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postgresql/src/backend/regex/regc_lex.c
Tom Lane 0e6aa8747d Avoid determining regexp subexpression matches, when possible. 
Identifying the precise match locations for parenthesized subexpressions
is a fairly expensive task given the way our regexp engine works, both
at regexp compile time (where we must create an optimized NFA for each
parenthesized subexpression) and at runtime (where determining exact
match locations requires laborious search).

Up to now we've made little attempt to optimize this situation.  This
patch identifies cases where we know at compile time that we won't
need to know subexpression match locations, and teaches the regexp
compiler to not bother creating per-subexpression regexps for
parenthesis pairs that are not referenced by backrefs elsewhere in
the regexp.  (To preserve semantics, we obviously still have to
pin down the match locations of backref references.)  Users could
have obtained the same results before this by being careful to
write "non capturing" parentheses wherever possible, but few people
bother with that.

Discussion: https://postgr.es/m/2219936.1628115334@sss.pgh.pa.us
2021-08-09 11:26:34 -04:00

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/*
* lexical analyzer
* This file is #included by regcomp.c.
*
* 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/regc_lex.c
*
*/
/* scanning macros (know about v) */
#define ATEOS() (v->now >= v->stop)
#define HAVE(n) (v->stop - v->now >= (n))
#define NEXT1(c) (!ATEOS() && *v->now == CHR(c))
#define NEXT2(a,b) (HAVE(2) && *v->now == CHR(a) && *(v->now+1) == CHR(b))
#define NEXT3(a,b,c) (HAVE(3) && *v->now == CHR(a) && \
*(v->now+1) == CHR(b) && \
*(v->now+2) == CHR(c))
#define SET(c) (v->nexttype = (c))
#define SETV(c, n) (v->nexttype = (c), v->nextvalue = (n))
#define RET(c) return (SET(c), 1)
#define RETV(c, n) return (SETV(c, n), 1)
#define FAILW(e) return (ERR(e), 0) /* ERR does SET(EOS) */
#define LASTTYPE(t) (v->lasttype == (t))
/* lexical contexts */
#define L_ERE 1 /* mainline ERE/ARE */
#define L_BRE 2 /* mainline BRE */
#define L_Q 3 /* REG_QUOTE */
#define L_EBND 4 /* ERE/ARE bound */
#define L_BBND 5 /* BRE bound */
#define L_BRACK 6 /* brackets */
#define L_CEL 7 /* collating element */
#define L_ECL 8 /* equivalence class */
#define L_CCL 9 /* character class */
#define INTOCON(c) (v->lexcon = (c))
#define INCON(con) (v->lexcon == (con))
/* construct pointer past end of chr array */
#define ENDOF(array) ((array) + sizeof(array)/sizeof(chr))
/*
* lexstart - set up lexical stuff, scan leading options
*/
static void
lexstart(struct vars *v)
{
prefixes(v); /* may turn on new type bits etc. */
NOERR();
if (v->cflags & REG_QUOTE)
{
assert(!(v->cflags & (REG_ADVANCED | REG_EXPANDED | REG_NEWLINE)));
INTOCON(L_Q);
}
else if (v->cflags & REG_EXTENDED)
{
assert(!(v->cflags & REG_QUOTE));
INTOCON(L_ERE);
}
else
{
assert(!(v->cflags & (REG_QUOTE | REG_ADVF)));
INTOCON(L_BRE);
}
v->nexttype = EMPTY; /* remember we were at the start */
next(v); /* set up the first token */
}
/*
* prefixes - implement various special prefixes
*/
static void
prefixes(struct vars *v)
{
/* literal string doesn't get any of this stuff */
if (v->cflags & REG_QUOTE)
return;
/* initial "***" gets special things */
if (HAVE(4) && NEXT3('*', '*', '*'))
switch (*(v->now + 3))
{
case CHR('?'): /* "***?" error, msg shows version */
ERR(REG_BADPAT);
return; /* proceed no further */
break;
case CHR('='): /* "***=" shifts to literal string */
NOTE(REG_UNONPOSIX);
v->cflags |= REG_QUOTE;
v->cflags &= ~(REG_ADVANCED | REG_EXPANDED | REG_NEWLINE);
v->now += 4;
return; /* and there can be no more prefixes */
break;
case CHR(':'): /* "***:" shifts to AREs */
NOTE(REG_UNONPOSIX);
v->cflags |= REG_ADVANCED;
v->now += 4;
break;
default: /* otherwise *** is just an error */
ERR(REG_BADRPT);
return;
break;
}
/* BREs and EREs don't get embedded options */
if ((v->cflags & REG_ADVANCED) != REG_ADVANCED)
return;
/* embedded options (AREs only) */
if (HAVE(3) && NEXT2('(', '?') && iscalpha(*(v->now + 2)))
{
NOTE(REG_UNONPOSIX);
v->now += 2;
for (; !ATEOS() && iscalpha(*v->now); v->now++)
switch (*v->now)
{
case CHR('b'): /* BREs (but why???) */
v->cflags &= ~(REG_ADVANCED | REG_QUOTE);
break;
case CHR('c'): /* case sensitive */
v->cflags &= ~REG_ICASE;
break;
case CHR('e'): /* plain EREs */
v->cflags |= REG_EXTENDED;
v->cflags &= ~(REG_ADVF | REG_QUOTE);
break;
case CHR('i'): /* case insensitive */
v->cflags |= REG_ICASE;
break;
case CHR('m'): /* Perloid synonym for n */
case CHR('n'): /* \n affects ^ $ . [^ */
v->cflags |= REG_NEWLINE;
break;
case CHR('p'): /* ~Perl, \n affects . [^ */
v->cflags |= REG_NLSTOP;
v->cflags &= ~REG_NLANCH;
break;
case CHR('q'): /* literal string */
v->cflags |= REG_QUOTE;
v->cflags &= ~REG_ADVANCED;
break;
case CHR('s'): /* single line, \n ordinary */
v->cflags &= ~REG_NEWLINE;
break;
case CHR('t'): /* tight syntax */
v->cflags &= ~REG_EXPANDED;
break;
case CHR('w'): /* weird, \n affects ^ $ only */
v->cflags &= ~REG_NLSTOP;
v->cflags |= REG_NLANCH;
break;
case CHR('x'): /* expanded syntax */
v->cflags |= REG_EXPANDED;
break;
default:
ERR(REG_BADOPT);
return;
}
if (!NEXT1(')'))
{
ERR(REG_BADOPT);
return;
}
v->now++;
if (v->cflags & REG_QUOTE)
v->cflags &= ~(REG_EXPANDED | REG_NEWLINE);
}
}
/*
* next - get next token
*/
static int /* 1 normal, 0 failure */
next(struct vars *v)
{
chr c;
/* errors yield an infinite sequence of failures */
if (ISERR())
return 0; /* the error has set nexttype to EOS */
/* remember flavor of last token */
v->lasttype = v->nexttype;
/* REG_BOSONLY */
if (v->nexttype == EMPTY && (v->cflags & REG_BOSONLY))
{
/* at start of a REG_BOSONLY RE */
RETV(SBEGIN, 0); /* same as \A */
}
/* skip white space etc. if appropriate (not in literal or []) */
if (v->cflags & REG_EXPANDED)
switch (v->lexcon)
{
case L_ERE:
case L_BRE:
case L_EBND:
case L_BBND:
skip(v);
break;
}
/* handle EOS, depending on context */
if (ATEOS())
{
switch (v->lexcon)
{
case L_ERE:
case L_BRE:
case L_Q:
RET(EOS);
break;
case L_EBND:
case L_BBND:
FAILW(REG_EBRACE);
break;
case L_BRACK:
case L_CEL:
case L_ECL:
case L_CCL:
FAILW(REG_EBRACK);
break;
}
assert(NOTREACHED);
}
/* okay, time to actually get a character */
c = *v->now++;
/* deal with the easy contexts, punt EREs to code below */
switch (v->lexcon)
{
case L_BRE: /* punt BREs to separate function */
return brenext(v, c);
break;
case L_ERE: /* see below */
break;
case L_Q: /* literal strings are easy */
RETV(PLAIN, c);
break;
case L_BBND: /* bounds are fairly simple */
case L_EBND:
switch (c)
{
case CHR('0'):
case CHR('1'):
case CHR('2'):
case CHR('3'):
case CHR('4'):
case CHR('5'):
case CHR('6'):
case CHR('7'):
case CHR('8'):
case CHR('9'):
RETV(DIGIT, (chr) DIGITVAL(c));
break;
case CHR(','):
RET(',');
break;
case CHR('}'): /* ERE bound ends with } */
if (INCON(L_EBND))
{
INTOCON(L_ERE);
if ((v->cflags & REG_ADVF) && NEXT1('?'))
{
v->now++;
NOTE(REG_UNONPOSIX);
RETV('}', 0);
}
RETV('}', 1);
}
else
FAILW(REG_BADBR);
break;
case CHR('\\'): /* BRE bound ends with \} */
if (INCON(L_BBND) && NEXT1('}'))
{
v->now++;
INTOCON(L_BRE);
RETV('}', 1);
}
else
FAILW(REG_BADBR);
break;
default:
FAILW(REG_BADBR);
break;
}
assert(NOTREACHED);
break;
case L_BRACK: /* brackets are not too hard */
switch (c)
{
case CHR(']'):
if (LASTTYPE('['))
RETV(PLAIN, c);
else
{
INTOCON((v->cflags & REG_EXTENDED) ?
L_ERE : L_BRE);
RET(']');
}
break;
case CHR('\\'):
NOTE(REG_UBBS);
if (!(v->cflags & REG_ADVF))
RETV(PLAIN, c);
NOTE(REG_UNONPOSIX);
if (ATEOS())
FAILW(REG_EESCAPE);
if (!lexescape(v))
return 0;
switch (v->nexttype)
{ /* not all escapes okay here */
case PLAIN:
case CCLASSS:
case CCLASSC:
return 1;
break;
}
/* not one of the acceptable escapes */
FAILW(REG_EESCAPE);
break;
case CHR('-'):
if (LASTTYPE('[') || NEXT1(']'))
RETV(PLAIN, c);
else
RETV(RANGE, c);
break;
case CHR('['):
if (ATEOS())
FAILW(REG_EBRACK);
switch (*v->now++)
{
case CHR('.'):
INTOCON(L_CEL);
/* might or might not be locale-specific */
RET(COLLEL);
break;
case CHR('='):
INTOCON(L_ECL);
NOTE(REG_ULOCALE);
RET(ECLASS);
break;
case CHR(':'):
INTOCON(L_CCL);
NOTE(REG_ULOCALE);
RET(CCLASS);
break;
default: /* oops */
v->now--;
RETV(PLAIN, c);
break;
}
assert(NOTREACHED);
break;
default:
RETV(PLAIN, c);
break;
}
assert(NOTREACHED);
break;
case L_CEL: /* collating elements are easy */
if (c == CHR('.') && NEXT1(']'))
{
v->now++;
INTOCON(L_BRACK);
RETV(END, '.');
}
else
RETV(PLAIN, c);
break;
case L_ECL: /* ditto equivalence classes */
if (c == CHR('=') && NEXT1(']'))
{
v->now++;
INTOCON(L_BRACK);
RETV(END, '=');
}
else
RETV(PLAIN, c);
break;
case L_CCL: /* ditto character classes */
if (c == CHR(':') && NEXT1(']'))
{
v->now++;
INTOCON(L_BRACK);
RETV(END, ':');
}
else
RETV(PLAIN, c);
break;
default:
assert(NOTREACHED);
break;
}
/* that got rid of everything except EREs and AREs */
assert(INCON(L_ERE));
/* deal with EREs and AREs, except for backslashes */
switch (c)
{
case CHR('|'):
RET('|');
break;
case CHR('*'):
if ((v->cflags & REG_ADVF) && NEXT1('?'))
{
v->now++;
NOTE(REG_UNONPOSIX);
RETV('*', 0);
}
RETV('*', 1);
break;
case CHR('+'):
if ((v->cflags & REG_ADVF) && NEXT1('?'))
{
v->now++;
NOTE(REG_UNONPOSIX);
RETV('+', 0);
}
RETV('+', 1);
break;
case CHR('?'):
if ((v->cflags & REG_ADVF) && NEXT1('?'))
{
v->now++;
NOTE(REG_UNONPOSIX);
RETV('?', 0);
}
RETV('?', 1);
break;
case CHR('{'): /* bounds start or plain character */
if (v->cflags & REG_EXPANDED)
skip(v);
if (ATEOS() || !iscdigit(*v->now))
{
NOTE(REG_UBRACES);
NOTE(REG_UUNSPEC);
RETV(PLAIN, c);
}
else
{
NOTE(REG_UBOUNDS);
INTOCON(L_EBND);
RET('{');
}
assert(NOTREACHED);
break;
case CHR('('): /* parenthesis, or advanced extension */
if ((v->cflags & REG_ADVF) && NEXT1('?'))
{
NOTE(REG_UNONPOSIX);
v->now++;
if (ATEOS())
FAILW(REG_BADRPT);
switch (*v->now++)
{
case CHR(':'): /* non-capturing paren */
RETV('(', 0);
break;
case CHR('#'): /* comment */
while (!ATEOS() && *v->now != CHR(')'))
v->now++;
if (!ATEOS())
v->now++;
assert(v->nexttype == v->lasttype);
return next(v);
break;
case CHR('='): /* positive lookahead */
NOTE(REG_ULOOKAROUND);
RETV(LACON, LATYPE_AHEAD_POS);
break;
case CHR('!'): /* negative lookahead */
NOTE(REG_ULOOKAROUND);
RETV(LACON, LATYPE_AHEAD_NEG);
break;
case CHR('<'):
if (ATEOS())
FAILW(REG_BADRPT);
switch (*v->now++)
{
case CHR('='): /* positive lookbehind */
NOTE(REG_ULOOKAROUND);
RETV(LACON, LATYPE_BEHIND_POS);
break;
case CHR('!'): /* negative lookbehind */
NOTE(REG_ULOOKAROUND);
RETV(LACON, LATYPE_BEHIND_NEG);
break;
default:
FAILW(REG_BADRPT);
break;
}
assert(NOTREACHED);
break;
default:
FAILW(REG_BADRPT);
break;
}
assert(NOTREACHED);
}
RETV('(', 1);
break;
case CHR(')'):
if (LASTTYPE('('))
NOTE(REG_UUNSPEC);
RETV(')', c);
break;
case CHR('['): /* easy except for [[:<:]] and [[:>:]] */
if (HAVE(6) && *(v->now + 0) == CHR('[') &&
*(v->now + 1) == CHR(':') &&
(*(v->now + 2) == CHR('<') ||
*(v->now + 2) == CHR('>')) &&
*(v->now + 3) == CHR(':') &&
*(v->now + 4) == CHR(']') &&
*(v->now + 5) == CHR(']'))
{
c = *(v->now + 2);
v->now += 6;
NOTE(REG_UNONPOSIX);
RET((c == CHR('<')) ? '<' : '>');
}
INTOCON(L_BRACK);
if (NEXT1('^'))
{
v->now++;
RETV('[', 0);
}
RETV('[', 1);
break;
case CHR('.'):
RET('.');
break;
case CHR('^'):
RET('^');
break;
case CHR('$'):
RET('$');
break;
case CHR('\\'): /* mostly punt backslashes to code below */
if (ATEOS())
FAILW(REG_EESCAPE);
break;
default: /* ordinary character */
RETV(PLAIN, c);
break;
}
/* ERE/ARE backslash handling; backslash already eaten */
assert(!ATEOS());
if (!(v->cflags & REG_ADVF))
{ /* only AREs have non-trivial escapes */
if (iscalnum(*v->now))
{
NOTE(REG_UBSALNUM);
NOTE(REG_UUNSPEC);
}
RETV(PLAIN, *v->now++);
}
return lexescape(v);
}
/*
* lexescape - parse an ARE backslash escape (backslash already eaten)
*
* This is used for ARE backslashes both normally and inside bracket
* expressions. In the latter case, not all escape types are allowed,
* but the caller must reject unwanted ones after we return.
*/
static int
lexescape(struct vars *v)
{
chr c;
static const chr alert[] = {
CHR('a'), CHR('l'), CHR('e'), CHR('r'), CHR('t')
};
static const chr esc[] = {
CHR('E'), CHR('S'), CHR('C')
};
const chr *save;
assert(v->cflags & REG_ADVF);
assert(!ATEOS());
c = *v->now++;
if (!iscalnum(c))
RETV(PLAIN, c);
NOTE(REG_UNONPOSIX);
switch (c)
{
case CHR('a'):
RETV(PLAIN, chrnamed(v, alert, ENDOF(alert), CHR('\007')));
break;
case CHR('A'):
RETV(SBEGIN, 0);
break;
case CHR('b'):
RETV(PLAIN, CHR('\b'));
break;
case CHR('B'):
RETV(PLAIN, CHR('\\'));
break;
case CHR('c'):
NOTE(REG_UUNPORT);
if (ATEOS())
FAILW(REG_EESCAPE);
RETV(PLAIN, (chr) (*v->now++ & 037));
break;
case CHR('d'):
NOTE(REG_ULOCALE);
RETV(CCLASSS, CC_DIGIT);
break;
case CHR('D'):
NOTE(REG_ULOCALE);
RETV(CCLASSC, CC_DIGIT);
break;
case CHR('e'):
NOTE(REG_UUNPORT);
RETV(PLAIN, chrnamed(v, esc, ENDOF(esc), CHR('\033')));
break;
case CHR('f'):
RETV(PLAIN, CHR('\f'));
break;
case CHR('m'):
RET('<');
break;
case CHR('M'):
RET('>');
break;
case CHR('n'):
RETV(PLAIN, CHR('\n'));
break;
case CHR('r'):
RETV(PLAIN, CHR('\r'));
break;
case CHR('s'):
NOTE(REG_ULOCALE);
RETV(CCLASSS, CC_SPACE);
break;
case CHR('S'):
NOTE(REG_ULOCALE);
RETV(CCLASSC, CC_SPACE);
break;
case CHR('t'):
RETV(PLAIN, CHR('\t'));
break;
case CHR('u'):
c = lexdigits(v, 16, 4, 4);
if (ISERR() || !CHR_IS_IN_RANGE(c))
FAILW(REG_EESCAPE);
RETV(PLAIN, c);
break;
case CHR('U'):
c = lexdigits(v, 16, 8, 8);
if (ISERR() || !CHR_IS_IN_RANGE(c))
FAILW(REG_EESCAPE);
RETV(PLAIN, c);
break;
case CHR('v'):
RETV(PLAIN, CHR('\v'));
break;
case CHR('w'):
NOTE(REG_ULOCALE);
RETV(CCLASSS, CC_WORD);
break;
case CHR('W'):
NOTE(REG_ULOCALE);
RETV(CCLASSC, CC_WORD);
break;
case CHR('x'):
NOTE(REG_UUNPORT);
c = lexdigits(v, 16, 1, 255); /* REs >255 long outside spec */
if (ISERR() || !CHR_IS_IN_RANGE(c))
FAILW(REG_EESCAPE);
RETV(PLAIN, c);
break;
case CHR('y'):
NOTE(REG_ULOCALE);
RETV(WBDRY, 0);
break;
case CHR('Y'):
NOTE(REG_ULOCALE);
RETV(NWBDRY, 0);
break;
case CHR('Z'):
RETV(SEND, 0);
break;
case CHR('1'):
case CHR('2'):
case CHR('3'):
case CHR('4'):
case CHR('5'):
case CHR('6'):
case CHR('7'):
case CHR('8'):
case CHR('9'):
save = v->now;
v->now--; /* put first digit back */
c = lexdigits(v, 10, 1, 255); /* REs >255 long outside spec */
if (ISERR())
FAILW(REG_EESCAPE);
/* ugly heuristic (first test is "exactly 1 digit?") */
if (v->now == save || ((int) c > 0 && (int) c <= v->nsubexp))
{
NOTE(REG_UBACKREF);
RETV(BACKREF, c);
}
/* oops, doesn't look like it's a backref after all... */
v->now = save;
/* and fall through into octal number */
/* FALLTHROUGH */
case CHR('0'):
NOTE(REG_UUNPORT);
v->now--; /* put first digit back */
c = lexdigits(v, 8, 1, 3);
if (ISERR())
FAILW(REG_EESCAPE);
if (c > 0xff)
{
/* out of range, so we handled one digit too much */
v->now--;
c >>= 3;
}
RETV(PLAIN, c);
break;
default:
assert(iscalpha(c));
FAILW(REG_EESCAPE); /* unknown alphabetic escape */
break;
}
assert(NOTREACHED);
}
/*
* lexdigits - slurp up digits and return chr value
*
* This does not account for overflow; callers should range-check the result
* if maxlen is large enough to make that possible.
*/
static chr /* chr value; errors signalled via ERR */
lexdigits(struct vars *v,
int base,
int minlen,
int maxlen)
{
uchr n; /* unsigned to avoid overflow misbehavior */
int len;
chr c;
int d;
const uchr ub = (uchr) base;
n = 0;
for (len = 0; len < maxlen && !ATEOS(); len++)
{
c = *v->now++;
switch (c)
{
case CHR('0'):
case CHR('1'):
case CHR('2'):
case CHR('3'):
case CHR('4'):
case CHR('5'):
case CHR('6'):
case CHR('7'):
case CHR('8'):
case CHR('9'):
d = DIGITVAL(c);
break;
case CHR('a'):
case CHR('A'):
d = 10;
break;
case CHR('b'):
case CHR('B'):
d = 11;
break;
case CHR('c'):
case CHR('C'):
d = 12;
break;
case CHR('d'):
case CHR('D'):
d = 13;
break;
case CHR('e'):
case CHR('E'):
d = 14;
break;
case CHR('f'):
case CHR('F'):
d = 15;
break;
default:
v->now--; /* oops, not a digit at all */
d = -1;
break;
}
if (d >= base)
{ /* not a plausible digit */
v->now--;
d = -1;
}
if (d < 0)
break; /* NOTE BREAK OUT */
n = n * ub + (uchr) d;
}
if (len < minlen)
ERR(REG_EESCAPE);
return (chr) n;
}
/*
* brenext - get next BRE token
*
* This is much like EREs except for all the stupid backslashes and the
* context-dependency of some things.
*/
static int /* 1 normal, 0 failure */
brenext(struct vars *v,
chr c)
{
switch (c)
{
case CHR('*'):
if (LASTTYPE(EMPTY) || LASTTYPE('(') || LASTTYPE('^'))
RETV(PLAIN, c);
RETV('*', 1);
break;
case CHR('['):
if (HAVE(6) && *(v->now + 0) == CHR('[') &&
*(v->now + 1) == CHR(':') &&
(*(v->now + 2) == CHR('<') ||
*(v->now + 2) == CHR('>')) &&
*(v->now + 3) == CHR(':') &&
*(v->now + 4) == CHR(']') &&
*(v->now + 5) == CHR(']'))
{
c = *(v->now + 2);
v->now += 6;
NOTE(REG_UNONPOSIX);
RET((c == CHR('<')) ? '<' : '>');
}
INTOCON(L_BRACK);
if (NEXT1('^'))
{
v->now++;
RETV('[', 0);
}
RETV('[', 1);
break;
case CHR('.'):
RET('.');
break;
case CHR('^'):
if (LASTTYPE(EMPTY))
RET('^');
if (LASTTYPE('('))
{
NOTE(REG_UUNSPEC);
RET('^');
}
RETV(PLAIN, c);
break;
case CHR('$'):
if (v->cflags & REG_EXPANDED)
skip(v);
if (ATEOS())
RET('$');
if (NEXT2('\\', ')'))
{
NOTE(REG_UUNSPEC);
RET('$');
}
RETV(PLAIN, c);
break;
case CHR('\\'):
break; /* see below */
default:
RETV(PLAIN, c);
break;
}
assert(c == CHR('\\'));
if (ATEOS())
FAILW(REG_EESCAPE);
c = *v->now++;
switch (c)
{
case CHR('{'):
INTOCON(L_BBND);
NOTE(REG_UBOUNDS);
RET('{');
break;
case CHR('('):
RETV('(', 1);
break;
case CHR(')'):
RETV(')', c);
break;
case CHR('<'):
NOTE(REG_UNONPOSIX);
RET('<');
break;
case CHR('>'):
NOTE(REG_UNONPOSIX);
RET('>');
break;
case CHR('1'):
case CHR('2'):
case CHR('3'):
case CHR('4'):
case CHR('5'):
case CHR('6'):
case CHR('7'):
case CHR('8'):
case CHR('9'):
NOTE(REG_UBACKREF);
RETV(BACKREF, (chr) DIGITVAL(c));
break;
default:
if (iscalnum(c))
{
NOTE(REG_UBSALNUM);
NOTE(REG_UUNSPEC);
}
RETV(PLAIN, c);
break;
}
assert(NOTREACHED);
return 0;
}
/*
* skip - skip white space and comments in expanded form
*/
static void
skip(struct vars *v)
{
const chr *start = v->now;
assert(v->cflags & REG_EXPANDED);
for (;;)
{
while (!ATEOS() && iscspace(*v->now))
v->now++;
if (ATEOS() || *v->now != CHR('#'))
break; /* NOTE BREAK OUT */
assert(NEXT1('#'));
while (!ATEOS() && *v->now != CHR('\n'))
v->now++;
/* leave the newline to be picked up by the iscspace loop */
}
if (v->now != start)
NOTE(REG_UNONPOSIX);
}
/*
* newline - return the chr for a newline
*
* This helps confine use of CHR to this source file.
*/
static chr
newline(void)
{
return CHR('\n');
}
/*
* chrnamed - return the chr known by a given (chr string) name
*
* The code is a bit clumsy, but this routine gets only such specialized
* use that it hardly matters.
*/
static chr
chrnamed(struct vars *v,
const chr *startp, /* start of name */
const chr *endp, /* just past end of name */
chr lastresort) /* what to return if name lookup fails */
{
chr c;
int errsave;
int e;
struct cvec *cv;
errsave = v->err;
v->err = 0;
c = element(v, startp, endp);
e = v->err;
v->err = errsave;
if (e != 0)
return lastresort;
cv = range(v, c, c, 0);
if (cv->nchrs == 0)
return lastresort;
return cv->chrs[0];
}
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