Import regex from OpenBSD
Change-Id: I7ad7d907ef65e4e345f94777d730813b1270a612
diff --git a/libc/regex/regexec.c b/libc/regex/regexec.c
new file mode 100644
index 0000000..7b3bfc7
--- /dev/null
+++ b/libc/regex/regexec.c
@@ -0,0 +1,160 @@
+/* $OpenBSD: regexec.c,v 1.11 2005/08/05 13:03:00 espie Exp $ */
+/*-
+ * Copyright (c) 1992, 1993, 1994 Henry Spencer.
+ * Copyright (c) 1992, 1993, 1994
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Henry Spencer.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#)regexec.c 8.3 (Berkeley) 3/20/94
+ */
+
+/*
+ * the outer shell of regexec()
+ *
+ * This file includes engine.c *twice*, after muchos fiddling with the
+ * macros that code uses. This lets the same code operate on two different
+ * representations for state sets.
+ */
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <ctype.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+
+/* macros for manipulating states, small version */
+#define states long
+#define states1 states /* for later use in regexec() decision */
+#define CLEAR(v) ((v) = 0)
+#define SET0(v, n) ((v) &= ~((unsigned long)1 << (n)))
+#define SET1(v, n) ((v) |= (unsigned long)1 << (n))
+#define ISSET(v, n) (((v) & ((unsigned long)1 << (n))) != 0)
+#define ASSIGN(d, s) ((d) = (s))
+#define EQ(a, b) ((a) == (b))
+#define STATEVARS long dummy /* dummy version */
+#define STATESETUP(m, n) /* nothing */
+#define STATETEARDOWN(m) /* nothing */
+#define SETUP(v) ((v) = 0)
+#define onestate long
+#define INIT(o, n) ((o) = (unsigned long)1 << (n))
+#define INC(o) ((o) <<= 1)
+#define ISSTATEIN(v, o) (((v) & (o)) != 0)
+/* some abbreviations; note that some of these know variable names! */
+/* do "if I'm here, I can also be there" etc without branches */
+#define FWD(dst, src, n) ((dst) |= ((unsigned long)(src)&(here)) << (n))
+#define BACK(dst, src, n) ((dst) |= ((unsigned long)(src)&(here)) >> (n))
+#define ISSETBACK(v, n) (((v) & ((unsigned long)here >> (n))) != 0)
+/* function names */
+#define SNAMES /* engine.c looks after details */
+
+#include "engine.c"
+
+/* now undo things */
+#undef states
+#undef CLEAR
+#undef SET0
+#undef SET1
+#undef ISSET
+#undef ASSIGN
+#undef EQ
+#undef STATEVARS
+#undef STATESETUP
+#undef STATETEARDOWN
+#undef SETUP
+#undef onestate
+#undef INIT
+#undef INC
+#undef ISSTATEIN
+#undef FWD
+#undef BACK
+#undef ISSETBACK
+#undef SNAMES
+
+/* macros for manipulating states, large version */
+#define states char *
+#define CLEAR(v) memset(v, 0, m->g->nstates)
+#define SET0(v, n) ((v)[n] = 0)
+#define SET1(v, n) ((v)[n] = 1)
+#define ISSET(v, n) ((v)[n])
+#define ASSIGN(d, s) memcpy(d, s, m->g->nstates)
+#define EQ(a, b) (memcmp(a, b, m->g->nstates) == 0)
+#define STATEVARS long vn; char *space
+#define STATESETUP(m, nv) { (m)->space = malloc((nv)*(m)->g->nstates); \
+ if ((m)->space == NULL) return(REG_ESPACE); \
+ (m)->vn = 0; }
+#define STATETEARDOWN(m) { free((m)->space); }
+#define SETUP(v) ((v) = &m->space[m->vn++ * m->g->nstates])
+#define onestate long
+#define INIT(o, n) ((o) = (n))
+#define INC(o) ((o)++)
+#define ISSTATEIN(v, o) ((v)[o])
+/* some abbreviations; note that some of these know variable names! */
+/* do "if I'm here, I can also be there" etc without branches */
+#define FWD(dst, src, n) ((dst)[here+(n)] |= (src)[here])
+#define BACK(dst, src, n) ((dst)[here-(n)] |= (src)[here])
+#define ISSETBACK(v, n) ((v)[here - (n)])
+/* function names */
+#define LNAMES /* flag */
+
+#include "engine.c"
+
+/*
+ - regexec - interface for matching
+ *
+ * We put this here so we can exploit knowledge of the state representation
+ * when choosing which matcher to call. Also, by this point the matchers
+ * have been prototyped.
+ */
+int /* 0 success, REG_NOMATCH failure */
+regexec(const regex_t *preg, const char *string, size_t nmatch,
+ regmatch_t pmatch[], int eflags)
+{
+ struct re_guts *g = preg->re_g;
+#ifdef REDEBUG
+# define GOODFLAGS(f) (f)
+#else
+# define GOODFLAGS(f) ((f)&(REG_NOTBOL|REG_NOTEOL|REG_STARTEND))
+#endif
+
+ if (preg->re_magic != MAGIC1 || g->magic != MAGIC2)
+ return(REG_BADPAT);
+ assert(!(g->iflags&BAD));
+ if (g->iflags&BAD) /* backstop for no-debug case */
+ return(REG_BADPAT);
+ eflags = GOODFLAGS(eflags);
+
+ if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags®_LARGE))
+ return(smatcher(g, (char *)string, nmatch, pmatch, eflags));
+ else
+ return(lmatcher(g, (char *)string, nmatch, pmatch, eflags));
+}