busybox/coreutils/head.c

/* vi: set sw=4 ts=4: */
/*
 * head implementation for busybox
 *
 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */

#include "busybox.h"

static const char head_opts[] =
	"n:"
#if ENABLE_FEATURE_FANCY_HEAD
	"c:qv"
#endif
	;

#if ENABLE_FEATURE_FANCY_HEAD
static const struct suffix_mult head_suffixes[] = {
	{ "b", 512 },
	{ "k", 1024 },
	{ "m", 1024*1024 },
	{ NULL, 0 }
};
#endif

static const char header_fmt_str[] = "\n==> %s <==\n";

int head_main(int argc, char **argv)
{
	unsigned long count = 10;
	unsigned long i;
#if ENABLE_FEATURE_FANCY_HEAD
	int count_bytes = 0;
	int header_threshhold = 1;
#endif

	FILE *fp;
	const char *fmt;
	char *p;
	int opt;
	int c;
	int retval = EXIT_SUCCESS;

#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD
	/* Allow legacy syntax of an initial numeric option without -n. */
	if (argc > 1 && argv[1][0] == '-'
	 && isdigit(argv[1][1])
	) {
		--argc;
		++argv;
		p = (*argv) + 1;
		goto GET_COUNT;
	}
#endif

	/* No size benefit in converting this to getopt32 */
	while ((opt = getopt(argc, argv, head_opts)) > 0) {
		switch (opt) {
#if ENABLE_FEATURE_FANCY_HEAD
		case 'q':
			header_threshhold = INT_MAX;
			break;
		case 'v':
			header_threshhold = -1;
			break;
		case 'c':
			count_bytes = 1;
			/* fall through */
#endif
		case 'n':
			p = optarg;
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD
 GET_COUNT:
#endif

#if !ENABLE_FEATURE_FANCY_HEAD
			count = xatoul(p);
#else
			count = xatoul_sfx(p, head_suffixes);
#endif
			break;
		default:
			bb_show_usage();
		}
	}

	argv += optind;
	if (!*argv) {
		*--argv = "-";
	}

	fmt = header_fmt_str + 1;
#if ENABLE_FEATURE_FANCY_HEAD
	if (argc - optind <= header_threshhold) {
		header_threshhold = 0;
	}
#else
	if (argc <= optind + 1) {
		fmt += 11;
	}
	/* Now define some things here to avoid #ifdefs in the code below.
	 * These should optimize out of the if conditions below. */
#define header_threshhold   1
#define count_bytes         0
#endif

	do {
		fp = fopen_or_warn_stdin(*argv);
		if (fp) {
			if (fp == stdin) {
				*argv = (char *) bb_msg_standard_input;
			}
			if (header_threshhold) {
				printf(fmt, *argv);
			}
			i = count;
			while (i && ((c = getc(fp)) != EOF)) {
				if (count_bytes || (c == '\n')) {
					--i;
				}
				putchar(c);
			}
			if (fclose_if_not_stdin(fp)) {
				bb_perror_msg("%s", *argv);	/* Avoid multibyte problems. */
				retval = EXIT_FAILURE;
			}
			die_if_ferror_stdout();
		}
		fmt = header_fmt_str;
	} while (*++argv);

	fflush_stdout_and_exit(retval);
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* head implementation for busybox
4	*
5	* Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
6	*
7	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8	*/
9
10	/* BB_AUDIT SUSv3 compliant */
11	/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
12	/* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */
13
14	#include "busybox.h"
15
16	static const char head_opts[] =
17	"n:"
18	#if ENABLE_FEATURE_FANCY_HEAD
19	"c:qv"
20	#endif
21	;
22
23	#if ENABLE_FEATURE_FANCY_HEAD
24	static const struct suffix_mult head_suffixes[] = {
25	{ "b", 512 },
26	{ "k", 1024 },
27	{ "m", 1024*1024 },
28	{ NULL, 0 }
29	};
30	#endif
31
32	static const char header_fmt_str[] = "\n==> %s <==\n";
33
34	int head_main(int argc, char **argv)
35	{
36	unsigned long count = 10;
37	unsigned long i;
38	#if ENABLE_FEATURE_FANCY_HEAD
39	int count_bytes = 0;
40	int header_threshhold = 1;
41	#endif
42
43	FILE *fp;
44	const char *fmt;
45	char *p;
46	int opt;
47	int c;
48	int retval = EXIT_SUCCESS;
49
50	#if ENABLE_INCLUDE_SUSv2 \|\| ENABLE_FEATURE_FANCY_HEAD
51	/* Allow legacy syntax of an initial numeric option without -n. */
52	if (argc > 1 && argv[1][0] == '-'
53	&& isdigit(argv[1][1])
54	) {
55	--argc;
56	++argv;
57	p = (*argv) + 1;
58	goto GET_COUNT;
59	}
60	#endif
61
62	/* No size benefit in converting this to getopt32 */
63	while ((opt = getopt(argc, argv, head_opts)) > 0) {
64	switch (opt) {
65	#if ENABLE_FEATURE_FANCY_HEAD
66	case 'q':
67	header_threshhold = INT_MAX;
68	break;
69	case 'v':
70	header_threshhold = -1;
71	break;
72	case 'c':
73	count_bytes = 1;
74	/* fall through */
75	#endif
76	case 'n':
77	p = optarg;
78	#if ENABLE_INCLUDE_SUSv2 \|\| ENABLE_FEATURE_FANCY_HEAD
79	GET_COUNT:
80	#endif
81
82	#if !ENABLE_FEATURE_FANCY_HEAD
83	count = xatoul(p);
84	#else
85	count = xatoul_sfx(p, head_suffixes);
86	#endif
87	break;
88	default:
89	bb_show_usage();
90	}
91	}
92
93	argv += optind;
94	if (!*argv) {
95	*--argv = "-";
96	}
97
98	fmt = header_fmt_str + 1;
99	#if ENABLE_FEATURE_FANCY_HEAD
100	if (argc - optind <= header_threshhold) {
101	header_threshhold = 0;
102	}
103	#else
104	if (argc <= optind + 1) {
105	fmt += 11;
106	}
107	/* Now define some things here to avoid #ifdefs in the code below.
108	* These should optimize out of the if conditions below. */
109	#define header_threshhold 1
110	#define count_bytes 0
111	#endif
112
113	do {
114	fp = fopen_or_warn_stdin(*argv);
115	if (fp) {
116	if (fp == stdin) {
117	argv = (char ) bb_msg_standard_input;
118	}
119	if (header_threshhold) {
120	printf(fmt, *argv);
121	}
122	i = count;
123	while (i && ((c = getc(fp)) != EOF)) {
124	if (count_bytes \|\| (c == '\n')) {
125	--i;
126	}
127	putchar(c);
128	}
129	if (fclose_if_not_stdin(fp)) {
130	bb_perror_msg("%s", argv); / Avoid multibyte problems. */
131	retval = EXIT_FAILURE;
132	}
133	die_if_ferror_stdout();
134	}
135	fmt = header_fmt_str;
136	} while (*++argv);
137
138	fflush_stdout_and_exit(retval);
139	}