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
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
use memmap2::MmapRaw;
use std::{
fs,
io::{self, Seek},
mem::ManuallyDrop,
ptr,
};
pub struct FileMmap {
file: fs::File,
mmap: ManuallyDrop<Box<MmapRaw>>,
}
impl Drop for FileMmap {
fn drop(&mut self) {
unsafe { ManuallyDrop::drop(&mut self.mmap) };
}
}
impl FileMmap {
pub fn new(path: &str) -> io::Result<Self> {
let mut file = fs::OpenOptions::new()
.read(true)
.write(true)
.create(true)
.open(&path)?;
file.seek(io::SeekFrom::End(0))?;
let mmap = ManuallyDrop::new(Box::new(MmapRaw::map_raw(&file)?));
Ok(FileMmap { file, mmap })
}
pub fn len(&self) -> io::Result<u64> {
Ok(self.file.metadata()?.len())
}
pub fn as_ptr(&self) -> *const u8 {
self.mmap.as_ptr()
}
pub unsafe fn offset(&self, addr: isize) -> *const u8 {
self.mmap.as_ptr().offset(addr)
}
pub unsafe fn bytes(&self, addr: isize, len: usize) -> &[u8] {
std::slice::from_raw_parts(self.mmap.as_ptr().offset(addr), len)
}
pub fn set_len(&mut self, len: u64) -> io::Result<()> {
let current_len = self.file.metadata()?.len();
if len > current_len && current_len > 0 {
self.file.set_len(len)?;
} else {
unsafe { ManuallyDrop::drop(&mut self.mmap) };
self.file.set_len(len)?;
self.mmap = ManuallyDrop::new(Box::new(MmapRaw::map_raw(&self.file).unwrap()));
}
Ok(())
}
pub fn append(&mut self, bytes: &[u8]) -> io::Result<u64> {
let addr = self.file.metadata()?.len();
self.set_len(addr + bytes.len() as u64)?;
unsafe {
self.write(addr as isize, bytes);
}
Ok(addr)
}
pub unsafe fn write(&mut self, addr: isize, bytes: &[u8]) {
let len = bytes.len();
ptr::copy(
bytes.as_ptr(),
self.mmap.as_ptr().offset(addr) as *mut u8,
len,
);
}
pub unsafe fn write_0(&mut self, addr: isize, len: usize) {
ptr::write_bytes(self.mmap.as_ptr().offset(addr) as *mut u8, 0, len);
}
}