Utf8Error in std::str - Rust (original) (raw)
Struct Utf8Error
1.0.0 · Source
pub struct Utf8Error { /* private fields */ }Expand description
Errors which can occur when attempting to interpret a sequence of u8as a string.
As such, the from_utf8 family of functions and methods for both Strings and &strs 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
}
}
}
}
}1.5.0 (const: 1.63.0) · Source
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());1.20.0 (const: 1.63.0) · Source
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 validcharwhose 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 a U+FFFD REPLACEMENT CHARACTER) in case of lossy decoding.
👎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.