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
#[cfg(feature = "bytes-buf")]
use bytes::{Bytes, BytesMut};
pub trait Buffer {
type Freeze;
fn with_capacity(capacity: usize) -> Self
where
Self: Sized;
fn is_empty(&self) -> bool;
fn extend_from_slice(&mut self, src: &[u8]);
fn reserve(&mut self, additional: usize);
fn freeze(self) -> Self::Freeze;
unsafe fn advance(&mut self, cnt: usize);
unsafe fn buf_ptr(&mut self) -> *mut u8;
}
impl Buffer for Vec<u8> {
type Freeze = Vec<u8>;
#[inline]
fn with_capacity(capacity: usize) -> Self
where
Self: Sized,
{
Vec::with_capacity(capacity)
}
#[inline]
fn is_empty(&self) -> bool {
self.is_empty()
}
#[inline]
fn extend_from_slice(&mut self, src: &[u8]) {
Buffer::reserve(self, src.len());
unsafe {
debug_assert!(self.capacity() - self.len() >= src.len());
std::ptr::copy_nonoverlapping(src.as_ptr(), self.buf_ptr(), src.len());
Buffer::advance(self, src.len())
}
}
#[inline]
fn reserve(&mut self, additional: usize) {
debug_assert!(self.len() <= self.capacity());
if self.capacity().wrapping_sub(self.len()) < additional {
self.reserve(additional);
}
}
#[inline]
fn freeze(mut self) -> Self::Freeze {
self.shrink_to_fit();
self
}
#[inline]
unsafe fn advance(&mut self, cnt: usize) {
self.set_len(self.len() + cnt);
}
#[inline]
unsafe fn buf_ptr(&mut self) -> *mut u8 {
self.as_mut_ptr().add(self.len())
}
}
#[cfg(feature = "bytes-buf")]
impl Buffer for BytesMut {
type Freeze = Bytes;
#[inline]
fn with_capacity(capacity: usize) -> Self
where
Self: Sized,
{
BytesMut::with_capacity(capacity)
}
#[inline]
fn is_empty(&self) -> bool {
self.is_empty()
}
#[inline]
fn extend_from_slice(&mut self, src: &[u8]) {
self.reserve(src.len());
unsafe {
debug_assert!(self.capacity() - self.len() >= src.len());
std::ptr::copy_nonoverlapping(src.as_ptr(), self.buf_ptr(), src.len());
self.advance(src.len())
}
}
#[inline(always)]
fn reserve(&mut self, additional: usize) {
self.reserve(additional);
}
#[inline(always)]
fn freeze(self) -> Self::Freeze {
self.freeze()
}
#[inline]
unsafe fn advance(&mut self, cnt: usize) {
let new_len = self.len() + cnt;
debug_assert!(
new_len <= self.capacity(),
"new_len = {}; capacity = {}",
new_len,
self.capacity()
);
self.set_len(new_len);
}
#[inline]
unsafe fn buf_ptr(&mut self) -> *mut u8 {
self.as_mut_ptr().add(self.len())
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test() {
let e = b"Hello world!";
let mut buf: Vec<u8> = Buffer::with_capacity(0);
Buffer::extend_from_slice(&mut buf, e);
assert_eq!(e, &Buffer::freeze(buf)[..]);
let mut buf: Vec<u8> = Buffer::with_capacity(124);
Buffer::extend_from_slice(&mut buf, e);
assert_eq!(e, &Buffer::freeze(buf)[..]);
let mut buf: Vec<u8> = Buffer::with_capacity(14);
Buffer::extend_from_slice(&mut buf, e);
}
}
#[cfg(all(test, feature = "bytes-buf"))]
mod test_bytes {
use super::*;
use bytes::BytesMut;
#[test]
fn test() {
let e = b"Hello world!";
let mut buf: BytesMut = Buffer::with_capacity(0);
Buffer::extend_from_slice(&mut buf, e);
assert_eq!(e, &Buffer::freeze(buf)[..]);
let mut buf: BytesMut = Buffer::with_capacity(124);
Buffer::extend_from_slice(&mut buf, e);
assert_eq!(e, &Buffer::freeze(buf)[..]);
}
}