counting_semaphore.h

// 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 <stdbool.h>
#include <stddef.h>
 
#include "pw_chrono/system_clock.h"
#include "pw_preprocessor/util.h"
 
#ifdef __cplusplus
 
#include "pw_sync_backend/counting_semaphore_native.h"
 
namespace pw::sync {
 
class CountingSemaphore {
 public:
  using native_handle_type = backend::NativeCountingSemaphoreHandle;
 
  CountingSemaphore();
  ~CountingSemaphore();
  CountingSemaphore(const CountingSemaphore&) = delete;
  CountingSemaphore(CountingSemaphore&&) = delete;
  CountingSemaphore& operator=(const CountingSemaphore&) = delete;
  CountingSemaphore& operator=(CountingSemaphore&&) = delete;
 
  void release(ptrdiff_t update = 1);
 
  void acquire();
 
  [[nodiscard]] bool try_acquire() noexcept;
 
  [[nodiscard]] bool try_acquire_for(chrono::SystemClock::duration timeout);
 
  [[nodiscard]] bool try_acquire_until(
      chrono::SystemClock::time_point deadline);
 
  [[nodiscard]] static constexpr ptrdiff_t max() noexcept {
    return backend::kCountingSemaphoreMaxValue;
  }
 
  native_handle_type native_handle();
 
 private:
  backend::NativeCountingSemaphore native_type_;
};
 
}  // namespace pw::sync
 
#include "pw_sync_backend/counting_semaphore_inline.h"
 
using pw_sync_CountingSemaphore = pw::sync::CountingSemaphore;
 
#else  // !defined(__cplusplus)
 
typedef struct pw_sync_CountingSemaphore pw_sync_CountingSemaphore;
 
#endif  // __cplusplus
 
PW_EXTERN_C_START
 
void pw_sync_CountingSemaphore_Release(pw_sync_CountingSemaphore* semaphore);
void pw_sync_CountingSemaphore_ReleaseNum(pw_sync_CountingSemaphore* semaphore,
                                          ptrdiff_t update);
void pw_sync_CountingSemaphore_Acquire(pw_sync_CountingSemaphore* semaphore);
bool pw_sync_CountingSemaphore_TryAcquire(pw_sync_CountingSemaphore* semaphore);
bool pw_sync_CountingSemaphore_TryAcquireFor(
    pw_sync_CountingSemaphore* semaphore,
    pw_chrono_SystemClock_Duration timeout);
bool pw_sync_CountingSemaphore_TryAcquireUntil(
    pw_sync_CountingSemaphore* semaphore,
    pw_chrono_SystemClock_TimePoint deadline);
ptrdiff_t pw_sync_CountingSemaphore_Max(void);
 
PW_EXTERN_C_END