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
232
233
234
235
236
237
238
239
240
241
242
|
use crate::buf::{IntoIter, UninitSlice};
use crate::{Buf, BufMut, Bytes};
#[cfg(feature = "std")]
use std::io::IoSlice;
/// A `Chain` sequences two buffers.
///
/// `Chain` is an adapter that links two underlying buffers and provides a
/// continuous view across both buffers. It is able to sequence either immutable
/// buffers ([`Buf`] values) or mutable buffers ([`BufMut`] values).
///
/// This struct is generally created by calling [`Buf::chain`]. Please see that
/// function's documentation for more detail.
///
/// # Examples
///
/// ```
/// use bytes::{Bytes, Buf};
///
/// let mut buf = (&b"hello "[..])
/// .chain(&b"world"[..]);
///
/// let full: Bytes = buf.copy_to_bytes(11);
/// assert_eq!(full[..], b"hello world"[..]);
/// ```
///
/// [`Buf::chain`]: trait.Buf.html#method.chain
/// [`Buf`]: trait.Buf.html
/// [`BufMut`]: trait.BufMut.html
#[derive(Debug)]
pub struct Chain<T, U> {
a: T,
b: U,
}
impl<T, U> Chain<T, U> {
/// Creates a new `Chain` sequencing the provided values.
pub(crate) fn new(a: T, b: U) -> Chain<T, U> {
Chain { a, b }
}
/// Gets a reference to the first underlying `Buf`.
///
/// # Examples
///
/// ```
/// use bytes::Buf;
///
/// let buf = (&b"hello"[..])
/// .chain(&b"world"[..]);
///
/// assert_eq!(buf.first_ref()[..], b"hello"[..]);
/// ```
pub fn first_ref(&self) -> &T {
&self.a
}
/// Gets a mutable reference to the first underlying `Buf`.
///
/// # Examples
///
/// ```
/// use bytes::Buf;
///
/// let mut buf = (&b"hello"[..])
/// .chain(&b"world"[..]);
///
/// buf.first_mut().advance(1);
///
/// let full = buf.copy_to_bytes(9);
/// assert_eq!(full, b"elloworld"[..]);
/// ```
pub fn first_mut(&mut self) -> &mut T {
&mut self.a
}
/// Gets a reference to the last underlying `Buf`.
///
/// # Examples
///
/// ```
/// use bytes::Buf;
///
/// let buf = (&b"hello"[..])
/// .chain(&b"world"[..]);
///
/// assert_eq!(buf.last_ref()[..], b"world"[..]);
/// ```
pub fn last_ref(&self) -> &U {
&self.b
}
/// Gets a mutable reference to the last underlying `Buf`.
///
/// # Examples
///
/// ```
/// use bytes::Buf;
///
/// let mut buf = (&b"hello "[..])
/// .chain(&b"world"[..]);
///
/// buf.last_mut().advance(1);
///
/// let full = buf.copy_to_bytes(10);
/// assert_eq!(full, b"hello orld"[..]);
/// ```
pub fn last_mut(&mut self) -> &mut U {
&mut self.b
}
/// Consumes this `Chain`, returning the underlying values.
///
/// # Examples
///
/// ```
/// use bytes::Buf;
///
/// let chain = (&b"hello"[..])
/// .chain(&b"world"[..]);
///
/// let (first, last) = chain.into_inner();
/// assert_eq!(first[..], b"hello"[..]);
/// assert_eq!(last[..], b"world"[..]);
/// ```
pub fn into_inner(self) -> (T, U) {
(self.a, self.b)
}
}
impl<T, U> Buf for Chain<T, U>
where
T: Buf,
U: Buf,
{
fn remaining(&self) -> usize {
self.a.remaining().checked_add(self.b.remaining()).unwrap()
}
fn chunk(&self) -> &[u8] {
if self.a.has_remaining() {
self.a.chunk()
} else {
self.b.chunk()
}
}
fn advance(&mut self, mut cnt: usize) {
let a_rem = self.a.remaining();
if a_rem != 0 {
if a_rem >= cnt {
self.a.advance(cnt);
return;
}
// Consume what is left of a
self.a.advance(a_rem);
cnt -= a_rem;
}
self.b.advance(cnt);
}
#[cfg(feature = "std")]
fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize {
let mut n = self.a.chunks_vectored(dst);
n += self.b.chunks_vectored(&mut dst[n..]);
n
}
fn copy_to_bytes(&mut self, len: usize) -> Bytes {
let a_rem = self.a.remaining();
if a_rem >= len {
self.a.copy_to_bytes(len)
} else if a_rem == 0 {
self.b.copy_to_bytes(len)
} else {
assert!(
len - a_rem <= self.b.remaining(),
"`len` greater than remaining"
);
let mut ret = crate::BytesMut::with_capacity(len);
ret.put(&mut self.a);
ret.put((&mut self.b).take(len - a_rem));
ret.freeze()
}
}
}
unsafe impl<T, U> BufMut for Chain<T, U>
where
T: BufMut,
U: BufMut,
{
fn remaining_mut(&self) -> usize {
self.a
.remaining_mut()
.saturating_add(self.b.remaining_mut())
}
fn chunk_mut(&mut self) -> &mut UninitSlice {
if self.a.has_remaining_mut() {
self.a.chunk_mut()
} else {
self.b.chunk_mut()
}
}
unsafe fn advance_mut(&mut self, mut cnt: usize) {
let a_rem = self.a.remaining_mut();
if a_rem != 0 {
if a_rem >= cnt {
self.a.advance_mut(cnt);
return;
}
// Consume what is left of a
self.a.advance_mut(a_rem);
cnt -= a_rem;
}
self.b.advance_mut(cnt);
}
}
impl<T, U> IntoIterator for Chain<T, U>
where
T: Buf,
U: Buf,
{
type Item = u8;
type IntoIter = IntoIter<Chain<T, U>>;
fn into_iter(self) -> Self::IntoIter {
IntoIter::new(self)
}
}
|
