
|
|
|
#[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<'a> From<&'a CStr> for CString {
|
|
fn from(s: &'a 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 {
|
|
fn as_ref(&self) -> &CStr {
|
|
self
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "cstring_asref", since = "1.7.0")]
|
|
impl AsRef<CStr> for CString {
|
|
fn as_ref(&self) -> &CStr {
|
|
self
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
use os::raw::c_char;
|
|
use borrow::Cow::{Borrowed, Owned};
|
|
use hash::{Hash, Hasher};
|
|
use collections::hash_map::DefaultHasher;
|
|
|
|
#[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]);
|
|
}
|
|
}
|