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/*- * 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. * 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. * * @(#)regcomp.c 8.5 (Berkeley) 3/20/94 */ #ifndef _NO_REGEX #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)regcomp.c 8.5 (Berkeley) 3/20/94"; #endif /* LIBC_SCCS and not lint */ #include <sys/cdefs.h> #include <sys/types.h> #include <stdio.h> #include <string.h> #include <ctype.h> #include <limits.h> #include <stdlib.h> #include <regex.h> #include "collate.h" #include "utils.h" #include "regex2.h" #include "cclass.h" #include "cname.h" /* * parse structure, passed up and down to avoid global variables and * other clumsinesses */ struct parse { char *next; /* next character in RE */ char *end; /* end of string (-> NUL normally) */ int error; /* has an error been seen? */ sop *strip; /* malloced strip */ sopno ssize; /* malloced strip size (allocated) */ sopno slen; /* malloced strip length (used) */ int ncsalloc; /* number of csets allocated */ struct re_guts *g; # define NPAREN 10 /* we need to remember () 1-9 for back refs */ sopno pbegin[NPAREN]; /* -> ( ([0] unused) */ sopno pend[NPAREN]; /* -> ) ([0] unused) */ }; /* ========= begin header generated by ./mkh ========= */ #ifdef __cplusplus extern "C" { #endif /* === regcomp.c === */ static void p_ere(struct parse *p, int stop); static void p_ere_exp(struct parse *p); static void p_str(struct parse *p); static void p_bre(struct parse *p, int end1, int end2); static int p_simp_re(struct parse *p, int starordinary); static int p_count(struct parse *p); static void p_bracket(struct parse *p); static void p_b_term(struct parse *p, cset *cs); static void p_b_cclass(struct parse *p, cset *cs); static void p_b_eclass(struct parse *p, cset *cs); static char p_b_symbol(struct parse *p); static char p_b_coll_elem(struct parse *p, int endc); static char othercase(int ch); static void bothcases(struct parse *p, int ch); static void ordinary(struct parse *p, int ch); static void nonnewline(struct parse *p); static void repeat(struct parse *p, sopno start, int from, int to); static int seterr(struct parse *p, int e); static cset *allocset(struct parse *p); static void freeset(struct parse *p, cset *cs); static int freezeset(struct parse *p, cset *cs); static int firstch(struct parse *p, cset *cs); static int nch(struct parse *p, cset *cs); static void mcadd(struct parse *p, cset *cs, char *cp); #if used static void mcsub(cset *cs, char *cp); static int mcin(cset *cs, char *cp); static char *mcfind(cset *cs, char *cp); #endif static void mcinvert(struct parse *p, cset *cs); static void mccase(struct parse *p, cset *cs); static int isinsets(struct re_guts *g, int c); static int samesets(struct re_guts *g, int c1, int c2); static void categorize(struct parse *p, struct re_guts *g); static sopno dupl(struct parse *p, sopno start, sopno finish); static void doemit(struct parse *p, sop op, size_t opnd); static void doinsert(struct parse *p, sop op, size_t opnd, sopno pos); static void dofwd(struct parse *p, sopno pos, sop value); static void enlarge(struct parse *p, sopno size); static void stripsnug(struct parse *p, struct re_guts *g); static void findmust(struct parse *p, struct re_guts *g); static int altoffset(sop *scan, int offset, int mccs); static void computejumps(struct parse *p, struct re_guts *g); static void computematchjumps(struct parse *p, struct re_guts *g); static sopno pluscount(struct parse *p, struct re_guts *g); #ifdef __cplusplus } #endif /* ========= end header generated by ./mkh ========= */ static char nuls[10]; /* place to point scanner in event of error */ /* * macros for use with parse structure * BEWARE: these know that the parse structure is named `p' !!! */ #define PEEK() (*p->next) #define PEEK2() (*(p->next+1)) #define MORE() (p->next < p->end) #define MORE2() (p->next+1 < p->end) #define SEE(c) (MORE() && PEEK() == (c)) #define SEETWO(a, b) (MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b)) #define EAT(c) ((SEE(c)) ? (NEXT(), 1) : 0) #define EATTWO(a, b) ((SEETWO(a, b)) ? (NEXT2(), 1) : 0) #define NEXT() (p->next++) #define NEXT2() (p->next += 2) #define NEXTn(n) (p->next += (n)) #define GETNEXT() (*p->next++) #define SETERROR(e) seterr(p, (e)) #define REQUIRE(co, e) ((co) || SETERROR(e)) #define MUSTSEE(c, e) (REQUIRE(MORE() && PEEK() == (c), e)) #define MUSTEAT(c, e) (REQUIRE(MORE() && GETNEXT() == (c), e)) #define MUSTNOTSEE(c, e) (REQUIRE(!MORE() || PEEK() != (c), e)) #define EMIT(op, sopnd) doemit(p, (sop)(op), (size_t)(sopnd)) #define INSERT(op, pos) doinsert(p, (sop)(op), HERE()-(pos)+1, pos) #define AHEAD(pos) dofwd(p, pos, HERE()-(pos)) #define ASTERN(sop, pos) EMIT(sop, HERE()-pos) #define HERE() (p->slen) #define THERE() (p->slen - 1) #define THERETHERE() (p->slen - 2) #define DROP(n) (p->slen -= (n)) #ifndef NDEBUG static int never = 0; /* for use in asserts; shuts lint up */ #else #define never 0 /* some <assert.h>s have bugs too */ #endif /* Macro used by computejump()/computematchjump() */ #define MIN(a,b) ((a)<(b)?(a):(b)) /* - regcomp - interface for parser and compilation = extern int regcomp(regex_t *, const char *, int); = #define REG_BASIC 0000 = #define REG_EXTENDED 0001 = #define REG_ICASE 0002 = #define REG_NOSUB 0004 = #define REG_NEWLINE 0010 = #define REG_NOSPEC 0020 = #define REG_PEND 0040 = #define REG_DUMP 0200 */ int /* 0 success, otherwise REG_something */ regcomp(preg, pattern, cflags) regex_t *preg; const char *pattern; int cflags; { struct parse pa; struct re_guts *g; struct parse *p = &pa; int i; size_t len; #ifdef REDEBUG # define GOODFLAGS(f) (f) #else # define GOODFLAGS(f) ((f)&~REG_DUMP) #endif cflags = GOODFLAGS(cflags); if ((cflags®_EXTENDED) && (cflags®_NOSPEC)) return(REG_INVARG); if (cflags®_PEND) { if (preg->re_endp < pattern) return(REG_INVARG); len = preg->re_endp - pattern; } else len = strlen((char *)pattern); /* do the mallocs early so failure handling is easy */ g = (struct re_guts *)malloc(sizeof(struct re_guts) + (NC-1)*sizeof(cat_t)); if (g == NULL) return(REG_ESPACE); p->ssize = len/(size_t)2*(size_t)3 + (size_t)1; /* ugh */ p->strip = (sop *)malloc(p->ssize * sizeof(sop)); p->slen = 0; if (p->strip == NULL) { free((char *)g); return(REG_ESPACE); } /* set things up */ p->g = g; p->next = (char *)pattern; /* convenience; we do not modify it */ p->end = p->next + len; p->error = 0; p->ncsalloc = 0; for (i = 0; i < NPAREN; i++) { p->pbegin[i] = 0; p->pend[i] = 0; } g->csetsize = NC; g->sets = NULL; g->setbits = NULL; g->ncsets = 0; g->cflags = cflags; g->iflags = 0; g->nbol = 0; g->neol = 0; g->must = NULL; g->moffset = -1; g->charjump = NULL; g->matchjump = NULL; g->mlen = 0; g->nsub = 0; g->ncategories = 1; /* category 0 is "everything else" */ g->categories = &g->catspace[-(CHAR_MIN)]; (void) memset((char *)g->catspace, 0, NC*sizeof(cat_t)); g->backrefs = 0; /* do it */ EMIT(OEND, 0); g->firststate = THERE(); if (cflags®_EXTENDED) p_ere(p, OUT); else if (cflags®_NOSPEC) p_str(p); else p_bre(p, OUT, OUT); EMIT(OEND, 0); g->laststate = THERE(); /* tidy up loose ends and fill things in */ categorize(p, g); stripsnug(p, g); findmust(p, g); /* only use Boyer-Moore algorithm if the pattern is bigger * than three characters */ if(g->mlen > 3) { computejumps(p, g); computematchjumps(p, g); if(g->matchjump == NULL && g->charjump != NULL) { free(g->charjump); g->charjump = NULL; } } g->nplus = pluscount(p, g); g->magic = MAGIC2; preg->re_nsub = g->nsub; preg->re_g = g; preg->re_magic = MAGIC1; #ifndef REDEBUG /* not debugging, so can't rely on the assert() in regexec() */ if (g->iflags&BAD) SETERROR(REG_ASSERT); #endif /* win or lose, we're done */ if (p->error != 0) /* lose */ regfree(preg); return(p->error); } /* - p_ere - ERE parser top level, concatenation and alternation == static void p_ere(struct parse *p, int stop); */ static void p_ere(p, stop) struct parse *p; int stop; /* character this ERE should end at */ { char c; sopno prevback; sopno prevfwd; sopno conc; int first = 1; /* is this the first alternative? */ for (;;) { /* do a bunch of concatenated expressions */ conc = HERE(); while (MORE() && (c = PEEK()) != '|' && c != stop) p_ere_exp(p); (void)REQUIRE(HERE() != conc, REG_EMPTY); /* require nonempty */ if (!EAT('|')) break; /* NOTE BREAK OUT */ if (first) { INSERT(OCH_, conc); /* offset is wrong */ prevfwd = conc; prevback = conc; first = 0; } ASTERN(OOR1, prevback); prevback = THERE(); AHEAD(prevfwd); /* fix previous offset */ prevfwd = HERE(); EMIT(OOR2, 0); /* offset is very wrong */ } if (!first) { /* tail-end fixups */ AHEAD(prevfwd); ASTERN(O_CH, prevback); } assert(!MORE() || SEE(stop)); } /* - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op == static void p_ere_exp(struct parse *p); */ static void p_ere_exp(p) struct parse *p; { char c; sopno pos; int count; int count2; sopno subno; int wascaret = 0; assert(MORE()); /* caller should have ensured this */ c = GETNEXT(); pos = HERE(); switch (c) { case '(': (void)REQUIRE(MORE(), REG_EPAREN); p->g->nsub++; subno = p->g->nsub; if (subno < NPAREN) p->pbegin[subno] = HERE(); EMIT(OLPAREN, subno); if (!SEE(')')) p_ere(p, ')'); if (subno < NPAREN) { p->pend[subno] = HERE(); assert(p->pend[subno] != 0); } EMIT(ORPAREN, subno); (void)MUSTEAT(')', REG_EPAREN); break; #ifndef POSIX_MISTAKE case ')': /* happens only if no current unmatched ( */ /* * You may ask, why the ifndef? Because I didn't notice * this until slightly too late for 1003.2, and none of the * other 1003.2 regular-expression reviewers noticed it at * all. So an unmatched ) is legal POSIX, at least until * we can get it fixed. */ SETERROR(REG_EPAREN); break; #endif case '^': EMIT(OBOL, 0); p->g->iflags |= USEBOL; p->g->nbol++; wascaret = 1; break; case '$': EMIT(OEOL, 0); p->g->iflags |= USEEOL; p->g->neol++; break; case '|': SETERROR(REG_EMPTY); break; case '*': case '+': case '?': SETERROR(REG_BADRPT); break; case '.': if (p->g->cflags®_NEWLINE) nonnewline(p); else EMIT(OANY, 0); break; case '[': p_bracket(p); break; case '\\': (void)REQUIRE(MORE(), REG_EESCAPE); c = GETNEXT(); ordinary(p, c); break; case '{': /* okay as ordinary except if digit follows */ (void)REQUIRE(!MORE() || !isdigit((uch)PEEK()), REG_BADRPT); /* FALLTHROUGH */ default: ordinary(p, c); break; } if (!MORE()) return; c = PEEK(); /* we call { a repetition if followed by a digit */ if (!( c == '*' || c == '+' || c == '?' || (c == '{' && MORE2() && isdigit((uch)PEEK2())) )) return; /* no repetition, we're done */ NEXT(); (void)REQUIRE(!wascaret, REG_BADRPT); switch (c) { case '*': /* implemented as +? */ /* this case does not require the (y|) trick, noKLUDGE */ INSERT(OPLUS_, pos); ASTERN(O_PLUS, pos); INSERT(OQUEST_, pos); ASTERN(O_QUEST, pos); break; case '+': INSERT(OPLUS_, pos); ASTERN(O_PLUS, pos); break; case '?': /* KLUDGE: emit y? as (y|) until subtle bug gets fixed */ INSERT(OCH_, pos); /* offset slightly wrong */ ASTERN(OOR1, pos); /* this one's right */ AHEAD(pos); /* fix the OCH_ */ EMIT(OOR2, 0); /* offset very wrong... */ AHEAD(THERE()); /* ...so fix it */ ASTERN(O_CH, THERETHERE()); break; case '{': count = p_count(p); if (EAT(',')) { if (isdigit((uch)PEEK())) { count2 = p_count(p); (void)REQUIRE(count <= count2, REG_BADBR); } else /* single number with comma */ count2 = INFINITY; } else /* just a single number */ count2 = count; repeat(p, pos, count, count2); if (!EAT('}')) { /* error heuristics */ while (MORE() && PEEK() != '}') NEXT(); (void)REQUIRE(MORE(), REG_EBRACE); SETERROR(REG_BADBR); } break; } if (!MORE()) return; c = PEEK(); if (!( c == '*' || c == '+' || c == '?' || (c == '{' && MORE2() && isdigit((uch)PEEK2())) ) ) return; SETERROR(REG_BADRPT); } /* - p_str - string (no metacharacters) "parser" == static void p_str(struct parse *p); */ static void p_str(p) struct parse *p; { (void)REQUIRE(MORE(), REG_EMPTY); while (MORE()) ordinary(p, GETNEXT()); } /* - p_bre - BRE parser top level, anchoring and concatenation == static void p_bre(struct parse *p, int end1, \ == int end2); * Giving end1 as OUT essentially eliminates the end1/end2 check. * * This implementation is a bit of a kludge, in that a trailing $ is first * taken as an ordinary character and then revised to be an anchor. The * only undesirable side effect is that '$' gets included as a character * category in such cases. This is fairly harmless; not worth fixing. * The amount of lookahead needed to avoid this kludge is excessive. */ static void p_bre(p, end1, end2) struct parse *p; int end1; /* first terminating character */ int end2; /* second terminating character */ { sopno start = HERE(); int first = 1; /* first subexpression? */ int wasdollar = 0; if (EAT('^')) { EMIT(OBOL, 0); p->g->iflags |= USEBOL; p->g->nbol++; } while (MORE() && !SEETWO(end1, end2)) { wasdollar = p_simp_re(p, first); first = 0; } if (wasdollar) { /* oops, that was a trailing anchor */ DROP(1); EMIT(OEOL, 0); p->g->iflags |= USEEOL; p->g->neol++; } (void)REQUIRE(HERE() != start, REG_EMPTY); /* require nonempty */ } /* - p_simp_re - parse a simple RE, an atom possibly followed by a repetition == static int p_simp_re(struct parse *p, int starordinary); */ static int /* was the simple RE an unbackslashed $? */ p_simp_re(p, starordinary) struct parse *p; int starordinary; /* is a leading * an ordinary character? */ { int c; int count; int count2; sopno pos; int i; sopno subno; # define BACKSL (1<<CHAR_BIT) pos = HERE(); /* repetion op, if any, covers from here */ assert(MORE()); /* caller should have ensured this */ c = GETNEXT(); if (c == '\\') { (void)REQUIRE(MORE(), REG_EESCAPE); c = BACKSL | GETNEXT(); } switch (c) { case '.': if (p->g->cflags®_NEWLINE) nonnewline(p); else EMIT(OANY, 0); break; case '[': p_bracket(p); break; case BACKSL|'{': SETERROR(REG_BADRPT); break; case BACKSL|'(': p->g->nsub++; subno = p->g->nsub; if (subno < NPAREN) p->pbegin[subno] = HERE(); EMIT(OLPAREN, subno); /* the MORE here is an error heuristic */ if (MORE() && !SEETWO('\\', ')')) p_bre(p, '\\', ')'); if (subno < NPAREN) { p->pend[subno] = HERE(); assert(p->pend[subno] != 0); } EMIT(ORPAREN, subno); (void)REQUIRE(EATTWO('\\', ')'), REG_EPAREN); break; case BACKSL|')': /* should not get here -- must be user */ case BACKSL|'}': SETERROR(REG_EPAREN); break; case BACKSL|'1': case BACKSL|'2': case BACKSL|'3': case BACKSL|'4': case BACKSL|'5': case BACKSL|'6': case BACKSL|'7': case BACKSL|'8': case BACKSL|'9': i = (c&~BACKSL) - '0'; assert(i < NPAREN); if (p->pend[i] != 0) { assert(i <= p->g->nsub); EMIT(OBACK_, i); assert(p->pbegin[i] != 0); assert(OP(p->strip[p->pbegin[i]]) == OLPAREN); assert(OP(p->strip[p->pend[i]]) == ORPAREN); (void) dupl(p, p->pbegin[i]+1, p->pend[i]); EMIT(O_BACK, i); } else SETERROR(REG_ESUBREG); p->g->backrefs = 1; break; case '*': (void)REQUIRE(starordinary, REG_BADRPT); /* FALLTHROUGH */ default: ordinary(p, (char)c); break; } if (EAT('*')) { /* implemented as +? */ /* this case does not require the (y|) trick, noKLUDGE */ INSERT(OPLUS_, pos); ASTERN(O_PLUS, pos); INSERT(OQUEST_, pos); ASTERN(O_QUEST, pos); } else if (EATTWO('\\', '{')) { count = p_count(p); if (EAT(',')) { if (MORE() && isdigit((uch)PEEK())) { count2 = p_count(p); (void)REQUIRE(count <= count2, REG_BADBR); } else /* single number with comma */ count2 = INFINITY; } else /* just a single number */ count2 = count; repeat(p, pos, count, count2); if (!EATTWO('\\', '}')) { /* error heuristics */ while (MORE() && !SEETWO('\\', '}')) NEXT(); (void)REQUIRE(MORE(), REG_EBRACE); SETERROR(REG_BADBR); } } else if (c == '$') /* $ (but not \$) ends it */ return(1); return(0); } /* - p_count - parse a repetition count == static int p_count(struct parse *p); */ static int /* the value */ p_count(p) struct parse *p; { int count = 0; int ndigits = 0; while (MORE() && isdigit((uch)PEEK()) && count <= DUPMAX) { count = count*10 + (GETNEXT() - '0'); ndigits++; } (void)REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR); return(count); } /* - p_bracket - parse a bracketed character list == static void p_bracket(struct parse *p); * * Note a significant property of this code: if the allocset() did SETERROR, * no set operations are done. */ static void p_bracket(p) struct parse *p; { cset *cs = allocset(p); int invert = 0; /* Dept of Truly Sickening Special-Case Kludges */ if (p->next + 5 < p->end && strncmp(p->next, "[:<:]]", 6) == 0) { EMIT(OBOW, 0); NEXTn(6); return; } if (p->next + 5 < p->end && strncmp(p->next, "[:>:]]", 6) == 0) { EMIT(OEOW, 0); NEXTn(6); return; } if (EAT('^')) invert++; /* make note to invert set at end */ if (EAT(']')) CHadd(cs, ']'); else if (EAT('-')) CHadd(cs, '-'); while (MORE() && PEEK() != ']' && !SEETWO('-', ']')) p_b_term(p, cs); if (EAT('-')) CHadd(cs, '-'); (void)MUSTEAT(']', REG_EBRACK); if (p->error != 0) /* don't mess things up further */ return; if (p->g->cflags®_ICASE) { int i; int ci; for (i = p->g->csetsize - 1; i >= 0; i--) if (CHIN(cs, i) && isalpha(i)) { ci = othercase(i); if (ci != i) CHadd(cs, ci); } if (cs->multis != NULL) mccase(p, cs); } if (invert) { int i; for (i = p->g->csetsize - 1; i >= 0; i--) if (CHIN(cs, i)) CHsub(cs, i); else CHadd(cs, i); if (p->g->cflags®_NEWLINE) CHsub(cs, '\n'); if (cs->multis != NULL) mcinvert(p, cs); } assert(cs->multis == NULL); /* xxx */ if (nch(p, cs) == 1) { /* optimize singleton sets */ ordinary(p, firstch(p, cs)); freeset(p, cs); } else EMIT(OANYOF, freezeset(p, cs)); } /* - p_b_term - parse one term of a bracketed character list == static void p_b_term(struct parse *p, cset *cs); */ static void p_b_term(p, cs) struct parse *p; cset *cs; { char c; char start, finish; int i; /* classify what we've got */ switch ((MORE()) ? PEEK() : '\0') { case '[': c = (MORE2()) ? PEEK2() : '\0'; break; case '-': SETERROR(REG_ERANGE); return; /* NOTE RETURN */ break; default: c = '\0'; break; } switch (c) { case ':': /* character class */ NEXT2(); (void)REQUIRE(MORE(), REG_EBRACK); c = PEEK(); (void)REQUIRE(c != '-' && c != ']', REG_ECTYPE); p_b_cclass(p, cs); (void)REQUIRE(MORE(), REG_EBRACK); (void)REQUIRE(EATTWO(':', ']'), REG_ECTYPE); break; case '=': /* equivalence class */ NEXT2(); (void)REQUIRE(MORE(), REG_EBRACK); c = PEEK(); (void)REQUIRE(c != '-' && c != ']', REG_ECOLLATE); p_b_eclass(p, cs); (void)REQUIRE(MORE(), REG_EBRACK); (void)REQUIRE(EATTWO('=', ']'), REG_ECOLLATE); break; default: /* symbol, ordinary character, or range */ /* xxx revision needed for multichar stuff */ start = p_b_symbol(p); if (SEE('-') && MORE2() && PEEK2() != ']') { /* range */ NEXT(); if (EAT('-')) finish = '-'; else finish = p_b_symbol(p); } else finish = start; if (start == finish) CHadd(cs, start); else { if (__collate_load_error) { (void)REQUIRE((uch)start <= (uch)finish, REG_ERANGE); for (i = (uch)start; i <= (uch)finish; i++) CHadd(cs, i); } else { (void)REQUIRE(__collate_range_cmp(start, finish) <= 0, REG_ERANGE); for (i = CHAR_MIN; i <= CHAR_MAX; i++) { if ( __collate_range_cmp(start, i) <= 0 && __collate_range_cmp(i, finish) <= 0 ) CHadd(cs, i); } } } break; } } /* - p_b_cclass - parse a character-class name and deal with it == static void p_b_cclass(struct parse *p, cset *cs); */ static void p_b_cclass(p, cs) struct parse *p; cset *cs; { int c; char *sp = p->next; struct cclass *cp; size_t len; while (MORE() && isalpha((uch)PEEK())) NEXT(); len = p->next - sp; for (cp = cclasses; cp->name != NULL; cp++) if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0') break; if (cp->name == NULL) { /* oops, didn't find it */ SETERROR(REG_ECTYPE); return; } switch (cp->fidx) { case CALNUM: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isalnum((uch)c)) CHadd(cs, c); break; case CALPHA: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isalpha((uch)c)) CHadd(cs, c); break; case CBLANK: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isblank((uch)c)) CHadd(cs, c); break; case CCNTRL: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (iscntrl((uch)c)) CHadd(cs, c); break; case CDIGIT: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isdigit((uch)c)) CHadd(cs, c); break; case CGRAPH: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isgraph((uch)c)) CHadd(cs, c); break; case CLOWER: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (islower((uch)c)) CHadd(cs, c); break; case CPRINT: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isprint((uch)c)) CHadd(cs, c); break; case CPUNCT: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (ispunct((uch)c)) CHadd(cs, c); break; case CSPACE: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isspace((uch)c)) CHadd(cs, c); break; case CUPPER: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isupper((uch)c)) CHadd(cs, c); break; case CXDIGIT: for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (isxdigit((uch)c)) CHadd(cs, c); break; } #if 0 for (u = cp->multis; *u != '\0'; u += strlen(u) + 1) MCadd(p, cs, u); #endif } /* - p_b_eclass - parse an equivalence-class name and deal with it == static void p_b_eclass(struct parse *p, cset *cs); * * This implementation is incomplete. xxx */ static void p_b_eclass(p, cs) struct parse *p; cset *cs; { char c; c = p_b_coll_elem(p, '='); CHadd(cs, c); } /* - p_b_symbol - parse a character or [..]ed multicharacter collating symbol == static char p_b_symbol(struct parse *p); */ static char /* value of symbol */ p_b_symbol(p) struct parse *p; { char value; (void)REQUIRE(MORE(), REG_EBRACK); if (!EATTWO('[', '.')) return(GETNEXT()); /* collating symbol */ value = p_b_coll_elem(p, '.'); (void)REQUIRE(EATTWO('.', ']'), REG_ECOLLATE); return(value); } /* - p_b_coll_elem - parse a collating-element name and look it up == static char p_b_coll_elem(struct parse *p, int endc); */ static char /* value of collating element */ p_b_coll_elem(p, endc) struct parse *p; int endc; /* name ended by endc,']' */ { char *sp = p->next; struct cname *cp; int len; while (MORE() && !SEETWO(endc, ']')) NEXT(); if (!MORE()) { SETERROR(REG_EBRACK); return(0); } len = p->next - sp; for (cp = cnames; cp->name != NULL; cp++) if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0') return(cp->code); /* known name */ if (len == 1) return(*sp); /* single character */ SETERROR(REG_ECOLLATE); /* neither */ return(0); } /* - othercase - return the case counterpart of an alphabetic == static char othercase(int ch); */ static char /* if no counterpart, return ch */ othercase(ch) int ch; { ch = (uch)ch; assert(isalpha(ch)); if (isupper(ch)) return(tolower(ch)); else if (islower(ch)) return(toupper(ch)); else /* peculiar, but could happen */ return(ch); } /* - bothcases - emit a dualcase version of a two-case character == static void bothcases(struct parse *p, int ch); * * Boy, is this implementation ever a kludge... */ static void bothcases(p, ch) struct parse *p; int ch; { char *oldnext = p->next; char *oldend = p->end; char bracket[3]; ch = (uch)ch; assert(othercase(ch) != ch); /* p_bracket() would recurse */ p->next = bracket; p->end = bracket+2; bracket[0] = ch; bracket[1] = ']'; bracket[2] = '\0'; p_bracket(p); assert(p->next == bracket+2); p->next = oldnext; p->end = oldend; } /* - ordinary - emit an ordinary character == static void ordinary(struct parse *p, int ch); */ static void ordinary(p, ch) struct parse *p; int ch; { cat_t *cap = p->g->categories; if ((p->g->cflags®_ICASE) && isalpha((uch)ch) && othercase(ch) != ch) bothcases(p, ch); else { EMIT(OCHAR, (uch)ch); if (cap[ch] == 0) cap[ch] = p->g->ncategories++; } } /* - nonnewline - emit REG_NEWLINE version of OANY == static void nonnewline(struct parse *p); * * Boy, is this implementation ever a kludge... */ static void nonnewline(p) struct parse *p; { char *oldnext = p->next; char *oldend = p->end; char bracket[4]; p->next = bracket; p->end = bracket+3; bracket[0] = '^'; bracket[1] = '\n'; bracket[2] = ']'; bracket[3] = '\0'; p_bracket(p); assert(p->next == bracket+3); p->next = oldnext; p->end = oldend; } /* - repeat - generate code for a bounded repetition, recursively if needed == static void repeat(struct parse *p, sopno start, int from, int to); */ static void repeat(p, start, from, to) struct parse *p; sopno start; /* operand from here to end of strip */ int from; /* repeated from this number */ int to; /* to this number of times (maybe INFINITY) */ { sopno finish = HERE(); # define N 2 # define INF 3 # define REP(f, t) ((f)*8 + (t)) # define MAP(n) (((n) <= 1) ? (n) : ((n) == INFINITY) ? INF : N) sopno copy; if (p->error != 0) /* head off possible runaway recursion */ return; assert(from <= to); switch (REP(MAP(from), MAP(to))) { case REP(0, 0): /* must be user doing this */ DROP(finish-start); /* drop the operand */ break; case REP(0, 1): /* as x{1,1}? */ case REP(0, N): /* as x{1,n}? */ case REP(0, INF): /* as x{1,}? */ /* KLUDGE: emit y? as (y|) until subtle bug gets fixed */ INSERT(OCH_, start); /* offset is wrong... */ repeat(p, start+1, 1, to); ASTERN(OOR1, start); AHEAD(start); /* ... fix it */ EMIT(OOR2, 0); AHEAD(THERE()); ASTERN(O_CH, THERETHERE()); break; case REP(1, 1): /* trivial case */ /* done */ break; case REP(1, N): /* as x?x{1,n-1} */ /* KLUDGE: emit y? as (y|) until subtle bug gets fixed */ INSERT(OCH_, start); ASTERN(OOR1, start); AHEAD(start); EMIT(OOR2, 0); /* offset very wrong... */ AHEAD(THERE()); /* ...so fix it */ ASTERN(O_CH, THERETHERE()); copy = dupl(p, start+1, finish+1); assert(copy == finish+4); repeat(p, copy, 1, to-1); break; case REP(1, INF): /* as x+ */ INSERT(OPLUS_, start); ASTERN(O_PLUS, start); break; case REP(N, N): /* as xx{m-1,n-1} */ copy = dupl(p, start, finish); repeat(p, copy, from-1, to-1); break; case REP(N, INF): /* as xx{n-1,INF} */ copy = dupl(p, start, finish); repeat(p, copy, from-1, to); break; default: /* "can't happen" */ SETERROR(REG_ASSERT); /* just in case */ break; } } /* - seterr - set an error condition == static int seterr(struct parse *p, int e); */ static int /* useless but makes type checking happy */ seterr(p, e) struct parse *p; int e; { if (p->error == 0) /* keep earliest error condition */ p->error = e; p->next = nuls; /* try to bring things to a halt */ p->end = nuls; return(0); /* make the return value well-defined */ } /* - allocset - allocate a set of characters for [] == static cset *allocset(struct parse *p); */ static cset * allocset(p) struct parse *p; { int no = p->g->ncsets++; size_t nc; size_t nbytes; cset *cs; size_t css = (size_t)p->g->csetsize; int i; if (no >= p->ncsalloc) { /* need another column of space */ p->ncsalloc += CHAR_BIT; nc = p->ncsalloc; assert(nc % CHAR_BIT == 0); nbytes = nc / CHAR_BIT * css; if (p->g->sets == NULL) p->g->sets = (cset *)malloc(nc * sizeof(cset)); else p->g->sets = (cset *)reallocf((char *)p->g->sets, nc * sizeof(cset)); if (p->g->setbits == NULL) p->g->setbits = (uch *)malloc(nbytes); else { p->g->setbits = (uch *)reallocf((char *)p->g->setbits, nbytes); /* xxx this isn't right if setbits is now NULL */ for (i = 0; i < no; i++) p->g->sets[i].ptr = p->g->setbits + css*(i/CHAR_BIT); } if (p->g->sets != NULL && p->g->setbits != NULL) (void) memset((char *)p->g->setbits + (nbytes - css), 0, css); else { no = 0; SETERROR(REG_ESPACE); /* caller's responsibility not to do set ops */ } } assert(p->g->sets != NULL); /* xxx */ cs = &p->g->sets[no]; cs->ptr = p->g->setbits + css*((no)/CHAR_BIT); cs->mask = 1 << ((no) % CHAR_BIT); cs->hash = 0; cs->smultis = 0; cs->multis = NULL; return(cs); } /* - freeset - free a now-unused set == static void freeset(struct parse *p, cset *cs); */ static void freeset(p, cs) struct parse *p; cset *cs; { int i; cset *top = &p->g->sets[p->g->ncsets]; size_t css = (size_t)p->g->csetsize; for (i = 0; i < css; i++) CHsub(cs, i); if (cs == top-1) /* recover only the easy case */ p->g->ncsets--; } /* - freezeset - final processing on a set of characters == static int freezeset(struct parse *p, cset *cs); * * The main task here is merging identical sets. This is usually a waste * of time (although the hash code minimizes the overhead), but can win * big if REG_ICASE is being used. REG_ICASE, by the way, is why the hash * is done using addition rather than xor -- all ASCII [aA] sets xor to * the same value! */ static int /* set number */ freezeset(p, cs) struct parse *p; cset *cs; { short h = cs->hash; int i; cset *top = &p->g->sets[p->g->ncsets]; cset *cs2; size_t css = (size_t)p->g->csetsize; /* look for an earlier one which is the same */ for (cs2 = &p->g->sets[0]; cs2 < top; cs2++) if (cs2->hash == h && cs2 != cs) { /* maybe */ for (i = 0; i < css; i++) if (!!CHIN(cs2, i) != !!CHIN(cs, i)) break; /* no */ if (i == css) break; /* yes */ } if (cs2 < top) { /* found one */ freeset(p, cs); cs = cs2; } return((int)(cs - p->g->sets)); } /* - firstch - return first character in a set (which must have at least one) == static int firstch(struct parse *p, cset *cs); */ static int /* character; there is no "none" value */ firstch(p, cs) struct parse *p; cset *cs; { int i; size_t css = (size_t)p->g->csetsize; for (i = 0; i < css; i++) if (CHIN(cs, i)) return((char)i); assert(never); return(0); /* arbitrary */ } /* - nch - number of characters in a set == static int nch(struct parse *p, cset *cs); */ static int nch(p, cs) struct parse *p; cset *cs; { int i; size_t css = (size_t)p->g->csetsize; int n = 0; for (i = 0; i < css; i++) if (CHIN(cs, i)) n++; return(n); } /* - mcadd - add a collating element to a cset == static void mcadd(struct parse *p, cset *cs, \ == char *cp); */ static void mcadd(p, cs, cp) struct parse *p; cset *cs; char *cp; { size_t oldend = cs->smultis; cs->smultis += strlen(cp) + 1; if (cs->multis == NULL) cs->multis = malloc(cs->smultis); else cs->multis = reallocf(cs->multis, cs->smultis); if (cs->multis == NULL) { SETERROR(REG_ESPACE); return; } (void) strcpy(cs->multis + oldend - 1, cp); cs->multis[cs->smultis - 1] = '\0'; } #if used /* - mcsub - subtract a collating element from a cset == static void mcsub(cset *cs, char *cp); */ static void mcsub(cs, cp) cset *cs; char *cp; { char *fp = mcfind(cs, cp); size_t len = strlen(fp); assert(fp != NULL); (void) memmove(fp, fp + len + 1, cs->smultis - (fp + len + 1 - cs->multis)); cs->smultis -= len; if (cs->smultis == 0) { free(cs->multis); cs->multis = NULL; return; } cs->multis = reallocf(cs->multis, cs->smultis); assert(cs->multis != NULL); } /* - mcin - is a collating element in a cset? == static int mcin(cset *cs, char *cp); */ static int mcin(cs, cp) cset *cs; char *cp; { return(mcfind(cs, cp) != NULL); } /* - mcfind - find a collating element in a cset == static char *mcfind(cset *cs, char *cp); */ static char * mcfind(cs, cp) cset *cs; char *cp; { char *p; if (cs->multis == NULL) return(NULL); for (p = cs->multis; *p != '\0'; p += strlen(p) + 1) if (strcmp(cp, p) == 0) return(p); return(NULL); } #endif /* - mcinvert - invert the list of collating elements in a cset == static void mcinvert(struct parse *p, cset *cs); * * This would have to know the set of possibilities. Implementation * is deferred. */ static void mcinvert(p, cs) struct parse *p; cset *cs; { assert(cs->multis == NULL); /* xxx */ } /* - mccase - add case counterparts of the list of collating elements in a cset == static void mccase(struct parse *p, cset *cs); * * This would have to know the set of possibilities. Implementation * is deferred. */ static void mccase(p, cs) struct parse *p; cset *cs; { assert(cs->multis == NULL); /* xxx */ } /* - isinsets - is this character in any sets? == static int isinsets(struct re_guts *g, int c); */ static int /* predicate */ isinsets(g, c) struct re_guts *g; int c; { uch *col; int i; int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT; unsigned uc = (uch)c; for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize) if (col[uc] != 0) return(1); return(0); } /* - samesets - are these two characters in exactly the same sets? == static int samesets(struct re_guts *g, int c1, int c2); */ static int /* predicate */ samesets(g, c1, c2) struct re_guts *g; int c1; int c2; { uch *col; int i; int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT; unsigned uc1 = (uch)c1; unsigned uc2 = (uch)c2; for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize) if (col[uc1] != col[uc2]) return(0); return(1); } /* - categorize - sort out character categories == static void categorize(struct parse *p, struct re_guts *g); */ static void categorize(p, g) struct parse *p; struct re_guts *g; { cat_t *cats = g->categories; int c; int c2; cat_t cat; /* avoid making error situations worse */ if (p->error != 0) return; for (c = CHAR_MIN; c <= CHAR_MAX; c++) if (cats[c] == 0 && isinsets(g, c)) { cat = g->ncategories++; cats[c] = cat; for (c2 = c+1; c2 <= CHAR_MAX; c2++) if (cats[c2] == 0 && samesets(g, c, c2)) cats[c2] = cat; } } /* - dupl - emit a duplicate of a bunch of sops == static sopno dupl(struct parse *p, sopno start, sopno finish); */ static sopno /* start of duplicate */ dupl(p, start, finish) struct parse *p; sopno start; /* from here */ sopno finish; /* to this less one */ { sopno ret = HERE(); sopno len = finish - start; assert(finish >= start); if (len == 0) return(ret); enlarge(p, p->ssize + len); /* this many unexpected additions */ assert(p->ssize >= p->slen + len); (void) memcpy((char *)(p->strip + p->slen), (char *)(p->strip + start), (size_t)len*sizeof(sop)); p->slen += len; return(ret); } /* - doemit - emit a strip operator == static void doemit(struct parse *p, sop op, size_t opnd); * * It might seem better to implement this as a macro with a function as * hard-case backup, but it's just too big and messy unless there are * some changes to the data structures. Maybe later. */ static void doemit(p, op, opnd) struct parse *p; sop op; size_t opnd; { /* avoid making error situations worse */ if (p->error != 0) return; /* deal with oversize operands ("can't happen", more or less) */ assert(opnd < 1<<OPSHIFT); /* deal with undersized strip */ if (p->slen >= p->ssize) enlarge(p, (p->ssize+1) / 2 * 3); /* +50% */ assert(p->slen < p->ssize); /* finally, it's all reduced to the easy case */ p->strip[p->slen++] = SOP(op, opnd); } /* - doinsert - insert a sop into the strip == static void doinsert(struct parse *p, sop op, size_t opnd, sopno pos); */ static void doinsert(p, op, opnd, pos) struct parse *p; sop op; size_t opnd; sopno pos; { sopno sn; sop s; int i; /* avoid making error situations worse */ if (p->error != 0) return; sn = HERE(); EMIT(op, opnd); /* do checks, ensure space */ assert(HERE() == sn+1); s = p->strip[sn]; /* adjust paren pointers */ assert(pos > 0); for (i = 1; i < NPAREN; i++) { if (p->pbegin[i] >= pos) { p->pbegin[i]++; } if (p->pend[i] >= pos) { p->pend[i]++; } } memmove((char *)&p->strip[pos+1], (char *)&p->strip[pos], (HERE()-pos-1)*sizeof(sop)); p->strip[pos] = s; } /* - dofwd - complete a forward reference == static void dofwd(struct parse *p, sopno pos, sop value); */ static void dofwd(p, pos, value) struct parse *p; sopno pos; sop value; { /* avoid making error situations worse */ if (p->error != 0) return; assert(value < 1<<OPSHIFT); p->strip[pos] = OP(p->strip[pos]) | value; } /* - enlarge - enlarge the strip == static void enlarge(struct parse *p, sopno size); */ static void enlarge(p, size) struct parse *p; sopno size; { sop *sp; if (p->ssize >= size) return; sp = (sop *)realloc(p->strip, size*sizeof(sop)); if (sp == NULL) { SETERROR(REG_ESPACE); return; } p->strip = sp; p->ssize = size; } /* - stripsnug - compact the strip == static void stripsnug(struct parse *p, struct re_guts *g); */ static void stripsnug(p, g) struct parse *p; struct re_guts *g; { g->nstates = p->slen; g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop)); if (g->strip == NULL) { SETERROR(REG_ESPACE); g->strip = p->strip; } } /* - findmust - fill in must and mlen with longest mandatory literal string == static void findmust(struct parse *p, struct re_guts *g); * * This algorithm could do fancy things like analyzing the operands of | * for common subsequences. Someday. This code is simple and finds most * of the interesting cases. * * Note that must and mlen got initialized during setup. */ static void findmust(p, g) struct parse *p; struct re_guts *g; { sop *scan; sop *start; sop *newstart; sopno newlen; sop s; char *cp; sopno i; int offset; int cs, mccs; /* avoid making error situations worse */ if (p->error != 0) return; /* Find out if we can handle OANYOF or not */ mccs = 0; for (cs = 0; cs < g->ncsets; cs++) if (g->sets[cs].multis != NULL) mccs = 1; /* find the longest OCHAR sequence in strip */ newlen = 0; offset = 0; g->moffset = 0; scan = g->strip + 1; do { s = *scan++; switch (OP(s)) { case OCHAR: /* sequence member */ if (newlen == 0) /* new sequence */ newstart = scan - 1; newlen++; break; case OPLUS_: /* things that don't break one */ case OLPAREN: case ORPAREN: break; case OQUEST_: /* things that must be skipped */ case OCH_: offset = altoffset(scan, offset, mccs); scan--; do { scan += OPND(s); s = *scan; /* assert() interferes w debug printouts */ if (OP(s) != O_QUEST && OP(s) != O_CH && OP(s) != OOR2) { g->iflags |= BAD; return; } } while (OP(s) != O_QUEST && OP(s) != O_CH); /* fallthrough */ case OBOW: /* things that break a sequence */ case OEOW: case OBOL: case OEOL: case O_QUEST: case O_CH: case OEND: if (newlen > g->mlen) { /* ends one */ start = newstart; g->mlen = newlen; if (offset > -1) { g->moffset += offset; offset = newlen; } else g->moffset = offset; } else { if (offset > -1) offset += newlen; } newlen = 0; break; case OANY: if (newlen > g->mlen) { /* ends one */ start = newstart; g->mlen = newlen; if (offset > -1) { g->moffset += offset; offset = newlen; } else g->moffset = offset; } else { if (offset > -1) offset += newlen; } if (offset > -1) offset++; newlen = 0; break; case OANYOF: /* may or may not invalidate offset */ /* First, everything as OANY */ if (newlen > g->mlen) { /* ends one */ start = newstart; g->mlen = newlen; if (offset > -1) { g->moffset += offset; offset = newlen; } else g->moffset = offset; } else { if (offset > -1) offset += newlen; } if (offset > -1) offset++; newlen = 0; /* And, now, if we found out we can't deal with * it, make offset = -1. */ if (mccs) offset = -1; break; default: /* Anything here makes it impossible or too hard * to calculate the offset -- so we give up; * save the last known good offset, in case the * must sequence doesn't occur later. */ if (newlen > g->mlen) { /* ends one */ start = newstart; g->mlen = newlen; if (offset > -1) g->moffset += offset; else g->moffset = offset; } offset = -1; newlen = 0; break; } } while (OP(s) != OEND); if (g->mlen == 0) { /* there isn't one */ g->moffset = -1; return; } /* turn it into a character string */ g->must = malloc((size_t)g->mlen + 1); if (g->must == NULL) { /* argh; just forget it */ g->mlen = 0; g->moffset = -1; return; } cp = g->must; scan = start; for (i = g->mlen; i > 0; i--) { while (OP(s = *scan++) != OCHAR) continue; assert(cp < g->must + g->mlen); *cp++ = (char)OPND(s); } assert(cp == g->must + g->mlen); *cp++ = '\0'; /* just on general principles */ } /* - altoffset - choose biggest offset among multiple choices == static int altoffset(sop *scan, int offset, int mccs); * * Compute, recursively if necessary, the largest offset among multiple * re paths. */ static int altoffset(scan, offset, mccs) sop *scan; int offset; int mccs; { int largest; int try; sop s; /* If we gave up already on offsets, return */ if (offset == -1) return -1; largest = 0; try = 0; s = *scan++; while (OP(s) != O_QUEST && OP(s) != O_CH) { switch (OP(s)) { case OOR1: if (try > largest) largest = try; try = 0; break; case OQUEST_: case OCH_: try = altoffset(scan, try, mccs); if (try == -1) return -1; scan--; do { scan += OPND(s); s = *scan; if (OP(s) != O_QUEST && OP(s) != O_CH && OP(s) != OOR2) return -1; } while (OP(s) != O_QUEST && OP(s) != O_CH); /* We must skip to the next position, or we'll * leave altoffset() too early. */ scan++; break; case OANYOF: if (mccs) return -1; case OCHAR: case OANY: try++; case OBOW: case OEOW: case OLPAREN: case ORPAREN: case OOR2: break; default: try = -1; break; } if (try == -1) return -1; s = *scan++; } if (try > largest) largest = try; return largest+offset; } /* - computejumps - compute char jumps for BM scan == static void computejumps(struct parse *p, struct re_guts *g); * * This algorithm assumes g->must exists and is has size greater than * zero. It's based on the algorithm found on Computer Algorithms by * Sara Baase. * * A char jump is the number of characters one needs to jump based on * the value of the character from the text that was mismatched. */ static void computejumps(p, g) struct parse *p; struct re_guts *g; { int ch; int mindex; /* Avoid making errors worse */ if (p->error != 0) return; g->charjump = (int*) malloc((NC + 1) * sizeof(int)); if (g->charjump == NULL) /* Not a fatal error */ return; /* Adjust for signed chars, if necessary */ g->charjump = &g->charjump[-(CHAR_MIN)]; /* If the character does not exist in the pattern, the jump * is equal to the number of characters in the pattern. */ for (ch = CHAR_MIN; ch < (CHAR_MAX + 1); ch++) g->charjump[ch] = g->mlen; /* If the character does exist, compute the jump that would * take us to the last character in the pattern equal to it * (notice that we match right to left, so that last character * is the first one that would be matched). */ for (mindex = 0; mindex < g->mlen; mindex++) g->charjump[g->must[mindex]] = g->mlen - mindex - 1; } /* - computematchjumps - compute match jumps for BM scan == static void computematchjumps(struct parse *p, struct re_guts *g); * * This algorithm assumes g->must exists and is has size greater than * zero. It's based on the algorithm found on Computer Algorithms by * Sara Baase. * * A match jump is the number of characters one needs to advance based * on the already-matched suffix. * Notice that all values here are minus (g->mlen-1), because of the way * the search algorithm works. */ static void computematchjumps(p, g) struct parse *p; struct re_guts *g; { int mindex; /* General "must" iterator */ int suffix; /* Keeps track of matching suffix */ int ssuffix; /* Keeps track of suffixes' suffix */ int* pmatches; /* pmatches[k] points to the next i * such that i+1...mlen is a substring * of k+1...k+mlen-i-1 */ /* Avoid making errors worse */ if (p->error != 0) return; pmatches = (int*) malloc(g->mlen * sizeof(unsigned int)); if (pmatches == NULL) { g->matchjump = NULL; return; } g->matchjump = (int*) malloc(g->mlen * sizeof(unsigned int)); if (g->matchjump == NULL) /* Not a fatal error */ return; /* Set maximum possible jump for each character in the pattern */ for (mindex = 0; mindex < g->mlen; mindex++) g->matchjump[mindex] = 2*g->mlen - mindex - 1; /* Compute pmatches[] */ for (mindex = g->mlen - 1, suffix = g->mlen; mindex >= 0; mindex--, suffix--) { pmatches[mindex] = suffix; /* If a mismatch is found, interrupting the substring, * compute the matchjump for that position. If no * mismatch is found, then a text substring mismatched * against the suffix will also mismatch against the * substring. */ while (suffix < g->mlen && g->must[mindex] != g->must[suffix]) { g->matchjump[suffix] = MIN(g->matchjump[suffix], g->mlen - mindex - 1); suffix = pmatches[suffix]; } } /* Compute the matchjump up to the last substring found to jump * to the beginning of the largest must pattern prefix matching * it's own suffix. */ for (mindex = 0; mindex <= suffix; mindex++) g->matchjump[mindex] = MIN(g->matchjump[mindex], g->mlen + suffix - mindex); ssuffix = pmatches[suffix]; while (suffix < g->mlen) { while (suffix <= ssuffix && suffix < g->mlen) { g->matchjump[suffix] = MIN(g->matchjump[suffix], g->mlen + ssuffix - suffix); suffix++; } if (suffix < g->mlen) ssuffix = pmatches[ssuffix]; } free(pmatches); } /* - pluscount - count + nesting == static sopno pluscount(struct parse *p, struct re_guts *g); */ static sopno /* nesting depth */ pluscount(p, g) struct parse *p; struct re_guts *g; { sop *scan; sop s; sopno plusnest = 0; sopno maxnest = 0; if (p->error != 0) return(0); /* there may not be an OEND */ scan = g->strip + 1; do { s = *scan++; switch (OP(s)) { case OPLUS_: plusnest++; break; case O_PLUS: if (plusnest > maxnest) maxnest = plusnest; plusnest--; break; } } while (OP(s) != OEND); if (plusnest != 0) g->iflags |= BAD; return(maxnest); } #endif /* !_NO_REGEX */
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