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regexec.c
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regexec.c
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/* regexec.c
*/
/*
* One Ring to rule them all, One Ring to find them
&
* [p.v of _The Lord of the Rings_, opening poem]
* [p.50 of _The Lord of the Rings_, I/iii: "The Shadow of the Past"]
* [p.254 of _The Lord of the Rings_, II/ii: "The Council of Elrond"]
*/
/* This file contains functions for executing a regular expression. See
* also regcomp.c which funnily enough, contains functions for compiling
* a regular expression.
*
* This file is also copied at build time to ext/re/re_exec.c, where
* it's built with -DPERL_EXT_RE_BUILD -DPERL_EXT_RE_DEBUG -DPERL_EXT.
* This causes the main functions to be compiled under new names and with
* debugging support added, which makes "use re 'debug'" work.
*/
/* NOTE: this is derived from Henry Spencer's regexp code, and should not
* confused with the original package (see point 3 below). Thanks, Henry!
*/
/* Additional note: this code is very heavily munged from Henry's version
* in places. In some spots I've traded clarity for efficiency, so don't
* blame Henry for some of the lack of readability.
*/
/* The names of the functions have been changed from regcomp and
* regexec to pregcomp and pregexec in order to avoid conflicts
* with the POSIX routines of the same names.
*/
#ifdef PERL_EXT_RE_BUILD
#include "re_top.h"
#endif
/*
* pregcomp and pregexec -- regsub and regerror are not used in perl
*
* Copyright (c) 1986 by University of Toronto.
* Written by Henry Spencer. Not derived from licensed software.
*
* Permission is granted to anyone to use this software for any
* purpose on any computer system, and to redistribute it freely,
* subject to the following restrictions:
*
* 1. The author is not responsible for the consequences of use of
* this software, no matter how awful, even if they arise
* from defects in it.
*
* 2. The origin of this software must not be misrepresented, either
* by explicit claim or by omission.
*
* 3. Altered versions must be plainly marked as such, and must not
* be misrepresented as being the original software.
*
**** Alterations to Henry's code are...
****
**** Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
**** 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
**** by Larry Wall and others
****
**** You may distribute under the terms of either the GNU General Public
**** License or the Artistic License, as specified in the README file.
*
* Beware that some of this code is subtly aware of the way operator
* precedence is structured in regular expressions. Serious changes in
* regular-expression syntax might require a total rethink.
*/
#include "EXTERN.h"
#define PERL_IN_REGEXEC_C
#include "perl.h"
#ifdef PERL_IN_XSUB_RE
# include "re_comp.h"
#else
# include "regcomp.h"
#endif
#define RF_tainted 1 /* tainted information used? */
#define RF_warned 2 /* warned about big count? */
#define RF_utf8 8 /* Pattern contains multibyte chars? */
#define UTF ((PL_reg_flags & RF_utf8) != 0)
#define RS_init 1 /* eval environment created */
#define RS_set 2 /* replsv value is set */
#ifndef STATIC
#define STATIC static
#endif
#define REGINCLASS(prog,p,c) (ANYOF_FLAGS(p) ? reginclass(prog,p,c,0,0) : ANYOF_BITMAP_TEST(p,*(c)))
/*
* Forwards.
*/
#define CHR_SVLEN(sv) (do_utf8 ? sv_len_utf8(sv) : SvCUR(sv))
#define CHR_DIST(a,b) (PL_reg_match_utf8 ? utf8_distance(a,b) : a - b)
#define HOPc(pos,off) \
(char *)(PL_reg_match_utf8 \
? reghop3((U8*)pos, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr)) \
: (U8*)(pos + off))
#define HOPBACKc(pos, off) \
(char*)(PL_reg_match_utf8\
? reghopmaybe3((U8*)pos, -off, (U8*)PL_bostr) \
: (pos - off >= PL_bostr) \
? (U8*)pos - off \
: NULL)
#define HOP3(pos,off,lim) (PL_reg_match_utf8 ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
#define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
#define LOAD_UTF8_CHARCLASS(class,str) STMT_START { \
if (!CAT2(PL_utf8_,class)) { bool ok; ENTER; save_re_context(); ok=CAT2(is_utf8_,class)((const U8*)str); assert(ok); LEAVE; } } STMT_END
#define LOAD_UTF8_CHARCLASS_ALNUM() LOAD_UTF8_CHARCLASS(alnum,"a")
#define LOAD_UTF8_CHARCLASS_DIGIT() LOAD_UTF8_CHARCLASS(digit,"0")
#define LOAD_UTF8_CHARCLASS_SPACE() LOAD_UTF8_CHARCLASS(space," ")
#define LOAD_UTF8_CHARCLASS_MARK() LOAD_UTF8_CHARCLASS(mark, "\xcd\x86")
/* TODO: Combine JUMPABLE and HAS_TEXT to cache OP(rn) */
/* for use after a quantifier and before an EXACT-like node -- japhy */
/* it would be nice to rework regcomp.sym to generate this stuff. sigh */
#define JUMPABLE(rn) ( \
OP(rn) == OPEN || \
(OP(rn) == CLOSE && (!cur_eval || cur_eval->u.eval.close_paren != ARG(rn))) || \
OP(rn) == EVAL || \
OP(rn) == SUSPEND || OP(rn) == IFMATCH || \
OP(rn) == PLUS || OP(rn) == MINMOD || \
OP(rn) == KEEPS || (PL_regkind[OP(rn)] == VERB) || \
(PL_regkind[OP(rn)] == CURLY && ARG1(rn) > 0) \
)
#define IS_EXACT(rn) (PL_regkind[OP(rn)] == EXACT)
#define HAS_TEXT(rn) ( IS_EXACT(rn) || PL_regkind[OP(rn)] == REF )
#if 0
/* Currently these are only used when PL_regkind[OP(rn)] == EXACT so
we don't need this definition. */
#define IS_TEXT(rn) ( OP(rn)==EXACT || OP(rn)==REF || OP(rn)==NREF )
#define IS_TEXTF(rn) ( OP(rn)==EXACTF || OP(rn)==REFF || OP(rn)==NREFF )
#define IS_TEXTFL(rn) ( OP(rn)==EXACTFL || OP(rn)==REFFL || OP(rn)==NREFFL )
#else
/* ... so we use this as its faster. */
#define IS_TEXT(rn) ( OP(rn)==EXACT )
#define IS_TEXTF(rn) ( OP(rn)==EXACTF )
#define IS_TEXTFL(rn) ( OP(rn)==EXACTFL )
#endif
/*
Search for mandatory following text node; for lookahead, the text must
follow but for lookbehind (rn->flags != 0) we skip to the next step.
*/
#define FIND_NEXT_IMPT(rn) STMT_START { \
while (JUMPABLE(rn)) { \
const OPCODE type = OP(rn); \
if (type == SUSPEND || PL_regkind[type] == CURLY) \
rn = NEXTOPER(NEXTOPER(rn)); \
else if (type == PLUS) \
rn = NEXTOPER(rn); \
else if (type == IFMATCH) \
rn = (rn->flags == 0) ? NEXTOPER(NEXTOPER(rn)) : rn + ARG(rn); \
else rn += NEXT_OFF(rn); \
} \
} STMT_END
static void restore_pos(pTHX_ void *arg);
STATIC CHECKPOINT
S_regcppush(pTHX_ I32 parenfloor)
{
dVAR;
const int retval = PL_savestack_ix;
#define REGCP_PAREN_ELEMS 4
const int paren_elems_to_push = (PL_regsize - parenfloor) * REGCP_PAREN_ELEMS;
int p;
GET_RE_DEBUG_FLAGS_DECL;
if (paren_elems_to_push < 0)
Perl_croak(aTHX_ "panic: paren_elems_to_push < 0");
#define REGCP_OTHER_ELEMS 7
SSGROW(paren_elems_to_push + REGCP_OTHER_ELEMS);
for (p = PL_regsize; p > parenfloor; p--) {
/* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
SSPUSHINT(PL_regoffs[p].end);
SSPUSHINT(PL_regoffs[p].start);
SSPUSHPTR(PL_reg_start_tmp[p]);
SSPUSHINT(p);
DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
" saving \\%"UVuf" %"IVdf"(%"IVdf")..%"IVdf"\n",
(UV)p, (IV)PL_regoffs[p].start,
(IV)(PL_reg_start_tmp[p] - PL_bostr),
(IV)PL_regoffs[p].end
));
}
/* REGCP_OTHER_ELEMS are pushed in any case, parentheses or no. */
SSPUSHPTR(PL_regoffs);
SSPUSHINT(PL_regsize);
SSPUSHINT(*PL_reglastparen);
SSPUSHINT(*PL_reglastcloseparen);
SSPUSHPTR(PL_reginput);
#define REGCP_FRAME_ELEMS 2
/* REGCP_FRAME_ELEMS are part of the REGCP_OTHER_ELEMS and
* are needed for the regexp context stack bookkeeping. */
SSPUSHINT(paren_elems_to_push + REGCP_OTHER_ELEMS - REGCP_FRAME_ELEMS);
SSPUSHINT(SAVEt_REGCONTEXT); /* Magic cookie. */
return retval;
}
/* These are needed since we do not localize EVAL nodes: */
#define REGCP_SET(cp) \
DEBUG_STATE_r( \
PerlIO_printf(Perl_debug_log, \
" Setting an EVAL scope, savestack=%"IVdf"\n", \
(IV)PL_savestack_ix)); \
cp = PL_savestack_ix
#define REGCP_UNWIND(cp) \
DEBUG_STATE_r( \
if (cp != PL_savestack_ix) \
PerlIO_printf(Perl_debug_log, \
" Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n", \
(IV)(cp), (IV)PL_savestack_ix)); \
regcpblow(cp)
STATIC char *
S_regcppop(pTHX_ const regexp *rex)
{
dVAR;
U32 i;
char *input;
GET_RE_DEBUG_FLAGS_DECL;
PERL_ARGS_ASSERT_REGCPPOP;
/* Pop REGCP_OTHER_ELEMS before the parentheses loop starts. */
i = SSPOPINT;
assert(i == SAVEt_REGCONTEXT); /* Check that the magic cookie is there. */
i = SSPOPINT; /* Parentheses elements to pop. */
input = (char *) SSPOPPTR;
*PL_reglastcloseparen = SSPOPINT;
*PL_reglastparen = SSPOPINT;
PL_regsize = SSPOPINT;
PL_regoffs=(regexp_paren_pair *) SSPOPPTR;
/* Now restore the parentheses context. */
for (i -= (REGCP_OTHER_ELEMS - REGCP_FRAME_ELEMS);
i > 0; i -= REGCP_PAREN_ELEMS) {
I32 tmps;
U32 paren = (U32)SSPOPINT;
PL_reg_start_tmp[paren] = (char *) SSPOPPTR;
PL_regoffs[paren].start = SSPOPINT;
tmps = SSPOPINT;
if (paren <= *PL_reglastparen)
PL_regoffs[paren].end = tmps;
DEBUG_BUFFERS_r(
PerlIO_printf(Perl_debug_log,
" restoring \\%"UVuf" to %"IVdf"(%"IVdf")..%"IVdf"%s\n",
(UV)paren, (IV)PL_regoffs[paren].start,
(IV)(PL_reg_start_tmp[paren] - PL_bostr),
(IV)PL_regoffs[paren].end,
(paren > *PL_reglastparen ? "(no)" : ""));
);
}
DEBUG_BUFFERS_r(
if (*PL_reglastparen + 1 <= rex->nparens) {
PerlIO_printf(Perl_debug_log,
" restoring \\%"IVdf"..\\%"IVdf" to undef\n",
(IV)(*PL_reglastparen + 1), (IV)rex->nparens);
}
);
#if 1
/* It would seem that the similar code in regtry()
* already takes care of this, and in fact it is in
* a better location to since this code can #if 0-ed out
* but the code in regtry() is needed or otherwise tests
* requiring null fields (pat.t#187 and split.t#{13,14}
* (as of patchlevel 7877) will fail. Then again,
* this code seems to be necessary or otherwise
* this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
* --jhi updated by dapm */
for (i = *PL_reglastparen + 1; i <= rex->nparens; i++) {
if (i > PL_regsize)
PL_regoffs[i].start = -1;
PL_regoffs[i].end = -1;
}
#endif
return input;
}
#define regcpblow(cp) LEAVE_SCOPE(cp) /* Ignores regcppush()ed data. */
/*
* pregexec and friends
*/
#ifndef PERL_IN_XSUB_RE
/*
- pregexec - match a regexp against a string
*/
I32
Perl_pregexec(pTHX_ REGEXP * const prog, char* stringarg, register char *strend,
char *strbeg, I32 minend, SV *screamer, U32 nosave)
/* strend: pointer to null at end of string */
/* strbeg: real beginning of string */
/* minend: end of match must be >=minend after stringarg. */
/* nosave: For optimizations. */
{
PERL_ARGS_ASSERT_PREGEXEC;
return
regexec_flags(prog, stringarg, strend, strbeg, minend, screamer, NULL,
nosave ? 0 : REXEC_COPY_STR);
}
#endif
/*
* Need to implement the following flags for reg_anch:
*
* USE_INTUIT_NOML - Useful to call re_intuit_start() first
* USE_INTUIT_ML
* INTUIT_AUTORITATIVE_NOML - Can trust a positive answer
* INTUIT_AUTORITATIVE_ML
* INTUIT_ONCE_NOML - Intuit can match in one location only.
* INTUIT_ONCE_ML
*
* Another flag for this function: SECOND_TIME (so that float substrs
* with giant delta may be not rechecked).
*/
/* Assumptions: if ANCH_GPOS, then strpos is anchored. XXXX Check GPOS logic */
/* If SCREAM, then SvPVX_const(sv) should be compatible with strpos and strend.
Otherwise, only SvCUR(sv) is used to get strbeg. */
/* XXXX We assume that strpos is strbeg unless sv. */
/* XXXX Some places assume that there is a fixed substring.
An update may be needed if optimizer marks as "INTUITable"
RExen without fixed substrings. Similarly, it is assumed that
lengths of all the strings are no more than minlen, thus they
cannot come from lookahead.
(Or minlen should take into account lookahead.)
NOTE: Some of this comment is not correct. minlen does now take account
of lookahead/behind. Further research is required. -- demerphq
*/
/* A failure to find a constant substring means that there is no need to make
an expensive call to REx engine, thus we celebrate a failure. Similarly,
finding a substring too deep into the string means that less calls to
regtry() should be needed.
REx compiler's optimizer found 4 possible hints:
a) Anchored substring;
b) Fixed substring;
c) Whether we are anchored (beginning-of-line or \G);
d) First node (of those at offset 0) which may distingush positions;
We use a)b)d) and multiline-part of c), and try to find a position in the
string which does not contradict any of them.
*/
/* Most of decisions we do here should have been done at compile time.
The nodes of the REx which we used for the search should have been
deleted from the finite automaton. */
char *
Perl_re_intuit_start(pTHX_ REGEXP * const rx, SV *sv, char *strpos,
char *strend, const U32 flags, re_scream_pos_data *data)
{
dVAR;
struct regexp *const prog = (struct regexp *)SvANY(rx);
register I32 start_shift = 0;
/* Should be nonnegative! */
register I32 end_shift = 0;
register char *s;
register SV *check;
char *strbeg;
char *t;
const bool do_utf8 = (sv && SvUTF8(sv)) ? 1 : 0; /* if no sv we have to assume bytes */
I32 ml_anch;
register char *other_last = NULL; /* other substr checked before this */
char *check_at = NULL; /* check substr found at this pos */
const I32 multiline = prog->extflags & RXf_PMf_MULTILINE;
RXi_GET_DECL(prog,progi);
#ifdef DEBUGGING
const char * const i_strpos = strpos;
#endif
GET_RE_DEBUG_FLAGS_DECL;
PERL_ARGS_ASSERT_RE_INTUIT_START;
RX_MATCH_UTF8_set(rx,do_utf8);
if (RX_UTF8(rx)) {
PL_reg_flags |= RF_utf8;
}
DEBUG_EXECUTE_r(
debug_start_match(rx, do_utf8, strpos, strend,
sv ? "Guessing start of match in sv for"
: "Guessing start of match in string for");
);
/* CHR_DIST() would be more correct here but it makes things slow. */
if (prog->minlen > strend - strpos) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
"String too short... [re_intuit_start]\n"));
goto fail;
}
strbeg = (sv && SvPOK(sv)) ? strend - SvCUR(sv) : strpos;
PL_regeol = strend;
if (do_utf8) {
if (!prog->check_utf8 && prog->check_substr)
to_utf8_substr(prog);
check = prog->check_utf8;
} else {
if (!prog->check_substr && prog->check_utf8)
to_byte_substr(prog);
check = prog->check_substr;
}
if (check == &PL_sv_undef) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
"Non-utf8 string cannot match utf8 check string\n"));
goto fail;
}
if (prog->extflags & RXf_ANCH) { /* Match at beg-of-str or after \n */
ml_anch = !( (prog->extflags & RXf_ANCH_SINGLE)
|| ( (prog->extflags & RXf_ANCH_BOL)
&& !multiline ) ); /* Check after \n? */
if (!ml_anch) {
if ( !(prog->extflags & RXf_ANCH_GPOS) /* Checked by the caller */
&& !(prog->intflags & PREGf_IMPLICIT) /* not a real BOL */
/* SvCUR is not set on references: SvRV and SvPVX_const overlap */
&& sv && !SvROK(sv)
&& (strpos != strbeg)) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Not at start...\n"));
goto fail;
}
if (prog->check_offset_min == prog->check_offset_max &&
!(prog->extflags & RXf_CANY_SEEN)) {
/* Substring at constant offset from beg-of-str... */
I32 slen;
s = HOP3c(strpos, prog->check_offset_min, strend);
if (SvTAIL(check)) {
slen = SvCUR(check); /* >= 1 */
if ( strend - s > slen || strend - s < slen - 1
|| (strend - s == slen && strend[-1] != '\n')) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "String too long...\n"));
goto fail_finish;
}
/* Now should match s[0..slen-2] */
slen--;
if (slen && (*SvPVX_const(check) != *s
|| (slen > 1
&& memNE(SvPVX_const(check), s, slen)))) {
report_neq:
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "String not equal...\n"));
goto fail_finish;
}
}
else if (*SvPVX_const(check) != *s
|| ((slen = SvCUR(check)) > 1
&& memNE(SvPVX_const(check), s, slen)))
goto report_neq;
check_at = s;
goto success_at_start;
}
}
/* Match is anchored, but substr is not anchored wrt beg-of-str. */
s = strpos;
start_shift = prog->check_offset_min; /* okay to underestimate on CC */
end_shift = prog->check_end_shift;
if (!ml_anch) {
const I32 end = prog->check_offset_max + CHR_SVLEN(check)
- (SvTAIL(check) != 0);
const I32 eshift = CHR_DIST((U8*)strend, (U8*)s) - end;
if (end_shift < eshift)
end_shift = eshift;
}
}
else { /* Can match at random position */
ml_anch = 0;
s = strpos;
start_shift = prog->check_offset_min; /* okay to underestimate on CC */
end_shift = prog->check_end_shift;
/* end shift should be non negative here */
}
#ifdef QDEBUGGING /* 7/99: reports of failure (with the older version) */
if (end_shift < 0)
Perl_croak(aTHX_ "panic: end_shift: %"IVdf" pattern:\n%s\n ",
(IV)end_shift, RX_PRECOMP(prog));
#endif
restart:
/* Find a possible match in the region s..strend by looking for
the "check" substring in the region corrected by start/end_shift. */
{
I32 srch_start_shift = start_shift;
I32 srch_end_shift = end_shift;
if (srch_start_shift < 0 && strbeg - s > srch_start_shift) {
srch_end_shift -= ((strbeg - s) - srch_start_shift);
srch_start_shift = strbeg - s;
}
DEBUG_OPTIMISE_MORE_r({
PerlIO_printf(Perl_debug_log, "Check offset min: %"IVdf" Start shift: %"IVdf" End shift %"IVdf" Real End Shift: %"IVdf"\n",
(IV)prog->check_offset_min,
(IV)srch_start_shift,
(IV)srch_end_shift,
(IV)prog->check_end_shift);
});
if (flags & REXEC_SCREAM) {
I32 p = -1; /* Internal iterator of scream. */
I32 * const pp = data ? data->scream_pos : &p;
if (PL_screamfirst[BmRARE(check)] >= 0
|| ( BmRARE(check) == '\n'
&& (BmPREVIOUS(check) == SvCUR(check) - 1)
&& SvTAIL(check) ))
s = screaminstr(sv, check,
srch_start_shift + (s - strbeg), srch_end_shift, pp, 0);
else
goto fail_finish;
/* we may be pointing at the wrong string */
if (s && RXp_MATCH_COPIED(prog))
s = strbeg + (s - SvPVX_const(sv));
if (data)
*data->scream_olds = s;
}
else {
U8* start_point;
U8* end_point;
if (prog->extflags & RXf_CANY_SEEN) {
start_point= (U8*)(s + srch_start_shift);
end_point= (U8*)(strend - srch_end_shift);
} else {
start_point= HOP3(s, srch_start_shift, srch_start_shift < 0 ? strbeg : strend);
end_point= HOP3(strend, -srch_end_shift, strbeg);
}
DEBUG_OPTIMISE_MORE_r({
PerlIO_printf(Perl_debug_log, "fbm_instr len=%d str=<%.*s>\n",
(int)(end_point - start_point),
(int)(end_point - start_point) > 20 ? 20 : (int)(end_point - start_point),
start_point);
});
s = fbm_instr( start_point, end_point,
check, multiline ? FBMrf_MULTILINE : 0);
}
}
/* Update the count-of-usability, remove useless subpatterns,
unshift s. */
DEBUG_EXECUTE_r({
RE_PV_QUOTED_DECL(quoted, do_utf8, PERL_DEBUG_PAD_ZERO(0),
SvPVX_const(check), RE_SV_DUMPLEN(check), 30);
PerlIO_printf(Perl_debug_log, "%s %s substr %s%s%s",
(s ? "Found" : "Did not find"),
(check == (do_utf8 ? prog->anchored_utf8 : prog->anchored_substr)
? "anchored" : "floating"),
quoted,
RE_SV_TAIL(check),
(s ? " at offset " : "...\n") );
});
if (!s)
goto fail_finish;
/* Finish the diagnostic message */
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - i_strpos)) );
/* XXX dmq: first branch is for positive lookbehind...
Our check string is offset from the beginning of the pattern.
So we need to do any stclass tests offset forward from that
point. I think. :-(
*/
check_at=s;
/* Got a candidate. Check MBOL anchoring, and the *other* substr.
Start with the other substr.
XXXX no SCREAM optimization yet - and a very coarse implementation
XXXX /ttx+/ results in anchored="ttx", floating="x". floating will
*always* match. Probably should be marked during compile...
Probably it is right to do no SCREAM here...
*/
if (do_utf8 ? (prog->float_utf8 && prog->anchored_utf8)
: (prog->float_substr && prog->anchored_substr))
{
/* Take into account the "other" substring. */
/* XXXX May be hopelessly wrong for UTF... */
if (!other_last)
other_last = strpos;
if (check == (do_utf8 ? prog->float_utf8 : prog->float_substr)) {
do_other_anchored:
{
char * const last = HOP3c(s, -start_shift, strbeg);
char *last1, *last2;
char * const saved_s = s;
SV* must;
t = s - prog->check_offset_max;
if (s - strpos > prog->check_offset_max /* signed-corrected t > strpos */
&& (!do_utf8
|| ((t = (char*)reghopmaybe3((U8*)s, -(prog->check_offset_max), (U8*)strpos))
&& t > strpos)))
NOOP;
else
t = strpos;
t = HOP3c(t, prog->anchored_offset, strend);
if (t < other_last) /* These positions already checked */
t = other_last;
last2 = last1 = HOP3c(strend, -prog->minlen, strbeg);
if (last < last1)
last1 = last;
/* XXXX It is not documented what units *_offsets are in.
We assume bytes, but this is clearly wrong.
Meaning this code needs to be carefully reviewed for errors.
dmq.
*/
/* On end-of-str: see comment below. */
must = do_utf8 ? prog->anchored_utf8 : prog->anchored_substr;
if (must == &PL_sv_undef) {
s = (char*)NULL;
DEBUG_r(must = prog->anchored_utf8); /* for debug */
}
else
s = fbm_instr(
(unsigned char*)t,
HOP3(HOP3(last1, prog->anchored_offset, strend)
+ SvCUR(must), -(SvTAIL(must)!=0), strbeg),
must,
multiline ? FBMrf_MULTILINE : 0
);
DEBUG_EXECUTE_r({
RE_PV_QUOTED_DECL(quoted, do_utf8, PERL_DEBUG_PAD_ZERO(0),
SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
PerlIO_printf(Perl_debug_log, "%s anchored substr %s%s",
(s ? "Found" : "Contradicts"),
quoted, RE_SV_TAIL(must));
});
if (!s) {
if (last1 >= last2) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
", giving up...\n"));
goto fail_finish;
}
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
", trying floating at offset %ld...\n",
(long)(HOP3c(saved_s, 1, strend) - i_strpos)));
other_last = HOP3c(last1, prog->anchored_offset+1, strend);
s = HOP3c(last, 1, strend);
goto restart;
}
else {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
(long)(s - i_strpos)));
t = HOP3c(s, -prog->anchored_offset, strbeg);
other_last = HOP3c(s, 1, strend);
s = saved_s;
if (t == strpos)
goto try_at_start;
goto try_at_offset;
}
}
}
else { /* Take into account the floating substring. */
char *last, *last1;
char * const saved_s = s;
SV* must;
t = HOP3c(s, -start_shift, strbeg);
last1 = last =
HOP3c(strend, -prog->minlen + prog->float_min_offset, strbeg);
if (CHR_DIST((U8*)last, (U8*)t) > prog->float_max_offset)
last = HOP3c(t, prog->float_max_offset, strend);
s = HOP3c(t, prog->float_min_offset, strend);
if (s < other_last)
s = other_last;
/* XXXX It is not documented what units *_offsets are in. Assume bytes. */
must = do_utf8 ? prog->float_utf8 : prog->float_substr;
/* fbm_instr() takes into account exact value of end-of-str
if the check is SvTAIL(ed). Since false positives are OK,
and end-of-str is not later than strend we are OK. */
if (must == &PL_sv_undef) {
s = (char*)NULL;
DEBUG_r(must = prog->float_utf8); /* for debug message */
}
else
s = fbm_instr((unsigned char*)s,
(unsigned char*)last + SvCUR(must)
- (SvTAIL(must)!=0),
must, multiline ? FBMrf_MULTILINE : 0);
DEBUG_EXECUTE_r({
RE_PV_QUOTED_DECL(quoted, do_utf8, PERL_DEBUG_PAD_ZERO(0),
SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
PerlIO_printf(Perl_debug_log, "%s floating substr %s%s",
(s ? "Found" : "Contradicts"),
quoted, RE_SV_TAIL(must));
});
if (!s) {
if (last1 == last) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
", giving up...\n"));
goto fail_finish;
}
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
", trying anchored starting at offset %ld...\n",
(long)(saved_s + 1 - i_strpos)));
other_last = last;
s = HOP3c(t, 1, strend);
goto restart;
}
else {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
(long)(s - i_strpos)));
other_last = s; /* Fix this later. --Hugo */
s = saved_s;
if (t == strpos)
goto try_at_start;
goto try_at_offset;
}
}
}
t= (char*)HOP3( s, -prog->check_offset_max, (prog->check_offset_max<0) ? strend : strpos);
DEBUG_OPTIMISE_MORE_r(
PerlIO_printf(Perl_debug_log,
"Check offset min:%"IVdf" max:%"IVdf" S:%"IVdf" t:%"IVdf" D:%"IVdf" end:%"IVdf"\n",
(IV)prog->check_offset_min,
(IV)prog->check_offset_max,
(IV)(s-strpos),
(IV)(t-strpos),
(IV)(t-s),
(IV)(strend-strpos)
)
);
if (s - strpos > prog->check_offset_max /* signed-corrected t > strpos */
&& (!do_utf8
|| ((t = (char*)reghopmaybe3((U8*)s, -prog->check_offset_max, (U8*) ((prog->check_offset_max<0) ? strend : strpos)))
&& t > strpos)))
{
/* Fixed substring is found far enough so that the match
cannot start at strpos. */
try_at_offset:
if (ml_anch && t[-1] != '\n') {
/* Eventually fbm_*() should handle this, but often
anchored_offset is not 0, so this check will not be wasted. */
/* XXXX In the code below we prefer to look for "^" even in
presence of anchored substrings. And we search even
beyond the found float position. These pessimizations
are historical artefacts only. */
find_anchor:
while (t < strend - prog->minlen) {
if (*t == '\n') {
if (t < check_at - prog->check_offset_min) {
if (do_utf8 ? prog->anchored_utf8 : prog->anchored_substr) {
/* Since we moved from the found position,
we definitely contradict the found anchored
substr. Due to the above check we do not
contradict "check" substr.
Thus we can arrive here only if check substr
is float. Redo checking for "other"=="fixed".
*/
strpos = t + 1;
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld, rescanning for anchored from offset %ld...\n",
PL_colors[0], PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
goto do_other_anchored;
}
/* We don't contradict the found floating substring. */
/* XXXX Why not check for STCLASS? */
s = t + 1;
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n",
PL_colors[0], PL_colors[1], (long)(s - i_strpos)));
goto set_useful;
}
/* Position contradicts check-string */
/* XXXX probably better to look for check-string
than for "\n", so one should lower the limit for t? */
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting lookup for check-string at offset %ld...\n",
PL_colors[0], PL_colors[1], (long)(t + 1 - i_strpos)));
other_last = strpos = s = t + 1;
goto restart;
}
t++;
}
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Did not find /%s^%s/m...\n",
PL_colors[0], PL_colors[1]));
goto fail_finish;
}
else {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Starting position does not contradict /%s^%s/m...\n",
PL_colors[0], PL_colors[1]));
}
s = t;
set_useful:
++BmUSEFUL(do_utf8 ? prog->check_utf8 : prog->check_substr); /* hooray/5 */
}
else {
/* The found string does not prohibit matching at strpos,
- no optimization of calling REx engine can be performed,
unless it was an MBOL and we are not after MBOL,
or a future STCLASS check will fail this. */
try_at_start:
/* Even in this situation we may use MBOL flag if strpos is offset
wrt the start of the string. */
if (ml_anch && sv && !SvROK(sv) /* See prev comment on SvROK */
&& (strpos != strbeg) && strpos[-1] != '\n'
/* May be due to an implicit anchor of m{.*foo} */
&& !(prog->intflags & PREGf_IMPLICIT))
{
t = strpos;
goto find_anchor;
}
DEBUG_EXECUTE_r( if (ml_anch)
PerlIO_printf(Perl_debug_log, "Position at offset %ld does not contradict /%s^%s/m...\n",
(long)(strpos - i_strpos), PL_colors[0], PL_colors[1]);
);
success_at_start:
if (!(prog->intflags & PREGf_NAUGHTY) /* XXXX If strpos moved? */
&& (do_utf8 ? (
prog->check_utf8 /* Could be deleted already */
&& --BmUSEFUL(prog->check_utf8) < 0
&& (prog->check_utf8 == prog->float_utf8)
) : (
prog->check_substr /* Could be deleted already */
&& --BmUSEFUL(prog->check_substr) < 0
&& (prog->check_substr == prog->float_substr)
)))
{
/* If flags & SOMETHING - do not do it many times on the same match */
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "... Disabling check substring...\n"));
SvREFCNT_dec(do_utf8 ? prog->check_utf8 : prog->check_substr);
if (do_utf8 ? prog->check_substr : prog->check_utf8)
SvREFCNT_dec(do_utf8 ? prog->check_substr : prog->check_utf8);
prog->check_substr = prog->check_utf8 = NULL; /* disable */
prog->float_substr = prog->float_utf8 = NULL; /* clear */
check = NULL; /* abort */
s = strpos;
/* XXXX This is a remnant of the old implementation. It
looks wasteful, since now INTUIT can use many
other heuristics. */
prog->extflags &= ~RXf_USE_INTUIT;
}
else
s = strpos;
}
/* Last resort... */
/* XXXX BmUSEFUL already changed, maybe multiple change is meaningful... */
/* trie stclasses are too expensive to use here, we are better off to
leave it to regmatch itself */
if (progi->regstclass && PL_regkind[OP(progi->regstclass)]!=TRIE) {
/* minlen == 0 is possible if regstclass is \b or \B,
and the fixed substr is ''$.
Since minlen is already taken into account, s+1 is before strend;
accidentally, minlen >= 1 guaranties no false positives at s + 1
even for \b or \B. But (minlen? 1 : 0) below assumes that
regstclass does not come from lookahead... */
/* If regstclass takes bytelength more than 1: If charlength==1, OK.
This leaves EXACTF only, which is dealt with in find_byclass(). */
const U8* const str = (U8*)STRING(progi->regstclass);
const int cl_l = (PL_regkind[OP(progi->regstclass)] == EXACT
? CHR_DIST(str+STR_LEN(progi->regstclass), str)
: 1);
char * endpos;
if (prog->anchored_substr || prog->anchored_utf8 || ml_anch)
endpos= HOP3c(s, (prog->minlen ? cl_l : 0), strend);
else if (prog->float_substr || prog->float_utf8)
endpos= HOP3c(HOP3c(check_at, -start_shift, strbeg), cl_l, strend);
else
endpos= strend;
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "start_shift: %"IVdf" check_at: %"IVdf" s: %"IVdf" endpos: %"IVdf"\n",
(IV)start_shift, (IV)(check_at - strbeg), (IV)(s - strbeg), (IV)(endpos - strbeg)));
t = s;
s = find_byclass(prog, progi->regstclass, s, endpos, NULL);
if (!s) {
#ifdef DEBUGGING
const char *what = NULL;
#endif
if (endpos == strend) {
DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
"Could not match STCLASS...\n") );
goto fail;
}
DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
"This position contradicts STCLASS...\n") );
if ((prog->extflags & RXf_ANCH) && !ml_anch)
goto fail;
/* Contradict one of substrings */
if (prog->anchored_substr || prog->anchored_utf8) {
if ((do_utf8 ? prog->anchored_utf8 : prog->anchored_substr) == check) {
DEBUG_EXECUTE_r( what = "anchored" );
hop_and_restart:
s = HOP3c(t, 1, strend);
if (s + start_shift + end_shift > strend) {
/* XXXX Should be taken into account earlier? */
DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
"Could not match STCLASS...\n") );
goto fail;
}
if (!check)
goto giveup;
DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
"Looking for %s substr starting at offset %ld...\n",
what, (long)(s + start_shift - i_strpos)) );
goto restart;
}
/* Have both, check_string is floating */
if (t + start_shift >= check_at) /* Contradicts floating=check */
goto retry_floating_check;
/* Recheck anchored substring, but not floating... */
s = check_at;
if (!check)
goto giveup;
DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
"Looking for anchored substr starting at offset %ld...\n",
(long)(other_last - i_strpos)) );
goto do_other_anchored;
}
/* Another way we could have checked stclass at the
current position only: */
if (ml_anch) {
s = t = t + 1;
if (!check)
goto giveup;
DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
"Looking for /%s^%s/m starting at offset %ld...\n",
PL_colors[0], PL_colors[1], (long)(t - i_strpos)) );
goto try_at_offset;
}
if (!(do_utf8 ? prog->float_utf8 : prog->float_substr)) /* Could have been deleted */
goto fail;
/* Check is floating subtring. */
retry_floating_check:
t = check_at - start_shift;
DEBUG_EXECUTE_r( what = "floating" );
goto hop_and_restart;
}
if (t != s) {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
"By STCLASS: moving %ld --> %ld\n",
(long)(t - i_strpos), (long)(s - i_strpos))
);
}
else {
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
"Does not contradict STCLASS...\n");
);
}
}
giveup:
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%s%s:%s match at offset %ld\n",
PL_colors[4], (check ? "Guessed" : "Giving up"),
PL_colors[5], (long)(s - i_strpos)) );
return s;
fail_finish: /* Substring not found */
if (prog->check_substr || prog->check_utf8) /* could be removed already */
BmUSEFUL(do_utf8 ? prog->check_utf8 : prog->check_substr) += 5; /* hooray */
fail:
DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch rejected by optimizer%s\n",
PL_colors[4], PL_colors[5]));
return NULL;
}