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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155

use std::str::CharIndices;

// FromStr but we own it so we can impl it on torin and skia_safe types.
pub trait Parse: Sized {
    type Err;

    fn parse(value: &str) -> Result<Self, Self::Err>;
}

pub trait ExtSplit {
    fn split_excluding_group(
        &self,
        delimiter: char,
        group_start: char,
        group_end: char,
    ) -> SplitExcludingGroup<'_>;
    fn split_ascii_whitespace_excluding_group(
        &self,
        group_start: char,
        group_end: char,
    ) -> SplitAsciiWhitespaceExcludingGroup<'_>;
}

impl ExtSplit for str {
    fn split_excluding_group(
        &self,
        delimiter: char,
        group_start: char,
        group_end: char,
    ) -> SplitExcludingGroup<'_> {
        SplitExcludingGroup {
            text: self,
            chars: self.char_indices(),
            delimiter,
            group_start,
            group_end,
            trailing_empty: true,
        }
    }

    fn split_ascii_whitespace_excluding_group(
        &self,
        group_start: char,
        group_end: char,
    ) -> SplitAsciiWhitespaceExcludingGroup<'_> {
        SplitAsciiWhitespaceExcludingGroup {
            text: self,
            chars: self.char_indices(),
            group_start,
            group_end,
        }
    }
}

#[derive(Clone, Debug)]
pub struct SplitExcludingGroup<'a> {
    pub text: &'a str,
    pub chars: CharIndices<'a>,
    pub delimiter: char,
    pub group_start: char,
    pub group_end: char,
    pub trailing_empty: bool,
}

impl<'a> Iterator for SplitExcludingGroup<'a> {
    type Item = &'a str;

    fn next(&mut self) -> Option<&'a str> {
        let first = self.chars.next();

        let (start, mut prev) = match first {
            None => {
                if self.text.ends_with(self.delimiter) && self.trailing_empty {
                    self.trailing_empty = false;
                    return Some("");
                }
                return None;
            }
            Some((_, c)) if c == self.delimiter => return Some(""),
            Some(v) => v,
        };

        let mut in_group = false;
        let mut nesting = -1;

        loop {
            if prev == self.group_start {
                if nesting == -1 {
                    in_group = true;
                }
                nesting += 1;
            } else if prev == self.group_end {
                nesting -= 1;
                if nesting == -1 {
                    in_group = false;
                }
            }

            prev = match self.chars.next() {
                None => return Some(&self.text[start..]),
                Some((end, c)) if c == self.delimiter && !in_group => {
                    return Some(&self.text[start..end])
                }
                Some((_, c)) => c,
            }
        }
    }
}

#[derive(Clone, Debug)]
pub struct SplitAsciiWhitespaceExcludingGroup<'a> {
    pub text: &'a str,
    pub chars: CharIndices<'a>,
    pub group_start: char,
    pub group_end: char,
}

impl<'a> Iterator for SplitAsciiWhitespaceExcludingGroup<'a> {
    type Item = &'a str;

    fn next(&mut self) -> Option<&'a str> {
        let first = self.chars.next();

        let (start, mut prev) = match first {
            None => return None,
            Some((_, c)) if c.is_ascii_whitespace() => return self.next(),
            Some(v) => v,
        };

        let mut in_group = false;
        let mut nesting = -1;

        loop {
            if prev == self.group_start {
                if nesting == -1 {
                    in_group = true;
                }
                nesting += 1;
            } else if prev == self.group_end {
                nesting -= 1;
                if nesting == -1 {
                    in_group = false;
                }
            }

            prev = match self.chars.next() {
                None => return Some(&self.text[start..]),
                Some((end, c)) if c.is_ascii_whitespace() && !in_group => {
                    return Some(&self.text[start..end])
                }
                Some((_, c)) => c,
            }
        }
    }
}