Struct OsStr

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pub struct OsStr { /* private fields */ }

Expand description

A UTF-8-encoded fixed string

NOTE: To support dynamic values (i.e. OsString), enable the string feature

Implementations§

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impl OsStr

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pub fn as_os_str(&self) -> &OsStr

Get the raw string as an std::ffi::OsStr

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pub fn to_os_string(&self) -> OsString

Get the raw string as an OsString

Methods from Deref<Target = OsStr>§

1.0.0 · Source

pub fn to_str(&self) -> Option<&str>

Yields a &str slice if the OsStr is valid Unicode.

This conversion may entail doing a check for UTF-8 validity.

§Examples

use std::ffi::OsStr;

let os_str = OsStr::new("foo");
assert_eq!(os_str.to_str(), Some("foo"));

1.0.0 · Source

pub fn to_string_lossy(&self) -> Cow<'_, str>

Converts an OsStr to a Cow<str>.

Any non-UTF-8 sequences are replaced with U+FFFD REPLACEMENT CHARACTER.

§Examples

Calling to_string_lossy on an OsStr with invalid unicode:

// Note, due to differences in how Unix and Windows represent strings,
// we are forced to complicate this example, setting up example `OsStr`s
// with different source data and via different platform extensions.
// Understand that in reality you could end up with such example invalid
// sequences simply through collecting user command line arguments, for
// example.

#[cfg(unix)] {
    use std::ffi::OsStr;
    use std::os::unix::ffi::OsStrExt;

    // Here, the values 0x66 and 0x6f correspond to 'f' and 'o'
    // respectively. The value 0x80 is a lone continuation byte, invalid
    // in a UTF-8 sequence.
    let source = [0x66, 0x6f, 0x80, 0x6f];
    let os_str = OsStr::from_bytes(&source[..]);

    assert_eq!(os_str.to_string_lossy(), "fo�o");
}
#[cfg(windows)] {
    use std::ffi::OsString;
    use std::os::windows::prelude::*;

    // Here the values 0x0066 and 0x006f correspond to 'f' and 'o'
    // respectively. The value 0xD800 is a lone surrogate half, invalid
    // in a UTF-16 sequence.
    let source = [0x0066, 0x006f, 0xD800, 0x006f];
    let os_string = OsString::from_wide(&source[..]);
    let os_str = os_string.as_os_str();

    assert_eq!(os_str.to_string_lossy(), "fo�o");
}

1.0.0 · Source

pub fn to_os_string(&self) -> OsString

Copies the slice into an owned OsString.

§Examples

use std::ffi::{OsStr, OsString};

let os_str = OsStr::new("foo");
let os_string = os_str.to_os_string();
assert_eq!(os_string, OsString::from("foo"));

1.9.0 · Source

pub fn is_empty(&self) -> bool

Checks whether the OsStr is empty.

§Examples

use std::ffi::OsStr;

let os_str = OsStr::new("");
assert!(os_str.is_empty());

let os_str = OsStr::new("foo");
assert!(!os_str.is_empty());

1.9.0 · Source

pub fn len(&self) -> usize

Returns the length of this OsStr.

Note that this does not return the number of bytes in the string in OS string form.

The length returned is that of the underlying storage used by OsStr. As discussed in the OsString introduction, OsString and OsStr store strings in a form best suited for cheap inter-conversion between native-platform and Rust string forms, which may differ significantly from both of them, including in storage size and encoding.

This number is simply useful for passing to other methods, like OsString::with_capacity to avoid reallocations.

See the main OsString documentation information about encoding and capacity units.

§Examples

use std::ffi::OsStr;

let os_str = OsStr::new("");
assert_eq!(os_str.len(), 0);

let os_str = OsStr::new("foo");
assert_eq!(os_str.len(), 3);

1.74.0 · Source

pub fn as_encoded_bytes(&self) -> &[u8] ⓘ

Converts an OS string slice to a byte slice. To convert the byte slice back into an OS string slice, use the OsStr::from_encoded_bytes_unchecked function.

The byte encoding is an unspecified, platform-specific, self-synchronizing superset of UTF-8. By being a self-synchronizing superset of UTF-8, this encoding is also a superset of 7-bit ASCII.

Note: As the encoding is unspecified, any sub-slice of bytes that is not valid UTF-8 should be treated as opaque and only comparable within the same Rust version built for the same target platform. For example, sending the slice over the network or storing it in a file will likely result in incompatible byte slices. See OsString for more encoding details and std::ffi for platform-specific, specified conversions.

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pub fn slice_encoded_bytes<R>(&self, range: R) -> &OsStr
where R: RangeBounds<usize>,

🔬This is a nightly-only experimental API. (os_str_slice)

Takes a substring based on a range that corresponds to the return value of OsStr::as_encoded_bytes.

The range’s start and end must lie on valid OsStr boundaries. A valid OsStr boundary is one of:

The start of the string
The end of the string
Immediately before a valid non-empty UTF-8 substring
Immediately after a valid non-empty UTF-8 substring

§Panics

Panics if range does not lie on valid OsStr boundaries or if it exceeds the end of the string.

§Example

#![feature(os_str_slice)]

use std::ffi::OsStr;

let os_str = OsStr::new("foo=bar");
let bytes = os_str.as_encoded_bytes();
if let Some(index) = bytes.iter().position(|b| *b == b'=') {
    let key = os_str.slice_encoded_bytes(..index);
    let value = os_str.slice_encoded_bytes(index + 1..);
    assert_eq!(key, "foo");
    assert_eq!(value, "bar");
}

1.53.0 · Source

pub fn to_ascii_lowercase(&self) -> OsString

Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To lowercase the value in-place, use OsStr::make_ascii_lowercase.

§Examples

use std::ffi::OsString;
let s = OsString::from("Grüße, Jürgen ❤");

assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());

1.53.0 · Source

pub fn to_ascii_uppercase(&self) -> OsString

Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To uppercase the value in-place, use OsStr::make_ascii_uppercase.

§Examples

use std::ffi::OsString;
let s = OsString::from("Grüße, Jürgen ❤");

assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());

1.53.0 · Source

pub fn is_ascii(&self) -> bool

Checks if all characters in this string are within the ASCII range.

§Examples

use std::ffi::OsString;

let ascii = OsString::from("hello!\n");
let non_ascii = OsString::from("Grüße, Jürgen ❤");

assert!(ascii.is_ascii());
assert!(!non_ascii.is_ascii());

1.53.0 · Source

pub fn eq_ignore_ascii_case<S>(&self, other: S) -> bool
where S: AsRef<OsStr>,

Checks that two strings are an ASCII case-insensitive match.

Same as to_ascii_lowercase(a) == to_ascii_lowercase(b), but without allocating and copying temporaries.

§Examples

use std::ffi::OsString;

assert!(OsString::from("Ferris").eq_ignore_ascii_case("FERRIS"));
assert!(OsString::from("Ferrös").eq_ignore_ascii_case("FERRöS"));
assert!(!OsString::from("Ferrös").eq_ignore_ascii_case("FERRÖS"));

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pub fn display(&self) -> Display<'_>

🔬This is a nightly-only experimental API. (os_str_display)

Returns an object that implements Display for safely printing an OsStr that may contain non-Unicode data. This may perform lossy conversion, depending on the platform. If you would like an implementation which escapes the OsStr please use Debug instead.

§Examples

#![feature(os_str_display)]
use std::ffi::OsStr;

let s = OsStr::new("Hello, world!");
println!("{}", s.display());

Trait Implementations§

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impl AsRef<OsStr> for OsStr

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fn as_ref(&self) -> &OsStr

Converts this type into a shared reference of the (usually inferred) input type.

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impl AsRef<Path> for OsStr

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fn as_ref(&self) -> &Path

Converts this type into a shared reference of the (usually inferred) input type.

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impl Borrow<OsStr> for OsStr

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fn borrow(&self) -> &OsStr

Immutably borrows from an owned value. Read more

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impl Clone for OsStr

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fn clone(&self) -> OsStr

Returns a copy of the value. Read more

1.0.0 · Source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

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impl Debug for OsStr

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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impl Default for OsStr

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fn default() -> OsStr

Returns the “default value” for a type. Read more

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impl Deref for OsStr

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type Target = OsStr

The resulting type after dereferencing.

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fn deref(&self) -> &OsStr

Dereferences the value.

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