LXR toybox/toys/posix/cksum.c

   1/* cksum.c - produce crc32 checksum value for each input
   2 *
   3 * Copyright 2008 Rob Landley <rob@landley.net>
   4 *
   5 * See http://opengroup.org/onlinepubs/9699919799/utilities/cksum.html
   6
   7USE_CKSUM(NEWTOY(cksum, "HIPLN", TOYFLAG_BIN))
   8USE_CRC32(NEWTOY(crc32, 0, TOYFLAG_BIN))
   9
  10config CKSUM
  11  bool "cksum"
  12  default y
  13  help
  14    usage: cksum [-IPLN] [file...]
  15
  16    For each file, output crc32 checksum value, length and name of file.
  17    If no files listed, copy from stdin.  Filename "-" is a synonym for stdin.
  18
  19    -H  Hexadecimal checksum (defaults to decimal)
  20    -L  Little endian (defaults to big endian)
  21    -P  Pre-inversion
  22    -I  Skip post-inversion
  23    -N  Do not include length in CRC calculation (or output)
  24
  25config CRC32
  26  bool "crc32"
  27  default y
  28  help
  29    usage: crc32 [file...]
  30
  31    Output crc32 checksum for each file.
  32*/
  33
  34#define FOR_cksum
  35#define FORCE_FLAGS
  36#include "toys.h"
  37
  38GLOBALS(
  39  unsigned crc_table[256];
  40)
  41
  42static unsigned cksum_be(unsigned crc, unsigned char c)
  43{
  44  return (crc<<8)^TT.crc_table[(crc>>24)^c];
  45}
  46
  47static unsigned cksum_le(unsigned crc, unsigned char c)
  48{
  49  return TT.crc_table[(crc^c)&0xff] ^ (crc>>8);
  50}
  51
  52static void do_cksum(int fd, char *name)
  53{
  54  unsigned crc = (toys.optflags & FLAG_P) ? 0xffffffff : 0;
  55  uint64_t llen = 0, llen2;
  56  unsigned (*cksum)(unsigned crc, unsigned char c);
  57  int len, i;
  58
  59  cksum = (toys.optflags & FLAG_L) ? cksum_le : cksum_be;
  60  // CRC the data
  61
  62  for (;;) {
  63    len = read(fd, toybuf, sizeof(toybuf));
  64    if (len<0) perror_msg_raw(name);
  65    if (len<1) break;
  66
  67    llen += len;
  68    for (i=0; i<len; i++) crc=cksum(crc, toybuf[i]);
  69  }
  70
  71  // CRC the length
  72
  73  llen2 = llen;
  74  if (!(toys.optflags & FLAG_N)) {
  75    while (llen) {
  76      crc = cksum(crc, llen);
  77      llen >>= 8;
  78    }
  79  }
  80
  81  printf((toys.optflags & FLAG_H) ? "%08x" : "%u",
  82    (toys.optflags & FLAG_I) ? crc : ~crc);
  83  if (!(toys.optflags&FLAG_N)) printf(" %"PRIu64, llen2);
  84  if (toys.optc) printf(" %s", name);
  85  xputc('\n');
  86}
  87
  88void cksum_main(void)
  89{
  90  crc_init(TT.crc_table, toys.optflags & FLAG_L);
  91  loopfiles(toys.optargs, do_cksum);
  92}
  93
  94void crc32_main(void)
  95{
  96  toys.optflags |= FLAG_H|FLAG_N|FLAG_P|FLAG_L;
  97  if (toys.optc) toys.optc--;
  98  cksum_main();
  99}
 100