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
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
//! Utilities to deal with characters.
use crate::constant::TAB_SIZE;
use crate::tokenizer::{Event, EventType, Point};
use std::str;
/// A range between two places.
#[derive(Debug)]
pub struct Position<'a> {
pub start: &'a Point,
pub end: &'a Point,
}
impl<'a> Position<'a> {
/// Get a position from an exit event.
///
/// Looks backwards for the corresponding `enter` event.
/// This does not support nested events (such as lists in lists).
///
/// ## Panics
///
/// This function panics if an enter event is given.
/// When `micromark` is used, this function never panics.
pub fn from_exit_event(events: &'a [Event], index: usize) -> Position<'a> {
let exit = &events[index];
debug_assert_eq!(
exit.event_type,
EventType::Exit,
"expected `from_exit_event` to be called on `exit` event"
);
let mut enter_index = index - 1;
loop {
let enter = &events[enter_index];
if enter.event_type == EventType::Enter && enter.token_type == exit.token_type {
return Position {
start: &enter.point,
end: &exit.point,
};
}
enter_index -= 1;
}
}
/// Turn a position into indices.
///
/// Indices are places in `bytes` where this position starts and ends.
///
/// > 👉 **Note**: indices cannot represent virtual spaces.
pub fn to_indices(&self) -> (usize, usize) {
(self.start.index, self.end.index)
}
}
/// Chars belonging to a range.
///
/// Includes information on virtual spaces before and after the chars.
#[derive(Debug)]
pub struct Slice<'a> {
pub bytes: &'a [u8],
pub before: usize,
pub after: usize,
}
impl<'a> Slice<'a> {
/// Get the slice belonging to a point.
pub fn from_point(bytes: &'a [u8], point: &Point) -> Slice<'a> {
let mut before = point.vs;
let mut start = point.index;
let end = if start < bytes.len() {
start + 1
} else {
start
};
// If we have virtual spaces before, it means we are past the actual
// character at that index, and those virtual spaces.
if before > 0 {
before = TAB_SIZE - before;
start += 1;
};
Slice {
bytes: if start < end { &bytes[start..end] } else { &[] },
before,
after: 0,
}
}
/// Create a slice from one index.
///
/// Indices are places in `bytes`.
///
/// > 👉 **Note**: indices cannot represent virtual spaces.
pub fn from_index(bytes: &'a [u8], index: usize) -> Slice<'a> {
Slice::from_indices(bytes, index, index + 1)
}
/// Get the slice belonging to a position.
pub fn from_position(bytes: &'a [u8], position: &Position) -> Slice<'a> {
let mut before = position.start.vs;
let mut after = position.end.vs;
let mut start = position.start.index;
let mut end = position.end.index;
// If we have virtual spaces before, it means we are past the actual
// character at that index, and those virtual spaces.
if before > 0 {
before = TAB_SIZE - before;
start += 1;
};
// If we have virtual spaces after, it means that character is included,
// and one less virtual space.
if after > 0 {
after -= 1;
end += 1;
}
Slice {
bytes: &bytes[start..end],
before,
after,
}
}
/// Create a slice from two indices.
///
/// Indices are places in `bytes`.
///
/// > 👉 **Note**: indices cannot represent virtual spaces.
pub fn from_indices(bytes: &'a [u8], start: usize, end: usize) -> Slice<'a> {
Slice {
bytes: &bytes[start..end],
before: 0,
after: 0,
}
}
/// Get the size of this slice, including virtual spaces.
pub fn len(&self) -> usize {
self.bytes.len() + self.before + self.after
}
/// Get the first byte in this slice, representing a virtual space as a
/// space.
pub fn head(&self) -> Option<u8> {
if self.before > 0 {
Some(b' ')
} else if self.bytes.is_empty() {
None
} else {
Some(self.bytes[0])
}
}
/// Turn the slice into a `&str`.
///
/// Does not support virtual spaces.
pub fn as_str(&self) -> &str {
str::from_utf8(self.bytes).unwrap()
}
/// Turn the slice into a `String`.
///
/// Support virtual spaces.
pub fn serialize(&self) -> String {
let mut string = String::with_capacity(self.len());
let mut index = self.before;
while index > 0 {
string.push(' ');
index -= 1;
}
string.push_str(self.as_str());
index = self.after;
while index > 0 {
string.push(' ');
index -= 1;
}
string
}
}
|
