28 lines
782 B
Rust
28 lines
782 B
Rust
use std::borrow::Cow;
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use std::convert::TryInto;
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use std::str;
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pub struct BEU32StrCodec;
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impl<'a> heed::BytesDecode<'a> for BEU32StrCodec {
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type DItem = (u32, &'a str);
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fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
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let (n_bytes, str_bytes) = bytes.split_at(4);
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let n = n_bytes.try_into().map(u32::from_be_bytes).ok()?;
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let s = str::from_utf8(str_bytes).ok()?;
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Some((n, s))
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}
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}
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impl<'a> heed::BytesEncode<'a> for BEU32StrCodec {
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type EItem = (u32, &'a str);
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fn bytes_encode((n, s): &Self::EItem) -> Option<Cow<[u8]>> {
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let mut bytes = Vec::with_capacity(s.len() + 4);
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bytes.extend_from_slice(&n.to_be_bytes());
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bytes.extend_from_slice(s.as_bytes());
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Some(Cow::Owned(bytes))
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}
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}
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