/* Tomas Mazvila GRP loginas */
/* Failas: tommaz2_aio02.c */

#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 1048576

int kp_test_open(const char *name);
int kp_test_close(int fd);
int write_open(const char *name);

int kp_test_open(const char *name){
        int dskr;
        dskr = open( name, O_RDONLY );
        if( dskr == -1 ){
                perror( name );
                exit(1);
        }
        printf( "dskr = %d\n", dskr );
        return dskr;
}
int write_open(const char *name){
        int dskr;
        dskr = open(name, O_WRONLY |  O_CREAT, 644);
        if( dskr == -1){
                perror(name);
                exit(1);
        }
        printf("dskr = %d\n", dskr);
        return dskr;
}
int kp_test_close(int fd){
        int rv;
        rv = close( fd );
        if( rv != 0 ) perror ( "close() failed" );
        else puts( "closed" );
        return rv;
}

int do_stuff(const int d, const int d2, struct aiocb *aiorp, void *buf, const int count) {
        int rv = 0;
        const struct aiocb *aioptr[1];
        memset((void *)aiorp, 0, sizeof(struct aiocb));

        aiorp->aio_fildes = d;
        aiorp->aio_buf = buf;
        aiorp->aio_nbytes = count;
        aiorp->aio_offset = 0;
        aioptr[0] = aiorp;

        rv = aio_read(aiorp);
        if( rv != 0 ){
                perror( "aio_read failed" );
                abort();
        }
        int aio_ret_v = 0;
        int total = 0;
        aio_suspend(aioptr, 1, NULL);
        aio_ret_v = aio_return(aiorp);
        total += aio_ret_v;
        while( aio_ret_v == 0){
                aio_read(aiorp);
                aio_suspend(aioptr, 1, NULL);
                aio_ret_v = aio_return(aiorp);
                total += aio_ret_v;
                printf(".\n");
        }
        aiorp -> aio_fildes = d2;
        do {
                aio_write(aiorp);
                aio_suspend(aioptr, 1, NULL);
                aio_ret_v = aio_return(aiorp);
        } while(aio_ret_v == 0);
        printf( "AIO complete, %d bytes read.\n", total );
        return rv;
}


int main( int argc, char * argv[] ){
        int d, d2;
        struct aiocb aior;
        char buffer[BUFFLEN];
        d = kp_test_open( "/dev/urandom" );
        d2 = write_open("testwrite.txt");
        do_stuff(d, d2, &aior, buffer, sizeof(buffer));
        kp_test_close( d );
        printf( "(C) 2018 Tomas Mazvila, %s\n", __FILE__ );
        return 0;
}