Struct `FromUtf8Error`

struct FromUtf8Error { ... }

A possible error value when converting a String from a UTF-8 byte vector.

This type is the error type for the from_utf8 method on String. It is designed in such a way to carefully avoid reallocations: the into_bytes method will give back the byte vector that was used in the conversion attempt.

The Utf8Error type provided by std::str represents an error that may occur when converting a slice of u8s to a &str. In this sense, it's an analogue to FromUtf8Error, and you can get one from a FromUtf8Error through the utf8_error method.

Examples

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let value = String::from_utf8(bytes);

assert!(value.is_err());
assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());

Implementations

`impl FromUtf8Error`

fn as_bytes(self: &Self) -> &[u8]

Returns a slice of u8s bytes that were attempted to convert to a String.

Examples

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let value = String::from_utf8(bytes);

assert_eq!(&[0, 159], value.unwrap_err().as_bytes());

fn into_utf8_lossy(self: Self) -> String

Converts the bytes into a String lossily, substituting invalid UTF-8 sequences with replacement characters.

See String::from_utf8_lossy for more details on replacement of invalid sequences, and String::from_utf8_lossy_owned for the String function which corresponds to this function.

Examples

#![feature(string_from_utf8_lossy_owned)]
// some invalid bytes
let input: Vec<u8> = b"Hello \xF0\x90\x80World".into();
let output = String::from_utf8(input).unwrap_or_else(|e| e.into_utf8_lossy());

assert_eq!(String::from("Hello �World"), output);

fn into_bytes(self: Self) -> Vec<u8>

Returns the bytes that were attempted to convert to a String.

This method is carefully constructed to avoid allocation. It will consume the error, moving out the bytes, so that a copy of the bytes does not need to be made.

Examples

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let value = String::from_utf8(bytes);

assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());

fn utf8_error(self: &Self) -> Utf8Error

Fetch a Utf8Error to get more details about the conversion failure.

The Utf8Error type provided by std::str represents an error that may occur when converting a slice of u8s to a &str. In this sense, it's an analogue to FromUtf8Error. See its documentation for more details on using it.

Examples

// some invalid bytes, in a vector
let bytes = vec![0, 159];

let error = String::from_utf8(bytes).unwrap_err().utf8_error();

// the first byte is invalid here
assert_eq!(1, error.valid_up_to());

`impl Clone for FromUtf8Error`

fn clone(self: &Self) -> FromUtf8Error

`impl Debug for FromUtf8Error`

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

`impl Display for FromUtf8Error`

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

`impl Eq for FromUtf8Error`

`impl Error for FromUtf8Error`

`impl Freeze for FromUtf8Error`

`impl PartialEq for FromUtf8Error`

fn eq(self: &Self, other: &FromUtf8Error) -> bool

`impl RefUnwindSafe for FromUtf8Error`

`impl Send for FromUtf8Error`

`impl StructuralPartialEq for FromUtf8Error`

`impl Sync for FromUtf8Error`

`impl Unpin for FromUtf8Error`

`impl UnwindSafe for FromUtf8Error`

`impl<T> Any for FromUtf8Error`

fn type_id(self: &Self) -> TypeId

`impl<T> Borrow for FromUtf8Error`

fn borrow(self: &Self) -> &T

`impl<T> BorrowMut for FromUtf8Error`

fn borrow_mut(self: &mut Self) -> &mut T

`impl<T> CloneToUninit for FromUtf8Error`

unsafe fn clone_to_uninit(self: &Self, dest: *mut u8)

`impl<T> From for FromUtf8Error`

fn from(t: T) -> T: Returns the argument unchanged.

`impl<T> ToOwned for FromUtf8Error`

fn to_owned(self: &Self) -> T
fn clone_into(self: &Self, target: &mut T)

`impl<T> ToString for FromUtf8Error`

fn to_string(self: &Self) -> String

`impl<T, U> Into for FromUtf8Error`

fn into(self: Self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

`impl<T, U> TryFrom for FromUtf8Error`

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

`impl<T, U> TryInto for FromUtf8Error`

fn try_into(self: Self) -> Result<U, <U as TryFrom<T>>::Error>