source: MondoRescue/branches/2.2.5/mindi-busybox/editors/cmp.c @ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 12 years ago

Update to busybox 1.7.2

  • Property svn:eol-style set to native
File size: 3.8 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini cmp implementation for busybox
4 *
5 * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9
10/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
11/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
12
13/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
14 *
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
21 *    in the '-l' case.
22 */
23
24#include "libbb.h"
25
26static FILE *cmp_xfopen_input(const char *filename)
27{
28    FILE *fp;
29
30    fp = fopen_or_warn_stdin(filename);
31    if (fp)
32        return fp;
33    xfunc_die();    /* We already output an error message. */
34}
35
36static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
37static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"d, line %d\n";
38// This fmt_l_opt uses gnu-isms.  SUSv3 would be "%.0s%.0s%"OFF_FMT"d %o %o\n"
39static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"d %3o %3o\n";
40
41static const char opt_chars[] ALIGN1 = "sl";
42#define CMP_OPT_s (1<<0)
43#define CMP_OPT_l (1<<1)
44
45int cmp_main(int argc, char **argv);
46int cmp_main(int argc, char **argv)
47{
48    FILE *fp1, *fp2, *outfile = stdout;
49    const char *filename1, *filename2 = "-";
50    USE_DESKTOP(off_t skip1 = 0, skip2 = 0;)
51    off_t char_pos = 0;
52    int line_pos = 1; /* Hopefully won't overflow... */
53    const char *fmt;
54    int c1, c2;
55    unsigned opt;
56    int retval = 0;
57
58    xfunc_error_retval = 2; /* 1 is returned if files are different. */
59
60    opt_complementary = "-1"
61            USE_DESKTOP(":?4")
62            SKIP_DESKTOP(":?2")
63            ":l--s:s--l";
64    opt = getopt32(argv, opt_chars);
65    argv += optind;
66
67    filename1 = *argv;
68    fp1 = cmp_xfopen_input(filename1);
69
70    if (*++argv) {
71        filename2 = *argv;
72#if ENABLE_DESKTOP
73        if (*++argv) {
74            skip1 = XATOOFF(*argv);
75            if (*++argv) {
76                skip2 = XATOOFF(*argv);
77            }
78        }
79#endif
80    }
81
82    fp2 = cmp_xfopen_input(filename2);
83    if (fp1 == fp2) {       /* Paranoia check... stdin == stdin? */
84        /* Note that we don't bother reading stdin.  Neither does gnu wc.
85         * But perhaps we should, so that other apps down the chain don't
86         * get the input.  Consider 'echo hello | (cmp - - && cat -)'.
87         */
88        return 0;
89    }
90
91    if (opt & CMP_OPT_l)
92        fmt = fmt_l_opt;
93    else
94        fmt = fmt_differ;
95
96#if ENABLE_DESKTOP
97    while (skip1) { getc(fp1); skip1--; }
98    while (skip2) { getc(fp2); skip2--; }
99#endif
100    do {
101        c1 = getc(fp1);
102        c2 = getc(fp2);
103        ++char_pos;
104        if (c1 != c2) {         /* Remember: a read error may have occurred. */
105            retval = 1;     /* But assume the files are different for now. */
106            if (c2 == EOF) {
107                /* We know that fp1 isn't at EOF or in an error state.  But to
108                 * save space below, things are setup to expect an EOF in fp1
109                 * if an EOF occurred.  So, swap things around.
110                 */
111                fp1 = fp2;
112                filename1 = filename2;
113                c1 = c2;
114            }
115            if (c1 == EOF) {
116                die_if_ferror(fp1, filename1);
117                fmt = fmt_eof;  /* Well, no error, so it must really be EOF. */
118                outfile = stderr;
119                /* There may have been output to stdout (option -l), so
120                 * make sure we fflush before writing to stderr. */
121                xfflush_stdout();
122            }
123            if (!(opt & CMP_OPT_s)) {
124                if (opt & CMP_OPT_l) {
125                    line_pos = c1;  /* line_pos is unused in the -l case. */
126                }
127                fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
128                if (opt) {  /* This must be -l since not -s. */
129                    /* If we encountered an EOF,
130                     * the while check will catch it. */
131                    continue;
132                }
133            }
134            break;
135        }
136        if (c1 == '\n') {
137            ++line_pos;
138        }
139    } while (c1 != EOF);
140
141    die_if_ferror(fp1, filename1);
142    die_if_ferror(fp2, filename2);
143
144    fflush_stdout_and_exit(retval);
145}
Note: See TracBrowser for help on using the repository browser.