4.3BSD - /usr/src/usr.bin/sum.c

   1: static char *sccsid = "@(#)sum.c	4.1 (Berkeley) 10/1/80";
   2: /*
   3:  * Sum bytes in file mod 2^16
   4:  */
   5: 
   6: #include <stdio.h>
   7: 
   8: main(argc,argv)
   9: char **argv;
  10: {
  11:     register unsigned sum;
  12:     register i, c;
  13:     register FILE *f;
  14:     register long nbytes;
  15:     int errflg = 0;
  16: 
  17:     i = 1;
  18:     do {
  19:         if(i < argc) {
  20:             if ((f = fopen(argv[i], "r")) == NULL) {
  21:                 fprintf(stderr, "sum: Can't open %s\n", argv[i]);
  22:                 errflg += 10;
  23:                 continue;
  24:             }
  25:         } else
  26:             f = stdin;
  27:         sum = 0;
  28:         nbytes = 0;
  29:         while ((c = getc(f)) != EOF) {
  30:             nbytes++;
  31:             if (sum&01)
  32:                 sum = (sum>>1) + 0x8000;
  33:             else
  34:                 sum >>= 1;
  35:             sum += c;
  36:             sum &= 0xFFFF;
  37:         }
  38:         if (ferror(f)) {
  39:             errflg++;
  40:             fprintf(stderr, "sum: read error on %s\n", argc>1?argv[i]:"-");
  41:         }
  42:         printf("%05u%6ld", sum, (nbytes+BUFSIZ-1)/BUFSIZ);
  43:         if(argc > 2)
  44:             printf(" %s", argv[i]);
  45:         printf("\n");
  46:         fclose(f);
  47:     } while(++i < argc);
  48:     exit(errflg);
  49: }

Defined functions

Defined variables