LXR busybox/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
  18enum { 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.  */
  24static unsigned sum_file(const char *file, unsigned type)
  25{
  26#define buf bb_common_bufsiz1
  27        unsigned long long total_bytes = 0;
  28        int fd, r;
  29        /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
  30        unsigned s = 0;
  31
  32        fd = open_or_warn_stdin(file);
  33        if (fd == -1)
  34                return 0;
  35
  36        while (1) {
  37                size_t bytes_read = safe_read(fd, buf, BUFSIZ);
  38
  39                if ((ssize_t)bytes_read <= 0) {
  40                        r = (fd && close(fd) != 0);
  41                        if (!bytes_read && !r)
  42                                /* no error */
  43                                break;
  44                        bb_simple_perror_msg(file);
  45                        return 0;
  46                }
  47
  48                total_bytes += bytes_read;
  49                if (type >= SUM_SYSV) {
  50                        do s += buf[--bytes_read]; while (bytes_read);
  51                } else {
  52                        r = 0;
  53                        do {
  54                                s = (s >> 1) + ((s & 1) << 15);
  55                                s += buf[r++];
  56                                s &= 0xffff; /* Keep it within bounds. */
  57                        } while (--bytes_read);
  58                }
  59        }
  60
  61        if (type < PRINT_NAME)
  62                file = "";
  63        if (type >= SUM_SYSV) {
  64                r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
  65                s = (r & 0xffff) + (r >> 16);
  66                printf("%d %llu %s\n", s, (total_bytes + 511) / 512, file);
  67        } else
  68                printf("%05d %5llu %s\n", s, (total_bytes + 1023) / 1024, file);
  69        return 1;
  70#undef buf
  71}
  72
  73int sum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  74int sum_main(int argc UNUSED_PARAM, char **argv)
  75{
  76        unsigned n;
  77        unsigned type = SUM_BSD;
  78
  79        n = getopt32(argv, "sr");
  80        argv += optind;
  81        if (n & 1) type = SUM_SYSV;
  82        /* give the bsd priority over sysv func */
  83        if (n & 2) type = SUM_BSD;
  84
  85        if (!argv[0]) {
  86                /* Do not print the name */
  87                n = sum_file("-", type);
  88        } else {
  89                /* Need to print the name if either
  90                   - more than one file given
  91                   - doing sysv */
  92                type += (argv[1] || type == SUM_SYSV);
  93                n = 1;
  94                do {
  95                        n &= sum_file(*argv, type);
  96                } while (*++argv);
  97        }
  98        return !n;
  99}
 100