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.
 * Also for use in uClibc (http://uclibc.org/) licensed under LGPLv2.1 or later.
 */

#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 *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 character.
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	niro	816	/* 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	niro	984	* Also for use in uClibc (http://uclibc.org/) licensed under LGPLv2.1 or later.
9	niro	816	*/
10
11			#include "libbb.h"
12
13			#if defined ENABLE_PARSE && ENABLE_PARSE
14			int parse_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
15			int parse_main(int argc UNUSED_PARAM, char **argv)
16			{
17			const char *delims = "# \t";
18			unsigned flags = PARSE_NORMAL;
19			int mintokens = 0, ntokens = 128;
20
21			opt_complementary = "-1:n+:m+:f+";
22			getopt32(argv, "n:m:d:f:", &ntokens, &mintokens, &delims, &flags);
23			//argc -= optind;
24			argv += optind;
25			while (*argv) {
26			parser_t p = config_open(argv);
27			if (p) {
28			int n;
29			char *t = xmalloc(sizeof(char ) * ntokens);
30			while ((n = config_read(p, t, ntokens, mintokens, delims, flags)) != 0) {
31			for (int i = 0; i < n; ++i)
32			printf("[%s]", t[i]);
33			puts("");
34			}
35			config_close(p);
36			}
37			argv++;
38			}
39			return EXIT_SUCCESS;
40			}
41			#endif
42
43			/*
44
45			Typical usage:
46
47			----- CUT -----
48			char *t[3]; // tokens placeholder
49			parser_t *p = config_open(filename);
50			if (p) {
51			// parse line-by-line
52			while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
53			// use tokens
54			bb_error_msg("TOKENS: [%s][%s][%s]", t[0], t[1], t[2]);
55			}
56			...
57			// free parser
58			config_close(p);
59			}
60			----- CUT -----
61
62			*/
63
64			parser_t* FAST_FUNC config_open2(const char filename, FILE FAST_FUNC (fopen_func)(const char path))
65			{
66			FILE* fp;
67			parser_t *parser;
68
69			fp = fopen_func(filename);
70			if (!fp)
71			return NULL;
72			parser = xzalloc(sizeof(*parser));
73			parser->fp = fp;
74			return parser;
75			}
76
77			parser_t* FAST_FUNC config_open(const char *filename)
78			{
79			return config_open2(filename, fopen_or_warn_stdin);
80			}
81
82	niro	984	static void config_free_data(parser_t *parser)
83	niro	816	{
84			free(parser->line);
85			parser->line = NULL;
86			if (PARSE_KEEP_COPY) { /* compile-time constant */
87			free(parser->data);
88			parser->data = NULL;
89			}
90			}
91
92			void FAST_FUNC config_close(parser_t *parser)
93			{
94			if (parser) {
95			config_free_data(parser);
96			fclose(parser->fp);
97			free(parser);
98			}
99			}
100
101			/*
102			0. If parser is NULL return 0.
103			1. Read a line from config file. If nothing to read then return 0.
104			Handle continuation character. Advance lineno for each physical line.
105	niro	984	Discard everything past comment character.
106	niro	816	2. if PARSE_TRIM is set (default), remove leading and trailing delimiters.
107			3. If resulting line is empty goto 1.
108			4. Look for first delimiter. If !PARSE_COLLAPSE or !PARSE_TRIM is set then
109			remember the token as empty.
110			5. Else (default) if number of seen tokens is equal to max number of tokens
111			(token is the last one) and PARSE_GREEDY is set then the remainder
112			of the line is the last token.
113			Else (token is not last or PARSE_GREEDY is not set) just replace
114			first delimiter with '\0' thus delimiting the token.
115			6. Advance line pointer past the end of token. If number of seen tokens
116			is less than required number of tokens then goto 4.
117			7. Check the number of seen tokens is not less the min number of tokens.
118			Complain or die otherwise depending on PARSE_MIN_DIE.
119			8. Return the number of seen tokens.
120
121			mintokens > 0 make config_read() print error message if less than mintokens
122			(but more than 0) are found. Empty lines are always skipped (not warned about).
123			*/
124			#undef config_read
125			int FAST_FUNC config_read(parser_t parser, char tokens, unsigned flags, const char delims)
126			{
127			char *line;
128			int ntokens, mintokens;
129			int t, len;
130
131			ntokens = flags & 0xFF;
132			mintokens = (flags & 0xFF00) >> 8;
133
134			if (parser == NULL)
135			return 0;
136
137			again:
138			memset(tokens, 0, sizeof(tokens[0]) * ntokens);
139			config_free_data(parser);
140
141			/* Read one line (handling continuations with backslash) */
142			line = bb_get_chunk_with_continuation(parser->fp, &len, &parser->lineno);
143			if (line == NULL)
144			return 0;
145			parser->line = line;
146
147			/* Strip trailing line-feed if any */
148			if (len && line[len-1] == '\n')
149			line[len-1] = '\0';
150
151			/* Skip token in the start of line? */
152			if (flags & PARSE_TRIM)
153			line += strspn(line, delims + 1);
154
155			if (line[0] == '\0' \|\| line[0] == delims[0])
156			goto again;
157
158			if (flags & PARSE_KEEP_COPY)
159			parser->data = xstrdup(line);
160
161			/* Tokenize the line */
162			for (t = 0; line && line != delims[0] && t < ntokens; t++) {
163			/* Pin token */
164			tokens[t] = line;
165
166			/* Combine remaining arguments? */
167			if ((t != (ntokens-1)) \|\| !(flags & PARSE_GREEDY)) {
168			/* Vanilla token, find next delimiter */
169			line += strcspn(line, delims[0] ? delims : delims + 1);
170			} else {
171			/* Combining, find comment char if any */
172			line = strchrnul(line, delims[0]);
173
174			/* Trim any extra delimiters from the end */
175			if (flags & PARSE_TRIM) {
176			while (strchr(delims + 1, line[-1]) != NULL)
177			line--;
178			}
179			}
180
181			/* Token not terminated? */
182			if (line[0] == delims[0])
183			*line = '\0';
184			else if (line[0] != '\0')
185			*(line++) = '\0';
186
187			#if 0 /* unused so far */
188			if (flags & PARSE_ESCAPE) {
189			const char *from;
190			char *to;
191
192			from = to = tokens[t];
193			while (*from) {
194			if (*from == '\\') {
195			from++;
196			*to++ = bb_process_escape_sequence(&from);
197			} else {
198			to++ = from++;
199			}
200			}
201			*to = '\0';
202			}
203			#endif
204
205			/* Skip possible delimiters */
206			if (flags & PARSE_COLLAPSE)
207			line += strspn(line, delims + 1);
208			}
209
210			if (t < mintokens) {
211			bb_error_msg("bad line %u: %d tokens found, %d needed",
212			parser->lineno, t, mintokens);
213			if (flags & PARSE_MIN_DIE)
214			xfunc_die();
215			goto again;
216			}
217
218			return t;
219			}