// This file is part of the SV-Benchmarks collection of verification tasks:
// https://gitlab.com/sosy-lab/benchmarking/sv-benchmarks
//
// SPDX-FileCopyrightText: 2005-2021 University of Tartu & Technische Universität München
//
// SPDX-License-Identifier: MIT

#include <assert.h>
extern void abort(void);
void reach_error() { assert(0); }
void __VERIFIER_assert(int cond) { if(!(cond)) { ERROR: {reach_error();abort();} } }

#include <pthread.h>

struct __anonstruct_PQUEUE_63 {
   int occupied ;
   pthread_mutex_t mtx ;
};
typedef struct __anonstruct_PQUEUE_63 PQUEUE;

PQUEUE pqb  ;

int pqueue_init(PQUEUE *qp)
{
  qp->occupied = 0;
  pthread_mutex_init(& qp->mtx, NULL);
  return (0);
}

int pqueue_put(PQUEUE *qp)
{
  pthread_mutex_lock(& qp->mtx);
  if (qp->occupied < 1000)
    (qp->occupied) ++;
  pthread_mutex_unlock(& qp->mtx);
  return (1);
}

int pqueue_get(PQUEUE *qp)
{
  int got = 0;
  pthread_mutex_lock(& qp->mtx);
  while (qp->occupied <= 0) {
    __VERIFIER_assert(qp->occupied == 0);
  }
  __VERIFIER_assert(qp->occupied != 0);
  if (qp->occupied > 0) {
    (qp->occupied) --;
    got = 1;
    pthread_mutex_unlock(& qp->mtx);
  } else {
    pthread_mutex_unlock(& qp->mtx);
  }
  return (got);
}

void *worker(void *arg )
{
  while (1) {
    pqueue_get(& pqb);
  }
  return NULL;
}

int main(int argc , char **argv )
{
  pthread_t tid;

  PQUEUE *qp = &pqb;
  pqueue_init(& pqb);
  pthread_create(& tid, NULL, & worker, NULL);

  for (int i = 1; i < argc; i++) {
    pqueue_put(& pqb);
  }
  return 0;
}