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/*
Minetest
Copyright (C) 2013 sapier <sapier AT gmx DOT net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "threading/semaphore.h"
#include <iostream>
#include <cstdlib>
#include <cassert>
#define UNUSED(expr) do { (void)(expr); } while (0)
#ifdef _WIN32
#include <climits>
#define MAX_SEMAPHORE_COUNT LONG_MAX - 1
#else
#include <cerrno>
#include <sys/time.h>
#include <pthread.h>
#if defined(__MACH__) && defined(__APPLE__)
#include <mach/mach.h>
#include <mach/task.h>
#include <mach/semaphore.h>
#include <sys/semaphore.h>
#include <unistd.h>
#undef sem_t
#undef sem_init
#undef sem_wait
#undef sem_post
#undef sem_destroy
#define sem_t semaphore_t
#define sem_init(s, p, c) semaphore_create(mach_task_self(), (s), 0, (c))
#define sem_wait(s) semaphore_wait(*(s))
#define sem_post(s) semaphore_signal(*(s))
#define sem_destroy(s) semaphore_destroy(mach_task_self(), *(s))
#endif
#endif
Semaphore::Semaphore(int val)
{
#ifdef _WIN32
semaphore = CreateSemaphore(NULL, val, MAX_SEMAPHORE_COUNT, NULL);
#else
int ret = sem_init(&semaphore, 0, val);
assert(!ret);
UNUSED(ret);
#endif
}
Semaphore::~Semaphore()
{
#ifdef _WIN32
CloseHandle(semaphore);
#else
int ret = sem_destroy(&semaphore);
#ifdef __ANDROID__
// Workaround for broken bionic semaphore implementation!
assert(!ret || errno == EBUSY);
#else
assert(!ret);
#endif
UNUSED(ret);
#endif
}
void Semaphore::post(unsigned int num)
{
assert(num > 0);
#ifdef _WIN32
ReleaseSemaphore(semaphore, num, NULL);
#else
for (unsigned i = 0; i < num; i++) {
int ret = sem_post(&semaphore);
assert(!ret);
UNUSED(ret);
}
#endif
}
void Semaphore::wait()
{
#ifdef _WIN32
WaitForSingleObject(semaphore, INFINITE);
#else
int ret = sem_wait(&semaphore);
assert(!ret);
UNUSED(ret);
#endif
}
bool Semaphore::wait(unsigned int time_ms)
{
#ifdef _WIN32
unsigned int ret = WaitForSingleObject(semaphore, time_ms);
if (ret == WAIT_OBJECT_0) {
return true;
} else {
assert(ret == WAIT_TIMEOUT);
return false;
}
#else
# if defined(__MACH__) && defined(__APPLE__)
mach_timespec_t wait_time;
wait_time.tv_sec = time_ms / 1000;
wait_time.tv_nsec = 1000000 * (time_ms % 1000);
errno = 0;
int ret = semaphore_timedwait(semaphore, wait_time);
switch (ret) {
case KERN_OPERATION_TIMED_OUT:
errno = ETIMEDOUT;
break;
case KERN_ABORTED:
errno = EINTR;
break;
default:
if (ret)
errno = EINVAL;
}
# else
int ret;
if (time_ms > 0) {
struct timespec wait_time;
struct timeval now;
if (gettimeofday(&now, NULL) == -1) {
std::cerr << "Semaphore::wait(ms): Unable to get time with gettimeofday!" << std::endl;
abort();
}
wait_time.tv_nsec = ((time_ms % 1000) * 1000 * 1000) + (now.tv_usec * 1000);
wait_time.tv_sec = (time_ms / 1000) + (wait_time.tv_nsec / (1000 * 1000 * 1000)) + now.tv_sec;
wait_time.tv_nsec %= 1000 * 1000 * 1000;
ret = sem_timedwait(&semaphore, &wait_time);
} else {
ret = sem_trywait(&semaphore);
}
# endif
assert(!ret || (errno == ETIMEDOUT || errno == EINTR || errno == EAGAIN));
return !ret;
#endif
}
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