1/* expand - convert tabs to spaces
2 * unexpand - convert spaces to tabs
3 *
4 * Copyright (C) 89, 91, 1995-2006 Free Software Foundation, Inc.
5 *
6 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
7 *
8 * David MacKenzie <djm@gnu.ai.mit.edu>
9 *
10 * Options for expand:
11 * -t num  --tabs=NUM      Convert tabs to num spaces (default 8 spaces).
12 * -i      --initial       Only convert initial tabs on each line to spaces.
13 *
14 * Options for unexpand:
15 * -a      --all           Convert all blanks, instead of just initial blanks.
16 * -f      --first-only    Convert only leading sequences of blanks (default).
17 * -t num  --tabs=NUM      Have tabs num characters apart instead of 8.
18 *
19 *  Busybox version (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
20 *
21 *  Caveat: this versions of expand and unexpand don't accept tab lists.
22 */
23
24#include "libbb.h"
25
26enum {
27	OPT_INITIAL     = 1 << 0,
28	OPT_TABS        = 1 << 1,
29	OPT_ALL         = 1 << 2,
30};
31
32static void xputchar(char c)
33{
34	if (putchar(c) < 0)
35		bb_error_msg_and_die(bb_msg_write_error);
36}
37
38#if ENABLE_EXPAND
39static void expand(FILE *file, unsigned tab_size, unsigned opt)
40{
41	char *line;
42	char *ptr;
43	int convert;
44	int pos;
45
46	/* Increment tab_size by 1 locally.*/
47	tab_size++;
48
49	while ((line = xmalloc_fgets(file)) != NULL) {
50		convert = 1;
51		pos = 0;
52		ptr = line;
53		while (*line) {
54			pos++;
55			if (*line == '\t' && convert) {
56				for (; pos < tab_size; pos++) {
57					xputchar(' ');
58				}
59			} else {
60				if ((opt & OPT_INITIAL) && !isblank(*line)) {
61					convert = 0;
62				}
63				xputchar(*line);
64			}
65			if (pos == tab_size) {
66				pos = 0;
67			}
68			line++;
69		}
70		free(ptr);
71	}
72}
73#endif
74
75#if ENABLE_UNEXPAND
76static void unexpand(FILE *file, unsigned int tab_size, unsigned opt)
77{
78	char *line;
79	char *ptr;
80	int convert;
81	int pos;
82	int i = 0;
83	int column = 0;
84
85	while ((line = xmalloc_fgets(file)) != NULL) {
86		convert = 1;
87		pos = 0;
88		ptr = line;
89		while (*line) {
90			while ((*line == ' ' || *line == '\t') && convert) {
91				pos += (*line == ' ') ? 1 : tab_size;
92				line++;
93				column++;
94				if ((opt & OPT_ALL) && column == tab_size) {
95					column = 0;
96					goto put_tab;
97				}
98			}
99			if (pos) {
100				i = pos / tab_size;
101				if (i) {
102					for (; i > 0; i--) {
103 put_tab:
104						xputchar('\t');
105					}
106				} else {
107					for (i = pos % tab_size; i > 0; i--) {
108						xputchar(' ');
109					}
110				}
111				pos = 0;
112			} else {
113				if (opt & OPT_INITIAL) {
114					convert = 0;
115				}
116				if (opt & OPT_ALL) {
117					column++;
118				}
119				xputchar(*line);
120				line++;
121			}
122		}
123		free(ptr);
124	}
125}
126#endif
127
128int expand_main(int argc, char **argv);
129int expand_main(int argc, char **argv)
130{
131	/* Default 8 spaces for 1 tab */
132	const char *opt_t = "8";
133	FILE *file;
134	unsigned tab_size;
135	unsigned opt;
136	int exit_status = EXIT_SUCCESS;
137
138#if ENABLE_FEATURE_EXPAND_LONG_OPTIONS
139	static const char expand_longopts[] ALIGN1 =
140		/* name, has_arg, val */
141		"initial\0"          No_argument       "i"
142		"tabs\0"             Required_argument "t"
143	;
144#endif
145#if ENABLE_FEATURE_UNEXPAND_LONG_OPTIONS
146	static const char unexpand_longopts[] ALIGN1 =
147		/* name, has_arg, val */
148		"first-only\0"       No_argument       "i"
149		"tabs\0"             Required_argument "t"
150		"all\0"              No_argument       "a"
151	;
152#endif
153
154	if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
155		USE_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
156		opt = getopt32(argv, "it:", &opt_t);
157	} else if (ENABLE_UNEXPAND) {
158		USE_FEATURE_UNEXPAND_LONG_OPTIONS(applet_long_options = unexpand_longopts);
159		/* -t NUM sets also -a */
160		opt_complementary = "ta";
161		opt = getopt32(argv, "ft:a", &opt_t);
162		/* -f --first-only is the default */
163		if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
164	}
165	tab_size = xatou_range(opt_t, 1, UINT_MAX);
166
167	argv += optind;
168
169	/* If no args are given, read from stdin */
170	if (!*argv) {
171		*--argv = (char*)bb_msg_standard_input;
172		goto use_stdin;
173	}
174
175	do {
176		if (NOT_LONE_CHAR(*argv, '-')) {
177			file = fopen_or_warn(*argv, "r");
178			if (!file) {
179				exit_status = EXIT_FAILURE;
180				continue;
181			}
182		} else {
183 use_stdin:
184			file = stdin;
185		}
186
187		if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
188			USE_EXPAND(expand(file, tab_size, opt));
189		else if (ENABLE_UNEXPAND)
190			USE_UNEXPAND(unexpand(file, tab_size, opt));
191
192		/* Check and close the file */
193		/* We do want all of them to execute, thus | instead of || */
194		if (ferror(file) | fclose_if_not_stdin(file)) {
195			bb_perror_msg("%s", *argv);
196			exit_status = EXIT_FAILURE;
197		}
198		/* If stdin also clear EOF */
199		if (file == stdin)
200			clearerr(file);
201	} while (*++argv);
202
203	/* Now close stdin also */
204	/* (if we didn't read from it, it's a no-op) */
205	if (fclose(stdin))
206		bb_perror_msg_and_die(bb_msg_standard_input);
207
208	fflush_stdout_and_exit(exit_status);
209}
210