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
	;

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

static const char header_fmt_str[] ALIGN1 = "\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
#if !ENABLE_FEATURE_FANCY_HEAD
			count = xatoul(p);
#else
			count = xatoul_sfx(p, head_suffixes);
#endif
			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			#if ENABLE_FEATURE_FANCY_HEAD
24			static const struct suffix_mult head_suffixes[] = {
25			{ "b", 512 },
26			{ "k", 1024 },
27			{ "m", 1024*1024 },
28	niro	984	{ "", 0 }
29	niro	532	};
30			#endif
31
32	niro	816	static const char header_fmt_str[] ALIGN1 = "\n==> %s <==\n";
33	niro	532
34	niro	816	int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
35	niro	532	int head_main(int argc, char **argv)
36			{
37			unsigned long count = 10;
38			unsigned long i;
39			#if ENABLE_FEATURE_FANCY_HEAD
40			int count_bytes = 0;
41			int header_threshhold = 1;
42			#endif
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	niro	984	if (argv[1] && argv[1][0] == '-'
53	niro	532	&& 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			#if !ENABLE_FEATURE_FANCY_HEAD
82			count = xatoul(p);
83			#else
84			count = xatoul_sfx(p, head_suffixes);
85			#endif
86			break;
87			default:
88			bb_show_usage();
89			}
90			}
91
92	niro	816	argc -= optind;
93	niro	532	argv += optind;
94	niro	816	if (!*argv)
95			--argv = (char)"-";
96	niro	532
97			fmt = header_fmt_str + 1;
98			#if ENABLE_FEATURE_FANCY_HEAD
99	niro	816	if (argc <= header_threshhold) {
100	niro	532	header_threshhold = 0;
101			}
102			#else
103	niro	816	if (argc <= 1) {
104			fmt += 11; /* "" */
105	niro	532	}
106			/* Now define some things here to avoid #ifdefs in the code below.
107			* These should optimize out of the if conditions below. */
108			#define header_threshhold 1
109			#define count_bytes 0
110			#endif
111
112			do {
113			fp = fopen_or_warn_stdin(*argv);
114			if (fp) {
115			if (fp == stdin) {
116			argv = (char ) bb_msg_standard_input;
117			}
118			if (header_threshhold) {
119			printf(fmt, *argv);
120			}
121			i = count;
122			while (i && ((c = getc(fp)) != EOF)) {
123			if (count_bytes \|\| (c == '\n')) {
124			--i;
125			}
126			putchar(c);
127			}
128			if (fclose_if_not_stdin(fp)) {
129	niro	984	bb_simple_perror_msg(*argv);
130	niro	532	retval = EXIT_FAILURE;
131			}
132			die_if_ferror_stdout();
133	niro	984	} else {
134			retval = EXIT_FAILURE;
135	niro	532	}
136			fmt = header_fmt_str;
137			} while (*++argv);
138
139			fflush_stdout_and_exit(retval);
140			}