Add regular expression matching support, based on OpenBSD regexec()/regcomp()

implementation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80493 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 157 insertions, 0 deletions

diff --git a/lib/Support/regex2.h b/lib/Support/regex2.h
new file mode 100644
index 0000000000..21659c3444
--- /dev/null
+++ b/lib/Support/regex2.h
@@ -0,0 +1,157 @@
+/*-
+ * This code is derived from OpenBSD's libc/regex, original license follows:
+ *
+ * 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.
+ *
+ *	@(#)regex2.h	8.4 (Berkeley) 3/20/94
+ */
+
+/*
+ * internals of regex_t
+ */
+#define	MAGIC1	((('r'^0200)<<8) | 'e')
+
+/*
+ * The internal representation is a *strip*, a sequence of
+ * operators ending with an endmarker.  (Some terminology etc. is a
+ * historical relic of earlier versions which used multiple strips.)
+ * Certain oddities in the representation are there to permit running
+ * the machinery backwards; in particular, any deviation from sequential
+ * flow must be marked at both its source and its destination.  Some
+ * fine points:
+ *
+ * - OPLUS_ and O_PLUS are *inside* the loop they create.
+ * - OQUEST_ and O_QUEST are *outside* the bypass they create.
+ * - OCH_ and O_CH are *outside* the multi-way branch they create, while
+ *   OOR1 and OOR2 are respectively the end and the beginning of one of
+ *   the branches.  Note that there is an implicit OOR2 following OCH_
+ *   and an implicit OOR1 preceding O_CH.
+ *
+ * In state representations, an operator's bit is on to signify a state
+ * immediately *preceding* "execution" of that operator.
+ */
+typedef unsigned long sop;	/* strip operator */
+typedef long sopno;
+#define	OPRMASK	0xf8000000LU
+#define	OPDMASK	0x07ffffffLU
+#define	OPSHIFT	((unsigned)27)
+#define	OP(n)	((n)&OPRMASK)
+#define	OPND(n)	((n)&OPDMASK)
+#define	SOP(op, opnd)	((op)|(opnd))
+/* operators			   meaning	operand			*/
+/*						(back, fwd are offsets)	*/
+#define	OEND	(1LU<<OPSHIFT)	/* endmarker	-			*/
+#define	OCHAR	(2LU<<OPSHIFT)	/* character	unsigned char		*/
+#define	OBOL	(3LU<<OPSHIFT)	/* left anchor	-			*/
+#define	OEOL	(4LU<<OPSHIFT)	/* right anchor	-			*/
+#define	OANY	(5LU<<OPSHIFT)	/* .		-			*/
+#define	OANYOF	(6LU<<OPSHIFT)	/* [...]	set number		*/
+#define	OBACK_	(7LU<<OPSHIFT)	/* begin \d	paren number		*/
+#define	O_BACK	(8LU<<OPSHIFT)	/* end \d	paren number		*/
+#define	OPLUS_	(9LU<<OPSHIFT)	/* + prefix	fwd to suffix		*/
+#define	O_PLUS	(10LU<<OPSHIFT)	/* + suffix	back to prefix		*/
+#define	OQUEST_	(11LU<<OPSHIFT)	/* ? prefix	fwd to suffix		*/
+#define	O_QUEST	(12LU<<OPSHIFT)	/* ? suffix	back to prefix		*/
+#define	OLPAREN	(13LU<<OPSHIFT)	/* (		fwd to )		*/
+#define	ORPAREN	(14LU<<OPSHIFT)	/* )		back to (		*/
+#define	OCH_	(15LU<<OPSHIFT)	/* begin choice	fwd to OOR2		*/
+#define	OOR1	(16LU<<OPSHIFT)	/* | pt. 1	back to OOR1 or OCH_	*/
+#define	OOR2	(17LU<<OPSHIFT)	/* | pt. 2	fwd to OOR2 or O_CH	*/
+#define	O_CH	(18LU<<OPSHIFT)	/* end choice	back to OOR1		*/
+#define	OBOW	(19LU<<OPSHIFT)	/* begin word	-			*/
+#define	OEOW	(20LU<<OPSHIFT)	/* end word	-			*/
+
+/*
+ * Structure for [] character-set representation.  Character sets are
+ * done as bit vectors, grouped 8 to a byte vector for compactness.
+ * The individual set therefore has both a pointer to the byte vector
+ * and a mask to pick out the relevant bit of each byte.  A hash code
+ * simplifies testing whether two sets could be identical.
+ *
+ * This will get trickier for multicharacter collating elements.  As
+ * preliminary hooks for dealing with such things, we also carry along
+ * a string of multi-character elements, and decide the size of the
+ * vectors at run time.
+ */
+typedef struct {
+	uch *ptr;		/* -> uch [csetsize] */
+	uch mask;		/* bit within array */
+	uch hash;		/* hash code */
+	size_t smultis;
+	char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
+} cset;
+/* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
+#define	CHadd(cs, c)	((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (c))
+#define	CHsub(cs, c)	((cs)->ptr[(uch)(c)] &= ~(cs)->mask, (cs)->hash -= (c))
+#define	CHIN(cs, c)	((cs)->ptr[(uch)(c)] & (cs)->mask)
+#define	MCadd(p, cs, cp)	mcadd(p, cs, cp)	/* llvm_regcomp() internal fns */
+#define	MCsub(p, cs, cp)	mcsub(p, cs, cp)
+#define	MCin(p, cs, cp)	mcin(p, cs, cp)
+
+/* stuff for character categories */
+typedef unsigned char cat_t;
+
+/*
+ * main compiled-expression structure
+ */
+struct re_guts {
+	int magic;
+#		define	MAGIC2	((('R'^0200)<<8)|'E')
+	sop *strip;		/* malloced area for strip */
+	int csetsize;		/* number of bits in a cset vector */
+	int ncsets;		/* number of csets in use */
+	cset *sets;		/* -> cset [ncsets] */
+	uch *setbits;		/* -> uch[csetsize][ncsets/CHAR_BIT] */
+	int cflags;		/* copy of llvm_regcomp() cflags argument */
+	sopno nstates;		/* = number of sops */
+	sopno firststate;	/* the initial OEND (normally 0) */
+	sopno laststate;	/* the final OEND */
+	int iflags;		/* internal flags */
+#		define	USEBOL	01	/* used ^ */
+#		define	USEEOL	02	/* used $ */
+#		define	REGEX_BAD	04	/* something wrong */
+	int nbol;		/* number of ^ used */
+	int neol;		/* number of $ used */
+	int ncategories;	/* how many character categories */
+	cat_t *categories;	/* ->catspace[-CHAR_MIN] */
+	char *must;		/* match must contain this string */
+	int mlen;		/* length of must */
+	size_t nsub;		/* copy of re_nsub */
+	int backrefs;		/* does it use back references? */
+	sopno nplus;		/* how deep does it nest +s? */
+	/* catspace must be last */
+	cat_t catspace[1];	/* actually [NC] */
+};
+
+/* misc utilities */
+#define	OUT	(CHAR_MAX+1)	/* a non-character value */
+#define	ISWORD(c)	(isalnum(c&0xff) || (c) == '_')