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 "libbb.h"

static const char head_opts[] ALIGN1 =
	"n:"
#if ENABLE_FEATURE_FANCY_HEAD
	"c:qv"
#endif
	;

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

#define header_fmt_str "\n==> %s <==\n"

int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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 (argv[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
			count = xatoul_sfx(p, head_suffixes);
			break;
		default:
			bb_show_usage();
		}
	}

	argc -= optind;
	argv += optind;
	if (!*argv)
		*--argv = (char*)"-";

	fmt = header_fmt_str + 1;
#if ENABLE_FEATURE_FANCY_HEAD
	if (argc <= header_threshhold) {
		header_threshhold = 0;
	}
#else
	if (argc <= 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_simple_perror_msg(*argv);
				retval = EXIT_FAILURE;
			}
			die_if_ferror_stdout();
		} else {
			retval = EXIT_FAILURE;
		}
		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 "libbb.h"
15
16	static const char head_opts[] ALIGN1 =
17	"n:"
18	#if ENABLE_FEATURE_FANCY_HEAD
19	"c:qv"
20	#endif
21	;
22
23	static const struct suffix_mult head_suffixes[] = {
24	{ "b", 512 },
25	{ "k", 1024 },
26	{ "m", 1024*1024 },
27	{ "", 0 }
28	};
29
30	#define header_fmt_str "\n==> %s <==\n"
31
32	int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
33	int head_main(int argc, char **argv)
34	{
35	unsigned long count = 10;
36	unsigned long i;
37	#if ENABLE_FEATURE_FANCY_HEAD
38	int count_bytes = 0;
39	int header_threshhold = 1;
40	#endif
41	FILE *fp;
42	const char *fmt;
43	char *p;
44	int opt;
45	int c;
46	int retval = EXIT_SUCCESS;
47
48	#if ENABLE_INCLUDE_SUSv2 \|\| ENABLE_FEATURE_FANCY_HEAD
49	/* Allow legacy syntax of an initial numeric option without -n. */
50	if (argv[1] && argv[1][0] == '-'
51	&& isdigit(argv[1][1])
52	) {
53	--argc;
54	++argv;
55	p = (*argv) + 1;
56	goto GET_COUNT;
57	}
58	#endif
59
60	/* No size benefit in converting this to getopt32 */
61	while ((opt = getopt(argc, argv, head_opts)) > 0) {
62	switch (opt) {
63	#if ENABLE_FEATURE_FANCY_HEAD
64	case 'q':
65	header_threshhold = INT_MAX;
66	break;
67	case 'v':
68	header_threshhold = -1;
69	break;
70	case 'c':
71	count_bytes = 1;
72	/* fall through */
73	#endif
74	case 'n':
75	p = optarg;
76	#if ENABLE_INCLUDE_SUSv2 \|\| ENABLE_FEATURE_FANCY_HEAD
77	GET_COUNT:
78	#endif
79	count = xatoul_sfx(p, head_suffixes);
80	break;
81	default:
82	bb_show_usage();
83	}
84	}
85
86	argc -= optind;
87	argv += optind;
88	if (!*argv)
89	--argv = (char)"-";
90
91	fmt = header_fmt_str + 1;
92	#if ENABLE_FEATURE_FANCY_HEAD
93	if (argc <= header_threshhold) {
94	header_threshhold = 0;
95	}
96	#else
97	if (argc <= 1) {
98	fmt += 11; /* "" */
99	}
100	/* Now define some things here to avoid #ifdefs in the code below.
101	* These should optimize out of the if conditions below. */
102	#define header_threshhold 1
103	#define count_bytes 0
104	#endif
105
106	do {
107	fp = fopen_or_warn_stdin(*argv);
108	if (fp) {
109	if (fp == stdin) {
110	argv = (char ) bb_msg_standard_input;
111	}
112	if (header_threshhold) {
113	printf(fmt, *argv);
114	}
115	i = count;
116	while (i && ((c = getc(fp)) != EOF)) {
117	if (count_bytes \|\| (c == '\n')) {
118	--i;
119	}
120	putchar(c);
121	}
122	if (fclose_if_not_stdin(fp)) {
123	bb_simple_perror_msg(*argv);
124	retval = EXIT_FAILURE;
125	}
126	die_if_ferror_stdout();
127	} else {
128	retval = EXIT_FAILURE;
129	}
130	fmt = header_fmt_str;
131	} while (*++argv);
132
133	fflush_stdout_and_exit(retval);
134	}