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	niro	532	/* 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	niro	816	#include "libbb.h"
15	niro	532
16	niro	816	static const char head_opts[] ALIGN1 =
17	niro	532	"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	niro	984	{ "", 0 }
28	niro	532	};
29
30	niro	1123	#define header_fmt_str "\n==> %s <==\n"
31	niro	532
32	niro	816	int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
33	niro	532	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	niro	984	if (argv[1] && argv[1][0] == '-'
51	niro	532	&& 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	niro	816	argc -= optind;
87	niro	532	argv += optind;
88	niro	816	if (!*argv)
89			--argv = (char)"-";
90	niro	532
91			fmt = header_fmt_str + 1;
92			#if ENABLE_FEATURE_FANCY_HEAD
93	niro	816	if (argc <= header_threshhold) {
94	niro	532	header_threshhold = 0;
95			}
96			#else
97	niro	816	if (argc <= 1) {
98			fmt += 11; /* "" */
99	niro	532	}
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	niro	984	bb_simple_perror_msg(*argv);
124	niro	532	retval = EXIT_FAILURE;
125			}
126			die_if_ferror_stdout();
127	niro	984	} else {
128			retval = EXIT_FAILURE;
129	niro	532	}
130			fmt = header_fmt_str;
131			} while (*++argv);
132
133			fflush_stdout_and_exit(retval);
134			}