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// Copyright 2020 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#pragma once
#include <algorithm>
#include "pw_assert/light.h"
#include "pw_chrono/system_clock.h"
#include "pw_interrupt/context.h"
#include "pw_sync/counting_semaphore.h"
#include "tx_api.h"
namespace pw::sync {
namespace backend {
inline constexpr char kCountingSemaphoreName[] = "pw::CountingSemaphore";
} // namespace backend
inline CountingSemaphore::CountingSemaphore() : native_type_() {
PW_ASSERT(
tx_semaphore_create(&native_type_,
const_cast<char*>(backend::kCountingSemaphoreName),
0) == TX_SUCCESS);
}
inline CountingSemaphore::~CountingSemaphore() {
PW_ASSERT(tx_semaphore_delete(&native_type_) == TX_SUCCESS);
}
inline void CountingSemaphore::release(ptrdiff_t update) {
for (; update > 0; --update) {
PW_ASSERT(tx_semaphore_put(&native_type_) == TX_SUCCESS);
}
}
inline void CountingSemaphore::acquire() {
// Enforce the pw::sync::CountingSemaphore IRQ contract.
PW_DASSERT(!interrupt::InInterruptContext());
PW_ASSERT(tx_semaphore_get(&native_type_, TX_WAIT_FOREVER) == TX_SUCCESS);
}
inline bool CountingSemaphore::try_acquire() noexcept {
const UINT result = tx_semaphore_get(&native_type_, TX_NO_WAIT);
if (result == TX_NO_INSTANCE) {
return false;
}
PW_ASSERT(result == TX_SUCCESS);
return true;
}
inline bool CountingSemaphore::try_acquire_until(
chrono::SystemClock::time_point until_at_least) {
// Note that if this deadline is in the future, it will get rounded up by
// one whole tick due to how try_acquire_for is implemented.
return try_acquire_for(until_at_least - chrono::SystemClock::now());
}
inline CountingSemaphore::native_handle_type
CountingSemaphore::native_handle() {
return native_type_;
}
} // namespace pw::sync
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