source: branches/3.2/mindi-busybox/editors/cmp.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 3.7 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 source tree.
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//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"
20
21#include "libbb.h"
22
23static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
24static 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"
26static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";
27
28static const char opt_chars[] ALIGN1 = "sl";
29#define CMP_OPT_s (1<<0)
30#define CMP_OPT_l (1<<1)
31
32int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
33int cmp_main(int argc UNUSED_PARAM, char **argv)
34{
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... */
39    const char *fmt;
40    int c1, c2;
41    unsigned opt;
42    int retval = 0;
43
44    opt_complementary = "-1"
45            IF_DESKTOP(":?4")
46            IF_NOT_DESKTOP(":?2")
47            ":l--s:s--l";
48    opt = getopt32(argv, opt_chars);
49    argv += optind;
50
51    filename1 = *argv;
52    if (*++argv) {
53        filename2 = *argv;
54        if (ENABLE_DESKTOP && *++argv) {
55            skip1 = XATOOFF(*argv);
56            if (*++argv) {
57                skip2 = XATOOFF(*argv);
58            }
59        }
60    }
61
62    xfunc_error_retval = 2;  /* missing file results in exitcode 2 */
63    if (opt & CMP_OPT_s)
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 -)'.
71         */
72        return 0;
73    }
74    logmode = LOGMODE_STDIO;
75
76    if (opt & CMP_OPT_l)
77        fmt = fmt_l_opt;
78    else
79        fmt = fmt_differ;
80
81    if (ENABLE_DESKTOP) {
82        while (skip1) { getc(fp1); skip1--; }
83        while (skip2) { getc(fp2); skip2--; }
84    }
85    do {
86        c1 = getc(fp1);
87        c2 = getc(fp2);
88        ++char_pos;
89        if (c1 != c2) {         /* Remember: a read error may have occurred. */
90            retval = 1;     /* But assume the files are different for now. */
91            if (c2 == EOF) {
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.
95                 */
96                fp1 = fp2;
97                filename1 = filename2;
98                c1 = c2;
99            }
100            if (c1 == EOF) {
101                die_if_ferror(fp1, filename1);
102                fmt = fmt_eof;  /* Well, no error, so it must really be EOF. */
103                outfile = stderr;
104                /* There may have been output to stdout (option -l), so
105                 * make sure we fflush before writing to stderr. */
106                fflush_all();
107            }
108            if (!(opt & CMP_OPT_s)) {
109                if (opt & CMP_OPT_l) {
110                    line_pos = c1;  /* line_pos is unused in the -l case. */
111                }
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. */
116                    continue;
117                }
118            }
119            break;
120        }
121        if (c1 == '\n') {
122            ++line_pos;
123        }
124    } while (c1 != EOF);
125
126    die_if_ferror(fp1, filename1);
127    die_if_ferror(fp2, filename2);
128
129    fflush_stdout_and_exit(retval);
130}
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