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comparison foosdk/sdk/pfc/event_std.h @ 1:20d02a178406 default tip

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author Paper <paper@tflc.us>
date Mon, 05 Jan 2026 02:15:46 -0500
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0:e9bb126753e7 1:20d02a178406
1 #pragma once
2
3 // Alternate lightweight implementation of pfc::event, with similar method sigantures but no support for multi-event-wait-for-any.
4 // It's a safe drop-in replacement for the regular event - code trying to use unsupported methods will fail to compile rather than behave incorrectly.
5
6 // Rationale:
7 // Mac/Linux multi-wait-capable pipe-backed event is relatively expensive, in terms of CPU, memory and file descriptors opened.
8 // On Windows, event_std still outperforms regular win32 event but the difference is mostly insignificant in real life use cases.
9
10 #include <mutex>
11 #include <condition_variable>
12 namespace pfc {
13 class event_std {
14 public:
15 void set_state(bool v = true) {
16 std::scoped_lock lock(m_mutex);
17 if (m_state != v) {
18 m_state = v;
19 if (v) m_condition.notify_all();
20 }
21 }
22 bool is_set() const { return m_state; }
23 void wait() {
24 std::unique_lock lock(m_mutex);
25 m_condition.wait(lock, [this] { return this->m_state; });
26 }
27 bool wait_for(double timeout) {
28 if (timeout < 0) { wait(); return true; }
29 std::unique_lock lock(m_mutex);
30 return m_condition.wait_for(lock, std::chrono::duration<double>(timeout), [this] { return this->m_state; });
31 }
32 void wait_and_clear() {
33 std::unique_lock lock(m_mutex);
34 m_condition.wait(lock, [this] { return this->m_state; });
35 m_state = false;
36 }
37 bool wait_for_and_clear(double timeout) {
38 if ( timeout < 0 ) {wait_and_clear(); return true;}
39 std::unique_lock lock(m_mutex);
40 bool rv = m_condition.wait_for(lock, std::chrono::duration<double>(timeout), [this] { return this->m_state; });
41 if ( rv ) m_state = false;
42 return rv;
43 }
44 private:
45 volatile bool m_state = false;
46 std::condition_variable m_condition;
47 std::mutex m_mutex;
48 };
49 }