X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/e82f7154f65062d9ac8b9677862774498b331058..372a98e2893234a482e59ca32313db1bb86146d7:/conf.h diff --git a/conf.h b/conf.h index e1713ee..5b78b13 100644 --- a/conf.h +++ b/conf.h @@ -1,10 +1,10 @@ /* -*-c-*- * - * $Id: conf.h,v 1.1 1999/07/01 08:56:23 mdw Exp $ + * $Id: conf.h,v 1.5 1999/10/22 22:46:44 mdw Exp $ * * Configuration parsing * - * (c) 1999 Mark Wooding + * (c) 1999 Straylight/Edgeware */ /*----- Licensing notice --------------------------------------------------* @@ -29,8 +29,22 @@ /*----- Revision history --------------------------------------------------* * * $Log: conf.h,v $ - * Revision 1.1 1999/07/01 08:56:23 mdw - * Initial revision + * 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. * */ @@ -43,22 +57,244 @@ /*----- Header files ------------------------------------------------------*/ +#include + #ifndef SCAN_H # include "scan.h" #endif +/*----- Magic numbers -----------------------------------------------------*/ + +#define CTOK_EOF (-1) +#define CTOK_WORD 256 + /*----- Functions provided ------------------------------------------------*/ +/* --- @undelim@ --- * + * + * Arguments: @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 undelim(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*/, ...); + +/* --- @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*/); + /* --- @conf_parse@ --- * * - * Arguments: @void *scp@ = pointer to a scanner structure + * Arguments: @scanner *sc@ = pointer to a scanner structure * * Returns: --- * * Use: Parses a configuration file fragment from the scanner */ -extern void conf_parse(void */*scp*/); +extern void conf_parse(scanner *sc); /*----- That's all, folks -------------------------------------------------*/