Move crates under a sub folder to clean up the code

crates/milli/src/heed_codec/str_str_u8_codec.rs

@@ -0,0 +1,62 @@
+use std::borrow::Cow;
+use std::ffi::CStr;
+use std::str;
+
+use heed::BoxedError;
+
+use super::SliceTooShortError;
+
+pub struct U8StrStrCodec;
+
+impl<'a> heed::BytesDecode<'a> for U8StrStrCodec {
+    type DItem = (u8, &'a str, &'a str);
+
+    fn bytes_decode(bytes: &'a [u8]) -> Result<Self::DItem, BoxedError> {
+        let (n, bytes) = bytes.split_first().ok_or(SliceTooShortError)?;
+        let cstr = CStr::from_bytes_until_nul(bytes)?;
+        let s1 = cstr.to_str()?;
+        // skip '\0' byte between the two strings.
+        let s2 = str::from_utf8(&bytes[s1.len() + 1..])?;
+        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<Cow<'a, [u8]>, 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<Self::DItem, BoxedError> {
+        let (n, bytes) = bytes.split_first().ok_or(SliceTooShortError)?;
+        let cstr = CStr::from_bytes_until_nul(bytes)?;
+        let s1_bytes = cstr.to_bytes();
+        // skip '\0' byte between the two strings.
+        let s2_bytes = &bytes[s1_bytes.len() + 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<Cow<'a, [u8]>, 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))
+    }
+}