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
use crate::ByteCount;
/// `Eos` contains information on the distance to the end of a stream.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd)]
pub struct Eos(ByteCount);
impl Eos {
/// Makes a new `Eos` instance.
pub fn new(is_eos_reached: bool) -> Self {
if is_eos_reached {
Eos(ByteCount::Finite(0))
} else {
Eos(ByteCount::Unknown)
}
}
/// Makes a new `Eos` instance that
/// has the given information about the number of remaining bytes in a stream.
pub fn with_remaining_bytes(n: ByteCount) -> Self {
Eos(n)
}
/// Returns `true` if the target stream has reached to the end, otherwise `false`.
pub fn is_reached(&self) -> bool {
self.0 == ByteCount::Finite(0)
}
/// Returns the information about the number of bytes remaining in the target stream.
pub fn remaining_bytes(&self) -> ByteCount {
self.0
}
/// Returns a new `Eos` instance that has moved backward from
/// the end of the target stream by the specified number of bytes.
///
/// # Examples
///
/// ```
/// use bytecodec::{ByteCount, Eos};
///
/// let eos = Eos::new(true);
/// assert_eq!(eos.is_reached(), true);
/// assert_eq!(eos.remaining_bytes(), ByteCount::Finite(0));
///
/// let eos = eos.back(5);
/// assert_eq!(eos.is_reached(), false);
/// assert_eq!(eos.remaining_bytes(), ByteCount::Finite(5));
/// ```
pub fn back(&self, bytes: u64) -> Self {
if let ByteCount::Finite(n) = self.0 {
Eos(ByteCount::Finite(n + bytes))
} else {
*self
}
}
}