use std::borrow::Cow; use std::str; use heed::BoxedError; pub struct U8StrStrCodec; impl<'a> heed::BytesDecode<'a> for U8StrStrCodec { type DItem = (u8, &'a str, &'a str); fn bytes_decode(bytes: &'a [u8]) -> Result { let (n, bytes) = bytes.split_first().unwrap(); let s1_end = bytes.iter().position(|b| *b == 0).unwrap(); let (s1_bytes, rest) = bytes.split_at(s1_end); let s2_bytes = &rest[1..]; let s1 = str::from_utf8(s1_bytes).ok().unwrap(); let s2 = str::from_utf8(s2_bytes).ok().unwrap(); Ok((*n, s1, s2)) } } impl<'a> heed::BytesEncode<'a> for U8StrStrCodec { type EItem = (u8, &'a str, &'a str); fn bytes_encode((n, s1, s2): &Self::EItem) -> Result, BoxedError> { let mut bytes = Vec::with_capacity(s1.len() + s2.len() + 1); bytes.push(*n); bytes.extend_from_slice(s1.as_bytes()); bytes.push(0); bytes.extend_from_slice(s2.as_bytes()); Ok(Cow::Owned(bytes)) } } pub struct UncheckedU8StrStrCodec; impl<'a> heed::BytesDecode<'a> for UncheckedU8StrStrCodec { type DItem = (u8, &'a [u8], &'a [u8]); fn bytes_decode(bytes: &'a [u8]) -> Result { let (n, bytes) = bytes.split_first().unwrap(); let s1_end = bytes.iter().position(|b| *b == 0).unwrap(); let (s1_bytes, rest) = bytes.split_at(s1_end); let s2_bytes = &rest[1..]; Ok((*n, s1_bytes, s2_bytes)) } } impl<'a> heed::BytesEncode<'a> for UncheckedU8StrStrCodec { type EItem = (u8, &'a [u8], &'a [u8]); fn bytes_encode((n, s1, s2): &Self::EItem) -> Result, BoxedError> { let mut bytes = Vec::with_capacity(s1.len() + s2.len() + 1); bytes.push(*n); bytes.extend_from_slice(s1); bytes.push(0); bytes.extend_from_slice(s2); Ok(Cow::Owned(bytes)) } }