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

// 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
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! Math expressions

use std::any::type_name;
use std::sync::Arc;

use arrow::array::ArrayRef;
use arrow::array::{BooleanArray, Float32Array, Float64Array};
use arrow::datatypes::DataType;
use arrow_array::Array;

use datafusion_common::exec_err;
use datafusion_common::{DataFusionError, Result};

macro_rules! downcast_arg {
    ($ARG:expr, $NAME:expr, $ARRAY_TYPE:ident) => {{
        $ARG.as_any().downcast_ref::<$ARRAY_TYPE>().ok_or_else(|| {
            DataFusionError::Internal(format!(
                "could not cast {} from {} to {}",
                $NAME,
                $ARG.data_type(),
                type_name::<$ARRAY_TYPE>()
            ))
        })?
    }};
}

macro_rules! make_function_scalar_inputs_return_type {
    ($ARG: expr, $NAME:expr, $ARGS_TYPE:ident, $RETURN_TYPE:ident, $FUNC: block) => {{
        let arg = downcast_arg!($ARG, $NAME, $ARGS_TYPE);

        arg.iter()
            .map(|a| match a {
                Some(a) => Some($FUNC(a)),
                _ => None,
            })
            .collect::<$RETURN_TYPE>()
    }};
}

/// Isnan SQL function
pub fn isnan(args: &[ArrayRef]) -> Result<ArrayRef> {
    match args[0].data_type() {
        DataType::Float64 => Ok(Arc::new(make_function_scalar_inputs_return_type!(
            &args[0],
            "x",
            Float64Array,
            BooleanArray,
            { f64::is_nan }
        )) as ArrayRef),

        DataType::Float32 => Ok(Arc::new(make_function_scalar_inputs_return_type!(
            &args[0],
            "x",
            Float32Array,
            BooleanArray,
            { f32::is_nan }
        )) as ArrayRef),

        other => exec_err!("Unsupported data type {other:?} for function isnan"),
    }
}

#[cfg(test)]
mod tests {

    use datafusion_common::cast::as_boolean_array;

    use super::*;

    #[test]
    fn test_isnan_f64() {
        let args: Vec<ArrayRef> = vec![Arc::new(Float64Array::from(vec![
            1.0,
            f64::NAN,
            3.0,
            -f64::NAN,
        ]))];

        let result = isnan(&args).expect("failed to initialize function isnan");
        let booleans =
            as_boolean_array(&result).expect("failed to initialize function isnan");

        assert_eq!(booleans.len(), 4);
        assert!(!booleans.value(0));
        assert!(booleans.value(1));
        assert!(!booleans.value(2));
        assert!(booleans.value(3));
    }

    #[test]
    fn test_isnan_f32() {
        let args: Vec<ArrayRef> = vec![Arc::new(Float32Array::from(vec![
            1.0,
            f32::NAN,
            3.0,
            f32::NAN,
        ]))];

        let result = isnan(&args).expect("failed to initialize function isnan");
        let booleans =
            as_boolean_array(&result).expect("failed to initialize function isnan");

        assert_eq!(booleans.len(), 4);
        assert!(!booleans.value(0));
        assert!(booleans.value(1));
        assert!(!booleans.value(2));
        assert!(booleans.value(3));
    }
}