Contents of /tags/mkinitrd-6_1_5/busybox/editors/cmp.c
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Wed Aug 5 17:52:52 2009 UTC (15 years, 1 month ago) by niro
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Wed Aug 5 17:52:52 2009 UTC (15 years, 1 month ago) by niro
File MIME type: text/plain
File size: 3787 byte(s)
tagged 'mkinitrd-6_1_5'
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 | |
26 | static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n"; |
27 | static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"d, line %d\n"; |
28 | // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"d %o %o\n" |
29 | static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"d %3o %3o\n"; |
30 | |
31 | static const char opt_chars[] ALIGN1 = "sl"; |
32 | #define CMP_OPT_s (1<<0) |
33 | #define CMP_OPT_l (1<<1) |
34 | |
35 | int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
36 | int cmp_main(int argc UNUSED_PARAM, char **argv) |
37 | { |
38 | FILE *fp1, *fp2, *outfile = stdout; |
39 | const char *filename1, *filename2 = "-"; |
40 | USE_DESKTOP(off_t skip1 = 0, skip2 = 0;) |
41 | off_t char_pos = 0; |
42 | int line_pos = 1; /* Hopefully won't overflow... */ |
43 | const char *fmt; |
44 | int c1, c2; |
45 | unsigned opt; |
46 | int retval = 0; |
47 | |
48 | xfunc_error_retval = 2; /* 1 is returned if files are different. */ |
49 | |
50 | opt_complementary = "-1" |
51 | USE_DESKTOP(":?4") |
52 | SKIP_DESKTOP(":?2") |
53 | ":l--s:s--l"; |
54 | opt = getopt32(argv, opt_chars); |
55 | argv += optind; |
56 | |
57 | filename1 = *argv; |
58 | fp1 = xfopen_stdin(filename1); |
59 | |
60 | if (*++argv) { |
61 | filename2 = *argv; |
62 | #if ENABLE_DESKTOP |
63 | if (*++argv) { |
64 | skip1 = XATOOFF(*argv); |
65 | if (*++argv) { |
66 | skip2 = XATOOFF(*argv); |
67 | } |
68 | } |
69 | #endif |
70 | } |
71 | |
72 | fp2 = xfopen_stdin(filename2); |
73 | if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */ |
74 | /* Note that we don't bother reading stdin. Neither does gnu wc. |
75 | * But perhaps we should, so that other apps down the chain don't |
76 | * get the input. Consider 'echo hello | (cmp - - && cat -)'. |
77 | */ |
78 | return 0; |
79 | } |
80 | |
81 | if (opt & CMP_OPT_l) |
82 | fmt = fmt_l_opt; |
83 | else |
84 | fmt = fmt_differ; |
85 | |
86 | #if ENABLE_DESKTOP |
87 | while (skip1) { getc(fp1); skip1--; } |
88 | while (skip2) { getc(fp2); skip2--; } |
89 | #endif |
90 | do { |
91 | c1 = getc(fp1); |
92 | c2 = getc(fp2); |
93 | ++char_pos; |
94 | if (c1 != c2) { /* Remember: a read error may have occurred. */ |
95 | retval = 1; /* But assume the files are different for now. */ |
96 | if (c2 == EOF) { |
97 | /* We know that fp1 isn't at EOF or in an error state. But to |
98 | * save space below, things are setup to expect an EOF in fp1 |
99 | * if an EOF occurred. So, swap things around. |
100 | */ |
101 | fp1 = fp2; |
102 | filename1 = filename2; |
103 | c1 = c2; |
104 | } |
105 | if (c1 == EOF) { |
106 | die_if_ferror(fp1, filename1); |
107 | fmt = fmt_eof; /* Well, no error, so it must really be EOF. */ |
108 | outfile = stderr; |
109 | /* There may have been output to stdout (option -l), so |
110 | * make sure we fflush before writing to stderr. */ |
111 | xfflush_stdout(); |
112 | } |
113 | if (!(opt & CMP_OPT_s)) { |
114 | if (opt & CMP_OPT_l) { |
115 | line_pos = c1; /* line_pos is unused in the -l case. */ |
116 | } |
117 | fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2); |
118 | if (opt) { /* This must be -l since not -s. */ |
119 | /* If we encountered an EOF, |
120 | * the while check will catch it. */ |
121 | continue; |
122 | } |
123 | } |
124 | break; |
125 | } |
126 | if (c1 == '\n') { |
127 | ++line_pos; |
128 | } |
129 | } while (c1 != EOF); |
130 | |
131 | die_if_ferror(fp1, filename1); |
132 | die_if_ferror(fp2, filename2); |
133 | |
134 | fflush_stdout_and_exit(retval); |
135 | } |