Function validate_view_impl

arrow-data/src/byte_view.rs:164–207

(views: &[u128], buffers: &[Buffer], f: F)

}

fn validate_view_impl<F>(views: &[u128], buffers: &[Buffer], f: F) -> Result<(), ArrowError>
where
    F: Fn(usize, &[u8]) -> Result<(), ArrowError>,
{
    for (idx, v) in views.iter().enumerate() {
        let len = *v as u32;
        if len <= MAX_INLINE_VIEW_LEN {
            if len < MAX_INLINE_VIEW_LEN && (v >> (32 + len * 8)) != 0 {
                return Err(ArrowError::InvalidArgumentError(format!(
                    "View at index {idx} contained non-zero padding for string of length {len}",
                )));
            }
            f(idx, &v.to_le_bytes()[4..4 + len as usize])?;
        } else {
            let view = ByteView::from(*v);
            let data = buffers.get(view.buffer_index as usize).ok_or_else(|| {
                ArrowError::InvalidArgumentError(format!(
                    "Invalid buffer index at {idx}: got index {} but only has {} buffers",
                    view.buffer_index,
                    buffers.len()
                ))
            })?;

            let start = view.offset as usize;
            let end = start + len as usize;
            let b = data.get(start..end).ok_or_else(|| {
                ArrowError::InvalidArgumentError(format!(
                    "Invalid buffer slice at {idx}: got {start}..{end} but buffer {} has length {}",
                    view.buffer_index,
                    data.len()
                ))
            })?;

            if !b.starts_with(&view.prefix.to_le_bytes()) {
                return Err(ArrowError::InvalidArgumentError(
                    "Mismatch between embedded prefix and data".to_string(),
                ));
            }

            f(idx, b)?;
        }
    }
    Ok(())
}