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Commit | Line | Data |
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1 | use std::ops::{Deref, DerefMut}; | |
2 | use std::sync::atomic::*; | |
3 | ||
4 | struct NABufferData<T> { | |
5 | data: T, | |
6 | refs: AtomicUsize, | |
7 | } | |
8 | ||
9 | impl<T> NABufferData<T> { | |
10 | fn new(data: T) -> Self { | |
11 | Self { | |
12 | data: data, | |
13 | refs: AtomicUsize::new(1), | |
14 | } | |
15 | } | |
16 | fn inc_refs(obj: &mut Self) { | |
17 | obj.refs.fetch_add(1, Ordering::SeqCst); | |
18 | } | |
19 | fn dec_refs(obj: &mut Self) { | |
20 | if obj.refs.fetch_sub(1, Ordering::SeqCst) == 0 { | |
21 | std::mem::forget(obj); | |
22 | } | |
23 | } | |
24 | fn get_num_refs(obj: &Self) -> usize { | |
25 | obj.refs.load(Ordering::Relaxed) | |
26 | } | |
27 | fn get_read_ptr(obj: &Self) -> &T { | |
28 | &obj.data | |
29 | } | |
30 | fn get_write_ptr(obj: &mut Self) -> Option<&mut T> { | |
31 | Some(&mut obj.data) | |
32 | } | |
33 | } | |
34 | ||
35 | pub struct NABufferRef<T> { | |
36 | ptr: *mut NABufferData<T>, | |
37 | } | |
38 | ||
39 | impl<T> NABufferRef<T> { | |
40 | pub fn new(val: T) -> Self { | |
41 | let bdata = NABufferData::new(val); | |
42 | let nbox: Box<_> = Box::new(bdata); | |
43 | Self { ptr: Box::into_raw(nbox) } | |
44 | } | |
45 | pub fn get_num_refs(&self) -> usize { | |
46 | unsafe { | |
47 | NABufferData::get_num_refs(self.ptr.as_mut().unwrap()) | |
48 | } | |
49 | } | |
50 | pub fn as_ref(&self) -> &T { | |
51 | unsafe { | |
52 | NABufferData::get_read_ptr(self.ptr.as_mut().unwrap()) | |
53 | } | |
54 | } | |
55 | pub fn as_mut(&mut self) -> Option<&mut T> { | |
56 | unsafe { | |
57 | NABufferData::get_write_ptr(self.ptr.as_mut().unwrap()) | |
58 | } | |
59 | } | |
60 | } | |
61 | ||
62 | impl<T> Deref for NABufferRef<T> { | |
63 | type Target = T; | |
64 | fn deref(&self) -> &T { self.as_ref() } | |
65 | } | |
66 | ||
67 | impl<T> DerefMut for NABufferRef<T> { | |
68 | fn deref_mut(&mut self) -> &mut T { self.as_mut().unwrap() } | |
69 | } | |
70 | ||
71 | impl<T> Clone for NABufferRef<T> { | |
72 | fn clone(&self) -> Self { | |
73 | unsafe { | |
74 | NABufferData::inc_refs(self.ptr.as_mut().unwrap()); | |
75 | } | |
76 | Self { ptr: self.ptr } | |
77 | } | |
78 | } | |
79 | ||
80 | impl<T> Drop for NABufferRef<T> { | |
81 | fn drop(&mut self) { | |
82 | unsafe { | |
83 | NABufferData::dec_refs(self.ptr.as_mut().unwrap()); | |
84 | } | |
85 | } | |
86 | } | |
87 |