rsdns/bytes/
wcursor.rs

1use crate::{Error, Result};
2
3#[derive(Debug)]
4pub struct WCursor<'a> {
5    buf: &'a mut [u8],
6    pos: usize,
7}
8
9impl<'a> WCursor<'a> {
10    #[inline]
11    pub fn new(buf: &'a mut [u8]) -> Self {
12        Self { buf, pos: 0 }
13    }
14
15    #[inline]
16    pub fn pos(&self) -> usize {
17        self.pos
18    }
19
20    #[inline]
21    pub fn reset_pos(&mut self) -> usize {
22        let mut new_pos = 0;
23        std::mem::swap(&mut self.pos, &mut new_pos);
24        new_pos
25    }
26
27    #[inline]
28    pub fn len(&self) -> usize {
29        let capacity = self.capacity();
30        capacity.saturating_sub(self.pos)
31    }
32
33    #[inline]
34    pub fn capacity(&self) -> usize {
35        self.buf.len()
36    }
37
38    #[inline]
39    pub fn slice(&mut self, size: usize) -> Result<&mut [u8]> {
40        if self.len() >= size {
41            Ok(unsafe { self.buf.get_unchecked_mut(self.pos..self.pos + size) })
42        } else {
43            Err(Error::BufferTooShort(self.pos() + size))
44        }
45    }
46
47    #[inline]
48    pub fn u16_be(&mut self, val: u16) -> Result<()> {
49        w_be!(self, u16, val)
50    }
51
52    #[inline]
53    pub fn u32_be(&mut self, val: u32) -> Result<()> {
54        w_be!(self, u32, val)
55    }
56
57    #[inline]
58    pub unsafe fn u16_be_unchecked(&mut self, val: u16) {
59        wu_be!(self, u16, val)
60    }
61
62    #[inline]
63    pub fn u8(&mut self, val: u8) -> Result<()> {
64        unsafe {
65            *self.slice(1)?.get_unchecked_mut(0) = val;
66        }
67        self.pos += 1;
68        Ok(())
69    }
70
71    #[inline]
72    pub unsafe fn u8_unchecked(&mut self, val: u8) {
73        unsafe {
74            *self.buf.get_unchecked_mut(self.pos) = val;
75        }
76        self.pos += 1;
77    }
78
79    #[inline]
80    pub unsafe fn bytes_unchecked(&mut self, buf: &[u8]) {
81        unsafe {
82            self.buf
83                .get_unchecked_mut(self.pos..self.pos + buf.len())
84                .copy_from_slice(buf);
85        }
86        self.pos += buf.len();
87    }
88}
rsdns/bytes/wcursor.rs

rsdns/bytes/
wcursor.rs
