1 /* vi: set sw=4 ts=4: */
3 * Mini cmp implementation for busybox
5 * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 /* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
11 /* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
13 //usage:#define cmp_trivial_usage
14 //usage: "[-l] [-s] FILE1 [FILE2" IF_DESKTOP(" [SKIP1 [SKIP2]]") "]"
15 //usage:#define cmp_full_usage "\n\n"
16 //usage: "Compare FILE1 with FILE2 (or stdin)\n"
17 //usage: "\n -l Write the byte numbers (decimal) and values (octal)"
18 //usage: "\n for all differing bytes"
19 //usage: "\n -s Quiet"
23 static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
24 static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n";
25 // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
26 static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";
28 static const char opt_chars[] ALIGN1 = "sl";
29 #define CMP_OPT_s (1<<0)
30 #define CMP_OPT_l (1<<1)
32 int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
33 int cmp_main(int argc UNUSED_PARAM, char **argv)
35 FILE *fp1, *fp2, *outfile = stdout;
36 const char *filename1, *filename2 = "-";
37 off_t skip1 = 0, skip2 = 0, char_pos = 0;
38 int line_pos = 1; /* Hopefully won't overflow... */
44 opt_complementary = "-1"
48 opt = getopt32(argv, opt_chars);
54 if (ENABLE_DESKTOP && *++argv) {
55 skip1 = XATOOFF(*argv);
57 skip2 = XATOOFF(*argv);
62 xfunc_error_retval = 2; /* missing file results in exitcode 2 */
64 logmode = 0; /* -s suppresses open error messages */
65 fp1 = xfopen_stdin(filename1);
66 fp2 = xfopen_stdin(filename2);
67 if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */
68 /* Note that we don't bother reading stdin. Neither does gnu wc.
69 * But perhaps we should, so that other apps down the chain don't
70 * get the input. Consider 'echo hello | (cmp - - && cat -)'.
74 logmode = LOGMODE_STDIO;
82 while (skip1) { getc(fp1); skip1--; }
83 while (skip2) { getc(fp2); skip2--; }
89 if (c1 != c2) { /* Remember: a read error may have occurred. */
90 retval = 1; /* But assume the files are different for now. */
92 /* We know that fp1 isn't at EOF or in an error state. But to
93 * save space below, things are setup to expect an EOF in fp1
94 * if an EOF occurred. So, swap things around.
97 filename1 = filename2;
101 die_if_ferror(fp1, filename1);
102 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
104 /* There may have been output to stdout (option -l), so
105 * make sure we fflush before writing to stderr. */
108 if (!(opt & CMP_OPT_s)) {
109 if (opt & CMP_OPT_l) {
110 line_pos = c1; /* line_pos is unused in the -l case. */
112 fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
113 if (opt) { /* This must be -l since not -s. */
114 /* If we encountered an EOF,
115 * the while check will catch it. */
126 die_if_ferror(fp1, filename1);
127 die_if_ferror(fp2, filename2);
129 fflush_stdout_and_exit(retval);