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//
// semaphore.c
//
// POSIX semaphore library
//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 
// 1. Redistributions of source code must retain the above copyright 
//    notice, this list of conditions and the following disclaimer.  
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.  
// 3. Neither the name of the project nor the names of its contributors
//    may be used to endorse or promote products derived from this software
//    without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
// SUCH DAMAGE.
// 

#include <os.h>
#include <semaphore.h>

int sem_init(sem_t *sem, int pshared, unsigned int value) {
  if (pshared) {
    errno = EPERM;
    return -1;
  }

  *sem = mksem(value);
  if (*sem < 0) {
    errno = ENOSPC;
    return -1;
  }

  return 0;
}

int sem_destroy(sem_t *sem) {
  if (!sem || *sem == -1) {
    errno = EINVAL;
    return -1;
  }

  if (close(*sem) < 0) {
    errno = EINVAL;
    return -1;
  }

  *sem = -1;
  return 0;
}

int sem_trywait(sem_t *sem) {
  if (!sem || *sem == -1) {
    errno = EINVAL;
    return -1;
  }

  if (waitone(*sem, 0) < 0) {
    errno = EAGAIN;
    return -1;
  }

  return 0;
}

int sem_wait(sem_t * sem) {
  if (!sem || *sem == -1) {
    errno = EINVAL;
    return -1;
  }

  if (waitone(*sem, INFINITE) < 0) return -1;
  return 0;
}

int sem_timedwait(sem_t *sem, const struct timespec *abstime) {
  struct timeval curtime;
  long timeout;

  if (!sem || *sem == -1) {
    errno = EINVAL;
    return -1;
  }

  if (gettimeofday(&curtime, NULL) < 0) return -1;
  timeout = ((long) (abstime->tv_sec - curtime.tv_sec) * 1000L +
             (long)((abstime->tv_nsec / 1000) - curtime.tv_usec) / 1000L);
  if (timeout < 0) timeout = 0L;

  if (waitone(*sem, timeout) < 0) return -1;
  return 0;
}

int sem_post(sem_t *sem) {
  if (!sem || *sem == -1) {
    errno = EINVAL;
    return -1;
  }

  if (semrel(*sem, 1) < 0) {
    errno = EINVAL;
    return -1;
  }

  return 0;
}

int sem_post_multiple(sem_t *sem, int count) {
  if (!sem || *sem == -1) {
    errno = EINVAL;
    return -1;
  }

  if (semrel(*sem, count) < 0) {
    errno = EINVAL;
    return -1;
  }

  return 0;
}

int sem_open(const char *name, int oflag, int mode, unsigned int value) {
  errno = ENOSYS;
  return -1;
}

int sem_close(sem_t *sem) {
  errno = ENOSYS;
  return -1;
}

int sem_unlink(const char *name) {
  errno = ENOSYS;
  return -1;
}

int sem_getvalue(sem_t *sem, int *sval) {
  errno = ENOSYS;
  return -1;
}