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regex2.h

/*
 * 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 long sop;       /* strip operator */
typedef long sopno;
#define     OPRMASK     0x7c000000
#define     OPDMASK     0x03ffffff
#define     OPSHIFT     (26)
#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.
 */
00082 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)  /* 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
 */
00103 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(c) || (c) == '_')

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