59 lines
1.7 KiB
C++
59 lines
1.7 KiB
C++
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// Copyright 2020 The Pigweed Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not
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// use this file except in compliance with the License. You may obtain a copy of
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// the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations under
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// the License.
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#include "pw_sync/counting_semaphore.h"
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#include "pw_assert/check.h"
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using pw::chrono::SystemClock;
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namespace pw::sync {
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void CountingSemaphore::release(ptrdiff_t update) {
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PW_DCHECK_UINT_GE(update, 0);
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{
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std::lock_guard lock(native_type_.mutex);
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PW_DCHECK_UINT_LE(update, CountingSemaphore::max() - native_type_.count);
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native_type_.count += update;
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native_type_.condition.notify_one();
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}
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}
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void CountingSemaphore::acquire() {
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std::unique_lock lock(native_type_.mutex);
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native_type_.condition.wait(lock, [&] { return native_type_.count != 0; });
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--native_type_.count;
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}
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bool CountingSemaphore::try_acquire() noexcept {
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std::lock_guard lock(native_type_.mutex);
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if (native_type_.count != 0) {
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--native_type_.count;
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return true;
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}
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return false;
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}
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bool CountingSemaphore::try_acquire_until(SystemClock::time_point deadline) {
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std::unique_lock lock(native_type_.mutex);
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if (native_type_.condition.wait_until(
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lock, deadline, [&] { return native_type_.count != 0; })) {
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--native_type_.count;
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return true;
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}
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return false;
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}
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} // namespace pw::sync
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