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arrow 53.4.0

Rust implementation of Apache Arrow
Documentation 
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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

use arrow::array::{ArrayRef, Int32Array, StringArray};
use arrow::pyarrow::{FromPyArrow, ToPyArrow};
use arrow::record_batch::RecordBatch;
use arrow_array::builder::{BinaryViewBuilder, StringViewBuilder};
use arrow_array::{Array, BinaryViewArray, StringViewArray};
use pyo3::Python;
use std::sync::Arc;

#[test]
fn test_to_pyarrow() {
    pyo3::prepare_freethreaded_python();

    let a: ArrayRef = Arc::new(Int32Array::from(vec![1, 2]));
    let b: ArrayRef = Arc::new(StringArray::from(vec!["a", "b"]));
    // The "very long string" will not be inlined, and force the creation of a data buffer.
    let c: ArrayRef = Arc::new(StringViewArray::from(vec!["short", "a very long string"]));
    let input = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap();
    println!("input: {:?}", input);

    let res = Python::with_gil(|py| {
        let py_input = input.to_pyarrow(py)?;
        let records = RecordBatch::from_pyarrow_bound(py_input.bind(py))?;
        let py_records = records.to_pyarrow(py)?;
        RecordBatch::from_pyarrow_bound(py_records.bind(py))
    })
    .unwrap();

    assert_eq!(input, res);
}

#[test]
fn test_to_pyarrow_byte_view() {
    pyo3::prepare_freethreaded_python();

    for num_variadic_buffers in 0..=2 {
        let string_view: ArrayRef = Arc::new(string_view_column(num_variadic_buffers));
        let binary_view: ArrayRef = Arc::new(binary_view_column(num_variadic_buffers));

        let input = RecordBatch::try_from_iter(vec![
            ("string_view", string_view),
            ("binary_view", binary_view),
        ])
        .unwrap();

        println!("input: {:?}", input);
        let res = Python::with_gil(|py| {
            let py_input = input.to_pyarrow(py)?;
            let records = RecordBatch::from_pyarrow_bound(py_input.bind(py))?;
            let py_records = records.to_pyarrow(py)?;
            RecordBatch::from_pyarrow_bound(py_records.bind(py))
        })
        .unwrap();

        assert_eq!(input, res);
    }
}

fn binary_view_column(num_variadic_buffers: usize) -> BinaryViewArray {
    let long_scalar = b"but soft what light through yonder window breaks".as_slice();
    let mut builder = BinaryViewBuilder::new().with_fixed_block_size(long_scalar.len() as u32);
    // Make sure there is at least one non-inlined value.
    builder.append_value("inlined".as_bytes());

    for _ in 0..num_variadic_buffers {
        builder.append_value(long_scalar);
    }

    let result = builder.finish();

    assert_eq!(result.data_buffers().len(), num_variadic_buffers);
    assert_eq!(result.len(), num_variadic_buffers + 1);

    result
}

fn string_view_column(num_variadic_buffers: usize) -> StringViewArray {
    let long_scalar = "but soft what light through yonder window breaks";
    let mut builder = StringViewBuilder::new().with_fixed_block_size(long_scalar.len() as u32);
    // Make sure there is at least one non-inlined value.
    builder.append_value("inlined");

    for _ in 0..num_variadic_buffers {
        builder.append_value(long_scalar);
    }

    let result = builder.finish();

    assert_eq!(result.data_buffers().len(), num_variadic_buffers);
    assert_eq!(result.len(), num_variadic_buffers + 1);

    result
}