busybox/editors/cmp.c

/* vi: set sw=4 ts=4: */
/*
 * Mini cmp implementation for busybox
 *
 * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */

/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
 *
 * Original version majorly reworked for SUSv3 compliance, bug fixes, and
 * size optimizations.  Changes include:
 * 1) Now correctly distinguishes between errors and actual file differences.
 * 2) Proper handling of '-' args.
 * 3) Actual error checking of i/o.
 * 4) Accept SUSv3 -l option.  Note that we use the slightly nicer gnu format
 *    in the '-l' case.
 */

#include "libbb.h"

static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n";
// This fmt_l_opt uses gnu-isms.  SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";

static const char opt_chars[] ALIGN1 = "sl";
#define CMP_OPT_s (1<<0)
#define CMP_OPT_l (1<<1)

int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cmp_main(int argc UNUSED_PARAM, char **argv)
{
	FILE *fp1, *fp2, *outfile = stdout;
	const char *filename1, *filename2 = "-";
	IF_DESKTOP(off_t skip1 = 0, skip2 = 0;)
	off_t char_pos = 0;
	int line_pos = 1; /* Hopefully won't overflow... */
	const char *fmt;
	int c1, c2;
	unsigned opt;
	int retval = 0;

	xfunc_error_retval = 2;	/* 1 is returned if files are different. */

	opt_complementary = "-1"
			IF_DESKTOP(":?4")
			IF_NOT_DESKTOP(":?2")
			":l--s:s--l";
	opt = getopt32(argv, opt_chars);
	argv += optind;

	filename1 = *argv;
	fp1 = xfopen_stdin(filename1);

	if (*++argv) {
		filename2 = *argv;
#if ENABLE_DESKTOP
		if (*++argv) {
			skip1 = XATOOFF(*argv);
			if (*++argv) {
				skip2 = XATOOFF(*argv);
			}
		}
#endif
	}

	fp2 = xfopen_stdin(filename2);
	if (fp1 == fp2) {		/* Paranoia check... stdin == stdin? */
		/* Note that we don't bother reading stdin.  Neither does gnu wc.
		 * But perhaps we should, so that other apps down the chain don't
		 * get the input.  Consider 'echo hello | (cmp - - && cat -)'.
		 */
		return 0;
	}

	if (opt & CMP_OPT_l)
		fmt = fmt_l_opt;
	else
		fmt = fmt_differ;

#if ENABLE_DESKTOP
	while (skip1) { getc(fp1); skip1--; }
	while (skip2) { getc(fp2); skip2--; }
#endif
	do {
		c1 = getc(fp1);
		c2 = getc(fp2);
		++char_pos;
		if (c1 != c2) {			/* Remember: a read error may have occurred. */
			retval = 1;		/* But assume the files are different for now. */
			if (c2 == EOF) {
				/* We know that fp1 isn't at EOF or in an error state.  But to
				 * save space below, things are setup to expect an EOF in fp1
				 * if an EOF occurred.  So, swap things around.
				 */
				fp1 = fp2;
				filename1 = filename2;
				c1 = c2;
			}
			if (c1 == EOF) {
				die_if_ferror(fp1, filename1);
				fmt = fmt_eof;	/* Well, no error, so it must really be EOF. */
				outfile = stderr;
				/* There may have been output to stdout (option -l), so
				 * make sure we fflush before writing to stderr. */
				fflush_all();
			}
			if (!(opt & CMP_OPT_s)) {
				if (opt & CMP_OPT_l) {
					line_pos = c1;	/* line_pos is unused in the -l case. */
				}
				fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
				if (opt) {	/* This must be -l since not -s. */
					/* If we encountered an EOF,
					 * the while check will catch it. */
					continue;
				}
			}
			break;
		}
		if (c1 == '\n') {
			++line_pos;
		}
	} while (c1 != EOF);

	die_if_ferror(fp1, filename1);
	die_if_ferror(fp2, filename2);

	fflush_stdout_and_exit(retval);
}
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"u, line %u\n";
28	// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
29	static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %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	IF_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	IF_DESKTOP(":?4")
52	IF_NOT_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	fflush_all();
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	}