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Trait rocket::mtls::oid::asn1_rs::nom::lib::std::convert::From

1.0.0 · source · [−]
pub trait From<T> {
    fn from(T) -> Self;
}
Available on crate feature mtls only.
Expand description

Used to do value-to-value conversions while consuming the input value. It is the reciprocal of Into.

One should always prefer implementing From over Into because implementing From automatically provides one with an implementation of Into thanks to the blanket implementation in the standard library.

Only implement Into when targeting a version prior to Rust 1.41 and converting to a type outside the current crate. From was not able to do these types of conversions in earlier versions because of Rust’s orphaning rules. See Into for more details.

Prefer using Into over using From when specifying trait bounds on a generic function. This way, types that directly implement Into can be used as arguments as well.

The From is also very useful when performing error handling. When constructing a function that is capable of failing, the return type will generally be of the form Result<T, E>. The From trait simplifies error handling by allowing a function to return a single error type that encapsulate multiple error types. See the “Examples” section and the book for more details.

Note: This trait must not fail. The From trait is intended for perfect conversions. If the conversion can fail or is not perfect, use TryFrom.

Generic Implementations

  • From<T> for U implies Into<U> for T
  • From is reflexive, which means that From<T> for T is implemented

Examples

String implements From<&str>:

An explicit conversion from a &str to a String is done as follows:

let string = "hello".to_string();
let other_string = String::from("hello");

assert_eq!(string, other_string);

While performing error handling it is often useful to implement From for your own error type. By converting underlying error types to our own custom error type that encapsulates the underlying error type, we can return a single error type without losing information on the underlying cause. The ‘?’ operator automatically converts the underlying error type to our custom error type by calling Into<CliError>::into which is automatically provided when implementing From. The compiler then infers which implementation of Into should be used.

use std::fs;
use std::io;
use std::num;

enum CliError {
    IoError(io::Error),
    ParseError(num::ParseIntError),
}

impl From<io::Error> for CliError {
    fn from(error: io::Error) -> Self {
        CliError::IoError(error)
    }
}

impl From<num::ParseIntError> for CliError {
    fn from(error: num::ParseIntError) -> Self {
        CliError::ParseError(error)
    }
}

fn open_and_parse_file(file_name: &str) -> Result<i32, CliError> {
    let mut contents = fs::read_to_string(&file_name)?;
    let num: i32 = contents.trim().parse()?;
    Ok(num)
}

Required Methods

Converts to this type from the input type.

Implementations on Foreign Types

Creates an Ipv6Addr from an eight element 16-bit array.

Examples
use std::net::Ipv6Addr;

let addr = Ipv6Addr::from([
    525u16, 524u16, 523u16, 522u16,
    521u16, 520u16, 519u16, 518u16,
]);
assert_eq!(
    Ipv6Addr::new(
        0x20d, 0x20c,
        0x20b, 0x20a,
        0x209, 0x208,
        0x207, 0x206
    ),
    addr
);

Converts a ChildStdin into a Stdio.

Examples

ChildStdin will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .stdin(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let _echo = Command::new("echo")
    .arg("Hello, world!")
    .stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

// "!dlrow ,olleH" echoed to console

Creates an Ipv6Addr from a sixteen element byte array.

Examples
use std::net::Ipv6Addr;

let addr = Ipv6Addr::from([
    25u8, 24u8, 23u8, 22u8, 21u8, 20u8, 19u8, 18u8,
    17u8, 16u8, 15u8, 14u8, 13u8, 12u8, 11u8, 10u8,
]);
assert_eq!(
    Ipv6Addr::new(
        0x1918, 0x1716,
        0x1514, 0x1312,
        0x1110, 0x0f0e,
        0x0d0c, 0x0b0a
    ),
    addr
);

Converts a SocketAddrV6 into a SocketAddr::V6.

Converts a PathBuf into an OsString

This conversion does not allocate or copy memory.

Converts a borrowed OsStr to a PathBuf.

Allocates a PathBuf and copies the data into it.

Converts an OsString into an Arc<OsStr> by moving the OsString data into a new Arc buffer.

Converts a PathBuf into an Arc<Path> by moving the PathBuf data into a new Arc buffer.

Creates a new mutex in an unlocked state ready for use. This is equivalent to Mutex::new.

Creates an IpAddr::V4 from a four element byte array.

Examples
use std::net::{IpAddr, Ipv4Addr};

let addr = IpAddr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(IpAddr::V4(Ipv4Addr::new(13, 12, 11, 10)), addr);

Converts a tuple struct (Into<IpAddr>, u16) into a SocketAddr.

This conversion creates a SocketAddr::V4 for an IpAddr::V4 and creates a SocketAddr::V6 for an IpAddr::V6.

u16 is treated as port of the newly created SocketAddr.

Converts a Box<OsStr> into an OsString without copying or allocating.

Moves the string into a Cow::Owned.

Converts a File into a Stdio.

Examples

File will be converted to Stdio using Stdio::from under the hood.

use std::fs::File;
use std::process::Command;

// With the `foo.txt` file containing `Hello, world!"
let file = File::open("foo.txt").unwrap();

let reverse = Command::new("rev")
    .stdin(file)  // Implicit File conversion into a Stdio
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH");

Converts the string reference into a Cow::Borrowed.

Convert a host byte order u128 into an Ipv6Addr.

Examples
use std::net::Ipv6Addr;

let addr = Ipv6Addr::from(0x102030405060708090A0B0C0D0E0F00D_u128);
assert_eq!(
    Ipv6Addr::new(
        0x1020, 0x3040, 0x5060, 0x7080,
        0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
    ),
    addr);

Converts an Ipv4Addr into a host byte order u32.

Examples
use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(0x12, 0x34, 0x56, 0x78);
assert_eq!(0x12345678, u32::from(addr));

Intended for use for errors not exposed to the user, where allocating onto the heap (for normal construction via Error::new) is too costly.

Converts an ErrorKind into an Error.

This conversion creates a new error with a simple representation of error kind.

Examples
use std::io::{Error, ErrorKind};

let not_found = ErrorKind::NotFound;
let error = Error::from(not_found);
assert_eq!("entity not found", format!("{error}"));

Construct an ExitCode from an arbitrary u8 value.

Converts a Path into an Arc by copying the Path data into a new Arc buffer.

Creates an IpAddr::V6 from a sixteen element byte array.

Examples
use std::net::{IpAddr, Ipv6Addr};

let addr = IpAddr::from([
    25u8, 24u8, 23u8, 22u8, 21u8, 20u8, 19u8, 18u8,
    17u8, 16u8, 15u8, 14u8, 13u8, 12u8, 11u8, 10u8,
]);
assert_eq!(
    IpAddr::V6(Ipv6Addr::new(
        0x1918, 0x1716,
        0x1514, 0x1312,
        0x1110, 0x0f0e,
        0x0d0c, 0x0b0a
    )),
    addr
);

Create a new cell with its contents set to value.

Example
#![feature(once_cell)]

use std::lazy::SyncOnceCell;

let a = SyncOnceCell::from(3);
let b = SyncOnceCell::new();
b.set(3)?;
assert_eq!(a, b);
Ok(())

Converts a String into a PathBuf

This conversion does not allocate or copy memory.

Converts the string reference into a Cow::Borrowed.

Converts a String into an OsString.

This conversion does not allocate or copy memory.

Converts a Box<Path> into a PathBuf.

This conversion does not allocate or copy memory.

Creates a clone-on-write pointer from a reference to PathBuf.

This conversion does not clone or allocate.

Creates an IpAddr::V6 from an eight element 16-bit array.

Examples
use std::net::{IpAddr, Ipv6Addr};

let addr = IpAddr::from([
    525u16, 524u16, 523u16, 522u16,
    521u16, 520u16, 519u16, 518u16,
]);
assert_eq!(
    IpAddr::V6(Ipv6Addr::new(
        0x20d, 0x20c,
        0x20b, 0x20a,
        0x209, 0x208,
        0x207, 0x206
    )),
    addr
);

Converts a clone-on-write pointer to an owned path.

Converting from a Cow::Owned does not clone or allocate.

Creates an Ipv4Addr from a four element byte array.

Examples
use std::net::Ipv4Addr;

let addr = Ipv4Addr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);

Converts a RecvError into a TryRecvError.

This conversion always returns TryRecvError::Disconnected.

No data is allocated on the heap.

Converts a Path into an Rc by copying the Path data into a new Rc buffer.

Copies any value implementing AsRef<OsStr> into a newly allocated OsString.

Copies this address to a new IpAddr::V6.

Examples
use std::net::{IpAddr, Ipv6Addr};

let addr = Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff);

assert_eq!(
    IpAddr::V6(addr),
    IpAddr::from(addr)
);

Converts an OsString into a PathBuf

This conversion does not allocate or copy memory.

Converts a PathBuf into an Rc<Path> by moving the PathBuf data into a new Rc buffer.

Copies this address to a new IpAddr::V4.

Examples
use std::net::{IpAddr, Ipv4Addr};

let addr = Ipv4Addr::new(127, 0, 0, 1);

assert_eq!(
    IpAddr::V4(addr),
    IpAddr::from(addr)
)

Converts a Cow<'a, OsStr> into an OsString, by copying the contents if they are borrowed.

Convert an Ipv6Addr into a host byte order u128.

Examples
use std::net::Ipv6Addr;

let addr = Ipv6Addr::new(
    0x1020, 0x3040, 0x5060, 0x7080,
    0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
);
assert_eq!(0x102030405060708090A0B0C0D0E0F00D_u128, u128::from(addr));

Creates a clone-on-write pointer from an owned instance of PathBuf.

This conversion does not clone or allocate.

Converts a ChildStderr into a Stdio.

Examples
use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .arg("non_existing_file.txt")
    .stderr(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let cat = Command::new("cat")
    .arg("-")
    .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

assert_eq!(
    String::from_utf8_lossy(&cat.stdout),
    "rev: cannot open non_existing_file.txt: No such file or directory\n"
);

Converts a host byte order u32 into an Ipv4Addr.

Examples
use std::net::Ipv4Addr;

let addr = Ipv4Addr::from(0x12345678);
assert_eq!(Ipv4Addr::new(0x12, 0x34, 0x56, 0x78), addr);

Converts a RecvError into a RecvTimeoutError.

This conversion always returns RecvTimeoutError::Disconnected.

No data is allocated on the heap.

Converts a [alloc::ffi::NulError] into a io::Error.

Converts a SendError<T> into a TrySendError<T>.

This conversion always returns a TrySendError::Disconnected containing the data in the SendError<T>.

No data is allocated on the heap.

Creates a clone-on-write pointer from a reference to Path.

This conversion does not clone or allocate.

Copies the string into a newly allocated Arc<OsStr>.

Converts an OsString into an Rc<OsStr> by moving the OsString data into a new Rc buffer.

Converts a SocketAddrV4 into a SocketAddr::V4.

Creates a new instance of an RwLock<T> which is unlocked. This is equivalent to RwLock::new.

Converts a ChildStdout into a Stdio.

Examples

ChildStdout will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let hello = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .spawn()
    .expect("failed echo command");

let reverse = Command::new("rev")
    .stdin(hello.stdout.unwrap())  // Converted into a Stdio here
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");

Copies the string into a newly allocated Rc<OsStr>.

source

impl From<__m256i> for Simd<u64, 4_usize>

source

impl From<__m512i> for Simd<i32, 16_usize>

Converts u8 to i32 losslessly.

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impl From<__m512i> for Simd<u64, 8_usize>

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impl From<Simd<i8, 32_usize>> for __m256i

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impl From<__m128> for Simd<f32, 4_usize>

Converts u16 to i128 losslessly.

Converts NonZeroU32 to NonZeroI64 losslessly.

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impl From<Simd<u16, 8_usize>> for __m128i

Converts a bool to a u8. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(u8::from(true), 1);
assert_eq!(u8::from(false), 0);

Converts u16 to i32 losslessly.

Converts u8 to f32 losslessly.

Converts i16 to isize losslessly.

Converts NonZeroI16 to NonZeroI128 losslessly.

Converts a *mut T into an AtomicPtr<T>.

Converts NonZeroU8 to NonZeroI32 losslessly.

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impl From<Simd<i8, 16_usize>> for __m128i

Converts a NonZeroUsize into an usize

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impl From<__m256i> for Simd<isize, 4_usize>

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impl From<__m256i> for Simd<u16, 16_usize>

Converts i16 to f32 losslessly.

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impl From<Simd<u16, 32_usize>> for __m512i

Converts a NonZeroU128 into an u128

Converts u8 to i64 losslessly.

Converts f32 to f64 losslessly.

Converts NonZeroU16 to NonZeroI32 losslessly.

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impl From<__m128i> for Simd<u32, 4_usize>

Converts u64 to i128 losslessly.

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impl From<Simd<u64, 8_usize>> for __m512i

Converts NonZeroU32 to NonZeroU128 losslessly.

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impl From<__m128i> for Simd<i8, 16_usize>

Converts a NonZeroI128 into an i128

Converts a NonZeroU32 into an u32

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impl From<__m128i> for Simd<u64, 2_usize>

Converts a bool to a i8. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(i8::from(true), 1);
assert_eq!(i8::from(false), 0);
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impl From<__m128i> for Simd<isize, 2_usize>

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impl From<Simd<f64, 4_usize>> for __m256d

Converts i32 to i64 losslessly.

Converts NonZeroI8 to NonZeroI128 losslessly.

Creates a new SyncUnsafeCell<T> containing the given value.

Converts a NonZeroI16 into an i16

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impl From<Simd<u16, 16_usize>> for __m256i

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impl From<__m128i> for Simd<i32, 4_usize>

Converts a bool to a i16. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(i16::from(true), 1);
assert_eq!(i16::from(false), 0);

Converts i8 to f32 losslessly.

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impl From<__m256i> for Simd<i32, 8_usize>

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impl From<__m512i> for Simd<usize, 8_usize>

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impl From<__m128i> for Simd<u16, 8_usize>

Converts NonZeroU8 to NonZeroUsize losslessly.

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impl From<__m256i> for Simd<u32, 8_usize>

Converts NonZeroI32 to NonZeroI64 losslessly.

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impl From<__m256i> for Simd<i16, 16_usize>

Converts u32 to i64 losslessly.

Converts a bool to a isize. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(isize::from(true), 1);
assert_eq!(isize::from(false), 0);

Converts u16 to u64 losslessly.

Converts u32 to u128 losslessly.

Converts NonZeroU32 to NonZeroI128 losslessly.

Converts u32 to f64 losslessly.

Converts u8 to i16 losslessly.

Converts NonZeroU16 to NonZeroUsize losslessly.

Converts i8 to isize losslessly.

Converts NonZeroU16 to NonZeroI128 losslessly.

Converts NonZeroU8 to NonZeroI64 losslessly.

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impl From<__m128i> for Simd<i64, 2_usize>

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impl From<Simd<i16, 8_usize>> for __m128i

Converts NonZeroI8 to NonZeroI64 losslessly.

Converts a NonZeroU16 into an u16

Converts a NonZeroI32 into an i32

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impl From<__m256i> for Simd<i8, 32_usize>

Converts NonZeroU8 to NonZeroU64 losslessly.

Converts u16 to f32 losslessly.

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impl From<__m128i> for Simd<i16, 8_usize>

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impl From<Simd<f64, 2_usize>> for __m128d

Converts a NonZeroU8 into an u8

Converts an i8 into an AtomicI8.

Converts a bool to a u32. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(u32::from(true), 1);
assert_eq!(u32::from(false), 0);
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impl From<Simd<i32, 4_usize>> for __m128i

Converts i8 to i16 losslessly.

Converts an u64 into an AtomicU64.

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impl From<__m512d> for Simd<f64, 8_usize>

Converts a &mut T to a NonNull<T>.

This conversion is safe and infallible since references cannot be null.

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impl From<Simd<isize, 8_usize>> for __m512i

Converts i16 to i128 losslessly.

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impl From<Simd<u64, 2_usize>> for __m128i

Converts i8 to f64 losslessly.

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impl From<Simd<f32, 8_usize>> for __m256

Converts a char into a u128.

Examples
use std::mem;

let c = '⚙';
let u = u128::from(c);
assert!(16 == mem::size_of_val(&u))

Converts u32 to i128 losslessly.

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impl From<Simd<f32, 16_usize>> for __m512

Converts u16 to u32 losslessly.

Converts NonZeroI8 to NonZeroI32 losslessly.

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impl From<Simd<usize, 2_usize>> for __m128i

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impl From<Simd<u8, 16_usize>> for __m128i

Converts NonZeroI8 to NonZeroI16 losslessly.

Converts a char into a u32.

Examples
use std::mem;

let c = 'c';
let u = u32::from(c);
assert!(4 == mem::size_of_val(&u))

Converts NonZeroU64 to NonZeroU128 losslessly.

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impl From<__m256> for Simd<f32, 8_usize>

Converts a bool to a u64. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(u64::from(true), 1);
assert_eq!(u64::from(false), 0);
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impl From<__m128i> for Simd<u8, 16_usize>

Converts u32 to u64 losslessly.

Converts u8 to u64 losslessly.

Moves the value into a Poll::Ready to make a Poll<T>.

Example
assert_eq!(Poll::from(true), Poll::Ready(true));

Converts NonZeroU8 to NonZeroU16 losslessly.

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impl From<Simd<i64, 2_usize>> for __m128i

Converts an i64 into an AtomicI64.

Converts NonZeroI16 to NonZeroIsize losslessly.

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impl From<Simd<i32, 16_usize>> for __m512i

Converts NonZeroU16 to NonZeroU32 losslessly.

Converts a NonZeroI64 into an i64

Converts NonZeroU32 to NonZeroU64 losslessly.

Converts i8 to i128 losslessly.

Converts u8 to i128 losslessly.

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impl From<__m512i> for Simd<i16, 32_usize>

Converts i32 to f64 losslessly.

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impl From<__m128d> for Simd<f64, 2_usize>

Converts u64 to u128 losslessly.

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impl From<Simd<usize, 4_usize>> for __m256i

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impl From<Simd<u8, 64_usize>> for __m512i

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impl From<Simd<isize, 4_usize>> for __m256i

Converts NonZeroU16 to NonZeroI64 losslessly.

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impl From<Simd<u32, 16_usize>> for __m512i

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impl From<__m512> for Simd<f32, 16_usize>

Converts u16 to u128 losslessly.

Converts i64 to i128 losslessly.

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impl From<Simd<u32, 4_usize>> for __m128i

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impl From<__m512i> for Simd<u16, 32_usize>

Converts a NonZeroI8 into an i8

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impl From<Simd<i32, 8_usize>> for __m256i

Converts i32 to i128 losslessly.

Converts NonZeroI16 to NonZeroI32 losslessly.

Converts NonZeroU16 to NonZeroU128 losslessly.

Converts u8 to isize losslessly.

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impl From<Simd<u32, 8_usize>> for __m256i

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impl From<__m256i> for Simd<i64, 4_usize>

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impl From<__m256d> for Simd<f64, 4_usize>

Converts a bool to a u128. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(u128::from(true), 1);
assert_eq!(u128::from(false), 0);
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impl From<Simd<i16, 16_usize>> for __m256i

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impl From<Simd<f64, 8_usize>> for __m512d

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impl From<Simd<isize, 2_usize>> for __m128i

Converts i8 to i64 losslessly.

source

impl From<Simd<u64, 4_usize>> for __m256i

Converts NonZeroU8 to NonZeroI128 losslessly.

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impl From<__m512i> for Simd<u32, 16_usize>

Converts i16 to f64 losslessly.

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impl From<Simd<i8, 64_usize>> for __m512i

Converts an u32 into an AtomicU32.

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impl From<__m512i> for Simd<i64, 8_usize>

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impl From<Simd<u8, 32_usize>> for __m256i

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impl From<__m256i> for Simd<usize, 4_usize>

Converts u16 to usize losslessly.

Converts a char into a u64.

Examples
use std::mem;

let c = '👤';
let u = u64::from(c);
assert!(8 == mem::size_of_val(&u))

Converts NonZeroU8 to NonZeroU128 losslessly.

Converts NonZeroI16 to NonZeroI64 losslessly.

Converts NonZeroU64 to NonZeroI128 losslessly.

Converts an isize into an AtomicIsize.

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impl From<Simd<i64, 4_usize>> for __m256i

Creates a new OnceCell<T> which already contains the given value.

Converts a bool to a i32. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(i32::from(true), 1);
assert_eq!(i32::from(false), 0);

Converts a bool to a u16. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(u16::from(true), 1);
assert_eq!(u16::from(false), 0);

Converts NonZeroU8 to NonZeroU32 losslessly.

Converts an u16 into an AtomicU16.

Converts a bool into an AtomicBool.

Examples
use std::sync::atomic::AtomicBool;
let atomic_bool = AtomicBool::from(true);
assert_eq!(format!("{atomic_bool:?}"), "true")

Converts a bool to a usize. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(usize::from(true), 1);
assert_eq!(usize::from(false), 0);

Creates a new Cell<T> containing the given value.

Converts a bool to a i128. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(i128::from(true), 1);
assert_eq!(i128::from(false), 0);

Converts a NonZeroU64 into an u64

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impl From<__m512i> for Simd<u8, 64_usize>

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impl From<Simd<f32, 4_usize>> for __m128

Converts an u8 into an AtomicU8.

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impl From<Simd<i16, 32_usize>> for __m512i

Converts a NonZeroIsize into an isize

Converts u8 to u16 losslessly.

Converts NonZeroI8 to NonZeroIsize losslessly.

Converts u8 to f64 losslessly.

source

impl From<__m512i> for Simd<i8, 64_usize>

Converts i16 to i32 losslessly.

Maps a byte in 0x00..=0xFF to a char whose code point has the same value, in U+0000..=U+00FF.

Unicode is designed such that this effectively decodes bytes with the character encoding that IANA calls ISO-8859-1. This encoding is compatible with ASCII.

Note that this is different from ISO/IEC 8859-1 a.k.a. ISO 8859-1 (with one less hyphen), which leaves some “blanks”, byte values that are not assigned to any character. ISO-8859-1 (the IANA one) assigns them to the C0 and C1 control codes.

Note that this is also different from Windows-1252 a.k.a. code page 1252, which is a superset ISO/IEC 8859-1 that assigns some (not all!) blanks to punctuation and various Latin characters.

To confuse things further, on the Web ascii, iso-8859-1, and windows-1252 are all aliases for a superset of Windows-1252 that fills the remaining blanks with corresponding C0 and C1 control codes.

Converts a u8 into a char.

Examples
use std::mem;

let u = 32 as u8;
let c = char::from(u);
assert!(4 == mem::size_of_val(&c))

Creates a new UnsafeCell<T> containing the given value.

Converts i16 to i64 losslessly.

source

impl From<__m512i> for Simd<isize, 8_usize>

Converts a bool to a i64. The resulting value is 0 for false and 1 for true values.

Examples
assert_eq!(i64::from(true), 1);
assert_eq!(i64::from(false), 0);

Converts NonZeroU8 to NonZeroIsize losslessly.

Converts a &T to a NonNull<T>.

This conversion is safe and infallible since references cannot be null.

source

impl From<Simd<usize, 8_usize>> for __m512i

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impl From<__m128i> for Simd<usize, 2_usize>

Converts an usize into an AtomicUsize.

Converts i8 to i32 losslessly.

Converts NonZeroI32 to NonZeroI128 losslessly.

Converts u8 to usize losslessly.

Converts an i16 into an AtomicI16.

Converts NonZeroI64 to NonZeroI128 losslessly.

source

impl From<__m256i> for Simd<u8, 32_usize>

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impl From<Simd<i64, 8_usize>> for __m512i

Converts u8 to u128 losslessly.

Converts NonZeroU8 to NonZeroI16 losslessly.

Converts u16 to f64 losslessly.

Creates a new RefCell<T> containing the given value.

Converts u16 to i64 losslessly.

Converts u8 to u32 losslessly.

Converts an i32 into an AtomicI32.

Converts NonZeroU16 to NonZeroU64 losslessly.

Creates a Borrowed variant of Cow from a slice.

This conversion does not allocate or clone the data.

Converts a string slice into a Borrowed variant. No heap allocation is performed, and the string is not copied.

Example
assert_eq!(Cow::from("eggplant"), Cow::Borrowed("eggplant"));

Allocate a reference-counted slice and move v’s items into it.

Example
let original: Box<Vec<i32>> = Box::new(vec![1, 2, 3]);
let shared: Rc<Vec<i32>> = Rc::from(original);
assert_eq!(vec![1, 2, 3], *shared);

Converts a generic type T into an Rc<T>

The conversion allocates on the heap and moves t from the stack into it.

Example
let x = 5;
let rc = Rc::new(5);

assert_eq!(Rc::from(x), rc);

Converts a String into an Owned variant. No heap allocation is performed, and the string is not copied.

Example
let s = "eggplant".to_string();
let s2 = "eggplant".to_string();
assert_eq!(Cow::from(s), Cow::<'static, str>::Owned(s2));

Converts a Box<T> into a Pin<Box<T>>

This conversion does not allocate on the heap and happens in place.

Converts an atomically reference-counted string slice into a byte slice.

Example
let string: Arc<str> = Arc::from("eggplant");
let bytes: Arc<[u8]> = Arc::from(string);
assert_eq!("eggplant".as_bytes(), bytes.as_ref());

Converts a Cow<'a, CStr> into a CString, by copying the contents if they are borrowed.

Move a boxed object to a new, reference-counted allocation.

Example
let unique: Box<str> = Box::from("eggplant");
let shared: Arc<str> = Arc::from(unique);
assert_eq!("eggplant", &shared[..]);

Allocate a reference-counted slice and fill it by cloning v’s items.

Example
let original: &[i32] = &[1, 2, 3];
let shared: Rc<[i32]> = Rc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);

Converts a Vec<NonZeroU8> into a CString without copying nor checking for inner null bytes.

Create an atomically reference-counted pointer from a clone-on-write pointer by copying its content.

Example
let cow: Cow<str> = Cow::Borrowed("eggplant");
let shared: Arc<str> = Arc::from(cow);
assert_eq!("eggplant", &shared[..]);

Use a Wake-able type as a Waker.

No heap allocations or atomic operations are used for this conversion.

Allocate a reference-counted str and copy v into it.

Example
let shared: Arc<str> = Arc::from("eggplant");
assert_eq!("eggplant", &shared[..]);

Allocate a reference-counted string slice and copy v into it.

Example
let shared: Rc<str> = Rc::from("statue");
assert_eq!("statue", &shared[..]);

Creates a Borrowed variant of Cow from a reference to Vec.

This conversion does not allocate or clone the data.

Converts a String reference into a Borrowed variant. No heap allocation is performed, and the string is not copied.

Example
let s = "eggplant".to_string();
assert_eq!(Cow::from(&s), Cow::Borrowed("eggplant"));

Converts a &CStr into a Arc<CStr>, by copying the contents into a newly allocated Arc.

Converts a T into an Arc<T>

The conversion moves the value into a newly allocated Arc. It is equivalent to calling Arc::new(t).

Example
let x = 5;
let arc = Arc::new(5);

assert_eq!(Arc::from(x), arc);

Creates an Owned variant of Cow from an owned instance of Vec.

This conversion does not allocate or clone the data.

Allocate a reference-counted str and copy v into it.

Example
let unique: String = "eggplant".to_owned();
let shared: Arc<str> = Arc::from(unique);
assert_eq!("eggplant", &shared[..]);

Converts a reference-counted string slice into a byte slice.

Example
let string: Rc<str> = Rc::from("eggplant");
let bytes: Rc<[u8]> = Rc::from(string);
assert_eq!("eggplant".as_bytes(), bytes.as_ref());

Converts a CStr into a borrowed Cow without copying or allocating.

Converts a CString into an Arc<CStr> by moving the CString data into a new Arc buffer.

Converts a CString into an Rc<CStr> by moving the CString data into a new Arc buffer.

Allocate a reference-counted string slice and copy v into it.

Example
let original: String = "statue".to_owned();
let shared: Rc<str> = Rc::from(original);
assert_eq!("statue", &shared[..]);

Use a Wake-able type as a RawWaker.

No heap allocations or atomic operations are used for this conversion.

Move a boxed object to a new, reference counted, allocation.

Example
let original: Box<i32> = Box::new(1);
let shared: Rc<i32> = Rc::from(original);
assert_eq!(1, *shared);

Create a reference-counted pointer from a clone-on-write pointer by copying its content.

Example
let cow: Cow<str> = Cow::Borrowed("eggplant");
let shared: Rc<str> = Rc::from(cow);
assert_eq!("eggplant", &shared[..]);

Converts a &CStr into a Rc<CStr>, by copying the contents into a newly allocated Rc.

Converts a Box<CStr> into a CString without copying or allocating.

Converts a &CString into a borrowed Cow without copying or allocating.

Allocate a reference-counted slice and fill it by cloning v’s items.

Example
let original: &[i32] = &[1, 2, 3];
let shared: Arc<[i32]> = Arc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);

Converts a CString into an owned Cow without copying or allocating.

Allocate a reference-counted slice and move v’s items into it.

Example
let unique: Vec<i32> = vec![1, 2, 3];
let shared: Arc<[i32]> = Arc::from(unique);
assert_eq!(&[1, 2, 3], &shared[..]);

Notes

The underlying pipe is not set to non-blocking.

Notes

The underlying pipe is not set to non-blocking.

Notes

The underlying pipe is not set to non-blocking.

On Windows, a corresponding From<&impl AsRawSocket> implementation exists.

The caller must ensure S is actually a socket.

Create a InlineString from the given &str.

Panics

If the given string’s size is greater than INLINE_STRING_CAPACITY, this method panics.

Examples
use indexmap::IndexMap;

let map1 = IndexMap::from([(1, 2), (3, 4)]);
let map2: IndexMap<_, _> = [(1, 2), (3, 4)].into();
assert_eq!(map1, map2);
Examples
use indexmap::IndexSet;

let set1 = IndexSet::from([1, 2, 3, 4]);
let set2: IndexSet<_> = [1, 2, 3, 4].into();
assert_eq!(set1, set2);

Convert from Result to Either with Ok => Right and Err => Left.

Requires the alloc feature.

Converts slice to a generic array reference with inferred length;

Length of the slice must be equal to the length of the array.

Converts mutable slice to a mutable generic array reference

Length of the slice must be equal to the length of the array.

Convert the Choice wrapper into a bool, depending on whether the underlying u8 was a 0 or a 1.

Note

This function exists to avoid having higher-level cryptographic protocol implementations duplicating this pattern.

The intended use case for this conversion is at the end of a higher-level primitive implementation: for example, in checking a keyed MAC, where the verification should happen in constant-time (and thus use a Choice) but it is safe to return a bool at the end of the verification.

Convert a serde_json::Error into an io::Error.

JSON syntax and data errors are turned into InvalidData IO errors. EOF errors are turned into UnexpectedEof IO errors.

use std::io;

enum MyError {
    Io(io::Error),
    Json(serde_json::Error),
}

impl From<serde_json::Error> for MyError {
    fn from(err: serde_json::Error) -> MyError {
        use serde_json::error::Category;
        match err.classify() {
            Category::Io => {
                MyError::Io(err.into())
            }
            Category::Syntax | Category::Data | Category::Eof => {
                MyError::Json(err)
            }
        }
    }
}

Implementors

Convert an Authority into a Uri.

Convert a PathAndQuery into a Uri.

Convert a Uri into Parts

Creates a new Header with name Accept and the value set to the HTTP rendering of this Accept header.

Creates a new Header with name Content-Type and the value set to the HTTP rendering of this Content-Type.

Optional

This function requires enabling the stream feature in your Cargo.toml.

Build a DER object from a BerObjectContent.

Build a DER object from an OID.

Stability note: This impl does not yet exist, but we are “reserving space” to add it in the future. See rust-lang/rust#64715 for details.

Returns a One stream that will yield value exactly once.

Example

use rocket::response::stream::One;

let mut stream = One::from("hello!");