root/lib/libc/regex/regex2.h
/*      $OpenBSD: regex2.h,v 1.12 2021/01/03 17:07:58 tb 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.
 *
 *      @(#)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 */
} cset;

static inline void
CHadd(cset *cs, char c)
{
        cs->ptr[(uch)c] |= cs->mask;
        cs->hash += c;
}

static inline void
CHsub(cset *cs, char c)
{
        cs->ptr[(uch)c] &= ~cs->mask;
        cs->hash -= c;
}

static inline int
CHIN(const cset *cs, char c)
{
        return (cs->ptr[(uch)c] & cs->mask) != 0;
}

/*
 * 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 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  BAD     04      /* something wrong */
        int nbol;               /* number of ^ used */
        int neol;               /* number of $ used */
        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? */
};

/* misc utilities */
#define OUT     (CHAR_MAX+1)    /* a non-character value */
#define ISWORD(c)       (isalnum(c) || (c) == '_')