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// Copyright 2023 Lance Developers.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Data encodings
//!

use arrow_array::{Array, ArrayRef, UInt32Array};
use async_trait::async_trait;

pub mod binary;
pub mod dictionary;
pub mod plain;

use crate::ReadBatchParams;
use lance_core::Result;

/// Encoder - Write an arrow array to the file.
#[async_trait]
pub trait Encoder {
    /// Write an slice of Arrays, and returns the file offset of the beginning of the batch.
    async fn encode(&mut self, array: &[&dyn Array]) -> Result<usize>;
}

/// Decoder - Read Arrow Data.
#[async_trait]
pub trait Decoder: Send + AsyncIndex<ReadBatchParams> {
    async fn decode(&self) -> Result<ArrayRef>;

    /// Take by indices.
    async fn take(&self, indices: &UInt32Array) -> Result<ArrayRef>;
}

#[async_trait]
pub trait AsyncIndex<IndexType> {
    type Output: Send + Sync;

    async fn get(&self, index: IndexType) -> Self::Output;
}