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
|
use std::cmp;
use std::mem::MaybeUninit;
use crate::misc::maybe_uninit_write_slice;
#[derive(Debug)]
pub(crate) struct InputBuf<'a> {
// Invariants: `0 <= pos_within_buf <= limit_within_buf <= buf.len()`.
buf: &'a [u8],
pos_within_buf: usize,
limit_within_buf: usize,
}
impl<'a> InputBuf<'a> {
#[inline]
pub(crate) fn assertions(&self) {
debug_assert!(self.pos_within_buf <= self.limit_within_buf);
debug_assert!(self.limit_within_buf <= self.buf.len());
}
pub(crate) fn empty() -> InputBuf<'a> {
InputBuf {
buf: &[],
pos_within_buf: 0,
limit_within_buf: 0,
}
}
pub(crate) fn from_bytes(buf: &'a [u8]) -> InputBuf<'a> {
InputBuf {
buf,
pos_within_buf: 0,
limit_within_buf: buf.len(),
}
}
pub(crate) unsafe fn from_bytes_ignore_lifetime(buf: &[u8]) -> InputBuf<'a> {
let buf = &*(buf as *const [u8]);
Self::from_bytes(buf)
}
pub(crate) fn update_limit(&mut self, limit: u64) {
let limit_within_buf = cmp::min(self.buf.len() as u64, limit);
assert!(limit_within_buf >= self.pos_within_buf as u64);
self.limit_within_buf = limit_within_buf as usize;
}
pub(crate) fn pos_within_buf(&self) -> usize {
self.pos_within_buf
}
#[inline(always)]
pub(crate) fn remaining_in_buf(&self) -> &'a [u8] {
// SAFETY: Invariants.
unsafe {
self.buf
.get_unchecked(self.pos_within_buf..self.limit_within_buf)
}
}
#[inline(always)]
pub(crate) fn consume(&mut self, amt: usize) {
assert!(amt <= self.remaining_in_buf().len());
self.pos_within_buf += amt;
}
#[inline(always)]
pub(crate) fn read_byte(&mut self) -> Option<u8> {
let r = self.remaining_in_buf().first().copied();
if let Some(..) = r {
self.pos_within_buf += 1;
}
r
}
pub(crate) fn read_bytes<'b>(&mut self, dest: &'b mut [MaybeUninit<u8>]) -> &'b mut [u8] {
// This panics if this has not enough data.
let r = maybe_uninit_write_slice(dest, &self.remaining_in_buf()[..dest.len()]);
self.pos_within_buf += r.len();
r
}
}
|
