re.c - master - niceSOFT/gawk

re.c
938 строк22 KB
Arnold D. Robbins
Use nl_langinfo() for UTF-8 check.
25 мар 2026, 18:05
25 мар 2026, 18:05ee8aba5
/*
 * re.c - compile regular expressions.
 */

/*
 * Copyright (C) 1991-2019, 2021-2026
 * the Free Software Foundation, Inc.
 *
 * This file is part of GAWK, the GNU implementation of the
 * AWK Programming Language.
 *
 * GAWK 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 3 of the License, or
 * (at your option) any later version.
 *
 * GAWK 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "awk.h"

#include "localeinfo.h"

static reg_syntax_t syn;
static void check_bracket_exp(char *s, size_t len);
static const char *get_minrx_regerror(int errcode, Regexp *rp);

static struct localeinfo localeinfo;

/* make_regexp --- generate compiled regular expressions */

Regexp *
make_regexp(char *s, size_t len, bool ignorecase, bool dfa, bool canfatal)
{
	static char metas[] = ".*+(){}[]|?^$\\";
	Regexp *rp;
	const char *rerr;
	const char *src = s;
	static char *buf = NULL;
	static size_t buflen;
	const char *end = s + len;
	char *dest;
	int c;
	static bool first = true;
	static bool no_dfa = false;
	int i;
	static struct dfa* dfaregs[2] = { NULL, NULL };
	static bool nul_warned = false;
	char save;
	size_t savelen;

	/*
	 * 10/2025: We used to have:
	 *
	 *	assert(s[len] == '\0');
	 *
	 * here, but data can come in, by way of re_update(), that is from $0 or
	 * elsewhere where there is no final '\0'. So we save and restore
	 * the character at s[len] and force a '\0' into position there.
	 * It needs to be a C string for use in error messages.
	 */
	savelen = len;
	save = s[len];
	s[len] = '\0';

	if (do_lint && ! nul_warned && memchr(s, '\0', len) != NULL) {
		nul_warned = true;
		lintwarn(_("behavior of matching a regexp containing NUL characters is not defined by POSIX"));
	}

	mbstate_t mbs;

	memset(&mbs, 0, sizeof(mbstate_t)); /* Initialize.  */

	if (first) {
		/* for debugging and testing */
		no_dfa = (getenv("GAWK_NO_DFA") != NULL);
		/* don't set first to false here, we do it below */
	}

	/* always check */
	check_bracket_exp((char *) s, len);

	/* Handle escaped characters first. */

	/*
	 * Build a copy of the string (in buf) with the
	 * escaped characters translated, and generate the regex
	 * from that.
	 */
	if (buf == NULL) {
		emalloc(buf, char *, len + 1);
		buflen = len;
	} else if (len > buflen) {
		erealloc(buf, char *, len + 1);
		buflen = len;
	}
	dest = buf;

	while (src < end) {
		/*
		 * Keep multibyte characters together. This avoids
		 * problems if a subsequent byte of a multibyte
		 * character happens to be a backslash.
		 */
		if (gawk_mb_cur_max > 1) {
			size_t mblen = mbrlen(src, end - src, &mbs);

			/*
			 * Incomplete (-2), invalid (-1), and
			 * null (0) characters are excluded here.
			 * They are read as a sequence of bytes.
			 */
			if (mblen > 1 && mblen < (size_t) -2) {
				size_t i;

				for (i = 0; i < mblen; i++)
					*dest++ = *src++;
				continue;
			}
		}

		/*
		 * From here *src is a single byte character.
		 */
		if (*src != '\\') {
			*dest++ = *src++;
			continue;
		}

		/* Escape sequence */
		c = *++src;
		switch (c) {
		case '\0':	/* \\ before \0, either dynamic data or real end of string */
			if (src >= s + len)
				*dest++ = '\\';	// at end of string, will fatal below
			else
				fatal(_("invalid NUL byte in dynamic regexp"));
			break;
		case 'a':
		case 'b':
		case 'f':
		case 'n':
		case 'r':
		case 't':
		case 'v':
		case 'x':
		case 'u':
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		{
			const char *result;
			size_t nbytes;
			enum escape_results ret;

			ret = parse_escape(& src, & result, & nbytes);
			switch (ret) {
			case ESCAPE_OK:
				/*
				 * Unix awk treats octal (and hex?) chars
				 * literally in re's, so escape regexp
				 * metacharacters.
				 */
				if (nbytes == 1
				    && do_traditional
				    && ! do_posix
				    && (isdigit(c) || c == 'x' || c == 'u')
				    && strchr(metas, *result) != NULL)
					*dest++ = '\\';

				if (nbytes == 1
				    && do_lint
				    && ! nul_warned
				    && *result == '\0') {
					nul_warned = true;
					lintwarn(_("behavior of matching a regexp containing NUL characters is not defined by POSIX"));
				}

				/* nbytes is now > 0 */
				while (nbytes--)
					*dest++ = *result++;
				break;
			case ESCAPE_CONV_ERR:
				/*
				 * Invalid code points produce '?' (0x3F).
				 * These are quoted so that they're taken
				 * literally. Unlike \u3F, a metachar.
				 */
				*dest++ = '\\';
				*dest++ = '?';
				break;
			default:
				/*
				 * The outer switch handles terminal
				 * backslashes and line continuations.
				 * parse_escape should never see them
				 * and therefore it should never return
				 * ESCAPE_TERM_BACKSLASH nor
				 * ESCAPE_LINE_CONTINUATION.
				 *
				 * This also catches unknown values.
				 */
				cant_happen("received bad result %d from parse_escape(), nbytes = %zu",
						(int) ret, nbytes);
			}
			break;
		}
		case '8':
		case '9':	/* a\9b not valid */
			*dest++ = c;
			src++;
		{
			static bool warned[2];

			if (! warned[c - '8']) {
				warning(_("regexp escape sequence `\\%c' treated as plain `%c'"), c, c);
				warned[c - '8'] = true;
			}
		}
			break;
		case 'y':	/* normally \b */
			/* gnu regex op */
			if (! do_traditional) {
				*dest++ = '\\';
				*dest++ = 'b';
				src++;
				break;
			}
			/* else, fall through */
		default:
		  {
			static const char *ok_to_escape = NULL;

			/*
			 * The posix and traditional flags do not change
			 * once the awk program is running. Therefore,
			 * neither does ok_to_escape. --posix implies
			 * --traditional, so only need to check do_traditional.
			 */
			if (ok_to_escape == NULL) {
				if (do_traditional)
					ok_to_escape = "{}()|*+?.^$\\[]/-";
				else
					ok_to_escape = "<>`'BywWsS{}()|*+?.^$\\[]/-";
			}

			if (strchr(ok_to_escape, c) == NULL) {
				static bool warned[256];

				if (! warned[c & 0xFF]) {
					warning(_("regexp escape sequence `\\%c' is not a known regexp operator"), c);
					warned[c & 0xFF] = true;
				}
			}
			*dest++ = '\\';
			*dest++ = (char) c;
			src++;
			break;
		  }
		} /* switch */
	} /* while */

	*dest = '\0';
	len = dest - buf;

	ezalloc(rp, Regexp *, sizeof(*rp));

	if (use_gnu_matchers) {
		rp->pat.allocated = 0;	/* regex will allocate the buffer */
		emalloc(rp->pat.fastmap, char *, 256);

		/*
		 * Lo these many years ago, had I known what a P.I.T.A. IGNORECASE
		 * was going to turn out to be, I wouldn't have bothered with it.
		 *
		 * In the case where we have a multibyte character set, we have no
		 * choice but to use RE_ICASE, since the casetable is for single-byte
		 * character sets only.
		 *
		 * On the other hand, if we do have a single-byte character set,
		 * using the casetable should give a performance improvement, since
		 * it's computed only once, not each time a regex is compiled.  We
		 * also think it's probably better for portability.  See the
		 * discussion by the definition of casetable[] in eval.c.
		 */

		ignorecase = !! ignorecase;	/* force to 1 or 0 */
		if (ignorecase) {
			if (gawk_mb_cur_max > 1) {
				syn |= RE_ICASE;
				rp->pat.translate = NULL;
			} else {
				syn &= ~RE_ICASE;
				rp->pat.translate = (RE_TRANSLATE_TYPE) casetable;
			}
		} else {
			rp->pat.translate = NULL;
			syn &= ~RE_ICASE;
		}

		/* initialize dfas to hold syntax */
		if (first) {
			first = false;
			dfaregs[0] = dfaalloc();
			dfaregs[1] = dfaalloc();
			dfasyntax(dfaregs[0], & localeinfo, syn, DFA_ANCHOR);
			dfasyntax(dfaregs[1], & localeinfo, syn | RE_ICASE, DFA_ANCHOR);
		}

		re_set_syntax(syn);

		if ((rerr = re_compile_pattern(buf, len, &(rp->pat))) != NULL) {
			refree(rp);
			if (! canfatal) {
				/* rerr already gettextized inside regex routines */
				error("%s: /%s/", rerr, s);
				return NULL;
			}
			fatal("invalid regexp: %s: /%s/", rerr, s);
		}

		/* gack. this must be done *after* re_compile_pattern */
		rp->pat.newline_anchor = false; /* don't get \n in middle of string */
		if (dfa && ! no_dfa) {
			rp->dfareg = dfaalloc();
			dfacopysyntax(rp->dfareg, dfaregs[ignorecase]);
			dfacomp(buf, len, rp->dfareg, true);
		} else
			rp->dfareg = NULL;
	} else {
		int flags = MINRX_REG_EXTENDED | MINRX_REG_BRACK_ESCAPE |
				MINRX_REG_BRACE_COMPAT | MINRX_REG_NATIVE1B;
		int ret;

		if (ignorecase)
			flags |= MINRX_REG_ICASE;

		if (syn == RE_SYNTAX_GNU_AWK)
			flags |= (MINRX_REG_EXTENSIONS_GNU | MINRX_REG_EXTENSIONS_BSD);
		else if (syn == RE_SYNTAX_AWK)
			flags |= MINRX_REG_MINDISABLE;

		if ((ret = minrx_regncomp(& rp->mre_pat, len, buf, flags)) != 0) {
			/* rerr already gettextized inside regex routines */
			rerr = get_minrx_regerror(ret, rp);

			refree(rp);
			if (! canfatal) {
				error("%s: /%s/", rerr, s);
				s[savelen] = save;
				return NULL;
			}
			fatal("invalid regexp: %s: /%s/", rerr, s);
		}

		// Allocate re_nsub + 1, since 0 is the whole thing and 1-N
		// are for actual parenthesized subexpressions.
		emalloc(rp->mre_regs, minrx_regmatch_t *,
			(rp->mre_pat.re_nsub + 1) * sizeof(minrx_regmatch_t));
	}

	/* Additional flags that help with RS as regexp. */
	for (i = 0; i < len; i++) {
		if (strchr(metas, buf[i]) != NULL) {
			rp->has_meta = true;
			break;
		}
	}

	for (i = len - 1; i >= 0; i--) {
		if (strchr("\\*+|?{}", buf[i]) != NULL) {
			rp->maybe_long = true;
			break;
		}
	}

	s[savelen] = save;
	return rp;
}

/* research --- do a regexp search. use dfa if possible */

int
research(Regexp *rp, char *str, int start,
	 size_t len, int flags)
{
	const char *ret = str;
	bool try_backref = false;
	bool need_start;
	bool no_bol;
	bool need_sub;
	int res;
	int minrx_flags = 0;

	need_start = ((flags & RE_NEED_START) != 0);
	no_bol = ((flags & RE_NO_BOL) != 0);
	need_sub = ((flags & RE_NEED_SUB) != 0);

	if (use_gnu_matchers) {
		if (no_bol)
			rp->pat.not_bol = 1;

		/*
		 * Always do dfa search if can; if it fails, then even if
		 * need_start is true, we won't bother with the regex search.
		 *
		 * The dfa matcher doesn't have a no_bol flag, so don't bother
		 * trying it in that case.
		 *
		 * 7/2008: Skip the dfa matcher if need_start. The dfa matcher
		 * has bugs in certain multibyte cases and it's too difficult
		 * to try to special case things.
		 * 7/2017: Apparently there are some cases where DFA gets
		 * stuck, even in the C locale, so we use dfa only if not need_start.
		 *
		 * Should that issue ever get resolved, note this comment:
		 *
		 * 7/2016: The dfa matcher can't handle a case where searching
		 * starts in the middle of a string, so don't bother trying it
		 * in that case.
		 *	if (rp->dfa && ! no_bol && start == 0) ...
		 */
		if (rp->dfareg != NULL && ! no_bol && ! need_start) {
			struct dfa *superset = dfasuperset(rp->dfareg);
			if (superset)
				ret = dfaexec(superset, str+start, str+start+len,
								true, NULL, NULL);

			if (ret && (! need_start
					|| (! superset && dfaisfast(rp->dfareg))))
				ret = dfaexec(rp->dfareg, str+start, str+start+len,
							true, NULL, &try_backref);
		}

		if (ret) {
			if (   rp->dfareg == NULL
				|| start != 0
				|| no_bol
				|| need_start
				|| try_backref) {
				/*
				 * Passing NULL as last arg speeds up search for cases
				 * where we don't need the start/end info.
				 */
				res = re_search(&(rp->pat), str, start+len,
					start, len, need_start ? &(rp->regs) : NULL);
			} else
				res = 1;
		} else
			res = -1;

		rp->pat.not_bol = 0;
	} else {
		int match_count = 0;

		if (need_sub)
			match_count = rp->mre_pat.re_nsub + 1;
		else if (need_start)
			match_count = 1;

		if (no_bol)
			minrx_flags |= MINRX_REG_NOTBOL;

		memset(rp->mre_regs, 0, (rp->mre_pat.re_nsub + 1) * sizeof(minrx_regmatch_t));

		if (start > 0) {
			rp->mre_regs[0].rm_eo = start;
			minrx_flags |= MINRX_REG_RESUME;
		}

		res = minrx_regnexec(&(rp->mre_pat),
				len, str,
				match_count,
				rp->mre_regs,
				minrx_flags);
		if (res == 0)
			res = rp->mre_regs[0].rm_so;
		else
			res = -1;
	}

	return res;
}

/* refree --- free up the dynamic memory used by a compiled regexp */

void
refree(Regexp *rp)
{
	if (rp == NULL)
		return;
	rp->pat.translate = NULL;
	regfree(& rp->pat);
	if (rp->regs.start)
		free(rp->regs.start);
	if (rp->regs.end)
		free(rp->regs.end);
	if (rp->dfareg != NULL) {
		dfafree(rp->dfareg);
		free(rp->dfareg);
	}
	efree(rp->mre_regs);
	minrx_regfree(& rp->mre_pat);
	efree(rp);
}

/* get_minrx_regerror --- return the error as a string, hide ugly POSIX interface */

static const char *
get_minrx_regerror(int errcode, Regexp *rp)
{
	static char *buf;
	static size_t bufsize;
	static int count;

	if (buf == NULL) {	// first time through, allocate the buffer
		bufsize = 100;
		emalloc(buf, char *, bufsize);
	}

	while ((count = minrx_regerror(errcode, & rp->mre_pat, buf, bufsize)) > bufsize) {
		bufsize *= 2;
		erealloc(buf, char *, bufsize);
	}

	return buf;
}

/* dfaerror --- print an error message for the dfa routines */

void
dfaerror(const char *s)
{
	fatal("%s", s);
	exit(EXIT_FATAL);
}

/* re_cache_get --- populate regexp cache if empty */

static inline Regexp *
re_cache_get(NODE *t)
{
	if (t->re_reg[IGNORECASE] == NULL)
		t->re_reg[IGNORECASE] = make_regexp(t->re_exp->stptr, t->re_exp->stlen, IGNORECASE, t->re_cnt, true);
	return t->re_reg[IGNORECASE];
}

/* re_update --- recompile a dynamic regexp */

Regexp *
re_update(NODE *t)
{
	NODE *t1;

	if (t->type == Node_val && (t->flags & REGEX) != 0)
		return re_cache_get(t->typed_re);

	if ((t->re_flags & CONSTANT) != 0) {
		/* it's a constant, so just return it as is */
		assert(t->type == Node_regex);
		return re_cache_get(t);
	}
	t1 = t->re_exp;
	if (t->re_text != NULL) {
		/* if contents haven't changed, just return it */
		if (cmp_nodes(t->re_text, t1, true) == 0)
			return re_cache_get(t);
		/* things changed, fall through to recompile */
		unref(t->re_text);
	}
	/* get fresh copy of the text of the regexp */
	t->re_text = dupnode(t1);

	/* text changed */

	/* free old */
	if (t->re_reg[0] != NULL) {
		refree(t->re_reg[0]);
		t->re_reg[0] = NULL;
	}
	if (t->re_reg[1] != NULL) {
		refree(t->re_reg[1]);
		t->re_reg[1] = NULL;
	}
	if (t->re_cnt > 0 && ++t->re_cnt > 10)
		/*
		 * The regex appears to update frequently, so disable DFA
		 * matching (which trades off expensive upfront compilation
		 * overhead for faster subsequent matching).
		 */
		t->re_cnt = 0;
	if (t->re_text == NULL) {
		/* reset regexp text if needed */
		t1 = t->re_exp;
		unref(t->re_text);
		t->re_text = dupnode(t1);
	}
	return re_cache_get(t);
}

/* resetup --- choose what kind of regexps we match */

void
resetup()
{
	// init localeinfo for dfa
	init_localeinfo(& localeinfo);

	/*
	 * Syntax bits: _that_ is yet another mind trip.  Recreational drugs
	 * are helpful for recovering from the experience.
	 *
	 *	Aharon Robbins <arnold@skeeve.com>
	 *	Sun, 21 Oct 2007 23:55:33 +0200
	 */

	/*
	 * Interval expressions are now on by default, as POSIX is
	 * wide-spread enough that people want it.
	 *
	 * 2/2022: BWK awk has supported interval expressions since
	 * March 2019, with an important fix added in Januay 2020.
	 * So we add that support even for --traditional. It's easier to
	 * do it here than to try to get the GLIBC / GNULIB folks to change
	 * the definition of RE_SYNTAX_AWK, which likely would cause
	 * binary compatibility issues.
	 */
	if (do_posix)
		syn = RE_SYNTAX_POSIX_AWK;	/* strict POSIX re's */
	else if (do_traditional)
		syn = RE_SYNTAX_AWK |		/* traditional Unix awk re's */
			RE_INTERVALS | RE_INVALID_INTERVAL_ORD | RE_NO_BK_BRACES;
	else
		syn = RE_SYNTAX_GNU_AWK;	/* POSIX re's + GNU ops */

	(void) re_set_syntax(syn);
}

/* using_utf8 --- are we using utf8 */

bool
using_utf8(void)
{
	const char *locale = nl_langinfo(CODESET);
	if (locale == NULL)
		return false;

	return strcmp(locale, "UTF-8") == 0;
}

/* reisstring --- return true if the RE match is a simple string match */

int
reisstring(const char *text, size_t len, Regexp *re, const char *buf)
{
	int res;
	const char *matched;

	/* simple checking for meta characters in re */
	if (re->has_meta)
		return false;	/* give up early, can't be string match */

	/* make accessable to gdb */
	matched = &buf[RESTART(re, buf)];

	res = (memcmp(text, matched, len) == 0);

	return res;
}

/* reflags2str --- make a regex flags value readable */

const char *
reflags2str(int flagval)
{
	static const struct flagtab values[] = {
		{ RE_BACKSLASH_ESCAPE_IN_LISTS, "RE_BACKSLASH_ESCAPE_IN_LISTS" },
		{ RE_BK_PLUS_QM, "RE_BK_PLUS_QM" },
		{ RE_CHAR_CLASSES, "RE_CHAR_CLASSES" },
		{ RE_CONTEXT_INDEP_ANCHORS, "RE_CONTEXT_INDEP_ANCHORS" },
		{ RE_CONTEXT_INDEP_OPS, "RE_CONTEXT_INDEP_OPS" },
		{ RE_CONTEXT_INVALID_OPS, "RE_CONTEXT_INVALID_OPS" },
		{ RE_DOT_NEWLINE, "RE_DOT_NEWLINE" },
		{ RE_DOT_NOT_NULL, "RE_DOT_NOT_NULL" },
		{ RE_HAT_LISTS_NOT_NEWLINE, "RE_HAT_LISTS_NOT_NEWLINE" },
		{ RE_INTERVALS, "RE_INTERVALS" },
		{ RE_LIMITED_OPS, "RE_LIMITED_OPS" },
		{ RE_NEWLINE_ALT, "RE_NEWLINE_ALT" },
		{ RE_NO_BK_BRACES, "RE_NO_BK_BRACES" },
		{ RE_NO_BK_PARENS, "RE_NO_BK_PARENS" },
		{ RE_NO_BK_REFS, "RE_NO_BK_REFS" },
		{ RE_NO_BK_VBAR, "RE_NO_BK_VBAR" },
		{ RE_NO_EMPTY_RANGES, "RE_NO_EMPTY_RANGES" },
		{ RE_UNMATCHED_RIGHT_PAREN_ORD, "RE_UNMATCHED_RIGHT_PAREN_ORD" },
		{ RE_NO_POSIX_BACKTRACKING, "RE_NO_POSIX_BACKTRACKING" },
		{ RE_NO_GNU_OPS, "RE_NO_GNU_OPS" },
		{ RE_DEBUG, "RE_DEBUG" },	// not actually used in the code anymore, :-(
		{ RE_INVALID_INTERVAL_ORD, "RE_INVALID_INTERVAL_ORD" },
		{ RE_ICASE, "RE_ICASE" },
		{ RE_CARET_ANCHORS_HERE, "RE_CARET_ANCHORS_HERE" },
		{ RE_CONTEXT_INVALID_DUP, "RE_CONTEXT_INVALID_DUP" },
		{ RE_NO_SUB, "RE_NO_SUB" },
		{ 0,	NULL },
	};

	if (flagval == RE_SYNTAX_EMACS) /* == 0 */
		return "RE_SYNTAX_EMACS";

	return genflags2str(flagval, values);
}

/*
 * dfawarn() is called by the dfa routines whenever a regex is compiled
 * must supply a dfawarn.
 */

void
dfawarn(const char *dfa_warning)
{
	/*
	 * This routine does nothing, since gawk does its own
	 * (better) check for bad [[:foo:]] syntax.
	 */
}

/* check_bracket_exp --- look for /[:space:]/ that should be /[[:space:]]/ */

static void
check_bracket_exp(char *s, size_t length)
{
	static struct reclass {
		const char *name;
		size_t len;
		bool warned;
	} classes[] = {
		/*
		 * Ordered by what we hope is frequency,
		 * since it's linear searched.
		 */
		{ "[:alpha:]", 9, false },
		{ "[:digit:]", 9, false },
		{ "[:alnum:]", 9, false },
		{ "[:upper:]", 9, false },
		{ "[:lower:]", 9, false },
		{ "[:space:]", 9, false },
		{ "[:xdigit:]", 10, false },
		{ "[:punct:]", 9, false },
		{ "[:print:]", 9, false },
		{ "[:graph:]", 9, false },
		{ "[:cntrl:]", 9, false },
		{ "[:blank:]", 9, false },
		{ NULL, 0 }
	};
	int i;
	bool found = false;
	char save;
	char *sp, *sp2, *end;
	int len;
	int count = 0;

	if (length == 0)
		return;

	end = s + length;
	save = s[length];
	s[length] = '\0';
	sp = s;

again:
	sp = sp2 = (char *) memchr(sp, '[', (end - sp));
	if (sp == NULL)
		goto done;

	sp++;
	count = 1;
	/*
	 * Skip over the following:
	 * [^]...]
	 * [\]...]
	 * []...]
	 */
	if (*sp == '^')
		sp++;
	if (*sp == '\\')
		sp += 2;
	else if (*sp == ']')
		sp++;

	for (; sp < end && *sp != '\0'; sp++) {
		if (*sp == '[')
			count++;
		else if (*sp == ']')
			count--;

		if (count == 0) {
			sp++;	/* skip past ']' */
			break;
		}
	}

	if (count > 0) {	/* bad regex, give up */
		goto done;
	}

	/* sp2 has start */

	for (i = 0; classes[i].name != NULL; i++) {
		if (classes[i].warned)
			continue;
		len = classes[i].len;
		if (   len == (sp - sp2)
		    && memcmp(sp2, classes[i].name, len) == 0) {
			found = true;
			break;
		}
	}

	if (found && ! classes[i].warned) {
		warning(_("regexp component `%.*s' should probably be `[%.*s]'"),
				len, sp2, len, sp2);
		classes[i].warned = true;
	}

	if (sp < end) {
		found = false;
		goto again;
	}
done:
	s[length] = save;
}

/* re_restart --- return start of match */

int
re_restart(Regexp *rp, const char *s)
{
	if (use_gnu_matchers)
		return rp->regs.start[0];
	else
		return rp->mre_regs[0].rm_so;
}

/* re_reend --- return end of match */

int
re_reend(Regexp *rp, const char *s)
{
	if (use_gnu_matchers)
		return rp->regs.end[0];
	else
		return rp->mre_regs[0].rm_eo;
}

/* re_resubpatstart --- return start of subpattern match */

int
re_subpatstart(Regexp *rp, const char *s, int n)
{
	if (use_gnu_matchers)
		return rp->regs.start[n];
	else
		return rp->mre_regs[n].rm_so;
}

/* re_resubpatend --- return end of subpattern match */

int
re_subpatend(Regexp *rp, const char *s, int n)
{
	if (use_gnu_matchers)
		return rp->regs.end[n];
	else
		return rp->mre_regs[n].rm_eo;
}

/* re_numsubpats --- return number of subpatterns */

int
re_numsubpats(Regexp *rp, const char *s)
{
	if (use_gnu_matchers)
		return rp->regs.num_regs;
	else
		return rp->mre_pat.re_nsub + 1;
}

/* minrxcompflags2str --- convert minrx compilation flags to a string */

const char *
minrxcompflags2str(int flagval)
{
	static const struct flagtab values[] = {
		{ MINRX_REG_EXTENDED, "MINRX_REG_EXTENDED" },
		{ MINRX_REG_ICASE, "MINRX_REG_ICASE" },
		{ MINRX_REG_MINIMAL, "MINRX_REG_MINIMAL" },
		{ MINRX_REG_NEWLINE, "MINRX_REG_NEWLINE" },
		{ MINRX_REG_NOSUB, "MINRX_REG_NOSUB" },
		{ MINRX_REG_BRACE_COMPAT, "MINRX_REG_BRACE_COMPAT" },
		{ MINRX_REG_BRACK_ESCAPE, "MINRX_REG_BRACK_ESCAPE" },
		{ MINRX_REG_EXTENSIONS_BSD, "MINRX_REG_EXTENSIONS_BSD" },
		{ MINRX_REG_EXTENSIONS_GNU, "MINRX_REG_EXTENSIONS_GNU" },
		{ MINRX_REG_NATIVE1B, "MINRX_REG_NATIVE1B" },
		{ MINRX_REG_MINDISABLE, "MINRX_REG_MINDISABLE" },
		{ 0,	NULL },
	};

	return genflags2str(flagval, values);
}

/* minrxexecflags2str --- convert minrx execution flags to a string */

const char *
minrxexecflags2str(int flagval)
{
	static const struct flagtab values[] = {
		{ MINRX_REG_NOTBOL, "MINRX_REG_NOTBOL" },
		{ MINRX_REG_NOTEOL, "MINRX_REG_NOTEOL" },
		{ MINRX_REG_FIRSTSUB, "MINRX_REG_FIRSTSUB" },
		{ MINRX_REG_NOSUBRESET, "MINRX_REG_NOSUBRESET" },
		{ MINRX_REG_RESUME, "MINRX_REG_RESUME" },
		{ MINRX_REG_NOFIRSTBYTES, "MINRX_REG_NOFIRSTBYTES" },
		{ 0,	NULL },
	};

	return genflags2str(flagval, values);
}