busybox/coreutils/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 "busybox.h"

static FILE *cmp_xfopen_input(const char * const filename)
{
	FILE *fp;

	fp = fopen_or_warn_stdin(filename);
	if (fp)
		return fp;
	exit(xfunc_error_retval);	/* We already output an error message. */
}

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

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

int cmp_main(int argc, char **argv)
{
	FILE *fp1, *fp2, *outfile = stdout;
	const char *filename1, *filename2 = "-";
	const char *fmt;
	int c1, c2, char_pos = 0, line_pos = 1;
	unsigned opt;
	int retval = 0;

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

	opt = getopt32(argc, argv, opt_chars);

	if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l))
			|| (((unsigned int)(--argc - optind)) > 1))
		bb_show_usage();

	fp1 = cmp_xfopen_input(filename1 = *(argv += optind));

	if (*++argv) {
		filename2 = *argv;
	}
	fp2 = cmp_xfopen_input(filename2);

	if (fp1 == fp2) {			/* Paranioa 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;

	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. */
				xfflush_stdout();
			}
			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 "busybox.h"
25
26	static FILE cmp_xfopen_input(const char const filename)
27	{
28	FILE *fp;
29
30	fp = fopen_or_warn_stdin(filename);
31	if (fp)
32	return fp;
33	exit(xfunc_error_retval); /* We already output an error message. */
34	}
35
36	static const char fmt_eof[] = "cmp: EOF on %s\n";
37	static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
38	// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%d %o %o\n"
39	static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
40
41	static const char opt_chars[] = "sl";
42	#define CMP_OPT_s (1<<0)
43	#define CMP_OPT_l (1<<1)
44
45	int cmp_main(int argc, char **argv)
46	{
47	FILE fp1, fp2, *outfile = stdout;
48	const char filename1, filename2 = "-";
49	const char *fmt;
50	int c1, c2, char_pos = 0, line_pos = 1;
51	unsigned opt;
52	int retval = 0;
53
54	xfunc_error_retval = 2; /* 1 is returned if files are different. */
55
56	opt = getopt32(argc, argv, opt_chars);
57
58	if (((opt & (CMP_OPT_s\|CMP_OPT_l)) == (CMP_OPT_s\|CMP_OPT_l))
59	\|\| (((unsigned int)(--argc - optind)) > 1))
60	bb_show_usage();
61
62	fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
63
64	if (*++argv) {
65	filename2 = *argv;
66	}
67	fp2 = cmp_xfopen_input(filename2);
68
69	if (fp1 == fp2) { /* Paranioa check... stdin == stdin? */
70	/* Note that we don't bother reading stdin. Neither does gnu wc.
71	* But perhaps we should, so that other apps down the chain don't
72	* get the input. Consider 'echo hello \| (cmp - - && cat -)'.
73	*/
74	return 0;
75	}
76
77	if (opt & CMP_OPT_l)
78	fmt = fmt_l_opt;
79	else
80	fmt = fmt_differ;
81
82	do {
83	c1 = getc(fp1);
84	c2 = getc(fp2);
85	++char_pos;
86	if (c1 != c2) { /* Remember: a read error may have occurred. */
87	retval = 1; /* But assume the files are different for now. */
88	if (c2 == EOF) {
89	/* We know that fp1 isn't at EOF or in an error state. But to
90	* save space below, things are setup to expect an EOF in fp1
91	* if an EOF occurred. So, swap things around.
92	*/
93	fp1 = fp2;
94	filename1 = filename2;
95	c1 = c2;
96	}
97	if (c1 == EOF) {
98	die_if_ferror(fp1, filename1);
99	fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
100	outfile = stderr;
101	/* There may have been output to stdout (option -l), so
102	* make sure we fflush before writing to stderr. */
103	xfflush_stdout();
104	}
105	if (!(opt & CMP_OPT_s)) {
106	if (opt & CMP_OPT_l) {
107	line_pos = c1; /* line_pos is unused in the -l case. */
108	}
109	fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
110	if (opt) { /* This must be -l since not -s. */
111	/* If we encountered an EOF,
112	* the while check will catch it. */
113	continue;
114	}
115	}
116	break;
117	}
118	if (c1 == '\n') {
119	++line_pos;
120	}
121	} while (c1 != EOF);
122
123	die_if_ferror(fp1, filename1);
124	die_if_ferror(fp2, filename2);
125
126	fflush_stdout_and_exit(retval);
127	}