arrow2 0.6.1

Unofficial implementation of Apache Arrow spec in safe Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

use std::sync::Arc;

use crate::{
    array::{Array, DictionaryArray, DictionaryKey, PrimitiveArray},
    bitmap::MutableBitmap,
    buffer::MutableBuffer,
};

use super::{
    make_growable,
    utils::{build_extend_null_bits, ExtendNullBits},
    Growable,
};

/// Concrete [`Growable`] for the [`DictionaryArray`].
/// # Implementation
/// This growable does not perform collision checks and instead concatenates
/// the values of each [`DictionaryArray`] one after the other.
pub struct GrowableDictionary<'a, K: DictionaryKey> {
    keys_values: Vec<&'a [K]>,
    key_values: MutableBuffer<K>,
    key_validity: MutableBitmap,
    offsets: Vec<usize>,
    values: Arc<dyn Array>,
    extend_null_bits: Vec<ExtendNullBits<'a>>,
}

fn concatenate_values<K: DictionaryKey>(
    arrays_keys: &[&PrimitiveArray<K>],
    arrays_values: &[&dyn Array],
    capacity: usize,
) -> (Arc<dyn Array>, Vec<usize>) {
    let mut mutable = make_growable(arrays_values, false, capacity);
    let mut offsets = Vec::with_capacity(arrays_keys.len() + 1);
    offsets.push(0);
    for (i, values) in arrays_values.iter().enumerate() {
        mutable.extend(i, 0, values.len());
        offsets.push(offsets[i] + values.len());
    }
    (mutable.as_arc(), offsets)
}

impl<'a, T: DictionaryKey> GrowableDictionary<'a, T> {
    /// Creates a new [`GrowableDictionary`] bound to `arrays` with a pre-allocated `capacity`.
    /// # Panics
    /// If `arrays` is empty.
    pub fn new(arrays: &[&'a DictionaryArray<T>], mut use_validity: bool, capacity: usize) -> Self {
        // if any of the arrays has nulls, insertions from any array requires setting bits
        // as there is at least one array with nulls.
        if arrays.iter().any(|array| array.null_count() > 0) {
            use_validity = true;
        };

        let arrays_keys = arrays.iter().map(|array| array.keys()).collect::<Vec<_>>();
        let keys_values = arrays_keys
            .iter()
            .map(|array| array.values().as_slice())
            .collect::<Vec<_>>();

        let extend_null_bits = arrays
            .iter()
            .map(|array| build_extend_null_bits(array.keys(), use_validity))
            .collect();

        let arrays_values = arrays
            .iter()
            .map(|array| array.values().as_ref())
            .collect::<Vec<_>>();

        let (values, offsets) = concatenate_values(&arrays_keys, &arrays_values, capacity);

        Self {
            offsets,
            values,
            keys_values,
            key_values: MutableBuffer::with_capacity(capacity),
            key_validity: MutableBitmap::with_capacity(capacity),
            extend_null_bits,
        }
    }

    #[inline]
    fn to(&mut self) -> DictionaryArray<T> {
        let validity = std::mem::take(&mut self.key_validity);
        let values = std::mem::take(&mut self.key_values);

        let keys = PrimitiveArray::<T>::from_data(T::DATA_TYPE, values.into(), validity.into());

        DictionaryArray::<T>::from_data(keys, self.values.clone())
    }
}

impl<'a, T: DictionaryKey> Growable<'a> for GrowableDictionary<'a, T> {
    #[inline]
    fn extend(&mut self, index: usize, start: usize, len: usize) {
        (self.extend_null_bits[index])(&mut self.key_validity, start, len);

        let values = &self.keys_values[index][start..start + len];
        let offset = self.offsets[index];
        self.key_values.extend(
            values
                .iter()
                .map(|x| T::from_usize(offset + x.to_usize().unwrap()).unwrap()),
        );
    }

    #[inline]
    fn extend_validity(&mut self, additional: usize) {
        self.key_values.extend_constant(additional, T::default());
        self.key_validity.extend_constant(additional, false);
    }

    #[inline]
    fn as_arc(&mut self) -> Arc<dyn Array> {
        Arc::new(self.to())
    }

    #[inline]
    fn as_box(&mut self) -> Box<dyn Array> {
        Box::new(self.to())
    }
}

impl<'a, T: DictionaryKey> From<GrowableDictionary<'a, T>> for DictionaryArray<T> {
    #[inline]
    fn from(val: GrowableDictionary<'a, T>) -> Self {
        let keys = PrimitiveArray::<T>::from_data(
            T::DATA_TYPE,
            val.key_values.into(),
            val.key_validity.into(),
        );

        DictionaryArray::<T>::from_data(keys, val.values)
    }
}