Minor refactoring. Introducing a codec type enum. (#1477)

fastfield_codecs/benches/bench.rs

@@ -5,11 +5,11 @@ extern crate test;
 #[cfg(test)]
 mod tests {
     use fastfield_codecs::bitpacked::{BitpackedFastFieldReader, BitpackedFastFieldSerializer};
-    use fastfield_codecs::linearinterpol::{
-        LinearInterpolFastFieldReader, LinearInterpolFastFieldSerializer,
+    use fastfield_codecs::blockwise_linear::{
+        BlockwiseLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader,
     };
-    use fastfield_codecs::multilinearinterpol::{
-        MultiLinearInterpolFastFieldReader, MultiLinearInterpolFastFieldSerializer,
+    use fastfield_codecs::linear::{
+        LinearInterpolFastFieldReader, LinearInterpolFastFieldSerializer,
     };
     use fastfield_codecs::*;
 
@@ -64,7 +64,7 @@ mod tests {
     #[bench]
     fn bench_fastfield_multilinearinterpol_create(b: &mut Bencher) {
         let data: Vec<_> = get_data();
-        bench_create::<MultiLinearInterpolFastFieldSerializer>(b, &data);
+        bench_create::<BlockwiseLinearInterpolFastFieldSerializer>(b, &data);
     }
     #[bench]
     fn bench_fastfield_bitpack_get(b: &mut Bencher) {
@@ -79,7 +79,7 @@ mod tests {
     #[bench]
     fn bench_fastfield_multilinearinterpol_get(b: &mut Bencher) {
         let data: Vec<_> = get_data();
-        bench_get::<MultiLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(
+        bench_get::<BlockwiseLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(
             b, &data,
         );
     }

fastfield_codecs/src/bitpacked.rs

@@ -4,7 +4,9 @@ use common::BinarySerializable;
 use ownedbytes::OwnedBytes;
 use tantivy_bitpacker::{compute_num_bits, BitPacker, BitUnpacker};
 
-use crate::{FastFieldCodecReader, FastFieldCodecSerializer, FastFieldDataAccess};
+use crate::{
+    FastFieldCodecReader, FastFieldCodecSerializer, FastFieldCodecType, FastFieldDataAccess,
+};
 
 /// Depending on the field type, a different
 /// fast field is required.
@@ -99,8 +101,9 @@ impl<'a, W: Write> BitpackedFastFieldSerializerLegacy<'a, W> {
 pub struct BitpackedFastFieldSerializer {}
 
 impl FastFieldCodecSerializer for BitpackedFastFieldSerializer {
-    const NAME: &'static str = "Bitpacked";
-    const ID: u8 = 1;
+    /// The CODEC_TYPE is an enum value used for serialization.
+    const CODEC_TYPE: FastFieldCodecType = FastFieldCodecType::Bitpacked;
+
     /// Serializes data with the BitpackedFastFieldSerializer.
     ///
     /// The serializer in fact encode the values by bitpacking

fastfield_codecs/src/multilinearinterpol.rs → fastfield_codecs/src/blockwise_linear.rs

@@ -17,8 +17,10 @@ use common::{BinarySerializable, CountingWriter, DeserializeFrom};
 use ownedbytes::OwnedBytes;
 use tantivy_bitpacker::{compute_num_bits, BitPacker, BitUnpacker};
 
-use crate::linearinterpol::{get_calculated_value, get_slope};
-use crate::{FastFieldCodecReader, FastFieldCodecSerializer, FastFieldDataAccess};
+use crate::linear::{get_calculated_value, get_slope};
+use crate::{
+    FastFieldCodecReader, FastFieldCodecSerializer, FastFieldCodecType, FastFieldDataAccess,
+};
 
 const CHUNK_SIZE: u64 = 512;
 
@@ -179,11 +181,10 @@ impl FastFieldCodecReader for MultiLinearInterpolFastFieldReader {
 }
 
 /// Same as LinearInterpolFastFieldSerializer, but working on chunks of CHUNK_SIZE elements.
-pub struct MultiLinearInterpolFastFieldSerializer {}
+pub struct BlockwiseLinearInterpolFastFieldSerializer {}
 
-impl FastFieldCodecSerializer for MultiLinearInterpolFastFieldSerializer {
-    const NAME: &'static str = "MultiLinearInterpol";
-    const ID: u8 = 3;
+impl FastFieldCodecSerializer for BlockwiseLinearInterpolFastFieldSerializer {
+    const CODEC_TYPE: FastFieldCodecType = FastFieldCodecType::BlockwiseLinearInterpol;
     /// Creates a new fast field serializer.
     fn serialize(
         write: &mut impl Write,
@@ -359,7 +360,7 @@ mod tests {
 
     fn create_and_validate(data: &[u64], name: &str) -> (f32, f32) {
         crate::tests::create_and_validate::<
-            MultiLinearInterpolFastFieldSerializer,
+            BlockwiseLinearInterpolFastFieldSerializer,
             MultiLinearInterpolFastFieldReader,
         >(data, name)
     }

fastfield_codecs/src/lib.rs

@@ -5,11 +5,12 @@ extern crate more_asserts;
 use std::io;
 use std::io::Write;
 
+use common::BinarySerializable;
 use ownedbytes::OwnedBytes;
 
 pub mod bitpacked;
-pub mod linearinterpol;
-pub mod multilinearinterpol;
+pub mod blockwise_linear;
+pub mod linear;
 
 pub trait FastFieldCodecReader: Sized {
     /// reads the metadata and returns the CodecReader
@@ -19,13 +20,50 @@ pub trait FastFieldCodecReader: Sized {
     fn max_value(&self) -> u64;
 }
 
+#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Copy)]
+#[repr(u8)]
+pub enum FastFieldCodecType {
+    Bitpacked = 1,
+    LinearInterpol = 2,
+    BlockwiseLinearInterpol = 3,
+    Gcd = 4,
+}
+
+impl BinarySerializable for FastFieldCodecType {
+    fn serialize<W: Write>(&self, wrt: &mut W) -> io::Result<()> {
+        self.to_code().serialize(wrt)
+    }
+
+    fn deserialize<R: io::Read>(reader: &mut R) -> io::Result<Self> {
+        let code = u8::deserialize(reader)?;
+        let codec_type: Self = Self::from_code(code)
+            .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidData, "Unknown code `{code}.`"))?;
+        Ok(codec_type)
+    }
+}
+
+impl FastFieldCodecType {
+    pub fn to_code(self) -> u8 {
+        self as u8
+    }
+
+    pub fn from_code(code: u8) -> Option<Self> {
+        match code {
+            1 => Some(Self::Bitpacked),
+            2 => Some(Self::LinearInterpol),
+            3 => Some(Self::BlockwiseLinearInterpol),
+            4 => Some(Self::Gcd),
+            _ => None,
+        }
+    }
+}
+
 /// The FastFieldSerializerEstimate trait is required on all variants
 /// of fast field compressions, to decide which one to choose.
 pub trait FastFieldCodecSerializer {
     /// A codex needs to provide a unique name and id, which is
     /// used for debugging and de/serialization.
-    const NAME: &'static str;
-    const ID: u8;
+    const CODEC_TYPE: FastFieldCodecType;
 
     /// Check if the Codec is able to compress the data
     fn is_applicable(fastfield_accessor: &impl FastFieldDataAccess) -> bool;
@@ -128,10 +166,10 @@ mod tests {
     use proptest::proptest;
 
     use crate::bitpacked::{BitpackedFastFieldReader, BitpackedFastFieldSerializer};
-    use crate::linearinterpol::{LinearInterpolFastFieldReader, LinearInterpolFastFieldSerializer};
-    use crate::multilinearinterpol::{
-        MultiLinearInterpolFastFieldReader, MultiLinearInterpolFastFieldSerializer,
+    use crate::blockwise_linear::{
+        BlockwiseLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader,
     };
+    use crate::linear::{LinearInterpolFastFieldReader, LinearInterpolFastFieldSerializer};
 
     pub fn create_and_validate<S: FastFieldCodecSerializer, R: FastFieldCodecReader>(
         data: &[u64],
@@ -151,8 +189,8 @@ mod tests {
             let val = reader.get_u64(doc as u64);
             if val != *orig_val {
                 panic!(
-                    "val {:?} does not match orig_val {:?}, in data set {}, data {:?}",
-                    val, orig_val, name, data
+                    "val {val:?} does not match orig_val {orig_val:?}, in data set {name}, data \
+                     {data:?}",
                 );
             }
         }
@@ -163,14 +201,14 @@ mod tests {
         #[test]
         fn test_proptest_small(data in proptest::collection::vec(any::<u64>(), 1..10)) {
             create_and_validate::<LinearInterpolFastFieldSerializer, LinearInterpolFastFieldReader>(&data, "proptest linearinterpol");
-            create_and_validate::<MultiLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(&data, "proptest multilinearinterpol");
+            create_and_validate::<BlockwiseLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(&data, "proptest multilinearinterpol");
             create_and_validate::<BitpackedFastFieldSerializer, BitpackedFastFieldReader>(&data, "proptest bitpacked");
         }
 
         #[test]
         fn test_proptest_large(data in proptest::collection::vec(any::<u64>(), 1..6000)) {
             create_and_validate::<LinearInterpolFastFieldSerializer, LinearInterpolFastFieldReader>(&data, "proptest linearinterpol");
-            create_and_validate::<MultiLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(&data, "proptest multilinearinterpol");
+            create_and_validate::<BlockwiseLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(&data, "proptest multilinearinterpol");
             create_and_validate::<BitpackedFastFieldSerializer, BitpackedFastFieldReader>(&data, "proptest bitpacked");
         }
 
@@ -193,19 +231,15 @@ mod tests {
     }
 
     fn test_codec<S: FastFieldCodecSerializer, R: FastFieldCodecReader>() {
-        let codec_name = S::NAME;
-        for (data, data_set_name) in get_codec_test_data_sets() {
-            let (estimate, actual) =
-                crate::tests::create_and_validate::<S, R>(&data, data_set_name);
+        let codec_name = format!("{:?}", S::CODEC_TYPE);
+        for (data, dataset_name) in get_codec_test_data_sets() {
+            let (estimate, actual) = crate::tests::create_and_validate::<S, R>(&data, dataset_name);
             let result = if estimate == f32::MAX {
                 "Disabled".to_string()
             } else {
-                format!("Estimate {:?} Actual {:?} ", estimate, actual)
+                format!("Estimate `{estimate}` Actual `{actual}`")
             };
-            println!(
-                "Codec {}, DataSet {}, {}",
-                codec_name, data_set_name, result
-            );
+            println!("Codec {codec_name}, DataSet {dataset_name}, {result}");
         }
     }
     #[test]
@@ -218,7 +252,8 @@ mod tests {
     }
     #[test]
     fn test_codec_multi_interpolation() {
-        test_codec::<MultiLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>();
+        test_codec::<BlockwiseLinearInterpolFastFieldSerializer, MultiLinearInterpolFastFieldReader>(
+        );
     }
 
     use super::*;
@@ -231,7 +266,7 @@ mod tests {
         assert_le!(linear_interpol_estimation, 0.01);
 
         let multi_linear_interpol_estimation =
-            MultiLinearInterpolFastFieldSerializer::estimate(&data);
+            BlockwiseLinearInterpolFastFieldSerializer::estimate(&data);
         assert_le!(multi_linear_interpol_estimation, 0.2);
         assert_le!(linear_interpol_estimation, multi_linear_interpol_estimation);
 
@@ -262,4 +297,16 @@ mod tests {
         assert_le!(bitpacked_estimation, 0.32);
         assert_le!(bitpacked_estimation, linear_interpol_estimation);
     }
+
+    #[test]
+    fn test_fast_field_codec_type_to_code() {
+        let mut count_codec = 0;
+        for code in 0..=255 {
+            if let Some(codec_type) = FastFieldCodecType::from_code(code) {
+                assert_eq!(codec_type.to_code(), code);
+                count_codec += 1;
+            }
+        }
+        assert_eq!(count_codec, 4);
+    }
 }

fastfield_codecs/src/linearinterpol.rs → fastfield_codecs/src/linear.rs

@@ -5,7 +5,9 @@ use common::{BinarySerializable, FixedSize};
 use ownedbytes::OwnedBytes;
 use tantivy_bitpacker::{compute_num_bits, BitPacker, BitUnpacker};
 
-use crate::{FastFieldCodecReader, FastFieldCodecSerializer, FastFieldDataAccess};
+use crate::{
+    FastFieldCodecReader, FastFieldCodecSerializer, FastFieldCodecType, FastFieldDataAccess,
+};
 
 /// Depending on the field type, a different
 /// fast field is required.
@@ -133,8 +135,8 @@ pub fn get_calculated_value(first_val: u64, pos: u64, slope: f32) -> u64 {
 }
 
 impl FastFieldCodecSerializer for LinearInterpolFastFieldSerializer {
-    const NAME: &'static str = "LinearInterpol";
-    const ID: u8 = 2;
+    const CODEC_TYPE: FastFieldCodecType = FastFieldCodecType::LinearInterpol;
+
     /// Creates a new fast field serializer.
     fn serialize(
         write: &mut impl Write,

fastfield_codecs/src/main.rs

@@ -1,8 +1,8 @@
 #[macro_use]
 extern crate prettytable;
-use fastfield_codecs::linearinterpol::LinearInterpolFastFieldSerializer;
-use fastfield_codecs::multilinearinterpol::MultiLinearInterpolFastFieldSerializer;
-use fastfield_codecs::{FastFieldCodecSerializer, FastFieldStats};
+use fastfield_codecs::blockwise_linear::BlockwiseLinearInterpolFastFieldSerializer;
+use fastfield_codecs::linear::LinearInterpolFastFieldSerializer;
+use fastfield_codecs::{FastFieldCodecSerializer, FastFieldCodecType, FastFieldStats};
 use prettytable::{Cell, Row, Table};
 
 fn main() {
@@ -15,7 +15,7 @@ fn main() {
         let mut results = vec![];
         let res = serialize_with_codec::<LinearInterpolFastFieldSerializer>(&data);
         results.push(res);
-        let res = serialize_with_codec::<MultiLinearInterpolFastFieldSerializer>(&data);
+        let res = serialize_with_codec::<BlockwiseLinearInterpolFastFieldSerializer>(&data);
         results.push(res);
         let res = serialize_with_codec::<fastfield_codecs::bitpacked::BitpackedFastFieldSerializer>(
             &data,
@@ -33,7 +33,7 @@ fn main() {
             .unwrap();
 
         table.add_row(Row::new(vec![Cell::new(data_set_name).style_spec("Bbb")]));
-        for (is_applicable, est, comp, name) in results {
+        for (is_applicable, est, comp, codec_type) in results {
             let (est_cell, ratio_cell) = if !is_applicable {
                 ("Codec Disabled".to_string(), "".to_string())
             } else {
@@ -46,7 +46,7 @@ fn main() {
             };
 
             table.add_row(Row::new(vec![
-                Cell::new(name).style_spec("bFg"),
+                Cell::new(&format!("{codec_type:?}")).style_spec("bFg"),
                 Cell::new(&ratio_cell).style_spec(style),
                 Cell::new(&est_cell).style_spec(""),
             ]));
@@ -93,17 +93,17 @@ pub fn get_codec_test_data_sets() -> Vec<(Vec<u64>, &'static str)> {
 
 pub fn serialize_with_codec<S: FastFieldCodecSerializer>(
     data: &[u64],
-) -> (bool, f32, f32, &'static str) {
+) -> (bool, f32, f32, FastFieldCodecType) {
     let is_applicable = S::is_applicable(&data);
     if !is_applicable {
-        return (false, 0.0, 0.0, S::NAME);
+        return (false, 0.0, 0.0, S::CODEC_TYPE);
     }
     let estimation = S::estimate(&data);
     let mut out = vec![];
     S::serialize(&mut out, &data).unwrap();
 
     let actual_compression = out.len() as f32 / (data.len() * 8) as f32;
-    (true, estimation, actual_compression, S::NAME)
+    (true, estimation, actual_compression, S::CODEC_TYPE)
 }
 
 pub fn stats_from_vec(data: &[u64]) -> FastFieldStats {