kernel/records/
text_budget.rs

1//! Clipping text to a byte budget without splitting a UTF-8 character.
2
3/// The result of clipping text to a byte cap.
4#[derive(Debug, PartialEq, Eq)]
5pub struct Clip<'a> {
6    /// The kept prefix, never longer than the cap and always char-aligned.
7    pub kept: &'a str,
8    /// Whether the text was longer than the cap and had to be trimmed.
9    pub overflowed: bool,
10    /// The full UTF-8 byte length of the original text.
11    pub total: usize,
12}
13
14/// Clip `text` so its UTF-8 length does not exceed `cap` bytes, trimming back to
15/// the nearest character boundary rather than splitting a multi-byte character.
16pub fn clip(text: &str, cap: usize) -> Clip<'_> {
17    let total = text.len();
18    if total <= cap {
19        return Clip {
20            kept: text,
21            overflowed: false,
22            total,
23        };
24    }
25    let mut end = cap;
26    while end > 0 && !text.is_char_boundary(end) {
27        end -= 1;
28    }
29    Clip {
30        kept: &text[..end],
31        overflowed: true,
32        total,
33    }
34}
kernel/records/text_budget.rs

kernel/records/
text_budget.rs
