1.0.0[−][src]Struct alloc::str::Utf8Error
Errors which can occur when attempting to interpret a sequence of u8
as a string.
As such, the from_utf8
family of functions and methods for both String
s
and &str
s make use of this error, for example.
Examples
This error type’s methods can be used to create functionality
similar to String::from_utf8_lossy
without allocating heap memory:
fn from_utf8_lossy<F>(mut input: &[u8], mut push: F) where F: FnMut(&str) { loop { match ::std::str::from_utf8(input) { Ok(valid) => { push(valid); break } Err(error) => { let (valid, after_valid) = input.split_at(error.valid_up_to()); unsafe { push(::std::str::from_utf8_unchecked(valid)) } push("\u{FFFD}"); if let Some(invalid_sequence_length) = error.error_len() { input = &after_valid[invalid_sequence_length..] } else { break } } } } }
Methods
impl Utf8Error
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pub fn valid_up_to(&self) -> usize
1.5.0[src]
Returns the index in the given string up to which valid UTF-8 was verified.
It is the maximum index such that from_utf8(&input[..index])
would return Ok(_)
.
Examples
Basic usage:
use std::str; // some invalid bytes, in a vector let sparkle_heart = vec![0, 159, 146, 150]; // std::str::from_utf8 returns a Utf8Error let error = str::from_utf8(&sparkle_heart).unwrap_err(); // the second byte is invalid here assert_eq!(1, error.valid_up_to());
pub fn error_len(&self) -> Option<usize>
1.20.0[src]
Provides more information about the failure:
-
None
: the end of the input was reached unexpectedly.self.valid_up_to()
is 1 to 3 bytes from the end of the input. If a byte stream (such as a file or a network socket) is being decoded incrementally, this could be a validchar
whose UTF-8 byte sequence is spanning multiple chunks. -
Some(len)
: an unexpected byte was encountered. The length provided is that of the invalid byte sequence that starts at the index given byvalid_up_to()
. Decoding should resume after that sequence (after inserting aU+FFFD REPLACEMENT CHARACTER
) in case of lossy decoding.
Trait Implementations
impl Eq for Utf8Error
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impl Clone for Utf8Error
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fn clone(&self) -> Utf8Error
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fn clone_from(&mut self, source: &Self)
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Performs copy-assignment from source
. Read more
impl Debug for Utf8Error
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impl Copy for Utf8Error
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impl PartialEq<Utf8Error> for Utf8Error
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impl Display for Utf8Error
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Auto Trait Implementations
Blanket Implementations
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&Self) -> T
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fn clone_into(&Self, &mut T)
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impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,