/* -*-c-*-
*
- * $Id: conf.h,v 1.1 1999/07/01 08:56:23 mdw Exp $
+ * $Id: conf.h,v 1.7 2002/02/22 23:42:56 mdw Exp $
*
* Configuration parsing
*
- * (c) 1999 Mark Wooding
+ * (c) 1999 Straylight/Edgeware
*/
/*----- Licensing notice --------------------------------------------------*
/*----- Revision history --------------------------------------------------*
*
* $Log: conf.h,v $
- * Revision 1.1 1999/07/01 08:56:23 mdw
- * Initial revision
+ * Revision 1.7 2002/02/22 23:42:56 mdw
+ * `fw'-specific configuration code moved out. This file might become part
+ * of a library some day.
+ *
+ * Revision 1.6 2002/01/13 14:48:16 mdw
+ * Make delimiters be a property of a scanner. Change the delimiter-
+ * changing functions' names.
+ *
+ * Revision 1.5 1999/10/22 22:46:44 mdw
+ * Improve documentation for conf_enum.
+ *
+ * Revision 1.4 1999/08/19 18:32:48 mdw
+ * Improve lexical analysis. In particular, `chmod' patterns don't have to
+ * be quoted any more.
+ *
+ * Revision 1.3 1999/07/27 18:30:14 mdw
+ * Improve documentation and layout for @CONF_BEGIN@ and friends. Remove
+ * irritating warning about unused label by introducing a spurious `goto'.
+ *
+ * Revision 1.2 1999/07/26 23:28:39 mdw
+ * Major reconstruction work for new design.
+ *
+ * Revision 1.1.1.1 1999/07/01 08:56:23 mdw
+ * Initial revision.
*
*/
/*----- 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_parse@ --- *
+/* --- @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
*
- * Arguments: @void *scp@ = pointer to a scanner structure
+ * 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: Parses a configuration file fragment from the scanner
+ * 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_parse(void */*scp*/);
+extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/);
/*----- That's all, folks -------------------------------------------------*/
~mdw / fwd / blobdiff