#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <aio.h>

#define BUFFLEN 1024*1024

int rm_open(const char *name){
   int dskr = open( name, O_RDONLY );
   if( dskr == -1 ){
      perror( name );
      exit(1);
   }
   printf( "dskr = %d\n", dskr );
   return dskr;
}

void rm_close(int fd){
	int rv = close( fd );
	if( rv != 0 ) perror ( "close() failed" );
	else puts( "closed" );
}

int rm_aio_read_start( const int d, struct aiocb *aiorp, void *buf, int count, int offset){
	memset( (void *)aiorp, 0, sizeof( struct aiocb ) );
	aiorp->aio_fildes = d;
	aiorp->aio_buf = buf;
	aiorp->aio_nbytes = count;
	aiorp->aio_offset = offset;
	printf("%d\n", aiorp->aio_offset);
	int rv = 0;
	rv = aio_read( aiorp );
	if( rv != 0 ){
		perror( "aio_read failed" );
		abort();
	}
	return rv;
}

void rm_dummy( const void *data, int n ){
	int i, cnt = 0;
	for( i = 0; i < n; i++ )
	  if( ((char*)data)[i] == '\0' ) cnt++;
	printf( "Number of '0' in data: %d\n", cnt );
}

void rm_aio_read_waitcomplete( struct aiocb *aiorp ){
	const struct aiocb *aioptr[1];
	aioptr[0] = aiorp;
	int rv = aio_suspend( aioptr, 1, NULL );
	if( rv != 0 ){
		perror( "aio_suspend failed" );
		abort();
	}
	rv = aio_return( aiorp );
	printf( "AIO complete, %d bytes read.\n", rv );
}

int main(){
	int offset = 0;
	struct aiocb aior;
	char buffer[BUFFLEN];
	int d = rm_open( "/dev/urandom" );
	int i = 0;
	while(i < 10){
		rm_aio_read_start( d, &aior, buffer, sizeof(buffer), offset );
		offset += sizeof( struct aiocb);
		rm_dummy( buffer, sizeof(buffer) );
		rm_aio_read_waitcomplete( &aior );
		i++;
	}
	rm_close( d );
	rm_dummy( buffer, sizeof(buffer) );
	return 0;
}