box/coreutils/sum.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * sum -- checksum and count the blocks in a file
   4  *     Like BSD sum or SysV sum -r, except like SysV sum if -s option is given.
   5  *
   6  * Copyright (C) 86, 89, 91, 1995-2002, 2004 Free Software Foundation, Inc.
   7  * Copyright (C) 2005 by Erik Andersen <andersen@codepoet.org>
   8  * Copyright (C) 2005 by Mike Frysinger <vapier@gentoo.org>
   9  *
  10  * Written by Kayvan Aghaiepour and David MacKenzie
  11  * Taken from coreutils and turned into a busybox applet by Mike Frysinger
  12  *
  13  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  14  */
  15
  16 #include "libbb.h"
  17
  18 enum { SUM_BSD, PRINT_NAME, SUM_SYSV };
  19
  20 /* BSD: calculate and print the rotated checksum and the size in 1K blocks
  21    The checksum varies depending on sizeof (int). */
  22 /* SYSV: calculate and print the checksum and the size in 512-byte blocks */
  23 /* Return 1 if successful.  */
  24 static unsigned sum_file(const char *file, const unsigned type)
  25 {
  26 #define buf bb_common_bufsiz1
  27         uintmax_t total_bytes = 0;
  28         int fd = 0, r;
  29
  30         /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
  31         unsigned s = 0;
  32
  33         if (NOT_LONE_DASH(file)) {
  34                 fd = open(file, O_RDONLY);
  35                 if (fd == -1)
  36                         goto ret_bad;
  37         }
  38
  39         while (1) {
  40                 size_t bytes_read = safe_read(fd, buf, BUFSIZ);
  41
  42                 if ((ssize_t)bytes_read <= 0) {
  43                         r = (fd && close(fd) != 0);
  44                         if (!bytes_read && !r)
  45                                 /* no error */
  46                                 break;
  47  ret_bad:
  48                         bb_perror_msg(file);
  49                         return 0;
  50                 }
  51
  52                 total_bytes += bytes_read;
  53                 if (type >= SUM_SYSV) {
  54                         do s += buf[--bytes_read]; while (bytes_read);
  55                 } else {
  56                         r = 0;
  57                         do {
  58                                 s = (s >> 1) + ((s & 1) << 15);
  59                                 s += buf[r++];
  60                                 s &= 0xffff; /* Keep it within bounds. */
  61                         } while (--bytes_read);
  62                 }
  63         }
  64
  65         if (type < PRINT_NAME)
  66                 file = "";
  67         if (type >= SUM_SYSV) {
  68                 r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
  69                 s = (r & 0xffff) + (r >> 16);
  70                 printf("%d %ju %s\n", s, (total_bytes+511)/512, file);
  71         } else
  72                 printf("%05d %5ju %s\n", s, (total_bytes+1023)/1024, file);
  73         return 1;
  74 #undef buf
  75 }
  76
  77 int sum_main(int argc, char **argv);
  78 int sum_main(int argc, char **argv)
  79 {
  80         unsigned n;
  81         unsigned type = SUM_BSD;
  82
  83         n = getopt32(argc, argv, "sr");
  84         if (n & 1) type = SUM_SYSV;
  85         /* give the bsd priority over sysv func */
  86         if (n & 2) type = SUM_BSD;
  87
  88         if (argc == optind) {
  89                 /* Do not print the name */
  90                 n = sum_file("-", type);
  91         } else {
  92                 /* Need to print the name if either
  93                    - more than one file given
  94                    - doing sysv */
  95                 type += argc - 1 > optind || type == SUM_SYSV;
  96                 for (n = 1; optind < argc; optind++)
  97                         n &= sum_file(argv[optind], type);
  98         }
  99         return !n;
 100 }