Introduce a function to retrieve the facet level range docids

src/heed_codec/facet/facet_level_value_f64_codec.rs

@@ -0,0 +1,62 @@
+use std::borrow::Cow;
+use std::convert::TryInto;
+
+use crate::facet::value_encoding::f64_into_bytes;
+
+// TODO do not de/serialize right bound when level = 0
+pub struct FacetLevelValueF64Codec;
+
+impl<'a> heed::BytesDecode<'a> for FacetLevelValueF64Codec {
+    type DItem = (u8, u8, f64, f64);
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (field_id, bytes) = bytes.split_first()?;
+        let (level, bytes) = bytes.split_first()?;
+
+        let left = bytes[16..24].try_into().ok().map(f64::from_be_bytes)?;
+        let right = bytes[24..].try_into().ok().map(f64::from_be_bytes)?;
+
+        Some((*field_id, *level, left, right))
+    }
+}
+
+impl heed::BytesEncode<'_> for FacetLevelValueF64Codec {
+    type EItem = (u8, u8, f64, f64);
+
+    fn bytes_encode((field_id, level, left, right): &Self::EItem) -> Option<Cow<[u8]>> {
+        let mut buffer = [0u8; 32];
+
+        // Write the globally ordered floats.
+        let bytes = f64_into_bytes(*left)?;
+        buffer[..8].copy_from_slice(&bytes[..]);
+
+        let bytes = f64_into_bytes(*right)?;
+        buffer[8..16].copy_from_slice(&bytes[..]);
+
+        // Then the f64 values just to be able to read them back.
+        let bytes = left.to_be_bytes();
+        buffer[16..24].copy_from_slice(&bytes[..]);
+
+        let bytes = right.to_be_bytes();
+        buffer[24..].copy_from_slice(&bytes[..]);
+
+        let mut bytes = Vec::with_capacity(buffer.len() + 2);
+        bytes.push(*field_id);
+        bytes.push(*level);
+        bytes.extend_from_slice(&buffer[..]);
+        Some(Cow::Owned(bytes))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use heed::{BytesEncode, BytesDecode};
+    use super::*;
+
+    #[test]
+    fn globally_ordered_f64() {
+        let bytes = FacetLevelValueF64Codec::bytes_encode(&(3, 0, -32.0, 32.0)).unwrap();
+        let (name, level, left, right) = FacetLevelValueF64Codec::bytes_decode(&bytes).unwrap();
+        assert_eq!((name, level, left, right), (3, 0, -32.0, 32.0));
+    }
+}

src/heed_codec/facet/facet_level_value_i64_codec.rs

@@ -0,0 +1,43 @@
+use std::borrow::Cow;
+use std::convert::TryInto;
+
+use crate::facet::value_encoding::{i64_from_bytes, i64_into_bytes};
+
+pub struct FacetLevelValueI64Codec;
+
+impl<'a> heed::BytesDecode<'a> for FacetLevelValueI64Codec {
+    type DItem = (u8, u8, i64, i64);
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (field_id, bytes) = bytes.split_first()?;
+        let (level, bytes) = bytes.split_first()?;
+
+        let left = bytes[..8].try_into().map(i64_from_bytes).ok()?;
+        let right = if *level != 0 {
+            bytes[8..].try_into().map(i64_from_bytes).ok()?
+        } else {
+            left
+        };
+
+        Some((*field_id, *level, left, right))
+    }
+}
+
+impl heed::BytesEncode<'_> for FacetLevelValueI64Codec {
+    type EItem = (u8, u8, i64, i64);
+
+    fn bytes_encode((field_id, level, left, right): &Self::EItem) -> Option<Cow<[u8]>> {
+        let left = i64_into_bytes(*left);
+        let right = i64_into_bytes(*right);
+
+        let mut bytes = Vec::with_capacity(2 + left.len() + right.len());
+        bytes.push(*field_id);
+        bytes.push(*level);
+        bytes.extend_from_slice(&left[..]);
+        if *level != 0 {
+            bytes.extend_from_slice(&right[..]);
+        }
+
+        Some(Cow::Owned(bytes))
+    }
+}

src/heed_codec/facet/facet_value_f64_codec.rs

@@ -1,50 +0,0 @@
-use std::borrow::Cow;
-use std::convert::TryInto;
-
-use crate::facet::value_encoding::f64_into_bytes;
-
-pub struct FacetValueF64Codec;
-
-impl<'a> heed::BytesDecode<'a> for FacetValueF64Codec {
-    type DItem = (u8, f64);
-
-    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
-        let (field_id, buffer) = bytes.split_first()?;
-        let value = buffer[8..].try_into().ok().map(f64::from_be_bytes)?;
-        Some((*field_id, value))
-    }
-}
-
-impl heed::BytesEncode<'_> for FacetValueF64Codec {
-    type EItem = (u8, f64);
-
-    fn bytes_encode((field_id, value): &Self::EItem) -> Option<Cow<[u8]>> {
-        let mut buffer = [0u8; 16];
-
-        // Write the globally ordered float.
-        let bytes = f64_into_bytes(*value)?;
-        buffer[..8].copy_from_slice(&bytes[..]);
-
-        // Then the f64 value just to be able to read it back.
-        let bytes = value.to_be_bytes();
-        buffer[8..].copy_from_slice(&bytes[..]);
-
-        let mut bytes = Vec::with_capacity(buffer.len() + 1);
-        bytes.push(*field_id);
-        bytes.extend_from_slice(&buffer[..]);
-        Some(Cow::Owned(bytes))
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use heed::{BytesEncode, BytesDecode};
-    use super::*;
-
-    #[test]
-    fn globally_ordered_f64() {
-        let bytes = FacetValueF64Codec::bytes_encode(&(3, -32.0)).unwrap();
-        let (name, value) = FacetValueF64Codec::bytes_decode(&bytes).unwrap();
-        assert_eq!((name, value), (3, -32.0));
-    }
-}

src/heed_codec/facet/facet_value_i64_codec.rs

@@ -1,28 +0,0 @@
-use std::borrow::Cow;
-use std::convert::TryInto;
-
-use crate::facet::value_encoding::{i64_from_bytes, i64_into_bytes};
-
-pub struct FacetValueI64Codec;
-
-impl<'a> heed::BytesDecode<'a> for FacetValueI64Codec {
-    type DItem = (u8, i64);
-
-    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
-        let (field_id, buffer) = bytes.split_first()?;
-        let value = buffer.try_into().map(i64_from_bytes).ok()?;
-        Some((*field_id, value))
-    }
-}
-
-impl heed::BytesEncode<'_> for FacetValueI64Codec {
-    type EItem = (u8, i64);
-
-    fn bytes_encode((field_id, value): &Self::EItem) -> Option<Cow<[u8]>> {
-        let value = i64_into_bytes(*value);
-        let mut bytes = Vec::with_capacity(value.len() + 1);
-        bytes.push(*field_id);
-        bytes.extend_from_slice(&value[..]);
-        Some(Cow::Owned(bytes))
-    }
-}

src/heed_codec/facet/mod.rs

@@ -1,7 +1,7 @@
-mod facet_value_f64_codec;
-mod facet_value_i64_codec;
+mod facet_level_value_f64_codec;
+mod facet_level_value_i64_codec;
 mod facet_value_string_codec;
 
-pub use self::facet_value_f64_codec::FacetValueF64Codec;
-pub use self::facet_value_i64_codec::FacetValueI64Codec;
+pub use self::facet_level_value_f64_codec::FacetLevelValueF64Codec;
+pub use self::facet_level_value_i64_codec::FacetLevelValueI64Codec;
 pub use self::facet_value_string_codec::FacetValueStringCodec;