/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved. The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

/*
 * Sum bytes in file mod 2^16
 */

#include <stdio.h>

int
main(int argc, char **argv)
{
        unsigned int sum;
        int i, c;
        FILE *f;
        long long nbytes;
        int errflg = 0;

        i = 1;
        do {
                if (i < argc) {
                        if ((f = fopen(argv[i], "r")) == NULL) {
                                (void) fprintf(stderr,
                                        "sum: Can't open %s\n", argv[i]);
                                errflg += 10;
                                continue;
                        }
                } else
                        f = stdin;
                sum = 0;
                nbytes = 0;
                while ((c = getc(f)) != EOF) {
                        nbytes++;
                        if (sum&01)
                                sum = (sum>>1) + 0x8000;
                        else
                                sum >>= 1;
                        sum += c;
                        sum &= 0xFFFF;
                }
                if (ferror(f)) {
                        errflg++;
                        (void) fprintf(stderr,
                                "sum: read error on %s\n",
                                argc > 1 ? argv[i] : "-");
                }

                (void) printf("%05u %5lld", sum,
                        (nbytes + BUFSIZ - 1) / BUFSIZ);
                if (argc > 2)
                        (void) printf(" %s", argv[i]);
                (void) printf("\n");
                (void) fclose(f);
        } while (++i < argc);

        return (errflg);
}