blob: 60737612446cbed3807d4ed73fcdbcff2fde9e26 [file] [log] [blame]
// Copyright 2021 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
// 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.
#include "pw_sync/binary_semaphore.h"
#include <algorithm>
#include "RTOS.h"
#include "pw_assert/check.h"
#include "pw_chrono/system_clock.h"
#include "pw_chrono_embos/system_clock_constants.h"
#include "pw_interrupt/context.h"
using pw::chrono::SystemClock;
namespace pw::sync {
bool BinarySemaphore::try_acquire_for(SystemClock::duration for_at_least) {
// Use non-blocking try_acquire for negative and zero length durations.
if (for_at_least <= SystemClock::duration::zero()) {
return try_acquire();
// On a tick based kernel we cannot tell how far along we are on the current
// tick, ergo we add one whole tick to the final duration.
constexpr SystemClock::duration kMaxTimeoutMinusOne =
pw::chrono::embos::kMaxTimeout - SystemClock::duration(1);
while (for_at_least > kMaxTimeoutMinusOne) {
if (OS_WaitCSemaTimed(&native_type_,
static_cast<OS_TIME>(kMaxTimeoutMinusOne.count()))) {
return true;
for_at_least -= kMaxTimeoutMinusOne;
return OS_WaitCSemaTimed(&native_type_,
static_cast<OS_TIME>(for_at_least.count() + 1));
} // namespace pw::sync