regex2.h

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/*-
 * 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) == '_')