FromUtf8Error in std::string - Rust (original) (raw)
Struct FromUtf8Error
1.0.0 · Source
pub struct FromUtf8Error { /* private fields */ }Expand description
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: theinto_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 FromUtf8Errorthrough 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());1.26.0 · Source
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());🔬This is a nightly-only experimental API. (string_from_utf8_lossy_owned #129436)
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 theString 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);1.0.0 · Source
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());1.0.0 · Source
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());👎Deprecated since 1.42.0: use the Display impl or to_string()
Returns the lower-level source of this error, if any. Read more
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
🔬This is a nightly-only experimental API. (error_generic_member_access #99301)
Provides type-based access to context intended for error reports. Read more
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.