tokio_process_tools/output_stream/
num_bytes.rs

1/// A wrapper type representing a number of bytes.
2///
3/// Use the [`NumBytesExt`] trait to conveniently create instances:
4/// ```
5/// use tokio_process_tools::NumBytesExt;
6/// let kb = 16.kilobytes();
7/// let mb = 2.megabytes();
8/// ```
9#[derive(Debug, Clone, Copy, PartialEq, Eq)]
10pub struct NumBytes(pub(crate) usize);
11
12impl NumBytes {
13    /// The largest representable byte count (`usize::MAX`).
14    ///
15    /// Use this when an API requires an explicit byte limit but you don't actually want to cap
16    /// it — for example, line-parsing options that require a non-zero `max_line_length` but you
17    /// trust the source to produce reasonable lines.
18    pub const MAX: NumBytes = NumBytes(usize::MAX);
19
20    /// Creates a `NumBytes` value of zero.
21    #[must_use]
22    pub fn zero() -> Self {
23        Self(0)
24    }
25
26    pub(crate) fn assert_non_zero(self, parameter_name: &str) {
27        assert!(
28            self.0 > 0,
29            "{parameter_name} must be greater than zero bytes"
30        );
31    }
32
33    /// The amount of bytes represented by this instance.
34    #[must_use]
35    pub fn bytes(&self) -> usize {
36        self.0
37    }
38}
39
40/// Extension trait providing convenience constructors for [`NumBytes`].
41///
42/// Implemented for `usize`, so integer literals can be used directly:
43///
44/// ```
45/// use tokio_process_tools::{NumBytes, NumBytesExt};
46///
47/// let small: NumBytes = 512.bytes();
48/// let medium: NumBytes = 16.kilobytes();
49/// let large: NumBytes = 2.megabytes();
50///
51/// assert_eq!(small.bytes(), 512);
52/// assert_eq!(medium.bytes(), 16 * 1024);
53/// assert_eq!(large.bytes(), 2 * 1024 * 1024);
54/// ```
55pub trait NumBytesExt {
56    /// Interprets the value as literal bytes.
57    fn bytes(self) -> NumBytes;
58
59    /// Interprets the value as kilobytes (value * 1024).
60    fn kilobytes(self) -> NumBytes;
61
62    /// Interprets the value as megabytes (value * 1024 * 1024).
63    fn megabytes(self) -> NumBytes;
64}
65
66impl NumBytesExt for usize {
67    fn bytes(self) -> NumBytes {
68        NumBytes(self)
69    }
70
71    fn kilobytes(self) -> NumBytes {
72        NumBytes(self * 1024)
73    }
74
75    fn megabytes(self) -> NumBytes {
76        NumBytes(self * 1024 * 1024)
77    }
78}
tokio_process_tools/output_stream/num_bytes.rs

tokio_process_tools/output_stream/
num_bytes.rs
