zarrs 0.23.9

//! The `zstd` bytes to bytes codec.
//!
//! Applies [Zstd](https://tools.ietf.org/html/rfc8878) compression.
//!
//! ### Compatible Implementations
//! This is expected to become a standardised extension.
//!
//! Some implementations have compatibility issues due to how the content size is encoded:
//! - <https://github.com/zarr-developers/numcodecs/issues/424>
//! - <https://github.com/google/neuroglancer/issues/625>
//!
//! ### Specification:
//! - <https://github.com/zarr-developers/zarr-extensions/tree/main/codecs/zstd>
//! - <https://github.com/zarr-developers/zarr-specs/pull/256>
//!
//! ### Codec `name` Aliases (Zarr V3)
//! - `zstd`
//!
//! ### Codec `id` Aliases (Zarr V2)
//! - `zstd`
//!
//! ### Codec `configuration` Example - [`ZstdCodecConfiguration`]:
//! ```rust
//! # let JSON = r#"
//! {
//!     "level": 1,
//!     "checksum": true
//! }
//! # "#;
//! # use zarrs::metadata_ext::codec::zstd::ZstdCodecConfiguration;
//! # serde_json::from_str::<ZstdCodecConfiguration>(JSON).unwrap();

mod zstd_codec;

use std::sync::Arc;

use zarrs_metadata::v2::MetadataV2;
use zarrs_metadata::v3::MetadataV3;
pub use zstd_codec::ZstdCodec;

use zarrs_codec::{Codec, CodecPluginV2, CodecPluginV3, CodecTraitsV2, CodecTraitsV3};
pub use zarrs_metadata_ext::codec::zstd::{
    ZstdCodecConfiguration, ZstdCodecConfigurationNumcodecs, ZstdCodecConfigurationV1,
    ZstdCompressionLevel,
};
use zarrs_plugin::PluginCreateError;

zarrs_plugin::impl_extension_aliases!(ZstdCodec, v3: "zstd", v2: "zstd");

// Register the V3 codec.
inventory::submit! {
    CodecPluginV3::new::<ZstdCodec>()
}

// Register the V2 codec.
inventory::submit! {
    CodecPluginV2::new::<ZstdCodec>()
}

impl CodecTraitsV3 for ZstdCodec {
    fn create(metadata: &MetadataV3) -> Result<Codec, PluginCreateError> {
        let configuration: ZstdCodecConfigurationV1 = metadata.to_typed_configuration()?;
        let codec = ZstdCodec::new(configuration.level.into(), configuration.checksum);
        Ok(Codec::BytesToBytes(Arc::new(codec)))
    }
}

impl CodecTraitsV2 for ZstdCodec {
    fn create(metadata: &MetadataV2) -> Result<Codec, PluginCreateError> {
        let configuration: ZstdCodecConfigurationNumcodecs = metadata.to_typed_configuration()?;
        let codec = ZstdCodec::new(configuration.level.into(), false);
        Ok(Codec::BytesToBytes(Arc::new(codec)))
    }
}

#[cfg(test)]
mod tests {
    use std::borrow::Cow;
    use std::sync::Arc;

    use super::*;
    use crate::array::BytesRepresentation;
    use zarrs_codec::{BytesPartialDecoderTraits, BytesToBytesCodecTraits, CodecOptions};
    use zarrs_storage::byte_range::ByteRange;

    const JSON_VALID: &str = r#"{
    "level": 22,
    "checksum": false
}"#;

    #[test]
    #[cfg_attr(miri, ignore)]
    fn codec_zstd_round_trip1() {
        let elements: Vec<u16> = (0..32).collect();
        let bytes = crate::array::transmute_to_bytes_vec(elements);
        let bytes_representation = BytesRepresentation::FixedSize(bytes.len() as u64);

        let configuration: ZstdCodecConfiguration = serde_json::from_str(JSON_VALID).unwrap();
        let codec = ZstdCodec::new_with_configuration(&configuration).unwrap();

        let encoded = codec
            .encode(Cow::Borrowed(&bytes), &CodecOptions::default())
            .unwrap();
        let decoded = codec
            .decode(encoded, &bytes_representation, &CodecOptions::default())
            .unwrap();
        assert_eq!(bytes, decoded.to_vec());
    }

    #[test]
    #[cfg_attr(miri, ignore)]
    fn codec_zstd_partial_decode() {
        let elements: Vec<u16> = (0..8).collect();
        let bytes = crate::array::transmute_to_bytes_vec(elements);
        let bytes_representation = BytesRepresentation::FixedSize(bytes.len() as u64);

        let configuration: ZstdCodecConfiguration = serde_json::from_str(JSON_VALID).unwrap();
        let codec = Arc::new(ZstdCodec::new_with_configuration(&configuration).unwrap());

        let encoded = codec
            .encode(Cow::Owned(bytes), &CodecOptions::default())
            .unwrap();
        let decoded_regions = [
            ByteRange::FromStart(4, Some(4)),
            ByteRange::FromStart(10, Some(2)),
        ];

        let input_handle = Arc::new(encoded);
        let partial_decoder = codec
            .partial_decoder(
                input_handle.clone(),
                &bytes_representation,
                &CodecOptions::default(),
            )
            .unwrap();
        assert_eq!(partial_decoder.size_held(), input_handle.size_held()); // zstd partial decoder does not hold bytes
        let decoded_partial_chunk = partial_decoder
            .partial_decode_many(
                Box::new(decoded_regions.into_iter()),
                &CodecOptions::default(),
            )
            .unwrap()
            .unwrap()
            .concat();

        let decoded_partial_chunk: Vec<u16> = decoded_partial_chunk
            .clone()
            .as_chunks::<2>()
            .0
            .iter()
            .map(|b| u16::from_ne_bytes(*b))
            .collect();
        let answer: Vec<u16> = vec![2, 3, 5];
        assert_eq!(answer, decoded_partial_chunk);
    }

    #[cfg(feature = "async")]
    #[tokio::test]
    #[cfg_attr(miri, ignore)]
    async fn codec_zstd_async_partial_decode() {
        let elements: Vec<u16> = (0..8).collect();
        let bytes = crate::array::transmute_to_bytes_vec(elements);
        let bytes_representation = BytesRepresentation::FixedSize(bytes.len() as u64);

        let configuration: ZstdCodecConfiguration = serde_json::from_str(JSON_VALID).unwrap();
        let codec = Arc::new(ZstdCodec::new_with_configuration(&configuration).unwrap());

        let encoded = codec
            .encode(Cow::Owned(bytes), &CodecOptions::default())
            .unwrap();
        let decoded_regions = [
            ByteRange::FromStart(4, Some(4)),
            ByteRange::FromStart(10, Some(2)),
        ];

        let input_handle = Arc::new(encoded);
        let partial_decoder = codec
            .async_partial_decoder(
                input_handle,
                &bytes_representation,
                &CodecOptions::default(),
            )
            .await
            .unwrap();
        let decoded_partial_chunk = partial_decoder
            .partial_decode_many(
                Box::new(decoded_regions.into_iter()),
                &CodecOptions::default(),
            )
            .await
            .unwrap()
            .unwrap()
            .concat();

        let decoded_partial_chunk: Vec<u16> = decoded_partial_chunk
            .clone()
            .as_chunks::<2>()
            .0
            .iter()
            .map(|b| u16::from_ne_bytes(*b))
            .collect();
        let answer: Vec<u16> = vec![2, 3, 5];
        assert_eq!(answer, decoded_partial_chunk);
    }
}