#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
//#include <fcntl.h>
#include <asm/fcntl.h>
                     
#define KB (1024)
#define MB (1024 * KB)
#define GB (1024 * MB)

int main(int argc, char** argv)
{
    char* dev = "/tmp/jöötti";
    unsigned long long blocksz = 64*MB;
    unsigned long long maxs = 0;
    unsigned iter = 0;
    const unsigned long long qgiga = 1024 * 1024 * 1024 / 4;
    
    char *buffer1, *buffer2;
    int i;
    int devfd;
    int err = 0;
    char ch;
    int round = 0;

    if (argc > 1) dev = argv[1];
    if (argc > 2) maxs = (long long)atoi(argv[2]) * (long long)MB;
    if (argc > 3) blocksz = (long long)atoi(argv[3]) * (long long)MB;
    if (argc > 4) iter = atoi(argv[4]);

    fprintf(stderr, "This test WILL RUIN THE CONTENTS OF %s!\n", dev);
    fprintf(stderr, "Are you 120%% sure you want to do this [Y/N] ? ");
    scanf("%c", &ch);
    fprintf(stderr, "\n");
    if (ch != 'Y') 
    {
       fprintf(stderr, "exiting.\n");
       exit(13);
    }

    fprintf(stderr, "testing %s, max size %llu, block size=%u...\n", 
            dev, maxs, blocksz);

    buffer1 = malloc(blocksz);
    buffer2 = malloc(blocksz);
    if (!buffer1 || !buffer2) 
    {
        perror("malloc failed");
        exit(1);
    }
    for (i = 0; i < blocksz; i++)
        buffer1[i] = (i + rand()) % 256;

    for (round = 0; round < iter || iter == 0; round++)
    {
        unsigned long long nwritten = 0, nread = 0;
        int nr = 0;
        time_t t = time(NULL);

        devfd = open(dev, O_LARGEFILE | O_WRONLY | O_TRUNC | O_CREAT);
        if (devfd < 0)
        {
           perror("open device failed");
           exit(1);
	}

        lseek64(devfd, 0, SEEK_SET);

	while ((nr = write(devfd, buffer1, blocksz)) > 0)
	{
	    nwritten += nr;
	    if (nwritten % qgiga == 0) fprintf(stderr, ".");
	    if (nwritten % (qgiga * 20) == 0) fprintf(stderr, "%lluG", nwritten / (qgiga * 4));
            if (maxs && nwritten > maxs) break;
	}
	fprintf(stderr, "\n");	

        fprintf(stderr, "round %i: Wrote %llu bytes, %2.1f MB/s.\n",
                round, nwritten,
		(float)nwritten / 1024.0 / 1024.0 / (float)(time(NULL) - t));

        close (devfd);

        devfd = open(dev, O_LARGEFILE | O_RDONLY);
        if (devfd < 0)
        {
           perror("open device failed");
           exit(1);
	}
        lseek64(devfd, 0, SEEK_SET);
        t = time(NULL);

	while ((nr = read(devfd, buffer2, blocksz)) > 0)
        {
             if (nr < 0)
             {
                perror("read");
                exit(-2);
             }
             if (memcmp(buffer1, buffer2, nr))
             {
                int l, erbytes = 0, erbytes2 = 0, erbytes3 = 0, l2;
                err++;
                for (l = 0; l < nr; l++)
                    if (buffer1[l] != buffer2[l])
                          erbytes++;
                for (l = 0; l < nr; l++)
                    if (buffer1[l] != buffer2[l])
                          erbytes2++;
                for (l = 0; l < nr; l++)
                    if (buffer1[l] != buffer2[l])
                          erbytes3++;
                fprintf(stderr, "\n%llu byte block at %llu DIFFERS in %i/%i/%i bytes (read %i)!\nFirst 50 bytes:\n",
                        blocksz, nread, erbytes, erbytes2, erbytes3, nr);

                for (l = l2 = 0; l < nr && l2 < 50; l++)
                    if (buffer1[l] != buffer2[l])
                    {
                          fprintf(stderr, "at %8i: %02x vs %02x\n", 
                                  l, (unsigned char)buffer1[l], (unsigned char)buffer2[l]);
                          l2++;
                    }
             }

             nread += nr;

 	     if (nread % qgiga == 0) fprintf(stderr, ".");
 	     if (nread % (qgiga * 20) == 0) fprintf(stderr, "%lluG", nread / (qgiga * 4));
             if (maxs && nread > maxs) break;
        }
	fprintf(stderr, "\n");	

        fprintf(stderr, "round %i: Read %llu bytes, %2.1f MB/s.\n",
                round, nread,
		(float)nread / 1024.0 / 1024.0 / (float)(time(NULL) - t));
		
	close(devfd);
    }

    close(devfd);
    free(buffer1);
    free(buffer2);

    return err;
}