arrow_array/array/

boolean_array.rs

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
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// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

use crate::array::print_long_array;
use crate::builder::BooleanBuilder;
use crate::iterator::BooleanIter;
use crate::{Array, ArrayAccessor, ArrayRef, Scalar};
use arrow_buffer::{bit_util, BooleanBuffer, Buffer, MutableBuffer, NullBuffer};
use arrow_data::{ArrayData, ArrayDataBuilder};
use arrow_schema::DataType;
use std::any::Any;
use std::sync::Arc;

/// An array of [boolean values](https://arrow.apache.org/docs/format/Columnar.html#fixed-size-primitive-layout)
///
/// # Example: From a Vec
///
/// ```
/// # use arrow_array::{Array, BooleanArray};
/// let arr: BooleanArray = vec![true, true, false].into();
/// ```
///
/// # Example: From an optional Vec
///
/// ```
/// # use arrow_array::{Array, BooleanArray};
/// let arr: BooleanArray = vec![Some(true), None, Some(false)].into();
/// ```
///
/// # Example: From an iterator
///
/// ```
/// # use arrow_array::{Array, BooleanArray};
/// let arr: BooleanArray = (0..5).map(|x| (x % 2 == 0).then(|| x % 3 == 0)).collect();
/// let values: Vec<_> = arr.iter().collect();
/// assert_eq!(&values, &[Some(true), None, Some(false), None, Some(false)])
/// ```
///
/// # Example: Using Builder
///
/// ```
/// # use arrow_array::Array;
/// # use arrow_array::builder::BooleanBuilder;
/// let mut builder = BooleanBuilder::new();
/// builder.append_value(true);
/// builder.append_null();
/// builder.append_value(false);
/// let array = builder.finish();
/// let values: Vec<_> = array.iter().collect();
/// assert_eq!(&values, &[Some(true), None, Some(false)])
/// ```
///
#[derive(Clone)]
pub struct BooleanArray {
    values: BooleanBuffer,
    nulls: Option<NullBuffer>,
}

impl std::fmt::Debug for BooleanArray {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "BooleanArray\n[\n")?;
        print_long_array(self, f, |array, index, f| {
            std::fmt::Debug::fmt(&array.value(index), f)
        })?;
        write!(f, "]")
    }
}

impl BooleanArray {
    /// Create a new [`BooleanArray`] from the provided values and nulls
    ///
    /// # Panics
    ///
    /// Panics if `values.len() != nulls.len()`
    pub fn new(values: BooleanBuffer, nulls: Option<NullBuffer>) -> Self {
        if let Some(n) = nulls.as_ref() {
            assert_eq!(values.len(), n.len());
        }
        Self { values, nulls }
    }

    /// Create a new [`BooleanArray`] with length `len` consisting only of nulls
    pub fn new_null(len: usize) -> Self {
        Self {
            values: BooleanBuffer::new_unset(len),
            nulls: Some(NullBuffer::new_null(len)),
        }
    }

    /// Create a new [`Scalar`] from `value`
    pub fn new_scalar(value: bool) -> Scalar<Self> {
        let values = match value {
            true => BooleanBuffer::new_set(1),
            false => BooleanBuffer::new_unset(1),
        };
        Scalar::new(Self::new(values, None))
    }

    /// Create a new [`BooleanArray`] from a [`Buffer`] specified by `offset` and `len`, the `offset` and `len` in bits
    /// Logically convert each bit in [`Buffer`] to boolean and use it to build [`BooleanArray`].
    /// using this method will make the following points self-evident:
    /// * there is no `null` in the constructed [`BooleanArray`];
    /// * without considering `buffer.into()`, this method is efficient because there is no need to perform pack and unpack operations on boolean;
    pub fn new_from_packed(buffer: impl Into<Buffer>, offset: usize, len: usize) -> Self {
        BooleanBuffer::new(buffer.into(), offset, len).into()
    }

    /// Create a new [`BooleanArray`] from `&[u8]`
    /// This method uses `new_from_packed` and constructs a [`Buffer`] using `value`, and offset is set to 0 and len is set to `value.len() * 8`
    /// using this method will make the following points self-evident:
    /// * there is no `null` in the constructed [`BooleanArray`];
    /// * the length of the constructed [`BooleanArray`] is always a multiple of 8;
    pub fn new_from_u8(value: &[u8]) -> Self {
        BooleanBuffer::new(Buffer::from(value), 0, value.len() * 8).into()
    }

    /// Returns the length of this array.
    pub fn len(&self) -> usize {
        self.values.len()
    }

    /// Returns whether this array is empty.
    pub fn is_empty(&self) -> bool {
        self.values.is_empty()
    }

    /// Returns a zero-copy slice of this array with the indicated offset and length.
    pub fn slice(&self, offset: usize, length: usize) -> Self {
        Self {
            values: self.values.slice(offset, length),
            nulls: self.nulls.as_ref().map(|n| n.slice(offset, length)),
        }
    }

    /// Returns a new boolean array builder
    pub fn builder(capacity: usize) -> BooleanBuilder {
        BooleanBuilder::with_capacity(capacity)
    }

    /// Returns the underlying [`BooleanBuffer`] holding all the values of this array
    pub fn values(&self) -> &BooleanBuffer {
        &self.values
    }

    /// Returns the number of non null, true values within this array
    pub fn true_count(&self) -> usize {
        match self.nulls() {
            Some(nulls) => {
                let null_chunks = nulls.inner().bit_chunks().iter_padded();
                let value_chunks = self.values().bit_chunks().iter_padded();
                null_chunks
                    .zip(value_chunks)
                    .map(|(a, b)| (a & b).count_ones() as usize)
                    .sum()
            }
            None => self.values().count_set_bits(),
        }
    }

    /// Returns the number of non null, false values within this array
    pub fn false_count(&self) -> usize {
        self.len() - self.null_count() - self.true_count()
    }

    /// Returns the boolean value at index `i`.
    ///
    /// # Safety
    /// This doesn't check bounds, the caller must ensure that index < self.len()
    pub unsafe fn value_unchecked(&self, i: usize) -> bool {
        self.values.value_unchecked(i)
    }

    /// Returns the boolean value at index `i`.
    /// # Panics
    /// Panics if index `i` is out of bounds
    pub fn value(&self, i: usize) -> bool {
        assert!(
            i < self.len(),
            "Trying to access an element at index {} from a BooleanArray of length {}",
            i,
            self.len()
        );
        // Safety:
        // `i < self.len()
        unsafe { self.value_unchecked(i) }
    }

    /// Returns an iterator that returns the values of `array.value(i)` for an iterator with each element `i`
    pub fn take_iter<'a>(
        &'a self,
        indexes: impl Iterator<Item = Option<usize>> + 'a,
    ) -> impl Iterator<Item = Option<bool>> + 'a {
        indexes.map(|opt_index| opt_index.map(|index| self.value(index)))
    }

    /// Returns an iterator that returns the values of `array.value(i)` for an iterator with each element `i`
    /// # Safety
    ///
    /// caller must ensure that the offsets in the iterator are less than the array len()
    pub unsafe fn take_iter_unchecked<'a>(
        &'a self,
        indexes: impl Iterator<Item = Option<usize>> + 'a,
    ) -> impl Iterator<Item = Option<bool>> + 'a {
        indexes.map(|opt_index| opt_index.map(|index| self.value_unchecked(index)))
    }

    /// Create a [`BooleanArray`] by evaluating the operation for
    /// each element of the provided array
    ///
    /// ```
    /// # use arrow_array::{BooleanArray, Int32Array};
    ///
    /// let array = Int32Array::from(vec![1, 2, 3, 4, 5]);
    /// let r = BooleanArray::from_unary(&array, |x| x > 2);
    /// assert_eq!(&r, &BooleanArray::from(vec![false, false, true, true, true]));
    /// ```
    pub fn from_unary<T: ArrayAccessor, F>(left: T, mut op: F) -> Self
    where
        F: FnMut(T::Item) -> bool,
    {
        let nulls = left.logical_nulls();
        let values = BooleanBuffer::collect_bool(left.len(), |i| unsafe {
            // SAFETY: i in range 0..len
            op(left.value_unchecked(i))
        });
        Self::new(values, nulls)
    }

    /// Create a [`BooleanArray`] by evaluating the binary operation for
    /// each element of the provided arrays
    ///
    /// ```
    /// # use arrow_array::{BooleanArray, Int32Array};
    ///
    /// let a = Int32Array::from(vec![1, 2, 3, 4, 5]);
    /// let b = Int32Array::from(vec![1, 2, 0, 2, 5]);
    /// let r = BooleanArray::from_binary(&a, &b, |a, b| a == b);
    /// assert_eq!(&r, &BooleanArray::from(vec![true, true, false, false, true]));
    /// ```
    ///
    /// # Panics
    ///
    /// This function panics if left and right are not the same length
    ///
    pub fn from_binary<T: ArrayAccessor, S: ArrayAccessor, F>(left: T, right: S, mut op: F) -> Self
    where
        F: FnMut(T::Item, S::Item) -> bool,
    {
        assert_eq!(left.len(), right.len());

        let nulls = NullBuffer::union(
            left.logical_nulls().as_ref(),
            right.logical_nulls().as_ref(),
        );
        let values = BooleanBuffer::collect_bool(left.len(), |i| unsafe {
            // SAFETY: i in range 0..len
            op(left.value_unchecked(i), right.value_unchecked(i))
        });
        Self::new(values, nulls)
    }

    /// Deconstruct this array into its constituent parts
    pub fn into_parts(self) -> (BooleanBuffer, Option<NullBuffer>) {
        (self.values, self.nulls)
    }
}

impl Array for BooleanArray {
    fn as_any(&self) -> &dyn Any {
        self
    }

    fn to_data(&self) -> ArrayData {
        self.clone().into()
    }

    fn into_data(self) -> ArrayData {
        self.into()
    }

    fn data_type(&self) -> &DataType {
        &DataType::Boolean
    }

    fn slice(&self, offset: usize, length: usize) -> ArrayRef {
        Arc::new(self.slice(offset, length))
    }

    fn len(&self) -> usize {
        self.values.len()
    }

    fn is_empty(&self) -> bool {
        self.values.is_empty()
    }

    fn shrink_to_fit(&mut self) {
        self.values.shrink_to_fit();
        if let Some(nulls) = &mut self.nulls {
            nulls.shrink_to_fit();
        }
    }

    fn offset(&self) -> usize {
        self.values.offset()
    }

    fn nulls(&self) -> Option<&NullBuffer> {
        self.nulls.as_ref()
    }

    fn logical_null_count(&self) -> usize {
        self.null_count()
    }

    fn get_buffer_memory_size(&self) -> usize {
        let mut sum = self.values.inner().capacity();
        if let Some(x) = &self.nulls {
            sum += x.buffer().capacity()
        }
        sum
    }

    fn get_array_memory_size(&self) -> usize {
        std::mem::size_of::<Self>() + self.get_buffer_memory_size()
    }
}

impl ArrayAccessor for &BooleanArray {
    type Item = bool;

    fn value(&self, index: usize) -> Self::Item {
        BooleanArray::value(self, index)
    }

    unsafe fn value_unchecked(&self, index: usize) -> Self::Item {
        BooleanArray::value_unchecked(self, index)
    }
}

impl From<Vec<bool>> for BooleanArray {
    fn from(data: Vec<bool>) -> Self {
        let mut mut_buf = MutableBuffer::new_null(data.len());
        {
            let mut_slice = mut_buf.as_slice_mut();
            for (i, b) in data.iter().enumerate() {
                if *b {
                    bit_util::set_bit(mut_slice, i);
                }
            }
        }
        let array_data = ArrayData::builder(DataType::Boolean)
            .len(data.len())
            .add_buffer(mut_buf.into());

        let array_data = unsafe { array_data.build_unchecked() };
        BooleanArray::from(array_data)
    }
}

impl From<Vec<Option<bool>>> for BooleanArray {
    fn from(data: Vec<Option<bool>>) -> Self {
        data.iter().collect()
    }
}

impl From<ArrayData> for BooleanArray {
    fn from(data: ArrayData) -> Self {
        assert_eq!(
            data.data_type(),
            &DataType::Boolean,
            "BooleanArray expected ArrayData with type {} got {}",
            DataType::Boolean,
            data.data_type()
        );
        assert_eq!(
            data.buffers().len(),
            1,
            "BooleanArray data should contain a single buffer only (values buffer)"
        );
        let values = BooleanBuffer::new(data.buffers()[0].clone(), data.offset(), data.len());

        Self {
            values,
            nulls: data.nulls().cloned(),
        }
    }
}

impl From<BooleanArray> for ArrayData {
    fn from(array: BooleanArray) -> Self {
        let builder = ArrayDataBuilder::new(DataType::Boolean)
            .len(array.values.len())
            .offset(array.values.offset())
            .nulls(array.nulls)
            .buffers(vec![array.values.into_inner()]);

        unsafe { builder.build_unchecked() }
    }
}

impl<'a> IntoIterator for &'a BooleanArray {
    type Item = Option<bool>;
    type IntoIter = BooleanIter<'a>;

    fn into_iter(self) -> Self::IntoIter {
        BooleanIter::<'a>::new(self)
    }
}

impl<'a> BooleanArray {
    /// constructs a new iterator
    pub fn iter(&'a self) -> BooleanIter<'a> {
        BooleanIter::<'a>::new(self)
    }
}

impl<Ptr: std::borrow::Borrow<Option<bool>>> FromIterator<Ptr> for BooleanArray {
    fn from_iter<I: IntoIterator<Item = Ptr>>(iter: I) -> Self {
        let iter = iter.into_iter();
        let (_, data_len) = iter.size_hint();
        let data_len = data_len.expect("Iterator must be sized"); // panic if no upper bound.

        let num_bytes = bit_util::ceil(data_len, 8);
        let mut null_builder = MutableBuffer::from_len_zeroed(num_bytes);
        let mut val_builder = MutableBuffer::from_len_zeroed(num_bytes);

        let data = val_builder.as_slice_mut();

        let null_slice = null_builder.as_slice_mut();
        iter.enumerate().for_each(|(i, item)| {
            if let Some(a) = item.borrow() {
                bit_util::set_bit(null_slice, i);
                if *a {
                    bit_util::set_bit(data, i);
                }
            }
        });

        let data = unsafe {
            ArrayData::new_unchecked(
                DataType::Boolean,
                data_len,
                None,
                Some(null_builder.into()),
                0,
                vec![val_builder.into()],
                vec![],
            )
        };
        BooleanArray::from(data)
    }
}

impl From<BooleanBuffer> for BooleanArray {
    fn from(values: BooleanBuffer) -> Self {
        Self {
            values,
            nulls: None,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use arrow_buffer::Buffer;
    use rand::{thread_rng, Rng};

    #[test]
    fn test_boolean_fmt_debug() {
        let arr = BooleanArray::from(vec![true, false, false]);
        assert_eq!(
            "BooleanArray\n[\n  true,\n  false,\n  false,\n]",
            format!("{arr:?}")
        );
    }

    #[test]
    fn test_boolean_with_null_fmt_debug() {
        let mut builder = BooleanArray::builder(3);
        builder.append_value(true);
        builder.append_null();
        builder.append_value(false);
        let arr = builder.finish();
        assert_eq!(
            "BooleanArray\n[\n  true,\n  null,\n  false,\n]",
            format!("{arr:?}")
        );
    }

    #[test]
    fn test_boolean_array_from_vec() {
        let buf = Buffer::from([10_u8]);
        let arr = BooleanArray::from(vec![false, true, false, true]);
        assert_eq!(&buf, arr.values().inner());
        assert_eq!(4, arr.len());
        assert_eq!(0, arr.offset());
        assert_eq!(0, arr.null_count());
        for i in 0..4 {
            assert!(!arr.is_null(i));
            assert!(arr.is_valid(i));
            assert_eq!(i == 1 || i == 3, arr.value(i), "failed at {i}")
        }
    }

    #[test]
    fn test_boolean_array_from_vec_option() {
        let buf = Buffer::from([10_u8]);
        let arr = BooleanArray::from(vec![Some(false), Some(true), None, Some(true)]);
        assert_eq!(&buf, arr.values().inner());
        assert_eq!(4, arr.len());
        assert_eq!(0, arr.offset());
        assert_eq!(1, arr.null_count());
        for i in 0..4 {
            if i == 2 {
                assert!(arr.is_null(i));
                assert!(!arr.is_valid(i));
            } else {
                assert!(!arr.is_null(i));
                assert!(arr.is_valid(i));
                assert_eq!(i == 1 || i == 3, arr.value(i), "failed at {i}")
            }
        }
    }

    #[test]
    fn test_boolean_array_from_packed() {
        let v = [1_u8, 2_u8, 3_u8];
        let arr = BooleanArray::new_from_packed(v, 0, 24);
        assert_eq!(24, arr.len());
        assert_eq!(0, arr.offset());
        assert_eq!(0, arr.null_count());
        assert!(arr.nulls.is_none());
        for i in 0..24 {
            assert!(!arr.is_null(i));
            assert!(arr.is_valid(i));
            assert_eq!(
                i == 0 || i == 9 || i == 16 || i == 17,
                arr.value(i),
                "failed t {i}"
            )
        }
    }

    #[test]
    fn test_boolean_array_from_slice_u8() {
        let v: Vec<u8> = vec![1, 2, 3];
        let slice = &v[..];
        let arr = BooleanArray::new_from_u8(slice);
        assert_eq!(24, arr.len());
        assert_eq!(0, arr.offset());
        assert_eq!(0, arr.null_count());
        assert!(arr.nulls().is_none());
        for i in 0..24 {
            assert!(!arr.is_null(i));
            assert!(arr.is_valid(i));
            assert_eq!(
                i == 0 || i == 9 || i == 16 || i == 17,
                arr.value(i),
                "failed t {i}"
            )
        }
    }

    #[test]
    fn test_boolean_array_from_iter() {
        let v = vec![Some(false), Some(true), Some(false), Some(true)];
        let arr = v.into_iter().collect::<BooleanArray>();
        assert_eq!(4, arr.len());
        assert_eq!(0, arr.offset());
        assert_eq!(0, arr.null_count());
        assert!(arr.nulls().is_none());
        for i in 0..3 {
            assert!(!arr.is_null(i));
            assert!(arr.is_valid(i));
            assert_eq!(i == 1 || i == 3, arr.value(i), "failed at {i}")
        }
    }

    #[test]
    fn test_boolean_array_from_nullable_iter() {
        let v = vec![Some(true), None, Some(false), None];
        let arr = v.into_iter().collect::<BooleanArray>();
        assert_eq!(4, arr.len());
        assert_eq!(0, arr.offset());
        assert_eq!(2, arr.null_count());
        assert!(arr.nulls().is_some());

        assert!(arr.is_valid(0));
        assert!(arr.is_null(1));
        assert!(arr.is_valid(2));
        assert!(arr.is_null(3));

        assert!(arr.value(0));
        assert!(!arr.value(2));
    }

    #[test]
    fn test_boolean_array_builder() {
        // Test building a boolean array with ArrayData builder and offset
        // 000011011
        let buf = Buffer::from([27_u8]);
        let buf2 = buf.clone();
        let data = ArrayData::builder(DataType::Boolean)
            .len(5)
            .offset(2)
            .add_buffer(buf)
            .build()
            .unwrap();
        let arr = BooleanArray::from(data);
        assert_eq!(&buf2, arr.values().inner());
        assert_eq!(5, arr.len());
        assert_eq!(2, arr.offset());
        assert_eq!(0, arr.null_count());
        for i in 0..3 {
            assert_eq!(i != 0, arr.value(i), "failed at {i}");
        }
    }

    #[test]
    #[should_panic(
        expected = "Trying to access an element at index 4 from a BooleanArray of length 3"
    )]
    fn test_fixed_size_binary_array_get_value_index_out_of_bound() {
        let v = vec![Some(true), None, Some(false)];
        let array = v.into_iter().collect::<BooleanArray>();

        array.value(4);
    }

    #[test]
    #[should_panic(expected = "BooleanArray data should contain a single buffer only \
                               (values buffer)")]
    // Different error messages, so skip for now
    // https://github.com/apache/arrow-rs/issues/1545
    #[cfg(not(feature = "force_validate"))]
    fn test_boolean_array_invalid_buffer_len() {
        let data = unsafe {
            ArrayData::builder(DataType::Boolean)
                .len(5)
                .build_unchecked()
        };
        drop(BooleanArray::from(data));
    }

    #[test]
    #[should_panic(expected = "BooleanArray expected ArrayData with type Boolean got Int32")]
    fn test_from_array_data_validation() {
        let _ = BooleanArray::from(ArrayData::new_empty(&DataType::Int32));
    }

    #[test]
    #[cfg_attr(miri, ignore)] // Takes too long
    fn test_true_false_count() {
        let mut rng = thread_rng();

        for _ in 0..10 {
            // No nulls
            let d: Vec<_> = (0..2000).map(|_| rng.gen_bool(0.5)).collect();
            let b = BooleanArray::from(d.clone());

            let expected_true = d.iter().filter(|x| **x).count();
            assert_eq!(b.true_count(), expected_true);
            assert_eq!(b.false_count(), d.len() - expected_true);

            // With nulls
            let d: Vec<_> = (0..2000)
                .map(|_| rng.gen_bool(0.5).then(|| rng.gen_bool(0.5)))
                .collect();
            let b = BooleanArray::from(d.clone());

            let expected_true = d.iter().filter(|x| matches!(x, Some(true))).count();
            assert_eq!(b.true_count(), expected_true);

            let expected_false = d.iter().filter(|x| matches!(x, Some(false))).count();
            assert_eq!(b.false_count(), expected_false);
        }
    }

    #[test]
    fn test_into_parts() {
        let boolean_array = [Some(true), None, Some(false)]
            .into_iter()
            .collect::<BooleanArray>();
        let (values, nulls) = boolean_array.into_parts();
        assert_eq!(values.values(), &[0b0000_0001]);
        assert!(nulls.is_some());
        assert_eq!(nulls.unwrap().buffer().as_slice(), &[0b0000_0101]);

        let boolean_array =
            BooleanArray::from(vec![false, false, false, false, false, false, false, true]);
        let (values, nulls) = boolean_array.into_parts();
        assert_eq!(values.values(), &[0b1000_0000]);
        assert!(nulls.is_none());
    }
}