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
136
137
138
139
140

use std::cmp::Ordering;
use std::fmt;

/// Immutable triple of strings stored on the heap in the same buffer.
#[derive(Eq, PartialEq, Clone, Default, Hash)]
pub struct StringTriple {
    buffer: String,
    split: (usize, usize),
}

impl<S1: Into<String>, S2: AsRef<str>, S3: AsRef<str>> From<(S1, S2, S3)> for StringTriple {
    #[inline]
    fn from((s1, s2, s3): (S1, S2, S3)) -> StringTriple {
        StringTriple::new(s1, s2, s3)
    }
}

impl StringTriple {
    /// Creates a `StringTriple` from a triple of strings.
    pub fn new<S1: Into<String>, S2: AsRef<str>, S3: AsRef<str>>(s1: S1, s2: S2, s3: S3) -> StringTriple {
        let s1 = s1.into();
        let s2 = s2.as_ref();
        let s3 = s3.as_ref();
        let split = (s1.len(), s1.len() + s2.len());

        let mut buffer = s1;
        buffer.push_str(s2.as_ref());
        buffer.push_str(s3.as_ref());
        StringTriple { buffer, split }
    }

    /// Creates a `StringTriple` from a string and split indices.
    #[inline]
    pub fn from_raw<S: Into<String>>(string: S, lsplit: usize, rsplit: usize) -> StringTriple {
        let buffer = string.into();
        let split = (lsplit, rsplit);

        assert!(lsplit <= buffer.len(), "StrTriple: left split index was out of bounds");
        assert!(rsplit <= buffer.len(), "StrTriple: right split index was out of bounds");
        assert!(lsplit <= rsplit, "StrTriple: split indices were in wrong order");
        StringTriple { buffer, split }
    }

    /// Creates a `StringTriple` from a string and split indices without checking the indices.
    #[inline]
    pub unsafe fn from_raw_unchecked<S: Into<String>>(string: S, lsplit: usize, rsplit: usize) -> StringTriple {
        let buffer = string.into();
        let split = (lsplit, rsplit);
        StringTriple { buffer, split }
    }

    /// Gets the first string in the triple.
    #[inline]
    pub fn left(&self) -> &str {
        unsafe {
            self.buffer.slice_unchecked(0, self.split.0)
        }
    }

    /// Gets the second string in the triple.
    #[inline]
    pub fn middle(&self) -> &str {
        unsafe {
            self.buffer.slice_unchecked(self.split.0, self.split.1)
        }
    }

    /// Gets the third string in the triple.
    #[inline]
    pub fn right(&self) -> &str {
        unsafe {
            self.buffer.slice_unchecked(self.split.1, self.buffer.len())
        }
    }
}

impl PartialOrd for StringTriple {
    fn partial_cmp(&self, rhs: &StringTriple) -> Option<Ordering> {
        Some(self.left().cmp(rhs.left()).then_with(|| self.middle().cmp(rhs.middle())).then_with(|| self.right().cmp(rhs.right())))
    }
}
impl Ord for StringTriple {
    fn cmp(&self, rhs: &StringTriple) -> Ordering {
        self.left().cmp(rhs.left()).then_with(|| self.middle().cmp(rhs.middle())).then_with(|| self.right().cmp(rhs.right()))
    }
}
impl fmt::Debug for StringTriple {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.debug_tuple("StringTriple::new")
            .field(&self.left().to_owned())
            .field(&self.middle().to_owned())
            .field(&self.right().to_owned())
            .finish()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn raw_left() {
        assert_eq!(StringTriple::from_raw("helloworldtoday", 5, 10).left(), "hello");
    }

    #[test]
    fn raw_middle() {
        assert_eq!(StringTriple::from_raw("helloworldtoday", 5, 10).middle(), "world");
    }

    #[test]
    fn raw_right() {
        assert_eq!(StringTriple::from_raw("helloworldtoday", 5, 10).right(), "today");
    }

    quickcheck! {
        fn partial_ord(s1: String, s2: String, s3: String, s4: String, s5: String, s6: String) -> bool {
            let lhs = StringTriple::new(&*s1, &s2, &s3);
            let rhs = StringTriple::new(&*s4, &s5, &s6);
            lhs.partial_cmp(&rhs) == (&s1, &s2, &s3).partial_cmp(&(&s4, &s5, &s6))
        }
        fn ord(s1: String, s2: String, s3: String, s4: String, s5: String, s6: String) -> bool {
            let lhs = StringTriple::new(&*s1, &s2, &s3);
            let rhs = StringTriple::new(&*s4, &s5, &s6);
            lhs.cmp(&rhs) == (&s1, &s2, &s3).cmp(&(&s4, &s5, &s6))
        }
        fn left(s1: String, s2: String, s3: String) -> bool {
            let pair = StringTriple::new(&*s1, &s2, &s3);
            pair.left() == s1
        }
        fn middle(s1: String, s2: String, s3: String) -> bool {
            let pair = StringTriple::new(&*s1, &s2, &s3);
            pair.middle() == s2
        }
        fn right(s1: String, s2: String, s3: String) -> bool {
            let pair = StringTriple::new(&*s1, &s2, &s3);
            pair.right() == s3
        }
    }
}