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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
//! Deal with bytes.
use crate::event::{Event, Kind, Point};
use crate::util::{
classify_character::{classify_opt, Kind as CharacterKind},
constant::TAB_SIZE,
};
use alloc::string::String;
use core::str;
/// Get a [`char`][] right before `index` in bytes (`&[u8]`).
///
/// In most cases, markdown operates on ASCII bytes.
/// In a few cases, it is unicode aware, so we need to find an actual char.
pub fn char_before_index(bytes: &[u8], index: usize) -> Option<char> {
let start = if index < 4 { 0 } else { index - 4 };
String::from_utf8_lossy(&bytes[start..index]).chars().last()
}
/// Get a [`char`][] right at `index` in bytes (`&[u8]`).
///
/// In most cases, markdown operates on ASCII bytes.
/// In a few cases, it is unicode aware, so we need to find an actual char.
pub fn char_after_index(bytes: &[u8], index: usize) -> Option<char> {
let end = if index + 4 > bytes.len() {
bytes.len()
} else {
index + 4
};
String::from_utf8_lossy(&bytes[index..end]).chars().next()
}
/// Classify a byte (or `char`).
pub fn byte_to_kind(bytes: &[u8], index: usize) -> CharacterKind {
if index == bytes.len() {
CharacterKind::Whitespace
} else {
let byte = bytes[index];
if byte.is_ascii_whitespace() {
CharacterKind::Whitespace
} else if byte.is_ascii_punctuation() {
CharacterKind::Punctuation
} else if byte.is_ascii_alphanumeric() {
CharacterKind::Other
} else {
// Otherwise: seems to be an ASCII control, so it seems to be a
// non-ASCII `char`.
classify_opt(char_after_index(bytes, index))
}
}
}
/// A range between two points.
#[derive(Debug)]
pub struct Position<'a> {
/// Start point.
pub start: &'a Point,
/// End 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.kind,
Kind::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.kind == Kind::Enter && enter.name == exit.name {
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)
}
}
/// Bytes belonging to a range.
///
/// Includes info on virtual spaces before and after the bytes.
#[derive(Debug)]
pub struct Slice<'a> {
/// Bytes.
pub bytes: &'a [u8],
/// Number of virtual spaces before the bytes.
pub before: usize,
/// Number of virtual spaces after the bytes.
pub after: usize,
}
impl<'a> Slice<'a> {
/// Get a slice for a single 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,
}
}
/// Get a slice for a single index.
///
/// > 👉 **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 a slice for 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,
}
}
/// Get a slice for two indices.
///
/// > 👉 **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`.
///
/// > 👉 **Note**: cannot represent 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
}
}
|
