1 | /* Copyright 2016 Google Inc. |
2 | |
3 | Licensed under the Apache License, Version 2.0 (the "License"); |
4 | you may not use this file except in compliance with the License. |
5 | You may obtain a copy of the License at |
6 | |
7 | http://www.apache.org/licenses/LICENSE-2.0 |
8 | |
9 | Unless required by applicable law or agreed to in writing, software |
10 | distributed under the License is distributed on an "AS IS" BASIS, |
11 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | See the License for the specific language governing permissions and |
13 | limitations under the License. */ |
14 | |
15 | #ifndef NSYNC_PUBLIC_NSYNC_COUNTER_H_ |
16 | #define NSYNC_PUBLIC_NSYNC_COUNTER_H_ |
17 | |
18 | #include <inttypes.h> |
19 | #include "nsync_cpp.h" |
20 | #include "nsync_mu.h" |
21 | #include "nsync_atomic.h" |
22 | #include "nsync_time.h" |
23 | |
24 | NSYNC_CPP_START_ |
25 | |
26 | struct nsync_dll_element_s_; |
27 | |
28 | /* An nsync_counter represents an unsigned integer that can count up and down, |
29 | and wake waiters when zero. */ |
30 | typedef struct nsync_counter_s_ *nsync_counter; |
31 | |
32 | /* Return a freshly allocated nsync_counter with the specified value, |
33 | of NULL if an nsync_counter cannot be created. |
34 | |
35 | Any non-NULL returned value should be passed to nsync_counter_free() when no |
36 | longer needed. */ |
37 | nsync_counter nsync_counter_new (uint32_t value); |
38 | |
39 | /* Free resources associated with c. Requires that c was allocated by |
40 | nsync_counter_new(), and no concurrent or future operations are applied to |
41 | c. */ |
42 | void nsync_counter_free (nsync_counter c); |
43 | |
44 | /* Add delta to c, and return its new value. It is a checkable runtime error |
45 | to decrement c below 0, or to increment c (i.e., apply a delta > 0) after a |
46 | waiter has waited. */ |
47 | uint32_t nsync_counter_add (nsync_counter c, int32_t delta); |
48 | |
49 | /* Return the current value of c. */ |
50 | uint32_t nsync_counter_value (nsync_counter c); |
51 | |
52 | /* Wait until c has value 0, or until abs_deadline, then return |
53 | the value of c. It is a checkable runtime error to increment c after |
54 | a waiter may have been woken due to the counter reaching zero. |
55 | If abs_deadline==nsync_time_no_deadline, the deadline |
56 | is far in the future. */ |
57 | uint32_t nsync_counter_wait (nsync_counter c, nsync_time abs_deadline); |
58 | |
59 | NSYNC_COUNTER_CPP_OVERLOAD_ |
60 | NSYNC_CPP_END_ |
61 | |
62 | #endif /*NSYNC_PUBLIC_NSYNC_COUNTER_H_*/ |
63 | |