source: branches/stable/mindi-busybox/coreutils/cmp.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 4.2 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 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 */
22
23/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
24/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
25
26/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
27 *
28 * Original version majorly reworked for SUSv3 compliance, bug fixes, and
29 * size optimizations.  Changes include:
30 * 1) Now correctly distinguishes between errors and actual file differences.
31 * 2) Proper handling of '-' args.
32 * 3) Actual error checking of i/o.
33 * 4) Accept SUSv3 -l option.  Note that we use the slightly nicer gnu format
34 *    in the '-l' case.
35 */
36
37#include <stdio.h>
38#include <stdlib.h>
39#include <unistd.h>
40#include "busybox.h"
41
42static FILE *cmp_xfopen_input(const char *filename)
43{
44    FILE *fp;
45
46    if ((fp = bb_wfopen_input(filename)) != NULL) {
47        return fp;
48    }
49
50    exit(bb_default_error_retval);  /* We already output an error message. */
51}
52
53static const char fmt_eof[] = "cmp: EOF on %s\n";
54static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
55// This fmt_l_opt uses gnu-isms.  SUSv3 would be "%.0s%.0s%d %o %o\n"
56static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
57
58static const char opt_chars[] = "sl";
59
60enum {
61    OPT_s = 1,
62    OPT_l = 2
63};
64
65int cmp_main(int argc, char **argv)
66{
67    FILE *fp1, *fp2, *outfile = stdout;
68    const char *filename1, *filename2;
69    const char *fmt;
70    int c1, c2, char_pos, line_pos;
71    int opt_flags;
72    int exit_val = 0;
73
74    bb_default_error_retval = 2;    /* 1 is returned if files are different. */
75
76    opt_flags = bb_getopt_ulflags(argc, argv, opt_chars);
77
78    if ((opt_flags == 3) || (((unsigned int)(--argc - optind)) > 1)) {
79        bb_show_usage();
80    }
81
82    fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
83
84    filename2 = "-";
85    if (*++argv) {
86        filename2 = *argv;
87    }
88    fp2 = cmp_xfopen_input(filename2);
89
90    if (fp1 == fp2) {           /* Paranioa check... stdin == stdin? */
91        /* Note that we don't bother reading stdin.  Neither does gnu wc.
92         * But perhaps we should, so that other apps down the chain don't
93         * get the input.  Consider 'echo hello | (cmp - - && cat -)'.
94         */
95        return 0;
96    }
97
98    fmt = fmt_differ;
99    if (opt_flags == OPT_l) {
100        fmt = fmt_l_opt;
101    }
102
103    char_pos = 0;
104    line_pos = 1;
105    do {
106        c1 = getc(fp1);
107        c2 = getc(fp2);
108        ++char_pos;
109        if (c1 != c2) {         /* Remember -- a read error may have occurred. */
110            exit_val = 1;       /* But assume the files are different for now. */
111            if (c2 == EOF) {
112                /* We know that fp1 isn't at EOF or in an error state.  But to
113                 * save space below, things are setup to expect an EOF in fp1
114                 * if an EOF occurred.  So, swap things around.
115                 */
116                fp1 = fp2;
117                filename1 = filename2;
118                c1 = c2;
119            }
120            if (c1 == EOF) {
121                bb_xferror(fp1, filename1);
122                fmt = fmt_eof;  /* Well, no error, so it must really be EOF. */
123                outfile = stderr;
124                /* There may have been output to stdout (option -l), so
125                 * make sure we fflush before writing to stderr. */
126                bb_xfflush_stdout();
127            }
128            if (opt_flags != OPT_s) {
129                if (opt_flags == OPT_l) {
130                    line_pos = c1;  /* line_pos is unused in the -l case. */
131                }
132                bb_fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
133                if (opt_flags) {    /* This must be -l since not -s. */
134                    /* If we encountered and EOF, the while check will catch it. */
135                    continue;
136                }
137            }
138            break;
139        }
140        if (c1 == '\n') {
141            ++line_pos;
142        }
143    } while (c1 != EOF);
144
145    bb_xferror(fp1, filename1);
146    bb_xferror(fp2, filename2);
147
148    bb_fflush_stdout_and_exit(exit_val);
149}
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