rc_u8_reader/
arc_mutex_u8_reader.rs

1use std::fmt::{self, Debug, Formatter};
2use std::io::{self, ErrorKind, Read, Seek, SeekFrom};
3use std::sync::{Arc, Mutex};
4
5pub struct ArcMutexU8Reader<T: AsRef<[u8]> + ?Sized> {
6    data: Arc<Mutex<T>>,
7    pos: usize,
8}
9
10impl<T: AsRef<[u8]> + ?Sized> Debug for ArcMutexU8Reader<T> {
11    #[inline]
12    fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
13        debug_helper::impl_debug_for_struct!(ArcMutexU8Reader, f, self, let .data = self.data.as_ref().lock().unwrap().as_ref(), .pos);
14    }
15}
16
17impl<T: AsRef<[u8]> + ?Sized> ArcMutexU8Reader<T> {
18    #[inline]
19    pub fn new(data: Arc<Mutex<T>>) -> ArcMutexU8Reader<T> {
20        ArcMutexU8Reader {
21            data,
22            pos: 0,
23        }
24    }
25}
26
27impl<T: AsRef<[u8]> + ?Sized> Read for ArcMutexU8Reader<T> {
28    fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
29        let data = self.data.lock().unwrap();
30        let data: &[u8] = &data.as_ref()[self.pos..];
31
32        let data_len = data.len();
33        let buf_len = buf.len();
34
35        let len = if data_len > buf_len {
36            let data = &data[..buf_len];
37
38            buf.copy_from_slice(data);
39
40            buf_len
41        } else {
42            buf[..data_len].copy_from_slice(data);
43
44            data_len
45        };
46
47        self.pos += len;
48
49        Ok(len)
50    }
51}
52
53impl<T: AsRef<[u8]> + ?Sized> Seek for ArcMutexU8Reader<T> {
54    fn seek(&mut self, style: SeekFrom) -> Result<u64, io::Error> {
55        let (base_pos, offset) = match style {
56            SeekFrom::Start(n) => {
57                let n = if n > usize::MAX as u64 {
58                    usize::MAX
59                } else {
60                    n as usize
61                };
62
63                self.pos = n;
64
65                return Ok(n as u64);
66            }
67            SeekFrom::End(n) => {
68                (
69                    {
70                        let data = self.data.lock().unwrap();
71                        let data: &[u8] = &data.as_ref()[self.pos..];
72
73                        data.len()
74                    },
75                    n,
76                )
77            }
78            SeekFrom::Current(n) => (self.pos, n),
79        };
80
81        let offset = if offset > isize::MAX as i64 {
82            isize::MAX
83        } else if offset < isize::MIN as i64 {
84            isize::MIN
85        } else {
86            offset as isize
87        };
88
89        let new_pos = if offset >= 0 {
90            base_pos.checked_add(offset as usize)
91        } else {
92            base_pos.checked_sub((offset.wrapping_neg()) as usize)
93        };
94
95        match new_pos {
96            Some(n) => {
97                self.pos = n;
98
99                Ok(self.pos as u64)
100            }
101            None => {
102                Err(io::Error::new(
103                    ErrorKind::InvalidInput,
104                    "invalid seek to a negative or overflowing position",
105                ))
106            }
107        }
108    }
109}
rc_u8_reader/arc_mutex_u8_reader.rs

rc_u8_reader/
arc_mutex_u8_reader.rs
