1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

//! contains FFI bindings to import and export [`Array`](crate::array::Array) via
//! Arrow's [C Data Interface](https://arrow.apache.org/docs/format/CDataInterface.html)
mod array;
mod bridge;
mod generated;
mod schema;
mod stream;

pub(crate) use array::try_from;
pub(crate) use array::{ArrowArrayRef, InternalArrowArray};

use std::sync::Arc;

use crate::array::Array;
use crate::datatypes::{DataType, Field};
use crate::error::Result;

use self::schema::to_field;

pub use generated::{ArrowArray, ArrowArrayStream, ArrowSchema};
pub use stream::{export_iterator, ArrowArrayStreamReader};

/// Exports an [`Arc<dyn Array>`] to the C data interface.
/// # Safety
/// The pointer `ptr` must be allocated and valid
pub unsafe fn export_array_to_c(array: Arc<dyn Array>, ptr: *mut ArrowArray) {
    let array = bridge::align_to_c_data_interface(array);

    std::ptr::write_unaligned(ptr, ArrowArray::new(array));
}

/// Exports a [`Field`] to the C data interface.
/// # Safety
/// The pointer `ptr` must be allocated and valid
pub unsafe fn export_field_to_c(field: &Field, ptr: *mut ArrowSchema) {
    std::ptr::write_unaligned(ptr, ArrowSchema::new(field));
}

/// Imports a [`Field`] from the C data interface.
/// # Safety
/// This function is intrinsically `unsafe` and relies on a [`ArrowSchema`]
/// valid according to the [C data interface](https://arrow.apache.org/docs/format/CDataInterface.html) (FFI).
pub unsafe fn import_field_from_c(field: &ArrowSchema) -> Result<Field> {
    to_field(field)
}

/// Imports an [`Array`] from the C data interface.
/// # Safety
/// This function is intrinsically `unsafe` and relies on a [`ArrowArray`]
/// valid according to the [C data interface](https://arrow.apache.org/docs/format/CDataInterface.html) (FFI).
pub unsafe fn import_array_from_c(
    array: Box<ArrowArray>,
    data_type: DataType,
) -> Result<Box<dyn Array>> {
    try_from(Arc::new(InternalArrowArray::new(array, data_type)))
}