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regcomp.c
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regcomp.c
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/*
* re_*comp and friends - compile REs
* This file #includes several others (see the bottom).
*
* Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
*
* Development of this software was funded, in part, by Cray Research Inc.,
* UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
* Corporation, none of whom are responsible for the results. The author
* thanks all of them.
*
* Redistribution and use in source and binary forms -- with or without
* modification -- are permitted for any purpose, provided that
* redistributions in source form retain this entire copyright notice and
* indicate the origin and nature of any modifications.
*
* I'd appreciate being given credit for this package in the documentation
* of software which uses it, but that is not a requirement.
*
* THIS SOFTWARE IS PROVIDED ``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
* HENRY SPENCER 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.
*
* src/backend/regex/regcomp.c
*
*/
#include "regex/regguts.h"
/*
* forward declarations, up here so forward datatypes etc. are defined early
*/
/* === regcomp.c === */
static void moresubs(struct vars *, int);
static int freev(struct vars *, int);
static void makesearch(struct vars *, struct nfa *);
static struct subre *parse(struct vars *, int, int, struct state *, struct state *);
static struct subre *parsebranch(struct vars *, int, int, struct state *, struct state *, int);
static struct subre *parseqatom(struct vars *, int, int, struct state *, struct state *, struct subre *);
static void nonword(struct vars *, int, struct state *, struct state *);
static void word(struct vars *, int, struct state *, struct state *);
static void charclass(struct vars *, enum char_classes,
struct state *, struct state *);
static void charclasscomplement(struct vars *, enum char_classes,
struct state *, struct state *);
static int scannum(struct vars *);
static void repeat(struct vars *, struct state *, struct state *, int, int);
static void bracket(struct vars *, struct state *, struct state *);
static void cbracket(struct vars *, struct state *, struct state *);
static void brackpart(struct vars *, struct state *, struct state *, bool *);
static const chr *scanplain(struct vars *);
static void onechr(struct vars *, chr, struct state *, struct state *);
static void optimizebracket(struct vars *, struct state *, struct state *);
static void wordchrs(struct vars *);
static void processlacon(struct vars *, struct state *, struct state *, int,
struct state *, struct state *);
static struct subre *subre(struct vars *, int, int, struct state *, struct state *);
static void freesubre(struct vars *, struct subre *);
static void freesubreandsiblings(struct vars *, struct subre *);
static void freesrnode(struct vars *, struct subre *);
static void optst(struct vars *, struct subre *);
static int numst(struct subre *, int);
static void markst(struct subre *);
static void cleanst(struct vars *);
static long nfatree(struct vars *, struct subre *, FILE *);
static long nfanode(struct vars *, struct subre *, int, FILE *);
static int newlacon(struct vars *, struct state *, struct state *, int);
static void freelacons(struct subre *, int);
static void rfree(regex_t *);
static int rcancelrequested(void);
static int rstacktoodeep(void);
#ifdef REG_DEBUG
static void dump(regex_t *, FILE *);
static void dumpst(struct subre *, FILE *, int);
static void stdump(struct subre *, FILE *, int);
static const char *stid(struct subre *, char *, size_t);
#endif
/* === regc_lex.c === */
static void lexstart(struct vars *);
static void prefixes(struct vars *);
static int next(struct vars *);
static int lexescape(struct vars *);
static chr lexdigits(struct vars *, int, int, int);
static int brenext(struct vars *, chr);
static void skip(struct vars *);
static chr newline(void);
static chr chrnamed(struct vars *, const chr *, const chr *, chr);
/* === regc_color.c === */
static void initcm(struct vars *, struct colormap *);
static void freecm(struct colormap *);
static color maxcolor(struct colormap *);
static color newcolor(struct colormap *);
static void freecolor(struct colormap *, color);
static color pseudocolor(struct colormap *);
static color subcolor(struct colormap *, chr);
static color subcolorhi(struct colormap *, color *);
static color newsub(struct colormap *, color);
static int newhicolorrow(struct colormap *, int);
static void newhicolorcols(struct colormap *);
static void subcolorcvec(struct vars *, struct cvec *, struct state *, struct state *);
static void subcoloronechr(struct vars *, chr, struct state *, struct state *, color *);
static void subcoloronerange(struct vars *, chr, chr, struct state *, struct state *, color *);
static void subcoloronerow(struct vars *, int, struct state *, struct state *, color *);
static void okcolors(struct nfa *, struct colormap *);
static void colorchain(struct colormap *, struct arc *);
static void uncolorchain(struct colormap *, struct arc *);
static void rainbow(struct nfa *, struct colormap *, int, color, struct state *, struct state *);
static void colorcomplement(struct nfa *, struct colormap *, int, struct state *, struct state *, struct state *);
#ifdef REG_DEBUG
static void dumpcolors(struct colormap *, FILE *);
static void dumpchr(chr, FILE *);
#endif
/* === regc_nfa.c === */
static struct nfa *newnfa(struct vars *, struct colormap *, struct nfa *);
static void freenfa(struct nfa *);
static struct state *newstate(struct nfa *);
static struct state *newfstate(struct nfa *, int flag);
static void dropstate(struct nfa *, struct state *);
static void freestate(struct nfa *, struct state *);
static void newarc(struct nfa *, int, color, struct state *, struct state *);
static void createarc(struct nfa *, int, color, struct state *, struct state *);
static struct arc *allocarc(struct nfa *);
static void freearc(struct nfa *, struct arc *);
static void changearcsource(struct arc *, struct state *);
static void changearctarget(struct arc *, struct state *);
static int hasnonemptyout(struct state *);
static struct arc *findarc(struct state *, int, color);
static void cparc(struct nfa *, struct arc *, struct state *, struct state *);
static void sortins(struct nfa *, struct state *);
static int sortins_cmp(const void *, const void *);
static void sortouts(struct nfa *, struct state *);
static int sortouts_cmp(const void *, const void *);
static void moveins(struct nfa *, struct state *, struct state *);
static void copyins(struct nfa *, struct state *, struct state *);
static void mergeins(struct nfa *, struct state *, struct arc **, int);
static void moveouts(struct nfa *, struct state *, struct state *);
static void copyouts(struct nfa *, struct state *, struct state *);
static void cloneouts(struct nfa *, struct state *, struct state *, struct state *, int);
static void delsub(struct nfa *, struct state *, struct state *);
static void deltraverse(struct nfa *, struct state *, struct state *);
static void dupnfa(struct nfa *, struct state *, struct state *, struct state *, struct state *);
static void duptraverse(struct nfa *, struct state *, struct state *);
static void removeconstraints(struct nfa *, struct state *, struct state *);
static void removetraverse(struct nfa *, struct state *);
static void cleartraverse(struct nfa *, struct state *);
static struct state *single_color_transition(struct state *, struct state *);
static void specialcolors(struct nfa *);
static long optimize(struct nfa *, FILE *);
static void pullback(struct nfa *, FILE *);
static int pull(struct nfa *, struct arc *, struct state **);
static void pushfwd(struct nfa *, FILE *);
static int push(struct nfa *, struct arc *, struct state **);
#define INCOMPATIBLE 1 /* destroys arc */
#define SATISFIED 2 /* constraint satisfied */
#define COMPATIBLE 3 /* compatible but not satisfied yet */
#define REPLACEARC 4 /* replace arc's color with constraint color */
static int combine(struct nfa *nfa, struct arc *con, struct arc *a);
static void fixempties(struct nfa *, FILE *);
static struct state *emptyreachable(struct nfa *, struct state *,
struct state *, struct arc **);
static int isconstraintarc(struct arc *);
static int hasconstraintout(struct state *);
static void fixconstraintloops(struct nfa *, FILE *);
static int findconstraintloop(struct nfa *, struct state *);
static void breakconstraintloop(struct nfa *, struct state *);
static void clonesuccessorstates(struct nfa *, struct state *, struct state *,
struct state *, struct arc *,
char *, char *, int);
static void cleanup(struct nfa *);
static void markreachable(struct nfa *, struct state *, struct state *, struct state *);
static void markcanreach(struct nfa *, struct state *, struct state *, struct state *);
static long analyze(struct nfa *);
static void checkmatchall(struct nfa *);
static bool checkmatchall_recurse(struct nfa *, struct state *, bool **);
static bool check_out_colors_match(struct state *, color, color);
static bool check_in_colors_match(struct state *, color, color);
static void compact(struct nfa *, struct cnfa *);
static void carcsort(struct carc *, size_t);
static int carc_cmp(const void *, const void *);
static void freecnfa(struct cnfa *);
static void dumpnfa(struct nfa *, FILE *);
#ifdef REG_DEBUG
static void dumpstate(struct state *, FILE *);
static void dumparcs(struct state *, FILE *);
static void dumparc(struct arc *, struct state *, FILE *);
static void dumpcnfa(struct cnfa *, FILE *);
static void dumpcstate(int, struct cnfa *, FILE *);
#endif
/* === regc_cvec.c === */
static struct cvec *newcvec(int, int);
static struct cvec *clearcvec(struct cvec *);
static void addchr(struct cvec *, chr);
static void addrange(struct cvec *, chr, chr);
static struct cvec *getcvec(struct vars *, int, int);
static void freecvec(struct cvec *);
/* === regc_pg_locale.c === */
static int pg_wc_isdigit(pg_wchar c);
static int pg_wc_isalpha(pg_wchar c);
static int pg_wc_isalnum(pg_wchar c);
static int pg_wc_isword(pg_wchar c);
static int pg_wc_isupper(pg_wchar c);
static int pg_wc_islower(pg_wchar c);
static int pg_wc_isgraph(pg_wchar c);
static int pg_wc_isprint(pg_wchar c);
static int pg_wc_ispunct(pg_wchar c);
static int pg_wc_isspace(pg_wchar c);
static pg_wchar pg_wc_toupper(pg_wchar c);
static pg_wchar pg_wc_tolower(pg_wchar c);
/* === regc_locale.c === */
static chr element(struct vars *, const chr *, const chr *);
static struct cvec *range(struct vars *, chr, chr, int);
static int before(chr, chr);
static struct cvec *eclass(struct vars *, chr, int);
static enum char_classes lookupcclass(struct vars *, const chr *, const chr *);
static struct cvec *cclasscvec(struct vars *, enum char_classes, int);
static int cclass_column_index(struct colormap *, chr);
static struct cvec *allcases(struct vars *, chr);
static int cmp(const chr *, const chr *, size_t);
static int casecmp(const chr *, const chr *, size_t);
/* internal variables, bundled for easy passing around */
struct vars
{
regex_t *re;
const chr *now; /* scan pointer into string */
const chr *stop; /* end of string */
int err; /* error code (0 if none) */
int cflags; /* copy of compile flags */
int lasttype; /* type of previous token */
int nexttype; /* type of next token */
chr nextvalue; /* value (if any) of next token */
int lexcon; /* lexical context type (see regc_lex.c) */
int nsubexp; /* subexpression count */
struct subre **subs; /* subRE pointer vector */
size_t nsubs; /* length of vector */
struct subre *sub10[10]; /* initial vector, enough for most */
struct nfa *nfa; /* the NFA */
struct colormap *cm; /* character color map */
color nlcolor; /* color of newline */
struct state *wordchrs; /* state in nfa holding word-char outarcs */
struct subre *tree; /* subexpression tree */
struct subre *treechain; /* all tree nodes allocated */
struct subre *treefree; /* any free tree nodes */
int ntree; /* number of tree nodes, plus one */
struct cvec *cv; /* interface cvec */
struct cvec *cv2; /* utility cvec */
struct subre *lacons; /* lookaround-constraint vector */
int nlacons; /* size of lacons[]; note that only slots
* numbered 1 .. nlacons-1 are used */
size_t spaceused; /* approx. space used for compilation */
};
/* parsing macros; most know that `v' is the struct vars pointer */
#define NEXT() (next(v)) /* advance by one token */
#define SEE(t) (v->nexttype == (t)) /* is next token this? */
#define EAT(t) (SEE(t) && next(v)) /* if next is this, swallow it */
#define VISERR(vv) ((vv)->err != 0) /* have we seen an error yet? */
#define ISERR() VISERR(v)
#define VERR(vv,e) ((vv)->nexttype = EOS, \
(vv)->err = ((vv)->err ? (vv)->err : (e)))
#define ERR(e) VERR(v, e) /* record an error */
#define NOERR() {if (ISERR()) return;} /* if error seen, return */
#define NOERRN() {if (ISERR()) return NULL;} /* NOERR with retval */
#define NOERRZ() {if (ISERR()) return 0;} /* NOERR with retval */
#define INSIST(c, e) do { if (!(c)) ERR(e); } while (0) /* error if c false */
#define NOTE(b) (v->re->re_info |= (b)) /* note visible condition */
#define EMPTYARC(x, y) newarc(v->nfa, EMPTY, 0, x, y)
/* token type codes, some also used as NFA arc types */
#define EMPTY 'n' /* no token present */
#define EOS 'e' /* end of string */
#define PLAIN 'p' /* ordinary character */
#define DIGIT 'd' /* digit (in bound) */
#define BACKREF 'b' /* back reference */
#define COLLEL 'I' /* start of [. */
#define ECLASS 'E' /* start of [= */
#define CCLASS 'C' /* start of [: */
#define END 'X' /* end of [. [= [: */
#define CCLASSS 's' /* char class shorthand escape */
#define CCLASSC 'c' /* complement char class shorthand escape */
#define RANGE 'R' /* - within [] which might be range delim. */
#define LACON 'L' /* lookaround constraint subRE */
#define AHEAD 'a' /* color-lookahead arc */
#define BEHIND 'r' /* color-lookbehind arc */
#define WBDRY 'w' /* word boundary constraint */
#define NWBDRY 'W' /* non-word-boundary constraint */
#define SBEGIN 'A' /* beginning of string (even if not BOL) */
#define SEND 'Z' /* end of string (even if not EOL) */
/* is an arc colored, and hence should belong to a color chain? */
/* the test on "co" eliminates RAINBOW arcs, which we don't bother to chain */
#define COLORED(a) \
((a)->co >= 0 && \
((a)->type == PLAIN || (a)->type == AHEAD || (a)->type == BEHIND))
/* static function list */
static const struct fns functions = {
rfree, /* regfree insides */
rcancelrequested, /* check for cancel request */
rstacktoodeep /* check for stack getting dangerously deep */
};
/*
* pg_regcomp - compile regular expression
*
* Note: on failure, no resources remain allocated, so pg_regfree()
* need not be applied to re.
*/
int
pg_regcomp(regex_t *re,
const chr *string,
size_t len,
int flags,
Oid collation)
{
struct vars var;
struct vars *v = &var;
struct guts *g;
int i;
size_t j;
#ifdef REG_DEBUG
FILE *debug = (flags & REG_PROGRESS) ? stdout : (FILE *) NULL;
#else
FILE *debug = (FILE *) NULL;
#endif
#define CNOERR() { if (ISERR()) return freev(v, v->err); }
/* sanity checks */
if (re == NULL || string == NULL)
return REG_INVARG;
if ((flags & REG_QUOTE) &&
(flags & (REG_ADVANCED | REG_EXPANDED | REG_NEWLINE)))
return REG_INVARG;
if (!(flags & REG_EXTENDED) && (flags & REG_ADVF))
return REG_INVARG;
/* Initialize locale-dependent support */
pg_set_regex_collation(collation);
/* initial setup (after which freev() is callable) */
v->re = re;
v->now = string;
v->stop = v->now + len;
v->err = 0;
v->cflags = flags;
v->nsubexp = 0;
v->subs = v->sub10;
v->nsubs = 10;
for (j = 0; j < v->nsubs; j++)
v->subs[j] = NULL;
v->nfa = NULL;
v->cm = NULL;
v->nlcolor = COLORLESS;
v->wordchrs = NULL;
v->tree = NULL;
v->treechain = NULL;
v->treefree = NULL;
v->cv = NULL;
v->cv2 = NULL;
v->lacons = NULL;
v->nlacons = 0;
v->spaceused = 0;
re->re_magic = REMAGIC;
re->re_info = 0; /* bits get set during parse */
re->re_csize = sizeof(chr);
re->re_collation = collation;
re->re_guts = NULL;
re->re_fns = VS(&functions);
/* more complex setup, malloced things */
re->re_guts = VS(MALLOC(sizeof(struct guts)));
if (re->re_guts == NULL)
return freev(v, REG_ESPACE);
g = (struct guts *) re->re_guts;
g->tree = NULL;
initcm(v, &g->cmap);
v->cm = &g->cmap;
g->lacons = NULL;
g->nlacons = 0;
ZAPCNFA(g->search);
v->nfa = newnfa(v, v->cm, (struct nfa *) NULL);
CNOERR();
/* set up a reasonably-sized transient cvec for getcvec usage */
v->cv = newcvec(100, 20);
if (v->cv == NULL)
return freev(v, REG_ESPACE);
/* parsing */
lexstart(v); /* also handles prefixes */
if ((v->cflags & REG_NLSTOP) || (v->cflags & REG_NLANCH))
{
/* assign newline a unique color */
v->nlcolor = subcolor(v->cm, newline());
okcolors(v->nfa, v->cm);
}
CNOERR();
v->tree = parse(v, EOS, PLAIN, v->nfa->init, v->nfa->final);
assert(SEE(EOS)); /* even if error; ISERR() => SEE(EOS) */
CNOERR();
assert(v->tree != NULL);
/* finish setup of nfa and its subre tree */
specialcolors(v->nfa);
CNOERR();
#ifdef REG_DEBUG
if (debug != NULL)
{
fprintf(debug, "\n\n\n========= RAW ==========\n");
dumpnfa(v->nfa, debug);
dumpst(v->tree, debug, 1);
}
#endif
optst(v, v->tree);
v->ntree = numst(v->tree, 1);
markst(v->tree);
cleanst(v);
#ifdef REG_DEBUG
if (debug != NULL)
{
fprintf(debug, "\n\n\n========= TREE FIXED ==========\n");
dumpst(v->tree, debug, 1);
}
#endif
/* build compacted NFAs for tree and lacons */
re->re_info |= nfatree(v, v->tree, debug);
CNOERR();
assert(v->nlacons == 0 || v->lacons != NULL);
for (i = 1; i < v->nlacons; i++)
{
struct subre *lasub = &v->lacons[i];
#ifdef REG_DEBUG
if (debug != NULL)
fprintf(debug, "\n\n\n========= LA%d ==========\n", i);
#endif
/* Prepend .* to pattern if it's a lookbehind LACON */
nfanode(v, lasub, !LATYPE_IS_AHEAD(lasub->latype), debug);
}
CNOERR();
if (v->tree->flags & SHORTER)
NOTE(REG_USHORTEST);
/* build compacted NFAs for tree, lacons, fast search */
#ifdef REG_DEBUG
if (debug != NULL)
fprintf(debug, "\n\n\n========= SEARCH ==========\n");
#endif
/* can sacrifice main NFA now, so use it as work area */
(DISCARD) optimize(v->nfa, debug);
CNOERR();
makesearch(v, v->nfa);
CNOERR();
compact(v->nfa, &g->search);
CNOERR();
/* looks okay, package it up */
re->re_nsub = v->nsubexp;
v->re = NULL; /* freev no longer frees re */
g->magic = GUTSMAGIC;
g->cflags = v->cflags;
g->info = re->re_info;
g->nsub = re->re_nsub;
g->tree = v->tree;
v->tree = NULL;
g->ntree = v->ntree;
g->compare = (v->cflags & REG_ICASE) ? casecmp : cmp;
g->lacons = v->lacons;
v->lacons = NULL;
g->nlacons = v->nlacons;
#ifdef REG_DEBUG
if (flags & REG_DUMP)
{
dump(re, stdout);
fflush(stdout);
}
#endif
assert(v->err == 0);
return freev(v, 0);
}
/*
* moresubs - enlarge subRE vector
*/
static void
moresubs(struct vars *v,
int wanted) /* want enough room for this one */
{
struct subre **p;
size_t n;
assert(wanted > 0 && (size_t) wanted >= v->nsubs);
n = (size_t) wanted * 3 / 2 + 1;
if (v->subs == v->sub10)
{
p = (struct subre **) MALLOC(n * sizeof(struct subre *));
if (p != NULL)
memcpy(VS(p), VS(v->subs),
v->nsubs * sizeof(struct subre *));
}
else
p = (struct subre **) REALLOC(v->subs, n * sizeof(struct subre *));
if (p == NULL)
{
ERR(REG_ESPACE);
return;
}
v->subs = p;
for (p = &v->subs[v->nsubs]; v->nsubs < n; p++, v->nsubs++)
*p = NULL;
assert(v->nsubs == n);
assert((size_t) wanted < v->nsubs);
}
/*
* freev - free vars struct's substructures where necessary
*
* Optionally does error-number setting, and always returns error code
* (if any), to make error-handling code terser.
*/
static int
freev(struct vars *v,
int err)
{
if (v->re != NULL)
rfree(v->re);
if (v->subs != v->sub10)
FREE(v->subs);
if (v->nfa != NULL)
freenfa(v->nfa);
if (v->tree != NULL)
freesubre(v, v->tree);
if (v->treechain != NULL)
cleanst(v);
if (v->cv != NULL)
freecvec(v->cv);
if (v->cv2 != NULL)
freecvec(v->cv2);
if (v->lacons != NULL)
freelacons(v->lacons, v->nlacons);
ERR(err); /* nop if err==0 */
return v->err;
}
/*
* makesearch - turn an NFA into a search NFA (implicit prepend of .*?)
* NFA must have been optimize()d already.
*/
static void
makesearch(struct vars *v,
struct nfa *nfa)
{
struct arc *a;
struct arc *b;
struct state *pre = nfa->pre;
struct state *s;
struct state *s2;
struct state *slist;
/* no loops are needed if it's anchored */
for (a = pre->outs; a != NULL; a = a->outchain)
{
assert(a->type == PLAIN);
if (a->co != nfa->bos[0] && a->co != nfa->bos[1])
break;
}
if (a != NULL)
{
/* add implicit .* in front */
rainbow(nfa, v->cm, PLAIN, COLORLESS, pre, pre);
/* and ^* and \A* too -- not always necessary, but harmless */
newarc(nfa, PLAIN, nfa->bos[0], pre, pre);
newarc(nfa, PLAIN, nfa->bos[1], pre, pre);
}
/*
* Now here's the subtle part. Because many REs have no lookback
* constraints, often knowing when you were in the pre state tells you
* little; it's the next state(s) that are informative. But some of them
* may have other inarcs, i.e. it may be possible to make actual progress
* and then return to one of them. We must de-optimize such cases,
* splitting each such state into progress and no-progress states.
*/
/* first, make a list of the states reachable from pre and elsewhere */
slist = NULL;
for (a = pre->outs; a != NULL; a = a->outchain)
{
s = a->to;
for (b = s->ins; b != NULL; b = b->inchain)
{
if (b->from != pre)
break;
}
/*
* We want to mark states as being in the list already by having non
* NULL tmp fields, but we can't just store the old slist value in tmp
* because that doesn't work for the first such state. Instead, the
* first list entry gets its own address in tmp.
*/
if (b != NULL && s->tmp == NULL)
{
s->tmp = (slist != NULL) ? slist : s;
slist = s;
}
}
/* do the splits */
for (s = slist; s != NULL; s = s2)
{
s2 = newstate(nfa);
NOERR();
copyouts(nfa, s, s2);
NOERR();
for (a = s->ins; a != NULL; a = b)
{
b = a->inchain;
if (a->from != pre)
{
cparc(nfa, a, a->from, s2);
freearc(nfa, a);
}
}
s2 = (s->tmp != s) ? s->tmp : NULL;
s->tmp = NULL; /* clean up while we're at it */
}
}
/*
* parse - parse an RE
*
* This is actually just the top level, which parses a bunch of branches
* tied together with '|'. If there's more than one, they appear in the
* tree as the children of a '|' subre.
*/
static struct subre *
parse(struct vars *v,
int stopper, /* EOS or ')' */
int type, /* LACON (lookaround subRE) or PLAIN */
struct state *init, /* initial state */
struct state *final) /* final state */
{
struct subre *branches; /* top level */
struct subre *lastbranch; /* latest branch */
assert(stopper == ')' || stopper == EOS);
branches = subre(v, '|', LONGER, init, final);
NOERRN();
lastbranch = NULL;
do
{ /* a branch */
struct subre *branch;
struct state *left; /* scaffolding for branch */
struct state *right;
left = newstate(v->nfa);
right = newstate(v->nfa);
NOERRN();
EMPTYARC(init, left);
EMPTYARC(right, final);
NOERRN();
branch = parsebranch(v, stopper, type, left, right, 0);
NOERRN();
if (lastbranch)
lastbranch->sibling = branch;
else
branches->child = branch;
branches->flags |= UP(branches->flags | branch->flags);
lastbranch = branch;
} while (EAT('|'));
assert(SEE(stopper) || SEE(EOS));
if (!SEE(stopper))
{
assert(stopper == ')' && SEE(EOS));
ERR(REG_EPAREN);
}
/* optimize out simple cases */
if (lastbranch == branches->child)
{ /* only one branch */
assert(lastbranch->sibling == NULL);
freesrnode(v, branches);
branches = lastbranch;
}
else if (!MESSY(branches->flags))
{ /* no interesting innards */
freesubreandsiblings(v, branches->child);
branches->child = NULL;
branches->op = '=';
}
return branches;
}
/*
* parsebranch - parse one branch of an RE
*
* This mostly manages concatenation, working closely with parseqatom().
* Concatenated things are bundled up as much as possible, with separate
* '.' nodes introduced only when necessary due to substructure.
*/
static struct subre *
parsebranch(struct vars *v,
int stopper, /* EOS or ')' */
int type, /* LACON (lookaround subRE) or PLAIN */
struct state *left, /* leftmost state */
struct state *right, /* rightmost state */
int partial) /* is this only part of a branch? */
{
struct state *lp; /* left end of current construct */
int seencontent; /* is there anything in this branch yet? */
struct subre *t;
lp = left;
seencontent = 0;
t = subre(v, '=', 0, left, right); /* op '=' is tentative */
NOERRN();
while (!SEE('|') && !SEE(stopper) && !SEE(EOS))
{
if (seencontent)
{ /* implicit concat operator */
lp = newstate(v->nfa);
NOERRN();
moveins(v->nfa, right, lp);
}
seencontent = 1;
/* NB, recursion in parseqatom() may swallow rest of branch */
t = parseqatom(v, stopper, type, lp, right, t);
NOERRN();
}
if (!seencontent)
{ /* empty branch */
if (!partial)
NOTE(REG_UUNSPEC);
assert(lp == left);
EMPTYARC(left, right);
}
return t;
}
/*
* parseqatom - parse one quantified atom or constraint of an RE
*
* The bookkeeping near the end cooperates very closely with parsebranch();
* in particular, it contains a recursion that can involve parsing the rest
* of the branch, making this function's name somewhat inaccurate.
*
* Usually, the return value is just "top", but in some cases where we
* have parsed the rest of the branch, we may deem "top" redundant and
* free it, returning some child subre instead.
*/
static struct subre *
parseqatom(struct vars *v,
int stopper, /* EOS or ')' */
int type, /* LACON (lookaround subRE) or PLAIN */
struct state *lp, /* left state to hang it on */
struct state *rp, /* right state to hang it on */
struct subre *top) /* subtree top */
{
struct state *s; /* temporaries for new states */
struct state *s2;
#define ARCV(t, val) newarc(v->nfa, t, val, lp, rp)
int m,
n;
struct subre *atom; /* atom's subtree */
struct subre *t;
int cap; /* capturing parens? */
int latype; /* lookaround constraint type */
int subno; /* capturing-parens or backref number */
int atomtype;
int qprefer; /* quantifier short/long preference */
int f;
struct subre **atomp; /* where the pointer to atom is */
/* initial bookkeeping */
atom = NULL;
assert(lp->nouts == 0); /* must string new code */
assert(rp->nins == 0); /* between lp and rp */
subno = 0; /* just to shut lint up */
/* an atom or constraint... */
atomtype = v->nexttype;
switch (atomtype)
{
/* first, constraints, which end by returning */
case '^':
ARCV('^', 1);
if (v->cflags & REG_NLANCH)
ARCV(BEHIND, v->nlcolor);
NEXT();
return top;
break;
case '$':
ARCV('$', 1);
if (v->cflags & REG_NLANCH)
ARCV(AHEAD, v->nlcolor);
NEXT();
return top;
break;
case SBEGIN:
ARCV('^', 1); /* BOL */
ARCV('^', 0); /* or BOS */
NEXT();
return top;
break;
case SEND:
ARCV('$', 1); /* EOL */
ARCV('$', 0); /* or EOS */
NEXT();
return top;
break;
case '<':
wordchrs(v);
s = newstate(v->nfa);
NOERRN();
nonword(v, BEHIND, lp, s);
word(v, AHEAD, s, rp);
NEXT();
return top;
break;
case '>':
wordchrs(v);
s = newstate(v->nfa);
NOERRN();
word(v, BEHIND, lp, s);
nonword(v, AHEAD, s, rp);
NEXT();
return top;
break;
case WBDRY:
wordchrs(v);
s = newstate(v->nfa);
NOERRN();
nonword(v, BEHIND, lp, s);
word(v, AHEAD, s, rp);
s = newstate(v->nfa);
NOERRN();
word(v, BEHIND, lp, s);
nonword(v, AHEAD, s, rp);
NEXT();
return top;
break;
case NWBDRY:
wordchrs(v);
s = newstate(v->nfa);
NOERRN();
word(v, BEHIND, lp, s);
word(v, AHEAD, s, rp);
s = newstate(v->nfa);
NOERRN();
nonword(v, BEHIND, lp, s);
nonword(v, AHEAD, s, rp);
NEXT();
return top;
break;
case LACON: /* lookaround constraint */
latype = v->nextvalue;
NEXT();
s = newstate(v->nfa);
s2 = newstate(v->nfa);
NOERRN();
t = parse(v, ')', LACON, s, s2);
freesubre(v, t); /* internal structure irrelevant */
NOERRN();
assert(SEE(')'));
NEXT();
processlacon(v, s, s2, latype, lp, rp);
return top;
break;
/* then errors, to get them out of the way */
case '*':
case '+':
case '?':
case '{':
ERR(REG_BADRPT);
return top;
break;
default:
ERR(REG_ASSERT);
return top;
break;
/* then plain characters, and minor variants on that theme */
case ')': /* unbalanced paren */
if ((v->cflags & REG_ADVANCED) != REG_EXTENDED)
{
ERR(REG_EPAREN);
return top;
}
/* legal in EREs due to specification botch */
NOTE(REG_UPBOTCH);
/* fall through into case PLAIN */
/* FALLTHROUGH */
case PLAIN:
onechr(v, v->nextvalue, lp, rp);
okcolors(v->nfa, v->cm);
NOERRN();
NEXT();
break;
case '[':
if (v->nextvalue == 1)
bracket(v, lp, rp);
else
cbracket(v, lp, rp);
assert(SEE(']') || ISERR());
NEXT();
break;
case CCLASSS:
charclass(v, (enum char_classes) v->nextvalue, lp, rp);
okcolors(v->nfa, v->cm);
NEXT();
break;
case CCLASSC:
charclasscomplement(v, (enum char_classes) v->nextvalue, lp, rp);
/* charclasscomplement() did okcolors() internally */
NEXT();
break;
case '.':
rainbow(v->nfa, v->cm, PLAIN,
(v->cflags & REG_NLSTOP) ? v->nlcolor : COLORLESS,
lp, rp);
NEXT();
break;
/* and finally the ugly stuff */
case '(': /* value flags as capturing or non */
cap = (type == LACON) ? 0 : v->nextvalue;
if (cap)
{
v->nsubexp++;
subno = v->nsubexp;
if ((size_t) subno >= v->nsubs)
moresubs(v, subno);
}
else
atomtype = PLAIN; /* something that's not '(' */
NEXT();
/*
* Make separate endpoint states to keep this sub-NFA distinct
* from what surrounds it. We need to be sure that when we
* duplicate the sub-NFA for a backref, we get the right
* states/arcs and no others. In particular, letting a backref
* duplicate the sub-NFA from lp to rp would be quite wrong,
* because we may add quantification superstructure around this
* atom below. (Perhaps we could skip the extra states for
* non-capturing parens, but it seems not worth the trouble.)
*/
s = newstate(v->nfa);
s2 = newstate(v->nfa);
NOERRN();
/* We may not need these arcs, but keep things connected for now */
EMPTYARC(lp, s);
EMPTYARC(s2, rp);
NOERRN();
atom = parse(v, ')', type, s, s2);
assert(SEE(')') || ISERR());
NEXT();
NOERRN();
if (cap)
{
if (atom->capno == 0)
{
/* normal case: just mark the atom as capturing */
atom->flags |= CAP;
atom->capno = subno;
}
else