/* System V Semaphores and pthreads. */
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

#include <pthread.h>
#include <sys/types.h>

#include "array.h"

#define massert( cond, msg )                                                  \
   if( cond ) {                                                               \
      perror( msg );                                                          \
      exit(-1);                                                               \
   }

#define TIME 1000000

char buf[] = "abcdefghijklmnopqrstuvwsyz";
pthread_mutex_t mut_main, mut_inv, mut_rev;

void *inv( void *data ) {
   int len = strlen(buf);
   while( 1 ) {
      massert(pthread_mutex_lock(&mut_inv) != 0, "pthread_mutex_lock");
         inverse(buf, len);
         usleep( TIME );
      massert(pthread_mutex_unlock(&mut_main) != 0, "pthread_mutex_unlock");
   }
}
void *rev( void* data ) {
   int len = strlen(buf);
   while( 1 ) {
      massert(pthread_mutex_lock(&mut_rev) != 0, "pthread_mutex_lock");
         reverse(buf, len);
         usleep( TIME );
      massert(pthread_mutex_unlock(&mut_main) != 0, "pthread_mutex_unlock");
   }
}  

int main( int argc, char* argv[] ) {
   
   pthread_t inv_pthread, rev_pthread;
   
   massert( pthread_mutex_init(&mut_main, NULL) != 0, "pthread_init_mutex");
   massert( pthread_mutex_init(&mut_rev, NULL) != 0, "pthread_init_mutex");
   massert( pthread_mutex_init(&mut_inv, NULL) != 0, "pthread_init_mutex");
   massert(pthread_create( &inv_pthread, NULL, inv, NULL ) != 0, "pthread" );
   massert(pthread_create( &rev_pthread, NULL, rev, NULL ) != 0, "pthread" );
  
   while(1) {
      massert(pthread_mutex_unlock(&mut_inv) != 0, "pthread_mutex_lock");
      massert(pthread_mutex_lock(&mut_main) != 0, "pthread_mutex_lock");
         puts(buf);
         usleep( TIME );
      massert(pthread_mutex_unlock(&mut_rev) != 0, "pthread_mutex_unlock");
      massert(pthread_mutex_lock(&mut_main) != 0, "pthread_mutex_lock");
         puts(buf);
         usleep( TIME );
   }

   pthread_exit( NULL );
   return 0;
}