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 */
15 static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
16 static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n";
17 // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
18 static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";
20 static const char opt_chars[] ALIGN1 = "sl";
21 #define CMP_OPT_s (1<<0)
22 #define CMP_OPT_l (1<<1)
24 int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
25 int cmp_main(int argc UNUSED_PARAM, char **argv)
27 FILE *fp1, *fp2, *outfile = stdout;
28 const char *filename1, *filename2 = "-";
29 off_t skip1 = 0, skip2 = 0, char_pos = 0;
30 int line_pos = 1; /* Hopefully won't overflow... */
36 xfunc_error_retval = 2; /* 1 is returned if files are different. */
38 opt_complementary = "-1"
42 opt = getopt32(argv, opt_chars);
46 fp1 = xfopen_stdin(filename1);
50 if (ENABLE_DESKTOP && *++argv) {
51 skip1 = XATOOFF(*argv);
53 skip2 = XATOOFF(*argv);
58 fp2 = xfopen_stdin(filename2);
59 if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */
60 /* Note that we don't bother reading stdin. Neither does gnu wc.
61 * But perhaps we should, so that other apps down the chain don't
62 * get the input. Consider 'echo hello | (cmp - - && cat -)'.
73 while (skip1) { getc(fp1); skip1--; }
74 while (skip2) { getc(fp2); skip2--; }
80 if (c1 != c2) { /* Remember: a read error may have occurred. */
81 retval = 1; /* But assume the files are different for now. */
83 /* We know that fp1 isn't at EOF or in an error state. But to
84 * save space below, things are setup to expect an EOF in fp1
85 * if an EOF occurred. So, swap things around.
88 filename1 = filename2;
92 die_if_ferror(fp1, filename1);
93 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
95 /* There may have been output to stdout (option -l), so
96 * make sure we fflush before writing to stderr. */
99 if (!(opt & CMP_OPT_s)) {
100 if (opt & CMP_OPT_l) {
101 line_pos = c1; /* line_pos is unused in the -l case. */
103 fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
104 if (opt) { /* This must be -l since not -s. */
105 /* If we encountered an EOF,
106 * the while check will catch it. */
117 die_if_ferror(fp1, filename1);
118 die_if_ferror(fp2, filename2);
120 fflush_stdout_and_exit(retval);