release/src/router/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 GPLv2 or later, see file LICENSE in this source tree.
  14  */
  15
  16 //usage:#define sum_trivial_usage
  17 //usage:       "[-rs] [FILE]..."
  18 //usage:#define sum_full_usage "\n\n"
  19 //usage:       "Checksum and count the blocks in a file\n"
  20 //usage:     "\n        -r      Use BSD sum algorithm (1K blocks)"
  21 //usage:     "\n        -s      Use System V sum algorithm (512byte blocks)"
  22
  23 #include "libbb.h"
  24
  25 enum { SUM_BSD, PRINT_NAME, SUM_SYSV };
  26
  27 /* BSD: calculate and print the rotated checksum and the size in 1K blocks
  28    The checksum varies depending on sizeof (int). */
  29 /* SYSV: calculate and print the checksum and the size in 512-byte blocks */
  30 /* Return 1 if successful.  */
  31 static unsigned sum_file(const char *file, unsigned type)
  32 {
  33 #define buf bb_common_bufsiz1
  34         unsigned long long total_bytes = 0;
  35         int fd, r;
  36         /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
  37         unsigned s = 0;
  38
  39         fd = open_or_warn_stdin(file);
  40         if (fd == -1)
  41                 return 0;
  42
  43         while (1) {
  44                 size_t bytes_read = safe_read(fd, buf, BUFSIZ);
  45
  46                 if ((ssize_t)bytes_read <= 0) {
  47                         r = (fd && close(fd) != 0);
  48                         if (!bytes_read && !r)
  49                                 /* no error */
  50                                 break;
  51                         bb_simple_perror_msg(file);
  52                         return 0;
  53                 }
  54
  55                 total_bytes += bytes_read;
  56                 if (type >= SUM_SYSV) {
  57                         do s += buf[--bytes_read]; while (bytes_read);
  58                 } else {
  59                         r = 0;
  60                         do {
  61                                 s = (s >> 1) + ((s & 1) << 15);
  62                                 s += buf[r++];
  63                                 s &= 0xffff; /* Keep it within bounds. */
  64                         } while (--bytes_read);
  65                 }
  66         }
  67
  68         if (type < PRINT_NAME)
  69                 file = "";
  70         if (type >= SUM_SYSV) {
  71                 r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
  72                 s = (r & 0xffff) + (r >> 16);
  73                 printf("%d %llu %s\n", s, (total_bytes + 511) / 512, file);
  74         } else
  75                 printf("%05d %5llu %s\n", s, (total_bytes + 1023) / 1024, file);
  76         return 1;
  77 #undef buf
  78 }
  79
  80 int sum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  81 int sum_main(int argc UNUSED_PARAM, char **argv)
  82 {
  83         unsigned n;
  84         unsigned type = SUM_BSD;
  85
  86         n = getopt32(argv, "sr");
  87         argv += optind;
  88         if (n & 1) type = SUM_SYSV;
  89         /* give the bsd priority over sysv func */
  90         if (n & 2) type = SUM_BSD;
  91
  92         if (!argv[0]) {
  93                 /* Do not print the name */
  94                 n = sum_file("-", type);
  95         } else {
  96                 /* Need to print the name if either
  97                  * - more than one file given
  98                  * - doing sysv */
  99                 type += (argv[1] || type == SUM_SYSV);
 100                 n = 1;
 101                 do {
 102                         n &= sum_file(*argv, type);
 103                 } while (*++argv);
 104         }
 105         return !n;
 106 }