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Commit | Line | Data |
---|---|---|
1a967e6b | 1 | use std::ops::{Deref, DerefMut}; |
e243ceb4 | 2 | use std::convert::AsRef; |
1a967e6b KS |
3 | use std::sync::atomic::*; |
4 | ||
5 | struct NABufferData<T> { | |
6 | data: T, | |
7 | refs: AtomicUsize, | |
8 | } | |
9 | ||
10 | impl<T> NABufferData<T> { | |
11 | fn new(data: T) -> Self { | |
12 | Self { | |
e243ceb4 | 13 | data, |
1a967e6b KS |
14 | refs: AtomicUsize::new(1), |
15 | } | |
16 | } | |
17 | fn inc_refs(obj: &mut Self) { | |
18 | obj.refs.fetch_add(1, Ordering::SeqCst); | |
19 | } | |
e243ceb4 | 20 | fn dec_refs(obj: &mut Self) -> bool { |
3485eca4 | 21 | obj.refs.fetch_sub(1, Ordering::SeqCst) == 1 |
1a967e6b KS |
22 | } |
23 | fn get_num_refs(obj: &Self) -> usize { | |
24 | obj.refs.load(Ordering::Relaxed) | |
25 | } | |
26 | fn get_read_ptr(obj: &Self) -> &T { | |
27 | &obj.data | |
28 | } | |
29 | fn get_write_ptr(obj: &mut Self) -> Option<&mut T> { | |
30 | Some(&mut obj.data) | |
31 | } | |
32 | } | |
33 | ||
34 | pub struct NABufferRef<T> { | |
35 | ptr: *mut NABufferData<T>, | |
36 | } | |
37 | ||
38 | impl<T> NABufferRef<T> { | |
39 | pub fn new(val: T) -> Self { | |
40 | let bdata = NABufferData::new(val); | |
41 | let nbox: Box<_> = Box::new(bdata); | |
42 | Self { ptr: Box::into_raw(nbox) } | |
43 | } | |
44 | pub fn get_num_refs(&self) -> usize { | |
45 | unsafe { | |
46 | NABufferData::get_num_refs(self.ptr.as_mut().unwrap()) | |
47 | } | |
48 | } | |
e243ceb4 | 49 | pub fn as_mut(&mut self) -> Option<&mut T> { |
1a967e6b | 50 | unsafe { |
e243ceb4 | 51 | NABufferData::get_write_ptr(self.ptr.as_mut().unwrap()) |
1a967e6b KS |
52 | } |
53 | } | |
e243ceb4 KS |
54 | } |
55 | ||
56 | impl<T> AsRef<T> for NABufferRef<T> { | |
57 | fn as_ref(&self) -> &T { | |
1a967e6b | 58 | unsafe { |
e243ceb4 | 59 | NABufferData::get_read_ptr(self.ptr.as_mut().unwrap()) |
1a967e6b KS |
60 | } |
61 | } | |
62 | } | |
63 | ||
64 | impl<T> Deref for NABufferRef<T> { | |
65 | type Target = T; | |
66 | fn deref(&self) -> &T { self.as_ref() } | |
67 | } | |
68 | ||
69 | impl<T> DerefMut for NABufferRef<T> { | |
70 | fn deref_mut(&mut self) -> &mut T { self.as_mut().unwrap() } | |
71 | } | |
72 | ||
73 | impl<T> Clone for NABufferRef<T> { | |
74 | fn clone(&self) -> Self { | |
75 | unsafe { | |
76 | NABufferData::inc_refs(self.ptr.as_mut().unwrap()); | |
77 | } | |
78 | Self { ptr: self.ptr } | |
79 | } | |
80 | } | |
81 | ||
82 | impl<T> Drop for NABufferRef<T> { | |
83 | fn drop(&mut self) { | |
84 | unsafe { | |
e243ceb4 | 85 | if NABufferData::dec_refs(self.ptr.as_mut().unwrap()) { |
639bb29a KS |
86 | let data = Box::from_raw(self.ptr); |
87 | std::mem::drop(data); | |
e243ceb4 | 88 | } |
1a967e6b KS |
89 | } |
90 | } | |
91 | } | |
92 | ||
49db8a11 KS |
93 | impl<T:Default> Default for NABufferRef<T> { |
94 | fn default() -> Self { | |
95 | Self::new(T::default()) | |
96 | } | |
97 | } |