lsm-tree 3.1.4

A K.I.S.S. implementation of log-structured merge trees (LSM-trees/LSMTs)
Documentation 
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// Copyright (c) 2024-present, fjall-rs
// This source code is licensed under both the Apache 2.0 and MIT License
// (found in the LICENSE-* files in the repository)

use crate::coding::{Decode, Encode};
use byteorder::{ReadBytesExt, WriteBytesExt};
use std::io::{Read, Write};

/// Compression algorithm to use
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum CompressionType {
    /// No compression
    ///
    /// Not recommended.
    None,

    /// LZ4 compression
    ///
    /// Recommended for use cases with a focus
    /// on speed over compression ratio.
    #[cfg(feature = "lz4")]
    Lz4,
}

impl std::fmt::Display for CompressionType {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}",
            match self {
                Self::None => "none",

                #[cfg(feature = "lz4")]
                Self::Lz4 => "lz4",
            }
        )
    }
}

impl Encode for CompressionType {
    fn encode_into<W: Write>(&self, writer: &mut W) -> Result<(), crate::Error> {
        match self {
            Self::None => {
                writer.write_u8(0)?;
            }

            #[cfg(feature = "lz4")]
            Self::Lz4 => {
                writer.write_u8(1)?;
            }
        }

        Ok(())
    }
}

impl Decode for CompressionType {
    fn decode_from<R: Read>(reader: &mut R) -> Result<Self, crate::Error> {
        let tag = reader.read_u8()?;

        match tag {
            0 => Ok(Self::None),

            #[cfg(feature = "lz4")]
            1 => Ok(Self::Lz4),

            tag => Err(crate::Error::InvalidTag(("CompressionType", tag))),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use test_log::test;

    #[test]
    fn compression_serialize_none() {
        let serialized = CompressionType::None.encode_into_vec();
        assert_eq!(1, serialized.len());
    }

    #[cfg(feature = "lz4")]
    mod lz4 {
        use super::*;
        use test_log::test;

        #[test]
        fn compression_serialize_none() {
            let serialized = CompressionType::Lz4.encode_into_vec();
            assert_eq!(1, serialized.len());
        }
    }
}