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Remove unsafe from encoder using extend pattern #13

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Merged
bonega merged 1 commit into from
Jan 6, 2026
Merged

Remove unsafe from encoder using extend pattern #13

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20 changes: 10 additions & 10 deletions src/encoder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,20 +16,20 @@ pub trait Encoder {
return Ok(src.into());
}
let len = s.chars().count();
let mut res = Vec::<u8>::with_capacity(len);
let mut res = Vec::with_capacity(len);

let res_ptr = res.as_mut_ptr();
// extend uses iterator size hint to skip per-element capacity checks
res.extend(
(0..len)
.map(|_| self.encode_grapheme(&mut src).or(fallback))
.flatten(),
);

for i in 0..len {
let byte = self
.encode_grapheme(&mut src)
.or(fallback)
.ok_or(EncodeError {})?;
unsafe { *res_ptr.add(i) = byte };
// If any encoding failed, we got fewer bytes than expected
if res.len() != len {
return Err(EncodeError {});
}

// Safety: len is calculated for graphemes, and `res` is now fully initialized.
unsafe { res.set_len(len) };
Ok(res.into())
}
}