#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <utime.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>

main( int argc, char **argv ) 
{
    int c, fd1, fd2, count, count2;
    char *source, *dest, *buffer, *buffer2;
    struct timespec ts;
    struct utimbuf ut;
    struct stat st;
    long blocksize = 64*1024;
    long nano = 30000000;
    long rate = 1024;		/* 64k every .06 seconds gives a rate
				   of approximately 1M/s */
    int sync = 0;
    time_t start, end;
    long long total = 0;
    

    while( (c = getopt( argc, argv, "b:n:r:s" ) ) != -1 )
	switch(c) {
	case 'b':
	    blocksize = atoi(optarg) * 1024;
	    break;
	case 'n':
	    nano = atoi(optarg);
	    break;
	case 'r':
	    rate = atoi(optarg);
	    break;
	case 's':
		sync++;
		break;
	default:
	    fprintf(stderr, "%s: Bad arg %c\n", argv[0], c );
	    exit(1);
	}

    source = argv[optind++];
    dest = argv[optind++];
    ts.tv_sec = 0;
    ts.tv_nsec = nano;

    if( (fd1 = open( source, O_RDONLY )) < 0 ) {
	fprintf(stderr, "%s: Can't open source %s: %s\n", argv[0], source, strerror(errno) );
	exit(1);
    }
#ifdef COMPARE
#define FD2MODE O_RDONLY
#else
#define FD2MODE O_WRONLY|O_CREAT|O_TRUNC
#endif
    if( (fd2 = open( dest, FD2MODE, 0666 )) < 0 ) {
	fprintf(stderr, "%s: Can't open dest %s: %s\n", argv[0], dest, strerror(errno) );
	exit(1);
    }
    if( fstat(fd1, &st) != 0 ) {
	fprintf( stderr, "%s: Can't stat source %s: %s\n", argv[0], source, strerror(errno));
	ut.actime = 0;
	ut.modtime = 0;
    } else {
	ut.actime = st.st_atime;
	ut.modtime = st.st_mtime;
    }
    time(&start);
    if( (buffer = malloc(blocksize)) == NULL ) {
	fprintf( stderr, "%s: Can't malloc mem: %s\n", argv[0], strerror(errno));
	exit(1);
    }
#ifdef COMPARE
    if( (buffer2 = malloc(blocksize)) == NULL ) {
	fprintf( stderr, "%s: Can't malloc mem: %s\n", argv[0], strerror(errno));
	exit(1);
    }
#endif
    while( (count = read( fd1, buffer, blocksize )) > 0 ) {
	total += count;
#ifdef COMPARE
	count2 = read( fd2, buffer2, blocksize );
	if( count != count2 ) {
	    fprintf( stderr, "%s: Bytes read differs\n", argv[0]);
	    exit(1);
	}
	while( count ) {
	    if( buffer[--count] != buffer2[--count2] ) {
		fprintf( stderr, "%s: Contents differ\n", argv[0] );
		exit(1);
	    }
	}
#else
	if( write( fd2, buffer, count ) != count ) {
	    fprintf( stderr, "%s: Write error: %s\n", argv[0], strerror(errno) );
	    exit(1);
	}
	if (sync)
	    fsync(fd2);
#endif
	nanosleep( &ts, NULL );
    }
    time(&end);
    printf( "Wrote %lld bytes in %ld seconds, %lld k/s\n", total, end - start, (total/1024)/(end-start) );
    close(fd1);
    close(fd2);
#ifndef COMPARE
    if( ut.modtime )
	utime( dest, &ut );
#endif
    exit(0);
}