BSD 4 release

[unix-history] / usr / src / cmd / sum.c

static char *sccsid = "@(#)sum.c        4.1 (Berkeley) 10/1/80";
/*
* Sum bytes in file mod 2^16
*/

#include <stdio.h>

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

       i = 1;
       do {
               if(i < argc) {
                       if ((f = fopen(argv[i], "r")) == NULL) {
                               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++;
                       fprintf(stderr, "sum: read error on %s\n", argc>1?argv[i]:"-");
               }
               printf("%05u%6ld", sum, (nbytes+BUFSIZ-1)/BUFSIZ);
               if(argc > 2)
                       printf(" %s", argv[i]);
               printf("\n");
               fclose(f);
       } while(++i < argc);
       exit(errflg);
}