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// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use crate::format::{BytesDisplay, format_bytes_debug};
use core::fmt::{self, Debug, Formatter};
use core::str::Utf8Error;
/// Filesystem label.
///
/// The label is at most 16 bytes, and may contain null bytes. The
/// encoding is not specified.
#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct Label([u8; 16]);
impl Label {
/// Create a label from raw bytes.
#[must_use]
pub const fn new(bytes: [u8; 16]) -> Self {
Self(bytes)
}
/// Convert the label to a UTF-8 string, if possible.
///
/// The first null byte, and any following bytes, are excluded from
/// the conversion.
pub fn to_str(&self) -> Result<&str, Utf8Error> {
core::str::from_utf8(self.as_bytes_up_to_first_null())
}
/// Get the raw bytes of the label. This may include null bytes.
#[must_use]
pub const fn as_bytes(&self) -> &[u8; 16] {
&self.0
}
/// Get the bytes up to the first null, or all of the bytes if there
/// is no null byte.
#[must_use]
fn as_bytes_up_to_first_null(&self) -> &[u8] {
if let Some(index) = self.0.iter().position(|c| *c == 0) {
&self.0[..index]
} else {
&self.0
}
}
/// Get an object that implements [`Display`] to allow conveniently
/// printing labels that may or may not be valid UTF-8. Non-UTF-8
/// characters will be replaced with '�'.
///
/// Null bytes are not included.
///
/// [`Display`]: core::fmt::Display
pub fn display(&self) -> BytesDisplay<'_> {
BytesDisplay(self.as_bytes_up_to_first_null())
}
}
impl Debug for Label {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
format_bytes_debug(self.as_bytes_up_to_first_null(), f)
}
}