Skip to content

ARROW-11270: [Rust] Array slice accessors #9215

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
tyrelr wants to merge 2 commits into from
Closed

ARROW-11270: [Rust] Array slice accessors #9215

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
0ef4bb4
Replace unsafe value_offset(i) functions with safe value_offsets() fu…
tyrelr Jan 13, 2021
dda0545
use unsafe access to the offset array where the offset has already be…
tyrelr Jan 23, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 2 additions & 2 deletions rust/arrow/src/array/array.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -399,7 +399,7 @@ mod tests {
let array = new_empty_array(&DataType::Utf8);
let a = array.as_any().downcast_ref::<StringArray>().unwrap();
assert_eq!(a.len(), 0);
assert_eq!(a.value_offset(0), 0i32);
assert_eq!(a.value_offsets()[0], 0i32);
}

#[test]
Expand All @@ -409,6 +409,6 @@ mod tests {
let array = new_empty_array(&data_type);
let a = array.as_any().downcast_ref::<ListArray>().unwrap();
assert_eq!(a.len(), 0);
assert_eq!(a.value_offset(0), 0i32);
assert_eq!(a.value_offsets()[0], 0i32);
}
}
106 changes: 72 additions & 34 deletions rust/arrow/src/array/array_binary.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -52,47 +52,62 @@ pub struct GenericBinaryArray<OffsetSize: BinaryOffsetSizeTrait> {
}

impl<OffsetSize: BinaryOffsetSizeTrait> GenericBinaryArray<OffsetSize> {
/// Returns the offset for the element at index `i`.
///
/// Note this doesn't do any bound checking, for performance reason.
#[inline]
pub fn value_offset(&self, i: usize) -> OffsetSize {
self.value_offset_at(self.data.offset() + i)
}

/// Returns the length for the element at index `i`.
///
/// Note this doesn't do any bound checking, for performance reason.
/// Returns the length for value at index `i`.
#[inline]
pub fn value_length(&self, mut i: usize) -> OffsetSize {
i += self.data.offset();
self.value_offset_at(i + 1) - self.value_offset_at(i)
}

/// Returns a clone of the value offset buffer
pub fn value_offsets(&self) -> Buffer {
self.data.buffers()[0].clone()
pub fn value_length(&self, i: usize) -> OffsetSize {
let offsets = self.value_offsets();
offsets[i + 1] - offsets[i]
}

/// Returns a clone of the value data buffer
pub fn value_data(&self) -> Buffer {
self.data.buffers()[1].clone()
}

/// Returns the offset values in the offsets buffer
#[inline]
fn value_offset_at(&self, i: usize) -> OffsetSize {
unsafe { *self.value_offsets.as_ptr().add(i) }
pub fn value_offsets(&self) -> &[OffsetSize] {
// Soundness
// pointer alignment & location is ensured by RawPtrBox
// buffer bounds/offset is ensured by the ArrayData instance.
unsafe {
std::slice::from_raw_parts(
self.value_offsets.as_ptr().add(self.data.offset()),
self.len() + 1,
)
}
}

/// Returns the element at index `i` as a byte slice.
/// Returns the element at index `i` as bytes slice
/// # Safety
/// Caller is responsible for ensuring that the index is within the bounds of the array
pub unsafe fn value_unchecked(&self, i: usize) -> &[u8] {
let end = *self.value_offsets().get_unchecked(i + 1);
let start = *self.value_offsets().get_unchecked(i);

// Soundness
// pointer alignment & location is ensured by RawPtrBox
// buffer bounds/offset is ensured by the value_offset invariants
std::slice::from_raw_parts(
self.value_data.as_ptr().offset(start.to_isize()),
(end - start).to_usize().unwrap(),
)
}

/// Returns the element at index `i` as bytes slice
pub fn value(&self, i: usize) -> &[u8] {
assert!(i < self.data.len(), "BinaryArray out of bounds access");
let offset = i.checked_add(self.data.offset()).unwrap();
//Soundness: length checked above, offset buffer length is 1 larger than logical array length
let end = unsafe { self.value_offsets().get_unchecked(i + 1) };
let start = unsafe { self.value_offsets().get_unchecked(i) };

// Soundness
// pointer alignment & location is ensured by RawPtrBox
// buffer bounds/offset is ensured by the value_offset invariants
unsafe {
let pos = self.value_offset_at(offset);
std::slice::from_raw_parts(
self.value_data.as_ptr().offset(pos.to_isize()),
(self.value_offset_at(offset + 1) - pos).to_usize().unwrap(),
self.value_data.as_ptr().offset(start.to_isize()),
(*end - *start).to_usize().unwrap(),
)
}
}
Expand Down Expand Up @@ -648,12 +663,19 @@ mod tests {
assert_eq!(3, binary_array.len());
assert_eq!(0, binary_array.null_count());
assert_eq!([b'h', b'e', b'l', b'l', b'o'], binary_array.value(0));
assert_eq!([b'h', b'e', b'l', b'l', b'o'], unsafe {
binary_array.value_unchecked(0)
});
assert_eq!([] as [u8; 0], binary_array.value(1));
assert_eq!([] as [u8; 0], unsafe { binary_array.value_unchecked(1) });
assert_eq!(
[b'p', b'a', b'r', b'q', b'u', b'e', b't'],
binary_array.value(2)
);
assert_eq!(5, binary_array.value_offset(2));
assert_eq!([b'p', b'a', b'r', b'q', b'u', b'e', b't'], unsafe {
binary_array.value_unchecked(2)
});
assert_eq!(5, binary_array.value_offsets()[2]);
assert_eq!(7, binary_array.value_length(2));
for i in 0..3 {
assert!(binary_array.is_valid(i));
Expand All @@ -672,9 +694,9 @@ mod tests {
[b'p', b'a', b'r', b'q', b'u', b'e', b't'],
binary_array.value(1)
);
assert_eq!(5, binary_array.value_offset(0));
assert_eq!(5, binary_array.value_offsets()[0]);
assert_eq!(0, binary_array.value_length(0));
assert_eq!(5, binary_array.value_offset(1));
assert_eq!(5, binary_array.value_offsets()[1]);
assert_eq!(7, binary_array.value_length(1));
}

Expand All @@ -695,12 +717,19 @@ mod tests {
assert_eq!(3, binary_array.len());
assert_eq!(0, binary_array.null_count());
assert_eq!([b'h', b'e', b'l', b'l', b'o'], binary_array.value(0));
assert_eq!([b'h', b'e', b'l', b'l', b'o'], unsafe {
binary_array.value_unchecked(0)
});
assert_eq!([] as [u8; 0], binary_array.value(1));
assert_eq!([] as [u8; 0], unsafe { binary_array.value_unchecked(1) });
assert_eq!(
[b'p', b'a', b'r', b'q', b'u', b'e', b't'],
binary_array.value(2)
);
assert_eq!(5, binary_array.value_offset(2));
assert_eq!([b'p', b'a', b'r', b'q', b'u', b'e', b't'], unsafe {
binary_array.value_unchecked(2)
});
assert_eq!(5, binary_array.value_offsets()[2]);
assert_eq!(7, binary_array.value_length(2));
for i in 0..3 {
assert!(binary_array.is_valid(i));
Expand All @@ -719,9 +748,12 @@ mod tests {
[b'p', b'a', b'r', b'q', b'u', b'e', b't'],
binary_array.value(1)
);
assert_eq!(5, binary_array.value_offset(0));
assert_eq!([b'p', b'a', b'r', b'q', b'u', b'e', b't'], unsafe {
binary_array.value_unchecked(1)
});
assert_eq!(5, binary_array.value_offsets()[0]);
assert_eq!(0, binary_array.value_length(0));
assert_eq!(5, binary_array.value_offset(1));
assert_eq!(5, binary_array.value_offsets()[1]);
assert_eq!(7, binary_array.value_length(1));
}

Expand Down Expand Up @@ -757,9 +789,12 @@ mod tests {

assert_eq!(binary_array1.len(), binary_array2.len());
assert_eq!(binary_array1.null_count(), binary_array2.null_count());
assert_eq!(binary_array1.value_offsets(), binary_array2.value_offsets());
for i in 0..binary_array1.len() {
assert_eq!(binary_array1.value(i), binary_array2.value(i));
assert_eq!(binary_array1.value_offset(i), binary_array2.value_offset(i));
assert_eq!(binary_array1.value(i), unsafe {
binary_array2.value_unchecked(i)
});
assert_eq!(binary_array1.value_length(i), binary_array2.value_length(i));
}
}
Expand Down Expand Up @@ -796,9 +831,12 @@ mod tests {

assert_eq!(binary_array1.len(), binary_array2.len());
assert_eq!(binary_array1.null_count(), binary_array2.null_count());
assert_eq!(binary_array1.value_offsets(), binary_array2.value_offsets());
for i in 0..binary_array1.len() {
assert_eq!(binary_array1.value(i), binary_array2.value(i));
assert_eq!(binary_array1.value_offset(i), binary_array2.value_offset(i));
assert_eq!(binary_array1.value(i), unsafe {
binary_array2.value_unchecked(i)
});
assert_eq!(binary_array1.value_length(i), binary_array2.value_length(i));
}
}
Expand Down
Loading