Home | History | Annotate | Download | only in posix 
      1 /* cksum.c - produce crc32 checksum value for each input
      2  *
      3  * Copyright 2008 Rob Landley <rob (at) landley.net>
      4  *
      5  * See http://opengroup.org/onlinepubs/9699919799/utilities/cksum.html
      6 
      7 USE_CKSUM(NEWTOY(cksum, "HIPLN", TOYFLAG_BIN))
      8 USE_CRC32(NEWTOY(crc32, 0, TOYFLAG_BIN))
      9 
     10 config 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 
     25 config 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 
     38 GLOBALS(
     39   unsigned crc_table[256];
     40 )
     41 
     42 static unsigned cksum_be(unsigned crc, unsigned char c)
     43 {
     44   return (crc<<8)^TT.crc_table[(crc>>24)^c];
     45 }
     46 
     47 static unsigned cksum_le(unsigned crc, unsigned char c)
     48 {
     49   return TT.crc_table[(crc^c)&0xff] ^ (crc>>8);
     50 }
     51 
     52 static 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 
     88 void cksum_main(void)
     89 {
     90   crc_init(TT.crc_table, toys.optflags & FLAG_L);
     91   loopfiles(toys.optargs, do_cksum);
     92 }
     93 
     94 void 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