1.0.0[−][src]Struct std::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 } } } } }Run
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());Run
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 Copy for Utf8Error
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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 PartialEq<Utf8Error> for Utf8Error
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impl Display for Utf8Error
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impl Error for Utf8Error
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fn description(&self) -> &str
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fn cause(&self) -> Option<&dyn Error>
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replaced by Error::source, which can support downcasting
The lower-level cause of this error, if any. Read more
fn source(&self) -> Option<&(dyn Error + 'static)>
1.30.0[src]
The lower-level source of this error, if any. Read more
Auto Trait Implementations
impl UnwindSafe for Utf8Error
impl RefUnwindSafe for Utf8Error
impl Unpin for Utf8Error
impl Send for Utf8Error
impl Sync for Utf8Error
Blanket Implementations
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,
ⓘImportant traits for &'_ mut Ffn 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,
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, target: &mut T)
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impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,