forked from schacon/perl
/
regcomp.c
2669 lines (2502 loc) · 66.1 KB
/
regcomp.c
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/* regcomp.c
*/
/*
* "A fair jaw-cracker dwarf-language must be." --Samwise Gamgee
*/
/* 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
/* need to replace pregcomp et al, so enable that */
# ifndef PERL_IN_XSUB_RE
# define PERL_IN_XSUB_RE
# endif
/* need access to debugger hooks */
# ifndef DEBUGGING
# define DEBUGGING
# endif
#endif
#ifdef PERL_IN_XSUB_RE
/* We *really* need to overwrite these symbols: */
# define Perl_pregcomp my_regcomp
# define Perl_regdump my_regdump
# define Perl_regprop my_regprop
/* *These* symbols are masked to allow static link. */
# define Perl_pregfree my_regfree
# define Perl_regnext my_regnext
#endif
/*SUPPRESS 112*/
/*
* 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) 1991-1997, Larry Wall
****
**** 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"
#include "perl.h"
#ifndef PERL_IN_XSUB_RE
# include "INTERN.h"
#endif
#define REG_COMP_C
#include "regcomp.h"
#ifdef op
#undef op
#endif /* op */
#ifdef MSDOS
# if defined(BUGGY_MSC6)
/* MSC 6.00A breaks on op/regexp.t test 85 unless we turn this off */
# pragma optimize("a",off)
/* But MSC 6.00A is happy with 'w', for aliases only across function calls*/
# pragma optimize("w",on )
# endif /* BUGGY_MSC6 */
#endif /* MSDOS */
#ifndef STATIC
#define STATIC static
#endif
#define ISMULT1(c) ((c) == '*' || (c) == '+' || (c) == '?')
#define ISMULT2(s) ((*s) == '*' || (*s) == '+' || (*s) == '?' || \
((*s) == '{' && regcurly(s)))
#ifdef atarist
#define PERL_META "^$.[()|?+*\\"
#else
#define META "^$.[()|?+*\\"
#endif
#ifdef SPSTART
#undef SPSTART /* dratted cpp namespace... */
#endif
/*
* Flags to be passed up and down.
*/
#define WORST 0 /* Worst case. */
#define HASWIDTH 0x1 /* Known to match non-null strings. */
#define SIMPLE 0x2 /* Simple enough to be STAR/PLUS operand. */
#define SPSTART 0x4 /* Starts with * or +. */
#define TRYAGAIN 0x8 /* Weeded out a declaration. */
/*
* Forward declarations for pregcomp()'s friends.
*/
#ifndef PERL_OBJECT
static regnode *reg _((I32, I32 *));
static regnode *reganode _((U8, U32));
static regnode *regatom _((I32 *));
static regnode *regbranch _((I32 *, I32));
static void regc _((U8, char *));
static regnode *regclass _((void));
STATIC I32 regcurly _((char *));
static regnode *reg_node _((U8));
static regnode *regpiece _((I32 *));
static void reginsert _((U8, regnode *));
static void regoptail _((regnode *, regnode *));
static void regtail _((regnode *, regnode *));
static char* regwhite _((char *, char *));
static char* nextchar _((void));
static void re_croak2 _((const char* pat1,const char* pat2,...)) __attribute__((noreturn));
#endif
/* Length of a variant. */
#ifndef PERL_OBJECT
typedef struct {
I32 len_min;
I32 len_delta;
I32 pos_min;
I32 pos_delta;
SV *last_found;
I32 last_end; /* min value, <0 unless valid. */
I32 last_start_min;
I32 last_start_max;
SV **longest; /* Either &l_fixed, or &l_float. */
SV *longest_fixed;
I32 offset_fixed;
SV *longest_float;
I32 offset_float_min;
I32 offset_float_max;
I32 flags;
} scan_data_t;
#endif
static scan_data_t zero_scan_data = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
#define SF_BEFORE_EOL (SF_BEFORE_SEOL|SF_BEFORE_MEOL)
#define SF_BEFORE_SEOL 0x1
#define SF_BEFORE_MEOL 0x2
#define SF_FIX_BEFORE_EOL (SF_FIX_BEFORE_SEOL|SF_FIX_BEFORE_MEOL)
#define SF_FL_BEFORE_EOL (SF_FL_BEFORE_SEOL|SF_FL_BEFORE_MEOL)
#ifdef NO_UNARY_PLUS
# define SF_FIX_SHIFT_EOL (0+2)
# define SF_FL_SHIFT_EOL (0+4)
#else
# define SF_FIX_SHIFT_EOL (+2)
# define SF_FL_SHIFT_EOL (+4)
#endif
#define SF_FIX_BEFORE_SEOL (SF_BEFORE_SEOL << SF_FIX_SHIFT_EOL)
#define SF_FIX_BEFORE_MEOL (SF_BEFORE_MEOL << SF_FIX_SHIFT_EOL)
#define SF_FL_BEFORE_SEOL (SF_BEFORE_SEOL << SF_FL_SHIFT_EOL)
#define SF_FL_BEFORE_MEOL (SF_BEFORE_MEOL << SF_FL_SHIFT_EOL) /* 0x20 */
#define SF_IS_INF 0x40
#define SF_HAS_PAR 0x80
#define SF_IN_PAR 0x100
#define SF_HAS_EVAL 0x200
#define SCF_DO_SUBSTR 0x400
STATIC void
scan_commit(scan_data_t *data)
{
STRLEN l = SvCUR(data->last_found);
STRLEN old_l = SvCUR(*data->longest);
if ((l >= old_l) && ((l > old_l) || (data->flags & SF_BEFORE_EOL))) {
sv_setsv(*data->longest, data->last_found);
if (*data->longest == data->longest_fixed) {
data->offset_fixed = l ? data->last_start_min : data->pos_min;
if (data->flags & SF_BEFORE_EOL)
data->flags
|= ((data->flags & SF_BEFORE_EOL) << SF_FIX_SHIFT_EOL);
else
data->flags &= ~SF_FIX_BEFORE_EOL;
} else {
data->offset_float_min = l ? data->last_start_min : data->pos_min;
data->offset_float_max = (l
? data->last_start_max
: data->pos_min + data->pos_delta);
if (data->flags & SF_BEFORE_EOL)
data->flags
|= ((data->flags & SF_BEFORE_EOL) << SF_FL_SHIFT_EOL);
else
data->flags &= ~SF_FL_BEFORE_EOL;
}
}
SvCUR_set(data->last_found, 0);
data->last_end = -1;
data->flags &= ~SF_BEFORE_EOL;
}
/* Stops at toplevel WHILEM as well as at `last'. At end *scanp is set
to the position after last scanned or to NULL. */
STATIC I32
study_chunk(regnode **scanp, I32 *deltap, regnode *last, scan_data_t *data, U32 flags)
/* scanp: Start here (read-write). */
/* deltap: Write maxlen-minlen here. */
/* last: Stop before this one. */
{
dTHR;
I32 min = 0, pars = 0, code;
regnode *scan = *scanp, *next;
I32 delta = 0;
int is_inf = (flags & SCF_DO_SUBSTR) && (data->flags & SF_IS_INF);
I32 is_par = OP(scan) == OPEN ? ARG(scan) : 0;
scan_data_t data_fake;
while (scan && OP(scan) != END && scan < last) {
/* Peephole optimizer: */
if (regkind[(U8)OP(scan)] == EXACT) {
regnode *n = regnext(scan);
U32 stringok = 1;
#ifdef DEBUGGING
regnode *stop = scan;
#endif
next = scan + (*OPERAND(scan) + 2 - 1)/sizeof(regnode) + 2;
/* Skip NOTHING, merge EXACT*. */
while (n &&
( regkind[(U8)OP(n)] == NOTHING ||
(stringok && (OP(n) == OP(scan))))
&& NEXT_OFF(n)
&& NEXT_OFF(scan) + NEXT_OFF(n) < I16_MAX) {
if (OP(n) == TAIL || n > next)
stringok = 0;
if (regkind[(U8)OP(n)] == NOTHING) {
NEXT_OFF(scan) += NEXT_OFF(n);
next = n + NODE_STEP_REGNODE;
#ifdef DEBUGGING
if (stringok)
stop = n;
#endif
n = regnext(n);
} else {
int oldl = *OPERAND(scan);
regnode *nnext = regnext(n);
if (oldl + *OPERAND(n) > U8_MAX)
break;
NEXT_OFF(scan) += NEXT_OFF(n);
*OPERAND(scan) += *OPERAND(n);
next = n + (*OPERAND(n) + 2 - 1)/sizeof(regnode) + 2;
/* Now we can overwrite *n : */
Move(OPERAND(n) + 1, OPERAND(scan) + oldl + 1,
*OPERAND(n) + 1, char);
#ifdef DEBUGGING
if (stringok)
stop = next - 1;
#endif
n = nnext;
}
}
#ifdef DEBUGGING
/* Allow dumping */
n = scan + (*OPERAND(scan) + 2 - 1)/sizeof(regnode) + 2;
while (n <= stop) {
/* Purify reports a benign UMR here sometimes, because we
* don't initialize the OP() slot of a node when that node
* is occupied by just the trailing null of the string in
* an EXACT node */
if (regkind[(U8)OP(n)] != NOTHING || OP(n) == NOTHING) {
OP(n) = OPTIMIZED;
NEXT_OFF(n) = 0;
}
n++;
}
#endif
}
if (OP(scan) != CURLYX) {
int max = (reg_off_by_arg[OP(scan)] ? I32_MAX : U16_MAX);
int off = (reg_off_by_arg[OP(scan)] ? ARG(scan) : NEXT_OFF(scan));
int noff;
regnode *n = scan;
/* Skip NOTHING and LONGJMP. */
while ((n = regnext(n))
&& ((regkind[(U8)OP(n)] == NOTHING && (noff = NEXT_OFF(n)))
|| ((OP(n) == LONGJMP) && (noff = ARG(n))))
&& off + noff < max)
off += noff;
if (reg_off_by_arg[OP(scan)])
ARG(scan) = off;
else
NEXT_OFF(scan) = off;
}
if (OP(scan) == BRANCH || OP(scan) == BRANCHJ
|| OP(scan) == IFTHEN || OP(scan) == SUSPEND) {
next = regnext(scan);
code = OP(scan);
if (OP(next) == code || code == IFTHEN || code == SUSPEND) {
I32 max1 = 0, min1 = I32_MAX, num = 0;
if (flags & SCF_DO_SUBSTR)
scan_commit(data);
while (OP(scan) == code) {
I32 deltanext, minnext;
num++;
data_fake.flags = 0;
next = regnext(scan);
scan = NEXTOPER(scan);
if (code != BRANCH)
scan = NEXTOPER(scan);
/* We suppose the run is continuous, last=next...*/
minnext = study_chunk(&scan, &deltanext, next,
&data_fake, 0);
if (min1 > minnext)
min1 = minnext;
if (max1 < minnext + deltanext)
max1 = minnext + deltanext;
if (deltanext == I32_MAX)
is_inf = 1;
scan = next;
if (data_fake.flags & (SF_HAS_PAR|SF_IN_PAR))
pars++;
if (data && (data_fake.flags & SF_HAS_EVAL))
data->flags |= SF_HAS_EVAL;
if (code == SUSPEND)
break;
}
if (code == IFTHEN && num < 2) /* Empty ELSE branch */
min1 = 0;
if (flags & SCF_DO_SUBSTR) {
data->pos_min += min1;
data->pos_delta += max1 - min1;
if (max1 != min1 || is_inf)
data->longest = &(data->longest_float);
}
min += min1;
delta += max1 - min1;
} else if (code == BRANCHJ) /* single branch is optimized. */
scan = NEXTOPER(NEXTOPER(scan));
else /* single branch is optimized. */
scan = NEXTOPER(scan);
continue;
} else if (OP(scan) == EXACT) {
min += *OPERAND(scan);
if (flags & SCF_DO_SUBSTR) { /* Update longest substr. */
I32 l = *OPERAND(scan);
/* The code below prefers earlier match for fixed
offset, later match for variable offset. */
if (data->last_end == -1) { /* Update the start info. */
data->last_start_min = data->pos_min;
data->last_start_max = is_inf
? I32_MAX : data->pos_min + data->pos_delta;
}
sv_catpvn(data->last_found, (char *)(OPERAND(scan)+1), l);
data->last_end = data->pos_min + l;
data->pos_min += l; /* As in the first entry. */
data->flags &= ~SF_BEFORE_EOL;
}
} else if (regkind[(U8)OP(scan)] == EXACT) {
if (flags & SCF_DO_SUBSTR)
scan_commit(data);
min += *OPERAND(scan);
if (data && (flags & SCF_DO_SUBSTR))
data->pos_min += *OPERAND(scan);
} else if (strchr(varies,OP(scan))) {
I32 mincount, maxcount, minnext, deltanext, pos_before, fl;
regnode *oscan = scan;
switch (regkind[(U8)OP(scan)]) {
case WHILEM:
scan = NEXTOPER(scan);
goto finish;
case PLUS:
if (flags & SCF_DO_SUBSTR) {
next = NEXTOPER(scan);
if (OP(next) == EXACT) {
mincount = 1;
maxcount = REG_INFTY;
next = regnext(scan);
scan = NEXTOPER(scan);
goto do_curly;
}
}
if (flags & SCF_DO_SUBSTR)
data->pos_min++;
min++;
/* Fall through. */
case STAR:
is_inf = 1;
scan = regnext(scan);
if (flags & SCF_DO_SUBSTR) {
scan_commit(data);
data->longest = &(data->longest_float);
}
goto optimize_curly_tail;
case CURLY:
mincount = ARG1(scan);
maxcount = ARG2(scan);
next = regnext(scan);
scan = NEXTOPER(scan) + EXTRA_STEP_2ARGS;
do_curly:
if (flags & SCF_DO_SUBSTR) {
if (mincount == 0) scan_commit(data);
pos_before = data->pos_min;
}
if (data) {
fl = data->flags;
data->flags &= ~(SF_HAS_PAR|SF_IN_PAR|SF_HAS_EVAL);
if (is_inf)
data->flags |= SF_IS_INF;
}
/* This will finish on WHILEM, setting scan, or on NULL: */
minnext = study_chunk(&scan, &deltanext, last, data,
mincount == 0
? (flags & ~SCF_DO_SUBSTR) : flags);
if (!scan) /* It was not CURLYX, but CURLY. */
scan = next;
if (PL_dowarn && (minnext + deltanext == 0)
&& !(data->flags & (SF_HAS_PAR|SF_IN_PAR))
&& maxcount <= 10000) /* Complement check for big count */
warn("Strange *+?{} on zero-length expression");
min += minnext * mincount;
is_inf |= (maxcount == REG_INFTY && (minnext + deltanext) > 0
|| deltanext == I32_MAX);
delta += (minnext + deltanext) * maxcount - minnext * mincount;
/* Try powerful optimization CURLYX => CURLYN. */
if ( OP(oscan) == CURLYX && data
&& data->flags & SF_IN_PAR
&& !(data->flags & SF_HAS_EVAL)
&& !deltanext && minnext == 1 ) {
/* Try to optimize to CURLYN. */
regnode *nxt = NEXTOPER(oscan) + EXTRA_STEP_2ARGS;
regnode *nxt1 = nxt, *nxt2;
/* Skip open. */
nxt = regnext(nxt);
if (!strchr(simple,OP(nxt))
&& !(regkind[(U8)OP(nxt)] == EXACT
&& *OPERAND(nxt) == 1))
goto nogo;
nxt2 = nxt;
nxt = regnext(nxt);
if (OP(nxt) != CLOSE)
goto nogo;
/* Now we know that nxt2 is the only contents: */
oscan->flags = ARG(nxt);
OP(oscan) = CURLYN;
OP(nxt1) = NOTHING; /* was OPEN. */
#ifdef DEBUGGING
OP(nxt1 + 1) = OPTIMIZED; /* was count. */
NEXT_OFF(nxt1+ 1) = 0; /* just for consistancy. */
NEXT_OFF(nxt2) = 0; /* just for consistancy with CURLY. */
OP(nxt) = OPTIMIZED; /* was CLOSE. */
OP(nxt + 1) = OPTIMIZED; /* was count. */
NEXT_OFF(nxt+ 1) = 0; /* just for consistancy. */
#endif
}
nogo:
/* Try optimization CURLYX => CURLYM. */
if ( OP(oscan) == CURLYX && data
&& !(data->flags & SF_HAS_PAR)
&& !(data->flags & SF_HAS_EVAL)
&& !deltanext ) {
/* XXXX How to optimize if data == 0? */
/* Optimize to a simpler form. */
regnode *nxt = NEXTOPER(oscan) + EXTRA_STEP_2ARGS; /* OPEN */
regnode *nxt2;
OP(oscan) = CURLYM;
while ( (nxt2 = regnext(nxt)) /* skip over embedded stuff*/
&& (OP(nxt2) != WHILEM))
nxt = nxt2;
OP(nxt2) = SUCCEED; /* Whas WHILEM */
/* Need to optimize away parenths. */
if (data->flags & SF_IN_PAR) {
/* Set the parenth number. */
regnode *nxt1 = NEXTOPER(oscan) + EXTRA_STEP_2ARGS; /* OPEN*/
if (OP(nxt) != CLOSE)
FAIL("panic opt close");
oscan->flags = ARG(nxt);
OP(nxt1) = OPTIMIZED; /* was OPEN. */
OP(nxt) = OPTIMIZED; /* was CLOSE. */
#ifdef DEBUGGING
OP(nxt1 + 1) = OPTIMIZED; /* was count. */
OP(nxt + 1) = OPTIMIZED; /* was count. */
NEXT_OFF(nxt1 + 1) = 0; /* just for consistancy. */
NEXT_OFF(nxt + 1) = 0; /* just for consistancy. */
#endif
#if 0
while ( nxt1 && (OP(nxt1) != WHILEM)) {
regnode *nnxt = regnext(nxt1);
if (nnxt == nxt) {
if (reg_off_by_arg[OP(nxt1)])
ARG_SET(nxt1, nxt2 - nxt1);
else if (nxt2 - nxt1 < U16_MAX)
NEXT_OFF(nxt1) = nxt2 - nxt1;
else
OP(nxt) = NOTHING; /* Cannot beautify */
}
nxt1 = nnxt;
}
#endif
/* Optimize again: */
study_chunk(&nxt1, &deltanext, nxt, NULL, 0);
} else
oscan->flags = 0;
}
if (data && fl & (SF_HAS_PAR|SF_IN_PAR))
pars++;
if (flags & SCF_DO_SUBSTR) {
SV *last_str = Nullsv;
int counted = mincount != 0;
if (data->last_end > 0 && mincount != 0) { /* Ends with a string. */
I32 b = pos_before >= data->last_start_min
? pos_before : data->last_start_min;
STRLEN l;
char *s = SvPV(data->last_found, l);
l -= b - data->last_start_min;
/* Get the added string: */
last_str = newSVpv(s + b - data->last_start_min, l);
if (deltanext == 0 && pos_before == b) {
/* What was added is a constant string */
if (mincount > 1) {
SvGROW(last_str, (mincount * l) + 1);
repeatcpy(SvPVX(last_str) + l,
SvPVX(last_str), l, mincount - 1);
SvCUR(last_str) *= mincount;
/* Add additional parts. */
SvCUR_set(data->last_found,
SvCUR(data->last_found) - l);
sv_catsv(data->last_found, last_str);
data->last_end += l * (mincount - 1);
}
}
}
/* It is counted once already... */
data->pos_min += minnext * (mincount - counted);
data->pos_delta += - counted * deltanext +
(minnext + deltanext) * maxcount - minnext * mincount;
if (mincount != maxcount) {
scan_commit(data);
if (mincount && last_str) {
sv_setsv(data->last_found, last_str);
data->last_end = data->pos_min;
data->last_start_min =
data->pos_min - SvCUR(last_str);
data->last_start_max = is_inf
? I32_MAX
: data->pos_min + data->pos_delta
- SvCUR(last_str);
}
data->longest = &(data->longest_float);
}
}
if (data && (fl & SF_HAS_EVAL))
data->flags |= SF_HAS_EVAL;
optimize_curly_tail:
if (OP(oscan) != CURLYX) {
while (regkind[(U8)OP(next = regnext(oscan))] == NOTHING
&& NEXT_OFF(next))
NEXT_OFF(oscan) += NEXT_OFF(next);
}
continue;
default: /* REF only? */
if (flags & SCF_DO_SUBSTR) {
scan_commit(data);
data->longest = &(data->longest_float);
}
is_inf = 1;
break;
}
} else if (strchr(simple,OP(scan))) {
if (flags & SCF_DO_SUBSTR) {
scan_commit(data);
data->pos_min++;
}
min++;
} else if (regkind[(U8)OP(scan)] == EOL && flags & SCF_DO_SUBSTR) {
data->flags |= (OP(scan) == MEOL
? SF_BEFORE_MEOL
: SF_BEFORE_SEOL);
} else if (regkind[(U8)OP(scan)] == BRANCHJ
&& (scan->flags || data)
&& (OP(scan) == IFMATCH || OP(scan) == UNLESSM)) {
I32 deltanext, minnext;
regnode *nscan;
data_fake.flags = 0;
next = regnext(scan);
nscan = NEXTOPER(NEXTOPER(scan));
minnext = study_chunk(&nscan, &deltanext, last, &data_fake, 0);
if (scan->flags) {
if (deltanext) {
FAIL("variable length lookbehind not implemented");
} else if (minnext > U8_MAX) {
FAIL2("lookbehind longer than %d not implemented", U8_MAX);
}
scan->flags = minnext;
}
if (data && data_fake.flags & (SF_HAS_PAR|SF_IN_PAR))
pars++;
if (data && (data_fake.flags & SF_HAS_EVAL))
data->flags |= SF_HAS_EVAL;
} else if (OP(scan) == OPEN) {
pars++;
} else if (OP(scan) == CLOSE && ARG(scan) == is_par) {
next = regnext(scan);
if ( next && (OP(next) != WHILEM) && next < last)
is_par = 0; /* Disable optimization */
} else if (OP(scan) == EVAL) {
if (data)
data->flags |= SF_HAS_EVAL;
}
/* Else: zero-length, ignore. */
scan = regnext(scan);
}
finish:
*scanp = scan;
*deltap = is_inf ? I32_MAX : delta;
if (flags & SCF_DO_SUBSTR && is_inf)
data->pos_delta = I32_MAX - data->pos_min;
if (is_par > U8_MAX)
is_par = 0;
if (is_par && pars==1 && data) {
data->flags |= SF_IN_PAR;
data->flags &= ~SF_HAS_PAR;
} else if (pars && data) {
data->flags |= SF_HAS_PAR;
data->flags &= ~SF_IN_PAR;
}
return min;
}
STATIC I32
add_data(I32 n, char *s)
{
dTHR;
if (PL_regcomp_rx->data) {
Renewc(PL_regcomp_rx->data,
sizeof(*PL_regcomp_rx->data) + sizeof(void*) * (PL_regcomp_rx->data->count + n - 1),
char, struct reg_data);
Renew(PL_regcomp_rx->data->what, PL_regcomp_rx->data->count + n, U8);
PL_regcomp_rx->data->count += n;
} else {
Newc(1207, PL_regcomp_rx->data, sizeof(*PL_regcomp_rx->data) + sizeof(void*) * (n - 1),
char, struct reg_data);
New(1208, PL_regcomp_rx->data->what, n, U8);
PL_regcomp_rx->data->count = n;
}
Copy(s, PL_regcomp_rx->data->what + PL_regcomp_rx->data->count - n, n, U8);
return PL_regcomp_rx->data->count - n;
}
/*
- pregcomp - compile a regular expression into internal code
*
* We can't allocate space until we know how big the compiled form will be,
* but we can't compile it (and thus know how big it is) until we've got a
* place to put the code. So we cheat: we compile it twice, once with code
* generation turned off and size counting turned on, and once "for real".
* This also means that we don't allocate space until we are sure that the
* thing really will compile successfully, and we never have to move the
* code and thus invalidate pointers into it. (Note that it has to be in
* one piece because free() must be able to free it all.) [NB: not true in perl]
*
* Beware that the optimization-preparation code in here knows about some
* of the structure of the compiled regexp. [I'll say.]
*/
regexp *
pregcomp(char *exp, char *xend, PMOP *pm)
{
dTHR;
register regexp *r;
regnode *scan;
SV **longest;
SV *longest_fixed;
SV *longest_float;
regnode *first;
I32 flags;
I32 minlen = 0;
I32 sawplus = 0;
I32 sawopen = 0;
if (exp == NULL)
FAIL("NULL regexp argument");
PL_regprecomp = savepvn(exp, xend - exp);
DEBUG_r(PerlIO_printf(Perl_debug_log, "compiling RE `%*s'\n",
xend - exp, PL_regprecomp));
PL_regflags = pm->op_pmflags;
PL_regsawback = 0;
PL_regseen = 0;
PL_seen_zerolen = *exp == '^' ? -1 : 0;
PL_seen_evals = 0;
PL_extralen = 0;
/* First pass: determine size, legality. */
PL_regcomp_parse = exp;
PL_regxend = xend;
PL_regnaughty = 0;
PL_regnpar = 1;
PL_regsize = 0L;
PL_regcode = &PL_regdummy;
regc((U8)MAGIC, (char*)PL_regcode);
if (reg(0, &flags) == NULL) {
Safefree(PL_regprecomp);
PL_regprecomp = Nullch;
return(NULL);
}
DEBUG_r(PerlIO_printf(Perl_debug_log, "size %d ", PL_regsize));
DEBUG_r(
if (!PL_colorset) {
int i = 0;
char *s = PerlEnv_getenv("TERMCAP_COLORS");
PL_colorset = 1;
if (s) {
PL_colors[0] = s = savepv(s);
while (++i < 4) {
s = strchr(s, '\t');
if (!s)
FAIL("Not enough TABs in TERMCAP_COLORS");
*s = '\0';
PL_colors[i] = ++s;
}
} else {
while (i < 4)
PL_colors[i++] = "";
}
/* Reset colors: */
PerlIO_printf(Perl_debug_log, "%s%s%s%s",
PL_colors[0],PL_colors[1],PL_colors[2],PL_colors[3]);
}
);
/* Small enough for pointer-storage convention?
If extralen==0, this means that we will not need long jumps. */
if (PL_regsize >= 0x10000L && PL_extralen)
PL_regsize += PL_extralen;
else
PL_extralen = 0;
/* Allocate space and initialize. */
Newc(1001, r, sizeof(regexp) + (unsigned)PL_regsize * sizeof(regnode),
char, regexp);
if (r == NULL)
FAIL("regexp out of space");
r->refcnt = 1;
r->prelen = xend - exp;
r->precomp = PL_regprecomp;
r->subbeg = r->subbase = NULL;
r->nparens = PL_regnpar - 1; /* set early to validate backrefs */
PL_regcomp_rx = r;
/* Second pass: emit code. */
PL_regcomp_parse = exp;
PL_regxend = xend;
PL_regnaughty = 0;
PL_regnpar = 1;
PL_regcode = r->program;
/* Store the count of eval-groups for security checks: */
PL_regcode->next_off = ((PL_seen_evals > U16_MAX) ? U16_MAX : PL_seen_evals);
regc((U8)MAGIC, (char*) PL_regcode++);
r->data = 0;
if (reg(0, &flags) == NULL)
return(NULL);
/* Dig out information for optimizations. */
r->reganch = pm->op_pmflags & PMf_COMPILETIME;
pm->op_pmflags = PL_regflags;
r->regstclass = NULL;
r->naughty = PL_regnaughty >= 10; /* Probably an expensive pattern. */
scan = r->program + 1; /* First BRANCH. */
/* XXXX To minimize changes to RE engine we always allocate
3-units-long substrs field. */
Newz(1004, r->substrs, 1, struct reg_substr_data);
if (OP(scan) != BRANCH) { /* Only one top-level choice. */
scan_data_t data;
I32 fake;
STRLEN longest_float_length, longest_fixed_length;
StructCopy(&zero_scan_data, &data, scan_data_t);
first = scan;
/* Skip introductions and multiplicators >= 1. */
while ((OP(first) == OPEN && (sawopen = 1)) ||
(OP(first) == BRANCH && OP(regnext(first)) != BRANCH) ||
(OP(first) == PLUS) ||
(OP(first) == MINMOD) ||
(regkind[(U8)OP(first)] == CURLY && ARG1(first) > 0) ) {
if (OP(first) == PLUS)
sawplus = 1;
else
first += regarglen[(U8)OP(first)];
first = NEXTOPER(first);
}
/* Starting-point info. */
again:
if (OP(first) == EXACT); /* Empty, get anchored substr later. */
else if (strchr(simple+2,OP(first)))
r->regstclass = first;
else if (regkind[(U8)OP(first)] == BOUND ||
regkind[(U8)OP(first)] == NBOUND)
r->regstclass = first;
else if (regkind[(U8)OP(first)] == BOL) {
r->reganch |= (OP(first) == MBOL ? ROPT_ANCH_MBOL: ROPT_ANCH_BOL);
first = NEXTOPER(first);
goto again;
}
else if (OP(first) == GPOS) {
r->reganch |= ROPT_ANCH_GPOS;
first = NEXTOPER(first);
goto again;
}
else if ((OP(first) == STAR &&
regkind[(U8)OP(NEXTOPER(first))] == ANY) &&
!(r->reganch & ROPT_ANCH) )
{
/* turn .* into ^.* with an implied $*=1 */
r->reganch |= ROPT_ANCH_BOL | ROPT_IMPLICIT;
first = NEXTOPER(first);
goto again;
}
if (sawplus && (!sawopen || !PL_regsawback))
r->reganch |= ROPT_SKIP; /* x+ must match 1st of run */
/* Scan is after the zeroth branch, first is atomic matcher. */
DEBUG_r(PerlIO_printf(Perl_debug_log, "first at %d\n",
first - scan + 1));
/*
* If there's something expensive in the r.e., find the
* longest literal string that must appear and make it the
* regmust. Resolve ties in favor of later strings, since
* the regstart check works with the beginning of the r.e.
* and avoiding duplication strengthens checking. Not a
* strong reason, but sufficient in the absence of others.
* [Now we resolve ties in favor of the earlier string if
* it happens that c_offset_min has been invalidated, since the
* earlier string may buy us something the later one won't.]
*/
minlen = 0;
data.longest_fixed = newSVpv("",0);
data.longest_float = newSVpv("",0);
data.last_found = newSVpv("",0);
data.longest = &(data.longest_fixed);
first = scan;
minlen = study_chunk(&first, &fake, scan + PL_regsize, /* Up to end */
&data, SCF_DO_SUBSTR);
if ( PL_regnpar == 1 && data.longest == &(data.longest_fixed)
&& data.last_start_min == 0 && data.last_end > 0
&& !PL_seen_zerolen
&& (!(PL_regseen & REG_SEEN_GPOS) || (r->reganch & ROPT_ANCH_GPOS)))
r->reganch |= ROPT_CHECK_ALL;
scan_commit(&data);
SvREFCNT_dec(data.last_found);
longest_float_length = SvCUR(data.longest_float);
if (longest_float_length
|| (data.flags & SF_FL_BEFORE_EOL
&& (!(data.flags & SF_FL_BEFORE_MEOL)
|| (PL_regflags & PMf_MULTILINE)))) {
if (SvCUR(data.longest_fixed)
&& data.offset_fixed == data.offset_float_min)
goto remove; /* Like in (a)+. */
r->float_substr = data.longest_float;
r->float_min_offset = data.offset_float_min;
r->float_max_offset = data.offset_float_max;
fbm_compile(r->float_substr, 0);
BmUSEFUL(r->float_substr) = 100;
if (data.flags & SF_FL_BEFORE_EOL /* Cannot have SEOL and MULTI */
&& (!(data.flags & SF_FL_BEFORE_MEOL)
|| (PL_regflags & PMf_MULTILINE)))
SvTAIL_on(r->float_substr);
} else {
remove:
r->float_substr = Nullsv;
SvREFCNT_dec(data.longest_float);
longest_float_length = 0;
}
longest_fixed_length = SvCUR(data.longest_fixed);
if (longest_fixed_length
|| (data.flags & SF_FIX_BEFORE_EOL /* Cannot have SEOL and MULTI */
&& (!(data.flags & SF_FIX_BEFORE_MEOL)
|| (PL_regflags & PMf_MULTILINE)))) {
r->anchored_substr = data.longest_fixed;
r->anchored_offset = data.offset_fixed;
fbm_compile(r->anchored_substr, 0);
BmUSEFUL(r->anchored_substr) = 100;
if (data.flags & SF_FIX_BEFORE_EOL /* Cannot have SEOL and MULTI */
&& (!(data.flags & SF_FIX_BEFORE_MEOL)
|| (PL_regflags & PMf_MULTILINE)))
SvTAIL_on(r->anchored_substr);
} else {
r->anchored_substr = Nullsv;
SvREFCNT_dec(data.longest_fixed);
longest_fixed_length = 0;
}
/* A temporary algorithm prefers floated substr to fixed one to dig more info. */
if (longest_fixed_length > longest_float_length) {
r->check_substr = r->anchored_substr;
r->check_offset_min = r->check_offset_max = r->anchored_offset;
if (r->reganch & ROPT_ANCH_SINGLE)
r->reganch |= ROPT_NOSCAN;
} else {
r->check_substr = r->float_substr;
r->check_offset_min = data.offset_float_min;
r->check_offset_max = data.offset_float_max;
}
} else {
/* Several toplevels. Best we can is to set minlen. */
I32 fake;
DEBUG_r(PerlIO_printf(Perl_debug_log, "\n"));
scan = r->program + 1;
minlen = study_chunk(&scan, &fake, scan + PL_regsize, NULL, 0);
r->check_substr = r->anchored_substr = r->float_substr = Nullsv;
}
r->minlen = minlen;
if (PL_regseen & REG_SEEN_GPOS)
r->reganch |= ROPT_GPOS_SEEN;
if (PL_regseen & REG_SEEN_LOOKBEHIND)
r->reganch |= ROPT_LOOKBEHIND_SEEN;
if (PL_regseen & REG_SEEN_EVAL)
r->reganch |= ROPT_EVAL_SEEN;
Newz(1002, r->startp, PL_regnpar, char*);
Newz(1002, r->endp, PL_regnpar, char*);
DEBUG_r(regdump(r));
return(r);
}
/*
- reg - regular expression, i.e. main body or parenthesized thing
*
* Caller must absorb opening parenthesis.
*
* Combining parenthesis handling with the base level of regular expression
* is a trifle forced, but the need to tie the tails of the branches to what
* follows makes it hard to avoid.
*/
STATIC regnode *
reg(I32 paren, I32 *flagp)
/* paren: Parenthesized? 0=top, 1=(, inside: changed to letter. */
{
dTHR;
register regnode *ret; /* Will be the head of the group. */
register regnode *br;
register regnode *lastbr;
register regnode *ender = 0;