polars_arrow::mmap

Function mmap_unchecked

Source 
pub unsafe fn mmap_unchecked<T: AsRef<[u8]>>(
    metadata: &FileMetadata,
    dictionaries: &Dictionaries,
    data: Arc<T>,
    chunk: usize,
) -> PolarsResult<RecordBatchT<Box<dyn Array>>>
Available on crate feature io_ipc only.
Expand description

Memory maps an record batch from an IPC file into a RecordBatchT.

§Errors

This function errors when:

  • The IPC file is not valid
  • the buffers on the file are un-aligned with their corresponding data. This can happen when:
    • the file was written with 8-bit alignment
    • the file contains type decimal 128 or 256

§Safety

The caller must ensure that data contains a valid buffers, for example:

  • Offsets in variable-sized containers must be in-bounds and increasing
  • Utf8 data is valid