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
|
//! Missing batteries for standard libraries.
use std::time::Instant;
mod macros;
pub mod panic_context;
#[inline(always)]
pub fn is_ci() -> bool {
option_env!("CI").is_some()
}
#[must_use]
pub fn timeit(label: &'static str) -> impl Drop {
struct Guard {
label: &'static str,
start: Instant,
}
impl Drop for Guard {
fn drop(&mut self) {
eprintln!("{}: {:.2?}", self.label, self.start.elapsed())
}
}
Guard { label, start: Instant::now() }
}
fn to_snake_case<F: Fn(&char) -> char>(s: &str, change_case: F) -> String {
let mut buf = String::with_capacity(s.len());
let mut prev = false;
for c in s.chars() {
// `&& prev` is required to not insert `_` before the first symbol.
if c.is_ascii_uppercase() && prev {
// This check is required to not translate `Weird_Case` into `weird__case`.
if !buf.ends_with('_') {
buf.push('_')
}
}
prev = true;
buf.push(change_case(&c));
}
buf
}
pub fn to_lower_snake_case(s: &str) -> String {
to_snake_case(s, char::to_ascii_lowercase)
}
pub fn to_upper_snake_case(s: &str) -> String {
to_snake_case(s, char::to_ascii_uppercase)
}
pub fn replace(buf: &mut String, from: char, to: &str) {
if !buf.contains(from) {
return;
}
// FIXME: do this in place.
*buf = buf.replace(from, to)
}
// https://github.com/rust-lang/rust/issues/74773
pub fn split_once(haystack: &str, delim: char) -> Option<(&str, &str)> {
let mut split = haystack.splitn(2, delim);
let prefix = split.next()?;
let suffix = split.next()?;
Some((prefix, suffix))
}
pub fn rsplit_once(haystack: &str, delim: char) -> Option<(&str, &str)> {
let mut split = haystack.rsplitn(2, delim);
let suffix = split.next()?;
let prefix = split.next()?;
Some((prefix, suffix))
}
pub fn trim_indent(mut text: &str) -> String {
if text.starts_with('\n') {
text = &text[1..];
}
let indent = text
.lines()
.filter(|it| !it.trim().is_empty())
.map(|it| it.len() - it.trim_start().len())
.min()
.unwrap_or(0);
lines_with_ends(text)
.map(
|line| {
if line.len() <= indent {
line.trim_start_matches(' ')
} else {
&line[indent..]
}
},
)
.collect()
}
pub fn lines_with_ends(text: &str) -> LinesWithEnds {
LinesWithEnds { text }
}
pub struct LinesWithEnds<'a> {
text: &'a str,
}
impl<'a> Iterator for LinesWithEnds<'a> {
type Item = &'a str;
fn next(&mut self) -> Option<&'a str> {
if self.text.is_empty() {
return None;
}
let idx = self.text.find('\n').map_or(self.text.len(), |it| it + 1);
let (res, next) = self.text.split_at(idx);
self.text = next;
Some(res)
}
}
// https://github.com/rust-lang/rust/issues/73831
pub fn partition_point<T, P>(slice: &[T], mut pred: P) -> usize
where
P: FnMut(&T) -> bool,
{
let mut left = 0;
let mut right = slice.len();
while left != right {
let mid = left + (right - left) / 2;
// SAFETY:
// When left < right, left <= mid < right.
// Therefore left always increases and right always decreases,
// and either of them is selected.
// In both cases left <= right is satisfied.
// Therefore if left < right in a step,
// left <= right is satisfied in the next step.
// Therefore as long as left != right, 0 <= left < right <= len is satisfied
// and if this case 0 <= mid < len is satisfied too.
let value = unsafe { slice.get_unchecked(mid) };
if pred(value) {
left = mid + 1;
} else {
right = mid;
}
}
left
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_trim_indent() {
assert_eq!(trim_indent(""), "");
assert_eq!(
trim_indent(
"
hello
world
"
),
"hello\nworld\n"
);
assert_eq!(
trim_indent(
"
hello
world"
),
"hello\nworld"
);
assert_eq!(trim_indent(" hello\n world\n"), "hello\nworld\n");
assert_eq!(
trim_indent(
"
fn main() {
return 92;
}
"
),
"fn main() {\n return 92;\n}\n"
);
}
}
|
