The R Project SVN R

/*-
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. 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
 */

/*
 * First, the stuff that ends up in the outside-world include file
 = typedef off_t regoff_t;
 = typedef struct {
 =  int re_magic;
 =  size_t re_nsub;     // number of parenthesized subexpressions
 =  const char *re_endp;    // end pointer for REG_PEND
 =  struct re_guts *re_g;   // none of your business :-)
 = } regex_t;
 = typedef struct {
 =  regoff_t rm_so;     // start of match
 =  regoff_t rm_eo;     // end of match
 = } regmatch_t;
 */
/*
 * 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 0xf8000000
#define OPDMASK 0x07ffffff
#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    (1<<OPSHIFT)    /* endmarker    -           */
#define OCHAR   (2<<OPSHIFT)    /* character    unsigned char       */
#define OBOL    (3<<OPSHIFT)    /* left anchor  -           */
#define OEOL    (4<<OPSHIFT)    /* right anchor -           */
#define OANY    (5<<OPSHIFT)    /* .        -           */
#define OANYOF  (6<<OPSHIFT)    /* [...]    set number      */
#define OBACK_  (7<<OPSHIFT)    /* begin \d paren number        */
#define O_BACK  (8<<OPSHIFT)    /* end \d   paren number        */
#define OPLUS_  (9<<OPSHIFT)    /* + prefix fwd to suffix       */
#define O_PLUS  (10<<OPSHIFT)   /* + suffix back to prefix      */
#define OQUEST_ (11<<OPSHIFT)   /* ? prefix fwd to suffix       */
#define O_QUEST (12<<OPSHIFT)   /* ? suffix back to prefix      */
#define OLPAREN (13<<OPSHIFT)   /* (        fwd to )        */
#define ORPAREN (14<<OPSHIFT)   /* )        back to (       */
#define OCH_    (15<<OPSHIFT)   /* begin choice fwd to OOR2     */
#define OOR1    (16<<OPSHIFT)   /* | pt. 1  back to OOR1 or OCH_    */
#define OOR2    (17<<OPSHIFT)   /* | pt. 2  fwd to OOR2 or O_CH */
#define O_CH    (18<<OPSHIFT)   /* end choice   back to OOR1        */
#define OBOW    (19<<OPSHIFT)   /* begin word   -           */
#define OEOW    (20<<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 */
    short 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 += (uch)(c))
#define CHsub(cs, c)    ((cs)->ptr[(uch)(c)] &= ~(cs)->mask, (cs)->hash -= (uch)(c))
#define CHIN(cs, c) ((cs)->ptr[(uch)(c)] & (cs)->mask)
#define MCadd(p, cs, cp)    mcadd(p, cs, cp)    /* 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 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 */
    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((uch)(c)) || (c) == '_')