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        if self.pos < capacity {
31            capacity - self.pos
32        } else {
33            0
34        }
35    }
36
37    #[inline]
38    pub fn capacity(&self) -> usize {
39        self.buf.len()
40    }
41
42    #[inline]
43    pub fn slice(&mut self, size: usize) -> Result<&mut [u8]> {
44        if self.len() >= size {
45            Ok(unsafe { self.buf.get_unchecked_mut(self.pos..self.pos + size) })
46        } else {
47            Err(Error::BufferTooShort(self.pos() + size))
48        }
49    }
50
51    #[inline]
52    pub fn u16_be(&mut self, val: u16) -> Result<()> {
53        w_be!(self, u16, val)
54    }
55
56    #[inline]
57    pub fn u32_be(&mut self, val: u32) -> Result<()> {
58        w_be!(self, u32, val)
59    }
60
61    #[inline]
62    pub unsafe fn u16_be_unchecked(&mut self, val: u16) {
63        wu_be!(self, u16, val)
64    }
65
66    #[inline]
67    pub fn u8(&mut self, val: u8) -> Result<()> {
68        unsafe { *self.slice(1)?.get_unchecked_mut(0) = val };
69        self.pos += 1;
70        Ok(())
71    }
72
73    #[inline]
74    pub unsafe fn u8_unchecked(&mut self, val: u8) {
75        *self.buf.get_unchecked_mut(self.pos) = val;
76        self.pos += 1;
77    }
78
79    #[inline]
80    pub unsafe fn bytes_unchecked(&mut self, buf: &[u8]) {
81        self.buf
82            .get_unchecked_mut(self.pos..self.pos + buf.len())
83            .copy_from_slice(buf);
84        self.pos += buf.len();
85    }
86}
rsdns/bytes/wcursor.rs

rsdns/bytes/
wcursor.rs
