busybox/libbb/parse_config.c

/* vi: set sw=4 ts=4: */
/*
 * config file parser helper
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

#if defined ENABLE_PARSE && ENABLE_PARSE
int parse_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int parse_main(int argc UNUSED_PARAM, char **argv)
{
	const char *delims = "# \t";
	unsigned flags = PARSE_NORMAL;
	int mintokens = 0, ntokens = 128;

	opt_complementary = "-1:n+:m+:f+";
	getopt32(argv, "n:m:d:f:", &ntokens, &mintokens, &delims, &flags);
	//argc -= optind;
	argv += optind;
	while (*argv) {
		parser_t *p = config_open(*argv);
		if (p) {
			int n;
			char **t = xmalloc(sizeof(char *) * ntokens);
			while ((n = config_read(p, t, ntokens, mintokens, delims, flags)) != 0) {
				for (int i = 0; i < n; ++i)
					printf("[%s]", t[i]);
				puts("");
			}
			config_close(p);
		}
		argv++;
	}
	return EXIT_SUCCESS;
}
#endif

/*

Typical usage:

----- CUT -----
	char *t[3];	// tokens placeholder
	parser_t *p = config_open(filename);
	if (p) {
		// parse line-by-line
		while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
			// use tokens
			bb_error_msg("TOKENS: [%s][%s][%s]", t[0], t[1], t[2]);
		}
		...
		// free parser
		config_close(p);
	}
----- CUT -----

*/

parser_t* FAST_FUNC config_open2(const char *filename, FILE* FAST_FUNC (*fopen_func)(const char *path))
{
	FILE* fp;
	parser_t *parser;

	fp = fopen_func(filename);
	if (!fp)
		return NULL;
	parser = xzalloc(sizeof(*parser));
	parser->fp = fp;
	return parser;
}

parser_t* FAST_FUNC config_open(const char *filename)
{
	return config_open2(filename, fopen_or_warn_stdin);
}

static void config_free_data(parser_t *const parser)
{
	free(parser->line);
	parser->line = NULL;
	if (PARSE_KEEP_COPY) { /* compile-time constant */
		free(parser->data);
		parser->data = NULL;
	}
}

void FAST_FUNC config_close(parser_t *parser)
{
	if (parser) {
		config_free_data(parser);
		fclose(parser->fp);
		free(parser);
	}
}

/*
0. If parser is NULL return 0.
1. Read a line from config file. If nothing to read then return 0.
   Handle continuation character. Advance lineno for each physical line.
   Discard everything past comment characher.
2. if PARSE_TRIM is set (default), remove leading and trailing delimiters.
3. If resulting line is empty goto 1.
4. Look for first delimiter. If !PARSE_COLLAPSE or !PARSE_TRIM is set then
   remember the token as empty.
5. Else (default) if number of seen tokens is equal to max number of tokens
   (token is the last one) and PARSE_GREEDY is set then the remainder
   of the line is the last token.
   Else (token is not last or PARSE_GREEDY is not set) just replace
   first delimiter with '\0' thus delimiting the token.
6. Advance line pointer past the end of token. If number of seen tokens
   is less than required number of tokens then goto 4.
7. Check the number of seen tokens is not less the min number of tokens.
   Complain or die otherwise depending on PARSE_MIN_DIE.
8. Return the number of seen tokens.

mintokens > 0 make config_read() print error message if less than mintokens
(but more than 0) are found. Empty lines are always skipped (not warned about).
*/
#undef config_read
int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const char *delims)
{
	char *line;
	int ntokens, mintokens;
	int t, len;

	ntokens = flags & 0xFF;
	mintokens = (flags & 0xFF00) >> 8;

	if (parser == NULL)
		return 0;

again:
	memset(tokens, 0, sizeof(tokens[0]) * ntokens);
	config_free_data(parser);

	/* Read one line (handling continuations with backslash) */
	line = bb_get_chunk_with_continuation(parser->fp, &len, &parser->lineno);
	if (line == NULL)
		return 0;
	parser->line = line;

	/* Strip trailing line-feed if any */
	if (len && line[len-1] == '\n')
		line[len-1] = '\0';

	/* Skip token in the start of line? */
	if (flags & PARSE_TRIM)
		line += strspn(line, delims + 1);

	if (line[0] == '\0' || line[0] == delims[0])
		goto again;

	if (flags & PARSE_KEEP_COPY)
		parser->data = xstrdup(line);

	/* Tokenize the line */
	for (t = 0; *line && *line != delims[0] && t < ntokens; t++) {
		/* Pin token */
		tokens[t] = line;

		/* Combine remaining arguments? */
		if ((t != (ntokens-1)) || !(flags & PARSE_GREEDY)) {
			/* Vanilla token, find next delimiter */
			line += strcspn(line, delims[0] ? delims : delims + 1);
		} else {
			/* Combining, find comment char if any */
			line = strchrnul(line, delims[0]);

			/* Trim any extra delimiters from the end */
			if (flags & PARSE_TRIM) {
				while (strchr(delims + 1, line[-1]) != NULL)
					line--;
			}
		}

		/* Token not terminated? */
		if (line[0] == delims[0])
			*line = '\0';
		else if (line[0] != '\0')
			*(line++) = '\0';

#if 0 /* unused so far */
		if (flags & PARSE_ESCAPE) {
			const char *from;
			char *to;

			from = to = tokens[t];
			while (*from) {
				if (*from == '\\') {
					from++;
					*to++ = bb_process_escape_sequence(&from);
				} else {
					*to++ = *from++;
				}
			}
			*to = '\0';
		}
#endif

		/* Skip possible delimiters */
		if (flags & PARSE_COLLAPSE)
			line += strspn(line, delims + 1);
	}

	if (t < mintokens) {
		bb_error_msg("bad line %u: %d tokens found, %d needed",
				parser->lineno, t, mintokens);
		if (flags & PARSE_MIN_DIE)
			xfunc_die();
		goto again;
	}

	return t;
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* config file parser helper
4	*
5	* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
6	*
7	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8	*/
9
10	#include "libbb.h"
11
12	#if defined ENABLE_PARSE && ENABLE_PARSE
13	int parse_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
14	int parse_main(int argc UNUSED_PARAM, char **argv)
15	{
16	const char *delims = "# \t";
17	unsigned flags = PARSE_NORMAL;
18	int mintokens = 0, ntokens = 128;
19
20	opt_complementary = "-1:n+:m+:f+";
21	getopt32(argv, "n:m:d:f:", &ntokens, &mintokens, &delims, &flags);
22	//argc -= optind;
23	argv += optind;
24	while (*argv) {
25	parser_t p = config_open(argv);
26	if (p) {
27	int n;
28	char *t = xmalloc(sizeof(char ) * ntokens);
29	while ((n = config_read(p, t, ntokens, mintokens, delims, flags)) != 0) {
30	for (int i = 0; i < n; ++i)
31	printf("[%s]", t[i]);
32	puts("");
33	}
34	config_close(p);
35	}
36	argv++;
37	}
38	return EXIT_SUCCESS;
39	}
40	#endif
41
42	/*
43
44	Typical usage:
45
46	----- CUT -----
47	char *t[3]; // tokens placeholder
48	parser_t *p = config_open(filename);
49	if (p) {
50	// parse line-by-line
51	while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
52	// use tokens
53	bb_error_msg("TOKENS: [%s][%s][%s]", t[0], t[1], t[2]);
54	}
55	...
56	// free parser
57	config_close(p);
58	}
59	----- CUT -----
60
61	*/
62
63	parser_t* FAST_FUNC config_open2(const char filename, FILE FAST_FUNC (fopen_func)(const char path))
64	{
65	FILE* fp;
66	parser_t *parser;
67
68	fp = fopen_func(filename);
69	if (!fp)
70	return NULL;
71	parser = xzalloc(sizeof(*parser));
72	parser->fp = fp;
73	return parser;
74	}
75
76	parser_t* FAST_FUNC config_open(const char *filename)
77	{
78	return config_open2(filename, fopen_or_warn_stdin);
79	}
80
81	static void config_free_data(parser_t *const parser)
82	{
83	free(parser->line);
84	parser->line = NULL;
85	if (PARSE_KEEP_COPY) { /* compile-time constant */
86	free(parser->data);
87	parser->data = NULL;
88	}
89	}
90
91	void FAST_FUNC config_close(parser_t *parser)
92	{
93	if (parser) {
94	config_free_data(parser);
95	fclose(parser->fp);
96	free(parser);
97	}
98	}
99
100	/*
101	0. If parser is NULL return 0.
102	1. Read a line from config file. If nothing to read then return 0.
103	Handle continuation character. Advance lineno for each physical line.
104	Discard everything past comment characher.
105	2. if PARSE_TRIM is set (default), remove leading and trailing delimiters.
106	3. If resulting line is empty goto 1.
107	4. Look for first delimiter. If !PARSE_COLLAPSE or !PARSE_TRIM is set then
108	remember the token as empty.
109	5. Else (default) if number of seen tokens is equal to max number of tokens
110	(token is the last one) and PARSE_GREEDY is set then the remainder
111	of the line is the last token.
112	Else (token is not last or PARSE_GREEDY is not set) just replace
113	first delimiter with '\0' thus delimiting the token.
114	6. Advance line pointer past the end of token. If number of seen tokens
115	is less than required number of tokens then goto 4.
116	7. Check the number of seen tokens is not less the min number of tokens.
117	Complain or die otherwise depending on PARSE_MIN_DIE.
118	8. Return the number of seen tokens.
119
120	mintokens > 0 make config_read() print error message if less than mintokens
121	(but more than 0) are found. Empty lines are always skipped (not warned about).
122	*/
123	#undef config_read
124	int FAST_FUNC config_read(parser_t parser, char tokens, unsigned flags, const char delims)
125	{
126	char *line;
127	int ntokens, mintokens;
128	int t, len;
129
130	ntokens = flags & 0xFF;
131	mintokens = (flags & 0xFF00) >> 8;
132
133	if (parser == NULL)
134	return 0;
135
136	again:
137	memset(tokens, 0, sizeof(tokens[0]) * ntokens);
138	config_free_data(parser);
139
140	/* Read one line (handling continuations with backslash) */
141	line = bb_get_chunk_with_continuation(parser->fp, &len, &parser->lineno);
142	if (line == NULL)
143	return 0;
144	parser->line = line;
145
146	/* Strip trailing line-feed if any */
147	if (len && line[len-1] == '\n')
148	line[len-1] = '\0';
149
150	/* Skip token in the start of line? */
151	if (flags & PARSE_TRIM)
152	line += strspn(line, delims + 1);
153
154	if (line[0] == '\0' \|\| line[0] == delims[0])
155	goto again;
156
157	if (flags & PARSE_KEEP_COPY)
158	parser->data = xstrdup(line);
159
160	/* Tokenize the line */
161	for (t = 0; line && line != delims[0] && t < ntokens; t++) {
162	/* Pin token */
163	tokens[t] = line;
164
165	/* Combine remaining arguments? */
166	if ((t != (ntokens-1)) \|\| !(flags & PARSE_GREEDY)) {
167	/* Vanilla token, find next delimiter */
168	line += strcspn(line, delims[0] ? delims : delims + 1);
169	} else {
170	/* Combining, find comment char if any */
171	line = strchrnul(line, delims[0]);
172
173	/* Trim any extra delimiters from the end */
174	if (flags & PARSE_TRIM) {
175	while (strchr(delims + 1, line[-1]) != NULL)
176	line--;
177	}
178	}
179
180	/* Token not terminated? */
181	if (line[0] == delims[0])
182	*line = '\0';
183	else if (line[0] != '\0')
184	*(line++) = '\0';
185
186	#if 0 /* unused so far */
187	if (flags & PARSE_ESCAPE) {
188	const char *from;
189	char *to;
190
191	from = to = tokens[t];
192	while (*from) {
193	if (*from == '\\') {
194	from++;
195	*to++ = bb_process_escape_sequence(&from);
196	} else {
197	to++ = from++;
198	}
199	}
200	*to = '\0';
201	}
202	#endif
203
204	/* Skip possible delimiters */
205	if (flags & PARSE_COLLAPSE)
206	line += strspn(line, delims + 1);
207	}
208
209	if (t < mintokens) {
210	bb_error_msg("bad line %u: %d tokens found, %d needed",
211	parser->lineno, t, mintokens);
212	if (flags & PARSE_MIN_DIE)
213	xfunc_die();
214	goto again;
215	}
216
217	return t;
218	}