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 tarball for details.
10 /* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
11 /* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
13 /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
15 * Original version majorly reworked for SUSv3 compliance, bug fixes, and
16 * size optimizations. Changes include:
17 * 1) Now correctly distinguishes between errors and actual file differences.
18 * 2) Proper handling of '-' args.
19 * 3) Actual error checking of i/o.
20 * 4) Accept SUSv3 -l option. Note that we use the slightly nicer gnu format
26 static FILE *cmp_xfopen_input(const char * const filename)
30 if ((fp = bb_wfopen_input(filename)) != NULL) {
34 exit(xfunc_error_retval); /* We already output an error message. */
37 static const char fmt_eof[] = "cmp: EOF on %s\n";
38 static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
39 // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%d %o %o\n"
40 static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
42 static const char opt_chars[] = "sl";
43 #define CMP_OPT_s (1<<0)
44 #define CMP_OPT_l (1<<1)
46 int cmp_main(int argc, char **argv)
48 FILE *fp1, *fp2, *outfile = stdout;
49 const char *filename1, *filename2 = "-";
51 int c1, c2, char_pos = 0, line_pos = 1;
55 xfunc_error_retval = 2; /* 1 is returned if files are different. */
57 opt = getopt32(argc, argv, opt_chars);
59 if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l))
60 || (((unsigned int)(--argc - optind)) > 1))
63 fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
68 fp2 = cmp_xfopen_input(filename2);
70 if (fp1 == fp2) { /* Paranioa check... stdin == stdin? */
71 /* Note that we don't bother reading stdin. Neither does gnu wc.
72 * But perhaps we should, so that other apps down the chain don't
73 * get the input. Consider 'echo hello | (cmp - - && cat -)'.
87 if (c1 != c2) { /* Remember: a read error may have occurred. */
88 retval = 1; /* But assume the files are different for now. */
90 /* We know that fp1 isn't at EOF or in an error state. But to
91 * save space below, things are setup to expect an EOF in fp1
92 * if an EOF occurred. So, swap things around.
95 filename1 = filename2;
99 die_if_ferror(fp1, filename1);
100 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
102 /* There may have been output to stdout (option -l), so
103 * make sure we fflush before writing to stderr. */
106 if (!(opt & CMP_OPT_s)) {
107 if (opt & CMP_OPT_l) {
108 line_pos = c1; /* line_pos is unused in the -l case. */
110 fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
111 if (opt) { /* This must be -l since not -s. */
112 /* If we encountered an EOF,
113 * the while check will catch it. */
124 die_if_ferror(fp1, filename1);
125 die_if_ferror(fp2, filename2);
127 fflush_stdout_and_exit(retval);