135 lines
5.2 KiB
C
135 lines
5.2 KiB
C
/*
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* First, the stuff that ends up in the outside-world include file
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= typedef off_t regoff_t;
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= typedef struct {
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= int re_magic;
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= size_t re_nsub; // number of parenthesized subexpressions
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= const char *re_endp; // end pointer for REG_PEND
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= struct re_guts *re_g; // none of your business :-)
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= } regex_t;
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= typedef struct {
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= regoff_t rm_so; // start of match
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= regoff_t rm_eo; // end of match
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= } regmatch_t;
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*/
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/*
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* internals of regex_t
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*/
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#define MAGIC1 ((('r'^0200)<<8) | 'e')
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/*
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* The internal representation is a *strip*, a sequence of
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* operators ending with an endmarker. (Some terminology etc. is a
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* historical relic of earlier versions which used multiple strips.)
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* Certain oddities in the representation are there to permit running
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* the machinery backwards; in particular, any deviation from sequential
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* flow must be marked at both its source and its destination. Some
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* fine points:
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*
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* - OPLUS_ and O_PLUS are *inside* the loop they create.
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* - OQUEST_ and O_QUEST are *outside* the bypass they create.
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* - OCH_ and O_CH are *outside* the multi-way branch they create, while
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* OOR1 and OOR2 are respectively the end and the beginning of one of
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* the branches. Note that there is an implicit OOR2 following OCH_
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* and an implicit OOR1 preceding O_CH.
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*
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* In state representations, an operator's bit is on to signify a state
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* immediately *preceding* "execution" of that operator.
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*/
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typedef long sop; /* strip operator */
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typedef long sopno;
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#define OPRMASK 0x7c000000
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#define OPDMASK 0x03ffffff
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#define OPSHIFT (26)
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#define OP(n) ((n)&OPRMASK)
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#define OPND(n) ((n)&OPDMASK)
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#define SOP(op, opnd) ((op)|(opnd))
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/* operators meaning operand */
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/* (back, fwd are offsets) */
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#define OEND (1<<OPSHIFT) /* endmarker - */
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#define OCHAR (2<<OPSHIFT) /* character unsigned char */
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#define OBOL (3<<OPSHIFT) /* left anchor - */
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#define OEOL (4<<OPSHIFT) /* right anchor - */
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#define OANY (5<<OPSHIFT) /* . - */
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#define OANYOF (6<<OPSHIFT) /* [...] set number */
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#define OBACK_ (7<<OPSHIFT) /* begin \d paren number */
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#define O_BACK (8<<OPSHIFT) /* end \d paren number */
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#define OPLUS_ (9<<OPSHIFT) /* + prefix fwd to suffix */
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#define O_PLUS (10<<OPSHIFT) /* + suffix back to prefix */
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#define OQUEST_ (11<<OPSHIFT) /* ? prefix fwd to suffix */
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#define O_QUEST (12<<OPSHIFT) /* ? suffix back to prefix */
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#define OLPAREN (13<<OPSHIFT) /* ( fwd to ) */
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#define ORPAREN (14<<OPSHIFT) /* ) back to ( */
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#define OCH_ (15<<OPSHIFT) /* begin choice fwd to OOR2 */
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#define OOR1 (16<<OPSHIFT) /* | pt. 1 back to OOR1 or OCH_ */
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#define OOR2 (17<<OPSHIFT) /* | pt. 2 fwd to OOR2 or O_CH */
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#define O_CH (18<<OPSHIFT) /* end choice back to OOR1 */
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#define OBOW (19<<OPSHIFT) /* begin word - */
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#define OEOW (20<<OPSHIFT) /* end word - */
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/*
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* Structure for [] character-set representation. Character sets are
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* done as bit vectors, grouped 8 to a byte vector for compactness.
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* The individual set therefore has both a pointer to the byte vector
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* and a mask to pick out the relevant bit of each byte. A hash code
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* simplifies testing whether two sets could be identical.
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*
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* This will get trickier for multicharacter collating elements. As
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* preliminary hooks for dealing with such things, we also carry along
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* a string of multi-character elements, and decide the size of the
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* vectors at run time.
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*/
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typedef struct {
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uch *ptr; /* -> uch [csetsize] */
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uch mask; /* bit within array */
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uch hash; /* hash code */
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size_t smultis;
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char *multis; /* -> char[smulti] ab\0cd\0ef\0\0 */
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} cset;
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/* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
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#define CHadd(cs, c) ((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (c))
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#define CHsub(cs, c) ((cs)->ptr[(uch)(c)] &= ~(cs)->mask, (cs)->hash -= (c))
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#define CHIN(cs, c) ((cs)->ptr[(uch)(c)] & (cs)->mask)
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#define MCadd(p, cs, cp) mcadd(p, cs, cp) /* regcomp() internal fns */
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#define MCsub(p, cs, cp) mcsub(p, cs, cp)
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#define MCin(p, cs, cp) mcin(p, cs, cp)
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/* stuff for character categories */
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typedef unsigned char cat_t;
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/*
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* main compiled-expression structure
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*/
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struct re_guts {
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int magic;
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# define MAGIC2 ((('R'^0200)<<8)|'E')
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sop *strip; /* malloced area for strip */
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int csetsize; /* number of bits in a cset vector */
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int ncsets; /* number of csets in use */
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cset *sets; /* -> cset [ncsets] */
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uch *setbits; /* -> uch[csetsize][ncsets/CHAR_BIT] */
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int cflags; /* copy of regcomp() cflags argument */
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sopno nstates; /* = number of sops */
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sopno firststate; /* the initial OEND (normally 0) */
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sopno laststate; /* the final OEND */
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int iflags; /* internal flags */
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# define USEBOL 01 /* used ^ */
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# define USEEOL 02 /* used $ */
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# define BAD 04 /* something wrong */
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int nbol; /* number of ^ used */
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int neol; /* number of $ used */
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int ncategories; /* how many character categories */
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cat_t *categories; /* ->catspace[-CHAR_MIN] */
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char *must; /* match must contain this string */
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int mlen; /* length of must */
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size_t nsub; /* copy of re_nsub */
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int backrefs; /* does it use back references? */
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sopno nplus; /* how deep does it nest +s? */
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/* catspace must be last */
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cat_t catspace[1]; /* actually [NC] */
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};
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/* misc utilities */
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#define OUT (CHAR_MAX+1) /* a non-character value */
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#define ISWORD(c) (isalnum(c) || (c) == '_')
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