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Diffstat (limited to 'src/threading/semaphore.cpp')
| -rw-r--r-- | src/threading/semaphore.cpp | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/threading/semaphore.cpp b/src/threading/semaphore.cpp new file mode 100644 index 000000000..77ceff509 --- /dev/null +++ b/src/threading/semaphore.cpp @@ -0,0 +1,162 @@ +/* +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 + 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; + + int ret = sem_timedwait(&semaphore, &wait_time); +# endif + + assert(!ret || (errno == ETIMEDOUT || errno == EINTR)); + return !ret; +#endif +} + |