asciidoc_parser/span/
slice.rs

1use std::ops::{Range, RangeFrom, RangeTo};
2
3use bytecount::num_chars;
4use memchr::Memchr;
5
6use super::Span;
7
8impl<'src> Span<'src> {
9    /// Returns the requested subrange of this input span.
10    pub(crate) fn slice(&self, range: Range<usize>) -> Self {
11        self.slice_internal(&self.data[range])
12    }
13
14    /// Returns the requested subrange of this input span.
15    pub(crate) fn slice_from(&self, range: RangeFrom<usize>) -> Self {
16        self.slice_internal(&self.data[range])
17    }
18
19    /// Returns the requested subrange of this input span.
20    pub(crate) fn slice_to(&self, range: RangeTo<usize>) -> Self {
21        self.slice_internal(&self.data[range])
22    }
23
24    /// Returns the first position where `predicate` returns `true`.
25    pub(crate) fn position<P>(&self, predicate: P) -> Option<usize>
26    where
27        P: Fn(char) -> bool,
28    {
29        for (o, c) in self.data.char_indices() {
30            if predicate(c) {
31                return Some(o);
32            }
33        }
34        None
35    }
36
37    fn slice_internal(&self, slice_data: &'src str) -> Self {
38        let offset = offset(self.data, slice_data);
39
40        if offset == 0 {
41            return Self {
42                data: slice_data,
43                line: self.line,
44                col: self.col,
45                offset: self.offset,
46            };
47        }
48
49        let old_data = &self.data[..offset];
50        let new_line_iter = Memchr::new(b'\n', old_data.as_bytes());
51
52        let mut lines_to_add = 0;
53        let mut last_index = None;
54        for i in new_line_iter {
55            lines_to_add += 1;
56            last_index = Some(i);
57        }
58        let last_index = last_index.map_or(0, |v| v + 1);
59
60        let col = num_chars(&old_data.as_bytes()[last_index..]);
61
62        Self {
63            data: slice_data,
64            line: self.line + lines_to_add,
65            col: if lines_to_add == 0 {
66                self.col + col
67            } else {
68                // When going to a new line, char starts at 1
69                col + 1
70            },
71            offset: self.offset + offset,
72        }
73    }
74}
75
76fn offset(first: &str, second: &str) -> usize {
77    let p1 = first.as_ptr();
78    let p2 = second.as_ptr();
79    p2 as usize - p1 as usize
80}
asciidoc_parser/span/slice.rs

asciidoc_parser/span/
slice.rs
