returns all buffers, as organized by Rust (i.e. null buffer is skipped if it's present in the spec of the type)
(&self, can_contain_null_mask: bool, variadic: bool)
| 415 | /// returns all buffers, as organized by Rust (i.e. null buffer is skipped if it's present |
| 416 | /// in the spec of the type) |
| 417 | fn buffers(&self, can_contain_null_mask: bool, variadic: bool) -> Result<Vec<Buffer>> { |
| 418 | // + 1: skip null buffer |
| 419 | let buffer_begin = can_contain_null_mask as usize; |
| 420 | let buffer_end = self.array.num_buffers() - usize::from(variadic); |
| 421 | |
| 422 | let variadic_buffer_lens = if variadic { |
| 423 | // Each views array has 1 (optional) null buffer, 1 views buffer, 1 lengths buffer. |
| 424 | // Rest are variadic. |
| 425 | let num_variadic_buffers = |
| 426 | self.array.num_buffers() - (2 + usize::from(can_contain_null_mask)); |
| 427 | if num_variadic_buffers == 0 { |
| 428 | &[] |
| 429 | } else { |
| 430 | let lengths = self.array.buffer(self.array.num_buffers() - 1); |
| 431 | // SAFETY: is lengths is non-null, then it must be valid for up to num_variadic_buffers. |
| 432 | unsafe { std::slice::from_raw_parts(lengths.cast::<i64>(), num_variadic_buffers) } |
| 433 | } |
| 434 | } else { |
| 435 | &[] |
| 436 | }; |
| 437 | |
| 438 | (buffer_begin..buffer_end) |
| 439 | .map(|index| { |
| 440 | let len = self.buffer_len(index, variadic_buffer_lens, &self.data_type)?; |
| 441 | match unsafe { create_buffer(self.owner.clone(), self.array, index, len) } { |
| 442 | Some(buf) => { |
| 443 | // External libraries may use a dangling pointer for a buffer with length 0. |
| 444 | // We respect the array length specified in the C Data Interface. Actually, |
| 445 | // if the length is incorrect, we cannot create a correct buffer even if |
| 446 | // the pointer is valid. |
| 447 | if buf.is_empty() { |
| 448 | Ok(MutableBuffer::new(0).into()) |
| 449 | } else { |
| 450 | Ok(buf) |
| 451 | } |
| 452 | } |
| 453 | None if len == 0 => { |
| 454 | // Null data buffer, which Rust doesn't allow. So create |
| 455 | // an empty buffer. |
| 456 | Ok(MutableBuffer::new(0).into()) |
| 457 | } |
| 458 | None => Err(ArrowError::CDataInterface(format!( |
| 459 | "The external buffer at position {index} is null." |
| 460 | ))), |
| 461 | } |
| 462 | }) |
| 463 | .collect() |
| 464 | } |
| 465 | |
| 466 | /// Returns the length, in bytes, of the buffer `i` (indexed according to the C data interface) |
| 467 | /// Rust implementation uses fixed-sized buffers, which require knowledge of their `len`. |