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
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
GLOBALS(unsigned crc_table[256];)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
cksum_le(unsigned crc,unsigned char c)47 static unsigned cksum_le(unsigned crc, unsigned char c)
48 {
49 return TT.crc_table[(crc^c)&0xff] ^ (crc>>8);
50 }
51
do_cksum(int fd,char * name)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
cksum_main(void)88 void cksum_main(void)
89 {
90 crc_init(TT.crc_table, toys.optflags & FLAG_L);
91 loopfiles(toys.optargs, do_cksum);
92 }
93
crc32_main(void)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