xref: /third_party/toybox/toys/posix/cmp.c (revision 0f66f451)
1/* cmp.c - Compare two files.
2 *
3 * Copyright 2012 Timothy Elliott <tle@holymonkey.com>
4 *
5 * See http://opengroup.org/onlinepubs/9699919799/utilities/cmp.html
6
7USE_CMP(NEWTOY(cmp, "<1>2ls(silent)(quiet)[!ls]", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_ARGFAIL(2)))
8
9config CMP
10  bool "cmp"
11  default y
12  help
13    usage: cmp [-l] [-s] FILE1 [FILE2 [SKIP1 [SKIP2]]]
14
15    Compare the contents of two files. (Or stdin and file if only one given.)
16
17    -l	Show all differing bytes
18    -s	Silent
19*/
20
21#define FOR_cmp
22#include "toys.h"
23
24GLOBALS(
25  int fd;
26  char *name;
27)
28
29static void do_cmp(int fd, char *name)
30{
31  int i, len1, len2, min_len, size = sizeof(toybuf)/2;
32  long byte_no = 1, line_no = 1;
33  char *buf2 = toybuf+size;
34
35  // First time through, cache the data and return.
36  if (!TT.fd) {
37    TT.name = name;
38    // On return the old filehandle is closed, and this assures that even
39    // if we were called with stdin closed, the new filehandle != 0.
40    TT.fd = dup(fd);
41    return;
42  }
43
44  toys.exitval = 0;
45
46  for (;;) {
47    len1 = readall(TT.fd, toybuf, size);
48    len2 = readall(fd, buf2, size);
49
50    min_len = len1 < len2 ? len1 : len2;
51    for (i=0; i<min_len; i++) {
52      if (toybuf[i] != buf2[i]) {
53        toys.exitval = 1;
54        if (toys.optflags & FLAG_l)
55          printf("%ld %o %o\n", byte_no, toybuf[i], buf2[i]);
56        else {
57          if (!(toys.optflags & FLAG_s))
58            printf("%s %s differ: char %ld, line %ld\n",
59              TT.name, name, byte_no, line_no);
60          goto out;
61        }
62      }
63      byte_no++;
64      if (toybuf[i] == '\n') line_no++;
65    }
66    if (len1 != len2) {
67      if (!(toys.optflags & FLAG_s))
68        fprintf(stderr, "cmp: EOF on %s\n", len1 < len2 ? TT.name : name);
69      toys.exitval = 1;
70      break;
71    }
72    if (len1 < 1) break;
73  }
74out:
75  if (CFG_TOYBOX_FREE) close(TT.fd);
76}
77
78void cmp_main(void)
79{
80  toys.exitval = 2;
81  loopfiles_rw(toys.optargs, O_CLOEXEC|(WARN_ONLY*!(toys.optflags&FLAG_s)), 0,
82    do_cmp);
83  if (toys.optc == 1) do_cmp(0, "-");
84}
85