iterstats 0.7.0

Statistics for rust iterators.
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

//! Calculate the range.

use crate::Iterstats;

/// Calculate the range (max & min) of an iterator in one pass.
pub trait Range<A = Self>: Sized {
    /// The type of the output.
    type Output;

    /// Calculate the range.
    fn range<I: Iterator<Item = A>>(iter: I) -> Option<(Self::Output, Self::Output)>;
}

macro_rules! range_impl {
    ($typ:ty) => {
        impl Range for $typ {
            type Output = $typ;

            fn range<I: Iterator<Item = Self>>(iter: I) -> Option<(Self::Output, Self::Output)> {
                let mut range = None;
                for item in iter {
                    if let Some((min, max)) = &mut range {
                        if item < *min {
                            *min = item;
                        }
                        if item > *max {
                            *max = item;
                        }
                    } else {
                        range = Some((item, item));
                    }
                }
                range
            }
        }

        impl Range for &$typ {
            type Output = $typ;

            fn range<I: Iterator<Item = Self>>(iter: I) -> Option<(Self::Output, Self::Output)> {
                iter.map(|i| *i).range()
            }
        }
    };
}

range_impl!(f64);
range_impl!(f32);
range_impl!(u128);
range_impl!(u64);
range_impl!(u32);
range_impl!(u16);
range_impl!(u8);
range_impl!(usize);
range_impl!(i128);
range_impl!(i64);
range_impl!(i32);
range_impl!(i16);
range_impl!(i8);
range_impl!(isize);

#[cfg(test)]
mod tests {

    use super::*;
    use paste::paste;

    macro_rules! test_range {
        ($name:ident: $typ:ty as $iter:expr ; iter => None) => {
            paste! {
                #[test]
                fn [<$name _iter>]() {
                    let range = <&$typ>::range($iter.iter());
                    assert!(range.is_none())
                }
            }
        };
        ($name:ident: $typ:ty as $iter:expr ; into_iter => None) => {
            paste! {
                #[test]
                fn [<$name _into_iter>]() {
                    let range = $typ::range($iter.into_iter());
                    assert!(range.is_none())
                }
            }
        };
        ($name:ident: $typ:ty as $iter:expr  => None) => {
            test_range!($name: $typ as $iter; iter => None);
            test_range!($name: $typ as $iter; into_iter => None);
        };
        ($name:ident: $typ:ty as $iter:expr ; iter => ($min:expr, $max:expr)) => {
            paste! {
                #[test]
                fn [<$name _iter>]() {
                    let (min, max) = <&$typ>::range($iter.iter()).unwrap();
                    assert_eq!(min, $min);
                    assert_eq!(max, $max)
                }
            }
        };
        ($name:ident: $typ:ty as $iter:expr ; into_iter => ($min:expr, $max:expr)) => {
            paste! {
                #[test]
                fn [<$name _into_iter>]() {
                    let (min, max) = $typ::range($iter.into_iter()).unwrap();
                    assert_eq!(min, $min);
                    assert_eq!(max, $max)
                }
            }
        };
        ($name:ident: $typ:ty as $iter:expr  => ($min:expr, $max:expr)) => {
            test_range!($name: $typ as $iter; iter => ($min, $max));
            test_range!($name: $typ as $iter; into_iter => ($min, $max));
        };
    }

    test_range!(empty: u32 as Vec::new() => None);

    test_range!(f64: f64 as [0.1, -32.1, 23.2, 0., f64::NAN] => (-32.1, 23.2));
    test_range!(f64_with_inf: f64 as [0.1, f64::NEG_INFINITY, -32.1, 23.2, f64::INFINITY, 0., f64::NAN] => (f64::NEG_INFINITY, f64::INFINITY));
    test_range!(f32: f32 as [0.1, -32.1, 23.2, 0., f32::NAN] => (-32.1, 23.2));
    test_range!(f32_with_inf: f32 as [0.1, f32::NEG_INFINITY, -32.1, 23.2, f32::INFINITY, 0., f32::NAN] => (f32::NEG_INFINITY, f32::INFINITY));
    test_range!(u128: u128 as [1, 32, 23, 0] => (0, 32));
    test_range!(u64: u64 as [1, 32, 23, 0] => (0, 32));
    test_range!(u32: u32 as [1, 32, 23, 0] => (0, 32));
    test_range!(u16: u16 as [1, 32, 23, 0] => (0, 32));
    test_range!(u8: u8 as [1, 32, 23, 0] => (0, 32));
    test_range!(usize: usize as [1, 32, 23, 0] => (0, 32));
    test_range!(i128: i128 as [-4, -34, -1, -3] => (-34, -1));
    test_range!(i64: i64 as [-4, -34, -1, -3] => (-34, -1));
    test_range!(i32: i32 as [-4, -34, -1, -3] => (-34, -1));
    test_range!(i16: i16 as [-4, -34, -1, -3] => (-34, -1));
    test_range!(i8: i8 as [-4, -34, -1, -3] => (-34, -1));
    test_range!(isize: isize as [-4, -34, -1, -3] => (-34, -1));
}