[fwd] / conf.h

/* -*-c-*-
 *
 * $Id: conf.h,v 1.9 2004/04/08 01:36:25 mdw Exp $
 *
 * Configuration parsing
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the `fw' port forwarder.
 *
 * `fw' is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * `fw' is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with `fw'; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef CONF_H
#define CONF_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <mLib/dstr.h>

#ifndef SCAN_H
#  include "scan.h"
#endif

/*----- Magic numbers -----------------------------------------------------*/

#define CTOK_EOF (-1)
#define CTOK_WORD 256

/*----- Functions provided ------------------------------------------------*/

/* --- @conf_undelim@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner definition
 *		@const char *d, *dd@ = pointer to characters to escape
 *
 * Returns:	---
 *
 * Use:		Modifies the tokenizer.  Characters in the first list will
 *		always be considered to begin a word.  Characters in the
 *		second list will always be allowed to continue a word.
 */

extern void conf_undelim(scanner */*sc*/,
			 const char */*d*/, const char */*dd*/);

/* --- @token@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner definition
 *
 * Returns:	Type of token scanned.
 *
 * Use:		Reads the next token from the character scanner.
 */

extern int token(scanner */*sc*/);

/* --- @error@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner definition
 *		@const char *msg@ = message skeleton string
 *		@...@ = extra arguments for the skeleton
 *
 * Returns:	Doesn't
 *
 * Use:		Reports an error at the current scanner location.
 */

extern void error(scanner */*sc*/, const char */*msg*/, ...);

/* --- @pushback@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner definition
 *
 * Returns:	---
 *
 * Use:		Pushes the current token back.  This is normally a precursor
 *		to pushing a new scanner source.
 */

extern void pushback(scanner */*sc*/);

/* --- @conf_enum@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to a scanner object
 *		@const char *list@ = comma-separated things to allow
 *		@unsigned @f = flags for the search
 *		@const char *err@ = error message if not found
 *
 * Returns:	Index into list, zero-based, or @-1@.
 *
 * Use:		Checks whether the current token is a string which matches
 *		one of the comma-separated items given.  The return value is
 *		the index (zero-based) of the matched string in the list.
 *
 *		The flags control the behaviour if no exact match is found.
 *		If @ENUM_ABBREV@ is set, and the current token is a left
 *		substring of exactly one of the possibilities, then that one
 *		is chosen.  If @ENUM_NONE@ is set, the value @-1@ is
 *		returned; otherwise an error is reported and the program is
 *		terminated.
 */

#define ENUM_ABBREV 1u
#define ENUM_NONE 2u

extern int conf_enum(scanner */*sc*/, const char */*list*/,
		     unsigned /*flags*/, const char */*err*/);

/* --- @conf_prefix@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to a scanner object
 *		@const char *p@ = pointer to prefix string to check
 *
 * Returns:	Nonzero if the prefix matches.
 *
 * Use:		If the current token is a word matching the given prefix
 *		string, then it and an optional `.' character are removed and
 *		a nonzero result is returned.  Otherwise the current token is
 *		left as it is, and zero is returned.
 *
 *		Typical options parsing code would remove an expected prefix,
 *		scan an option anyway (since qualifying prefixes are
 *		optional) and if a match is found, claim the option.  If no
 *		match is found, and a prefix was stripped, then an error
 *		should be reported.
 */

extern int conf_prefix(scanner */*sc*/, const char */*p*/);

/* --- @CONF_BEGIN@, @CONF_END@ --- *
 *
 * Arguments:	@sc@ = scanner to read from
 *		@prefix@ = prefix to scan for
 *		@desc@ = description of what we're parsing
 *
 * Use:		Bracket an options parsing routine.  The current token is
 *		checked to see whether it matches the prefix.  If so, it is
 *		removed and the following token examined.  If that's a `.'
 *		then it's removed.  If it's a `{' then the enclosed
 *		option-parsing code is executed in a loop until a matching
 *		'}' is found.  If the options parser doesn't accept an
 *		option, the behaviour is dependent on whether a prefix was
 *		seen: if so, an error is reported; otherwse a zero return is
 *		made.
 */

#define CS_PLAIN 0
#define CS_PREFIX 1
#define CS_BRACE 2
#define CS_UNKNOWN 3

#define CONF_BEGIN(sc, prefix, desc) do {				\
  scanner *_conf_sc = (sc);						\
  const char *_conf_desc = (desc);					\
  int _conf_state = CS_PLAIN;						\
									\
  /* --- Read the initial prefix --- */					\
									\
  if (_conf_sc->t == CTOK_WORD &&					\
      strcmp(_conf_sc->d.buf, (prefix)) == 0) {				\
    token(_conf_sc);							\
    _conf_state = CS_PREFIX;						\
    if (_conf_sc->t == '.')						\
      token(_conf_sc);							\
    else if (_conf_sc->t == '{') {					\
      token(_conf_sc);							\
      _conf_state = CS_BRACE;						\
    }									\
  }									\
									\
  /* --- Ensure the next token is a word --- */				\
									\
  if (_conf_sc->t != CTOK_WORD)						\
    error(_conf_sc, "parse error, expected option keyword");		\
  do {

#define CONF_END							\
									\
    /* --- Reject an option --- *					\
     *									\
     * We could get here as a result of an explicit @CONF_REJECT@ or	\
     * because the option wasn't accepted.				\
     */									\
									\
    goto _conf_reject;							\
  _conf_reject:								\
    if (_conf_state == CS_PLAIN)					\
      _conf_state = CS_UNKNOWN;						\
    else {								\
      error(_conf_sc, "unknown %s option `%s'",				\
	    _conf_desc, _conf_sc->d.buf);				\
    }									\
									\
    /* --- Accept an option --- *					\
     *									\
     * It's safe to drop through from above.  Either an error will have	\
     * been reported, or the state is not @CS_BRACE@.			\
     */									\
									\
  _conf_accept:								\
    if (_conf_state == CS_BRACE && _conf_sc->t == ';')			\
      token(_conf_sc);							\
  } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD);	\
									\
  /* --- Check for a closing brace --- */				\
									\
  if (_conf_state == CS_BRACE) {					\
    if (_conf_sc->t == '}')						\
      token(_conf_sc);							\
    else								\
      error(_conf_sc, "parse error, expected `}'");			\
  }									\
									\
  /* --- Return an appropriate value --- */				\
									\
  return (_conf_state != CS_UNKNOWN);					\
} while (0)

/* --- @CONF_ACCEPT@, @CONF_REJECT@ --- *
 *
 * Arguments:	---
 *
 * Use:		Within an options parser (between @CONF_BEGIN@ and
 *		@CONF_END@), accept or reject an option.
 */

#define CONF_ACCEPT goto _conf_accept
#define CONF_REJECT goto _conf_reject

/* --- @CONF_QUAL@ --- *
 *
 * Arguments:	---
 *
 * Use:		Evaluates to a nonzero value if the current option is
 *		qualified.  This can be used to decide whether abbreviations
 *		for options should be accepted.
 */

#define CONF_QUAL (_conf_state != CS_PLAIN)

/* --- @conf_name@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner
 *		@char delim@ = delimiter character to look for
 *		@dstr *d@ = pointer to dynamic string for output
 *
 * Returns:	---
 *
 * Use:		Reads in a compound name consisting of words separated by
 *		delimiters.  Leading and trailing delimiters are permitted,
 *		although they'll probably cause confusion if used.  The name
 *		may be enclosed in square brackets if that helps at all.
 *
 *		Examples of compound names are filenames (delimited by `/')
 *		and IP addresses (delimited by `.').
 */

extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif
Commit	Line	Data
e82f7154	1	/* --c--
e82f7154	2	*
7481fc9c	3	* $Id: conf.h,v 1.9 2004/04/08 01:36:25 mdw Exp $
e82f7154	4	*
	5	* Configuration parsing
	6	*
61e3dbdf	7	* (c) 1999 Straylight/Edgeware
e82f7154	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of the `fw' port forwarder.
	13	*
	14	* `fw' is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License as published by
	16	* the Free Software Foundation; either version 2 of the License, or
	17	* (at your option) any later version.
	18	*
	19	* `fw' is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU General Public License
	25	* along with `fw'; if not, write to the Free Software Foundation,
	26	* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	27	*/
	28
e82f7154	29	#ifndef CONF_H
	30	#define CONF_H
	31
	32	#ifdef __cplusplus
	33	extern "C" {
	34	#endif
	35
	36	/----- Header files ------------------------------------------------------/
	37
61e3dbdf	38	#include <mLib/dstr.h>
61e3dbdf	39
e82f7154	40	#ifndef SCAN_H
	41	# include "scan.h"
	42	#endif
	43
61e3dbdf	44	/----- Magic numbers -----------------------------------------------------/
	45
	46	#define CTOK_EOF (-1)
	47	#define CTOK_WORD 256
	48
e82f7154	49	/----- Functions provided ------------------------------------------------/
e82f7154	50
2234f01d	51	/* --- @conf_undelim@ --- *
e73034b0	52	*
2234f01d	53	* Arguments: @scanner *sc@ = pointer to scanner definition
2234f01d	54	* @const char d, dd@ = pointer to characters to escape
e73034b0	55	*
	56	* Returns: ---
	57	*
	58	* Use: Modifies the tokenizer. Characters in the first list will
	59	* always be considered to begin a word. Characters in the
	60	* second list will always be allowed to continue a word.
	61	*/
	62
2234f01d	63	extern void conf_undelim(scanner /sc*/,
2234f01d	64	const char /d/, const char /dd/);
e73034b0	65
61e3dbdf	66	/* --- @token@ --- *
	67	*
	68	* Arguments: @scanner *sc@ = pointer to scanner definition
	69	*
	70	* Returns: Type of token scanned.
	71	*
	72	* Use: Reads the next token from the character scanner.
	73	*/
	74
	75	extern int token(scanner /sc*/);
	76
	77	/* --- @error@ --- *
	78	*
	79	* Arguments: @scanner *sc@ = pointer to scanner definition
	80	* @const char *msg@ = message skeleton string
	81	* @...@ = extra arguments for the skeleton
	82	*
	83	* Returns: Doesn't
	84	*
	85	* Use: Reports an error at the current scanner location.
	86	*/
	87
	88	extern void error(scanner /sc/, const char /msg/, ...);
	89
c36e735a	90	/* --- @pushback@ --- *
	91	*
	92	* Arguments: @scanner *sc@ = pointer to scanner definition
	93	*
	94	* Returns: ---
	95	*
	96	* Use: Pushes the current token back. This is normally a precursor
	97	* to pushing a new scanner source.
	98	*/
	99
	100	extern void pushback(scanner /sc*/);
	101
61e3dbdf	102	/* --- @conf_enum@ --- *
	103	*
	104	* Arguments: @scanner *sc@ = pointer to a scanner object
	105	* @const char *list@ = comma-separated things to allow
	106	* @unsigned @f = flags for the search
	107	* @const char *err@ = error message if not found
	108	*
	109	* Returns: Index into list, zero-based, or @-1@.
	110	*
	111	* Use: Checks whether the current token is a string which matches
82793759	112	* one of the comma-separated items given. The return value is
	113	* the index (zero-based) of the matched string in the list.
	114	*
	115	* The flags control the behaviour if no exact match is found.
	116	* If @ENUM_ABBREV@ is set, and the current token is a left
	117	* substring of exactly one of the possibilities, then that one
	118	* is chosen. If @ENUM_NONE@ is set, the value @-1@ is
	119	* returned; otherwise an error is reported and the program is
	120	* terminated.
61e3dbdf	121	*/
	122
	123	#define ENUM_ABBREV 1u
	124	#define ENUM_NONE 2u
	125
	126	extern int conf_enum(scanner /sc/, const char /list/,
	127	unsigned /flags/, const char /err*/);
	128
	129	/* --- @conf_prefix@ --- *
	130	*
	131	* Arguments: @scanner *sc@ = pointer to a scanner object
	132	* @const char *p@ = pointer to prefix string to check
	133	*
	134	* Returns: Nonzero if the prefix matches.
	135	*
	136	* Use: If the current token is a word matching the given prefix
	137	* string, then it and an optional `.' character are removed and
	138	* a nonzero result is returned. Otherwise the current token is
	139	* left as it is, and zero is returned.
	140	*
	141	* Typical options parsing code would remove an expected prefix,
	142	* scan an option anyway (since qualifying prefixes are
	143	* optional) and if a match is found, claim the option. If no
	144	* match is found, and a prefix was stripped, then an error
	145	* should be reported.
	146	*/
	147
	148	extern int conf_prefix(scanner /sc/, const char /p/);
	149
022008ac	150	/* --- @CONF_BEGIN@, @CONF_END@ --- *
61e3dbdf	151	*
	152	* Arguments: @sc@ = scanner to read from
	153	* @prefix@ = prefix to scan for
	154	* @desc@ = description of what we're parsing
	155	*
022008ac	156	* Use: Bracket an options parsing routine. The current token is
	157	* checked to see whether it matches the prefix. If so, it is
	158	* removed and the following token examined. If that's a `.'
	159	* then it's removed. If it's a `{' then the enclosed
	160	* option-parsing code is executed in a loop until a matching
	161	* '}' is found. If the options parser doesn't accept an
	162	* option, the behaviour is dependent on whether a prefix was
	163	* seen: if so, an error is reported; otherwse a zero return is
	164	* made.
61e3dbdf	165	*/
	166
	167	#define CS_PLAIN 0
	168	#define CS_PREFIX 1
	169	#define CS_BRACE 2
	170	#define CS_UNKNOWN 3
	171
	172	#define CONF_BEGIN(sc, prefix, desc) do { \
	173	scanner *_conf_sc = (sc); \
	174	const char *_conf_desc = (desc); \
	175	int _conf_state = CS_PLAIN; \
022008ac	176	\
	177	/* --- Read the initial prefix --- */ \
	178	\
61e3dbdf	179	if (_conf_sc->t == CTOK_WORD && \
	180	strcmp(_conf_sc->d.buf, (prefix)) == 0) { \
	181	token(_conf_sc); \
	182	_conf_state = CS_PREFIX; \
	183	if (_conf_sc->t == '.') \
	184	token(_conf_sc); \
	185	else if (_conf_sc->t == '{') { \
	186	token(_conf_sc); \
	187	_conf_state = CS_BRACE; \
	188	} \
	189	} \
022008ac	190	\
	191	/* --- Ensure the next token is a word --- */ \
	192	\
61e3dbdf	193	if (_conf_sc->t != CTOK_WORD) \
	194	error(_conf_sc, "parse error, expected option keyword"); \
	195	do {
	196
61e3dbdf	197	#define CONF_END \
022008ac	198	\
	199	/* --- Reject an option --- * \
	200	* \
	201	* We could get here as a result of an explicit @CONF_REJECT@ or \
	202	* because the option wasn't accepted. \
	203	*/ \
	204	\
0ac54f22	205	goto _conf_reject; \
61e3dbdf	206	_conf_reject: \
	207	if (_conf_state == CS_PLAIN) \
	208	_conf_state = CS_UNKNOWN; \
	209	else { \
	210	error(_conf_sc, "unknown %s option `%s'", \
	211	_conf_desc, _conf_sc->d.buf); \
	212	} \
022008ac	213	\
	214	/* --- Accept an option --- * \
	215	* \
	216	* It's safe to drop through from above. Either an error will have \
	217	* been reported, or the state is not @CS_BRACE@. \
	218	*/ \
	219	\
61e3dbdf	220	_conf_accept: \
	221	if (_conf_state == CS_BRACE && _conf_sc->t == ';') \
	222	token(_conf_sc); \
	223	} while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD); \
022008ac	224	\
	225	/* --- Check for a closing brace --- */ \
	226	\
61e3dbdf	227	if (_conf_state == CS_BRACE) { \
	228	if (_conf_sc->t == '}') \
	229	token(_conf_sc); \
	230	else \
	231	error(_conf_sc, "parse error, expected `}'"); \
	232	} \
022008ac	233	\
	234	/* --- Return an appropriate value --- */ \
	235	\
61e3dbdf	236	return (_conf_state != CS_UNKNOWN); \
	237	} while (0)
	238
022008ac	239	/* --- @CONF_ACCEPT@, @CONF_REJECT@ --- *
	240	*
	241	* Arguments: ---
	242	*
	243	* Use: Within an options parser (between @CONF_BEGIN@ and
	244	* @CONF_END@), accept or reject an option.
	245	*/
	246
	247	#define CONF_ACCEPT goto _conf_accept
	248	#define CONF_REJECT goto _conf_reject
	249
	250	/* --- @CONF_QUAL@ --- *
	251	*
	252	* Arguments: ---
	253	*
	254	* Use: Evaluates to a nonzero value if the current option is
	255	* qualified. This can be used to decide whether abbreviations
	256	* for options should be accepted.
	257	*/
	258
	259	#define CONF_QUAL (_conf_state != CS_PLAIN)
	260
61e3dbdf	261	/* --- @conf_name@ --- *
	262	*
	263	* Arguments: @scanner *sc@ = pointer to scanner
	264	* @char delim@ = delimiter character to look for
	265	* @dstr *d@ = pointer to dynamic string for output
	266	*
	267	* Returns: ---
	268	*
	269	* Use: Reads in a compound name consisting of words separated by
	270	* delimiters. Leading and trailing delimiters are permitted,
	271	* although they'll probably cause confusion if used. The name
	272	* may be enclosed in square brackets if that helps at all.
	273	*
	274	* Examples of compound names are filenames (delimited by `/')
	275	* and IP addresses (delimited by `.').
	276	*/
	277
	278	extern void conf_name(scanner /sc/, char /delim/, dstr /d/);
	279
e82f7154	280	/----- That's all, folks -------------------------------------------------/
	281
	282	#ifdef __cplusplus
	283	}
	284	#endif
	285
	286	#endif