diff options
Diffstat (limited to 'regexec.c')
| -rw-r--r-- | regexec.c | 367 |
1 files changed, 301 insertions, 66 deletions
@@ -270,25 +270,33 @@ S_cache_re(pTHX_ regexp *prog) /* Assumptions: if ANCH_GPOS, then strpos is anchored. XXXX Check GPOS logic */ -/* If SCREAM, then sv should be compatible with strpos and strend. +/* If SCREAM, then SvPVX(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. */ +/* 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. */ + char * Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos, char *strend, U32 flags, re_scream_pos_data *data) { - I32 start_shift; + register I32 start_shift; /* Should be nonnegative! */ - I32 end_shift; - char *s; + register I32 end_shift; + register char *s; + register SV *check; char *t; I32 ml_anch; + char *tmp; + register char *other_last = Nullch; DEBUG_r( if (!PL_colorset) reginitcolors() ); DEBUG_r(PerlIO_printf(Perl_debug_log, - "%sGuessing start of match:%s `%s%.60s%s%s' against `%s%.*s%s%s'\n", + "%sGuessing start of match, REx%s `%s%.60s%s%s' against `%s%.*s%s%s'...\n", PL_colors[4],PL_colors[5],PL_colors[0], prog->precomp, PL_colors[1], @@ -299,128 +307,296 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos, (strend - strpos > 60 ? "..." : "")) ); - if (prog->minlen > strend - strpos) + if (prog->minlen > strend - strpos) { + DEBUG_r(PerlIO_printf(Perl_debug_log, "String too short...\n")); goto fail; - - /* XXXX Move further down? */ - start_shift = prog->check_offset_min; /* okay to underestimate on CC */ - /* Should be nonnegative! */ - end_shift = prog->minlen - start_shift - - CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0); - - if (prog->reganch & ROPT_ANCH) { + } + if (prog->reganch & ROPT_ANCH) { /* Match at beg-of-str or after \n */ ml_anch = !( (prog->reganch & ROPT_ANCH_SINGLE) || ( (prog->reganch & ROPT_ANCH_BOL) - && !PL_multiline ) ); + && !PL_multiline ) ); /* Check after \n? */ if ((prog->check_offset_min == prog->check_offset_max) && !ml_anch) { - /* Anchored... */ + /* Substring at constant offset from beg-of-str... */ I32 slen; if ( !(prog->reganch & ROPT_ANCH_GPOS) /* Checked by the caller */ - && (sv && (strpos + SvCUR(sv) != strend)) ) + && (sv && (strpos + SvCUR(sv) != strend)) ) { + DEBUG_r(PerlIO_printf(Perl_debug_log, "Not at start...\n")); goto fail; - + } PL_regeol = strend; /* Used in HOP() */ - s = (char*)HOP((U8*)strpos, prog->check_offset_min); + s = HOPc(strpos, prog->check_offset_min); if (SvTAIL(prog->check_substr)) { slen = SvCUR(prog->check_substr); /* >= 1 */ - if ( strend - s > slen || strend - s < slen - 1 ) { - s = Nullch; - goto finish; - } - if ( strend - s == slen && strend[-1] != '\n') { - s = Nullch; - goto finish; + if ( strend - s > slen || strend - s < slen - 1 + || (strend - s == slen && strend[-1] != '\n')) { + DEBUG_r(PerlIO_printf(Perl_debug_log, "String too long...\n")); + goto fail_finish; } /* Now should match s[0..slen-2] */ slen--; if (slen && (*SvPVX(prog->check_substr) != *s || (slen > 1 - && memNE(SvPVX(prog->check_substr), s, slen)))) - s = Nullch; + && memNE(SvPVX(prog->check_substr), s, slen)))) { + report_neq: + DEBUG_r(PerlIO_printf(Perl_debug_log, "String not equal...\n")); + goto fail_finish; + } } else if (*SvPVX(prog->check_substr) != *s || ((slen = SvCUR(prog->check_substr)) > 1 && memNE(SvPVX(prog->check_substr), s, slen))) - s = Nullch; - else - s = strpos; - goto finish; + goto report_neq; + goto success_at_start; } + /* Match is anchored, but substr is not anchored wrt beg-of-str. */ s = strpos; - if (!ml_anch && (s + prog->check_offset_max < strend - prog->minlen)) - end_shift += strend - s - prog->minlen - prog->check_offset_max; + start_shift = prog->check_offset_min; /* okay to underestimate on CC */ + /* Should be nonnegative! */ + end_shift = prog->minlen - start_shift - + CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0); + if (!ml_anch) { + I32 end = prog->check_offset_max + CHR_SVLEN(prog->check_substr) + - (SvTAIL(prog->check_substr) != 0); + I32 eshift = strend - s - end; + + if (end_shift < eshift) + end_shift = eshift; + } } - else { + else { /* Can match at random position */ ml_anch = 0; s = strpos; + start_shift = prog->check_offset_min; /* okay to underestimate on CC */ + /* Should be nonnegative! */ + end_shift = prog->minlen - start_shift - + CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0); } - restart: +#ifdef DEBUGGING /* 7/99: reports of failure (with the older version) */ if (end_shift < 0) - end_shift = 0; /* can happen when strend == strpos */ + croak("panic: end_shift"); +#endif + + check = prog->check_substr; + restart: + /* Find a possible match in the region s..strend by looking for + the "check" substring in the region corrected by start/end_shift. */ if (flags & REXEC_SCREAM) { - SV *c = prog->check_substr; char *strbeg = SvPVX(sv); /* XXXX Assume PV_force() on SCREAM! */ I32 p = -1; /* Internal iterator of scream. */ I32 *pp = data ? data->scream_pos : &p; - if (PL_screamfirst[BmRARE(c)] >= 0 - || ( BmRARE(c) == '\n' - && (BmPREVIOUS(c) == SvCUR(c) - 1) - && SvTAIL(c) )) - s = screaminstr(sv, prog->check_substr, - start_shift + (strpos - strbeg), end_shift, pp, 0); + if (PL_screamfirst[BmRARE(check)] >= 0 + || ( BmRARE(check) == '\n' + && (BmPREVIOUS(check) == SvCUR(check) - 1) + && SvTAIL(check) )) + s = screaminstr(sv, check, + start_shift + (s - strbeg), end_shift, pp, 0); else - s = Nullch; + goto fail_finish; if (data) *data->scream_olds = s; } else s = fbm_instr((unsigned char*)s + start_shift, (unsigned char*)strend - end_shift, - prog->check_substr, PL_multiline ? FBMrf_MULTILINE : 0); + check, PL_multiline ? FBMrf_MULTILINE : 0); /* Update the count-of-usability, remove useless subpatterns, unshift s. */ - finish: - if (!s) { - ++BmUSEFUL(prog->check_substr); /* hooray */ - goto fail; /* not present */ + + DEBUG_r(PerlIO_printf(Perl_debug_log, "%s %s substr `%s%.*s%s'%s%s", + (s ? "Found" : "Did not find"), + ((check == prog->anchored_substr) ? "anchored" : "floating"), + PL_colors[0], + SvCUR(check) - (SvTAIL(check)!=0), SvPVX(check), + PL_colors[1], (SvTAIL(check) ? "$" : ""), + (s ? " at offset " : "...\n") ) ); + + if (!s) + goto fail_finish; + + /* Finish the diagnostic message */ + DEBUG_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - strpos)) ); + + /* Got a candidate. Check MBOL anchoring, and the *other* substr. + Start with the other substr. + XXXX no SCREAM optimization yet - and a very coarse implementation + XXXX /ttx+/ results in anchored=`ttx', floating=`x'. floating will + *always* match. Probably should be marked during compile... + Probably it is right to do no SCREAM here... + */ + + if (prog->float_substr && prog->anchored_substr) { + /* Take into account the anchored substring. */ + /* XXXX May be hopelessly wrong for UTF... */ + if (!other_last) + other_last = strpos - 1; + if (check == prog->float_substr) { + char *last = s - start_shift, *last1, *last2; + char *s1 = s; + + tmp = PL_bostr; + t = s - prog->check_offset_max; + if (s - strpos > prog->check_offset_max /* signed-corrected t > strpos */ + && (!(prog->reganch & ROPT_UTF8) + || (PL_bostr = strpos, /* Used in regcopmaybe() */ + (t = reghopmaybe_c(s, -(prog->check_offset_max))) + && t > strpos))) + ; + else + t = strpos; + t += prog->anchored_offset; + if (t <= other_last) + t = other_last + 1; + PL_bostr = tmp; + last2 = last1 = strend - prog->minlen; + if (last < last1) + last1 = last; + /* XXXX It is not documented what units *_offsets are in. Assume bytes. */ + /* On end-of-str: see comment below. */ + s = fbm_instr((unsigned char*)t, + (unsigned char*)last1 + prog->anchored_offset + + SvCUR(prog->anchored_substr) + - (SvTAIL(prog->anchored_substr)!=0), + prog->anchored_substr, PL_multiline ? FBMrf_MULTILINE : 0); + DEBUG_r(PerlIO_printf(Perl_debug_log, "%s anchored substr `%s%.*s%s'%s", + (s ? "Found" : "Contradicts"), + PL_colors[0], + SvCUR(prog->anchored_substr) + - (SvTAIL(prog->anchored_substr)!=0), + SvPVX(prog->anchored_substr), + PL_colors[1], (SvTAIL(prog->anchored_substr) ? "$" : ""))); + if (!s) { + if (last1 >= last2) { + DEBUG_r(PerlIO_printf(Perl_debug_log, + ", giving up...\n")); + goto fail_finish; + } + DEBUG_r(PerlIO_printf(Perl_debug_log, + ", trying floating at offset %ld...\n", + (long)(s1 + 1 - strpos))); + PL_regeol = strend; /* Used in HOP() */ + other_last = last1 + prog->anchored_offset; + s = HOPc(last, 1); + goto restart; + } + else { + DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n", + (long)(s - strpos))); + t = s - prog->anchored_offset; + other_last = s - 1; + if (t == strpos) + goto try_at_start; + s = s1; + goto try_at_offset; + } + } + else { /* Take into account the floating substring. */ + char *last, *last1; + char *s1 = s; + + t = s - start_shift; + last1 = last = strend - prog->minlen + prog->float_min_offset; + if (last - t > prog->float_max_offset) + last = t + prog->float_max_offset; + s = t + prog->float_min_offset; + if (s <= other_last) + s = other_last + 1; + /* XXXX It is not documented what units *_offsets are in. Assume bytes. */ + /* 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. */ + s = fbm_instr((unsigned char*)s, + (unsigned char*)last + SvCUR(prog->float_substr) + - (SvTAIL(prog->float_substr)!=0), + prog->float_substr, PL_multiline ? FBMrf_MULTILINE : 0); + DEBUG_r(PerlIO_printf(Perl_debug_log, "%s floating substr `%s%.*s%s'%s", + (s ? "Found" : "Contradicts"), + PL_colors[0], + SvCUR(prog->float_substr) + - (SvTAIL(prog->float_substr)!=0), + SvPVX(prog->float_substr), + PL_colors[1], (SvTAIL(prog->float_substr) ? "$" : ""))); + if (!s) { + if (last1 == last) { + DEBUG_r(PerlIO_printf(Perl_debug_log, + ", giving up...\n")); + goto fail_finish; + } + DEBUG_r(PerlIO_printf(Perl_debug_log, + ", trying anchored starting at offset %ld...\n", + (long)(s1 + 1 - strpos))); + other_last = last; + PL_regeol = strend; /* Used in HOP() */ + s = HOPc(t, 1); + goto restart; + } + else { + DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n", + (long)(s - strpos))); + other_last = s - 1; + if (t == strpos) + goto try_at_start; + s = s1; + goto try_at_offset; + } + } } - else if (s - strpos > prog->check_offset_max && - ((prog->reganch & ROPT_UTF8) - ? ((t = reghopmaybe_c(s, -(prog->check_offset_max))) - && t >= strpos) - : (t = s - prog->check_offset_max) != 0) ) { + + t = s - prog->check_offset_max; + tmp = PL_bostr; + if (s - strpos > prog->check_offset_max /* signed-corrected t > strpos */ + && (!(prog->reganch & ROPT_UTF8) + || (PL_bostr = strpos, /* Used in regcopmaybe() */ + ((t = reghopmaybe_c(s, -(prog->check_offset_max))) + && t > strpos)))) { + PL_bostr = tmp; + /* Fixed substring is found far enough so that the match + cannot start at strpos. */ + try_at_offset: if (ml_anch && t[-1] != '\n') { - find_anchor: - while (t < strend - end_shift - prog->minlen) { + find_anchor: /* Eventually fbm_*() should handle this */ + while (t < strend - prog->minlen) { if (*t == '\n') { if (t < s - prog->check_offset_min) { s = t + 1; + DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n", + PL_colors[0],PL_colors[1], (long)(s - strpos))); goto set_useful; } + DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting at offset %ld...\n", + PL_colors[0],PL_colors[1], (long)(t + 1 - strpos))); s = t + 1; goto restart; } t++; } - s = Nullch; - goto finish; + DEBUG_r(PerlIO_printf(Perl_debug_log, "Did not find /%s^%s/m...\n", + PL_colors[0],PL_colors[1])); + goto fail_finish; } s = t; set_useful: - ++BmUSEFUL(prog->check_substr); /* hooray/2 */ + ++BmUSEFUL(prog->check_substr); /* hooray/5 */ } else { - if (ml_anch && sv + PL_bostr = tmp; + /* The found string does not prohibit matching at beg-of-str + - no optimization of calling REx engine can be performed, + unless it was an MBOL and we are not after MBOL. */ + 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 && (strpos + SvCUR(sv) != strend) && strpos[-1] != '\n') { t = strpos; goto find_anchor; } + success_at_start: if (!(prog->reganch & ROPT_NAUGHTY) && --BmUSEFUL(prog->check_substr) < 0 && prog->check_substr == prog->float_substr) { /* boo */ @@ -435,11 +611,14 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos, s = strpos; } - DEBUG_r(PerlIO_printf(Perl_debug_log, "%sFound%s at offset %ld\n", - PL_colors[4],PL_colors[5], (long)(s - strpos)) ); + DEBUG_r(PerlIO_printf(Perl_debug_log, "%sGuessed:%s match at offset %ld\n", + PL_colors[4], PL_colors[5], (long)(s - strpos)) ); return s; + + fail_finish: /* Substring not found */ + BmUSEFUL(prog->check_substr) += 5; /* hooray */ fail: - DEBUG_r(PerlIO_printf(Perl_debug_log, "%sNot found...%s\n", + DEBUG_r(PerlIO_printf(Perl_debug_log, "%sMatch rejected by optimizer%s\n", PL_colors[4],PL_colors[5])); return Nullch; } @@ -504,6 +683,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char * PL_reg_flags = 0; PL_reg_eval_set = 0; + PL_reg_maxiter = 0; if (prog->reganch & ROPT_UTF8) PL_reg_flags |= RF_utf8; @@ -552,7 +732,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char * DEBUG_r( if (!PL_colorset) reginitcolors() ); DEBUG_r(PerlIO_printf(Perl_debug_log, - "%sMatching%s `%s%.60s%s%s' against `%s%.*s%s%s'\n", + "%sMatching REx%s `%s%.60s%s%s' against `%s%.*s%s%s'\n", PL_colors[4],PL_colors[5],PL_colors[0], prog->precomp, PL_colors[1], @@ -1838,6 +2018,7 @@ S_regmatch(pTHX_ regnode *prog) case REFF: n = ARG(scan); /* which paren pair */ ln = PL_regstartp[n]; + PL_reg_leftiter = PL_reg_maxiter; /* Void cache */ if (*PL_reglastparen < n || ln == -1) sayNO; /* Do not match unless seen CLOSEn. */ if (ln == PL_regendp[n]) @@ -1982,6 +2163,10 @@ S_regmatch(pTHX_ regnode *prog) *PL_reglastparen = 0; PL_reg_call_cc = &state; PL_reginput = locinput; + + /* XXXX This is too dramatic a measure... */ + PL_reg_maxiter = 0; + if (regmatch(re->program + 1)) { ReREFCNT_dec(re); regcpblow(cp); @@ -1999,6 +2184,10 @@ S_regmatch(pTHX_ regnode *prog) PL_regcc = state.cc; PL_reg_re = state.re; cache_re(PL_reg_re); + + /* XXXX This is too dramatic a measure... */ + PL_reg_maxiter = 0; + sayNO; } sw = SvTRUE(ret); @@ -2026,6 +2215,7 @@ S_regmatch(pTHX_ regnode *prog) sw = (*PL_reglastparen >= n && PL_regendp[n] != -1); break; case IFTHEN: + PL_reg_leftiter = PL_reg_maxiter; /* Void cache */ if (sw) next = NEXTOPER(NEXTOPER(scan)); else { @@ -2064,7 +2254,7 @@ S_regmatch(pTHX_ regnode *prog) /* * This is really hard to understand, because after we match * what we're trying to match, we must make sure the rest of - * the RE is going to match for sure, and to do that we have + * the REx is going to match for sure, and to do that we have * to go back UP the parse tree by recursing ever deeper. And * if it fails, we have to reset our parent's current state * that we can try again after backing off. @@ -2124,6 +2314,51 @@ S_regmatch(pTHX_ regnode *prog) sayNO; } + if (scan->flags) { + /* Check whether we already were at this position. + Postpone detection until we know the match is not + *that* much linear. */ + if (!PL_reg_maxiter) { + PL_reg_maxiter = (PL_regeol - PL_bostr + 1) * (scan->flags>>4); + PL_reg_leftiter = PL_reg_maxiter; + } + if (PL_reg_leftiter-- == 0) { + I32 size = (PL_reg_maxiter + 7)/8; + if (PL_reg_poscache) { + if (PL_reg_poscache_size < size) { + Renew(PL_reg_poscache, size, char); + PL_reg_poscache_size = size; + } + Zero(PL_reg_poscache, size, char); + } + else { + PL_reg_poscache_size = size; + Newz(29, PL_reg_poscache, size, char); + } + DEBUG_r( + PerlIO_printf(Perl_debug_log, + "%sDetected a super-linear match, switching on caching%s...\n", + PL_colors[4], PL_colors[5]) + ); + } + if (PL_reg_leftiter < 0) { + I32 o = locinput - PL_bostr, b; + + o = (scan->flags & 0xf) - 1 + o * (scan->flags>>4); + b = o % 8; + o /= 8; + if (PL_reg_poscache[o] & (1<<b)) { + DEBUG_r( + PerlIO_printf(Perl_debug_log, + "%*s already tried at this position...\n", + REPORT_CODE_OFF+PL_regindent*2, "") + ); + sayNO; + } + PL_reg_poscache[o] |= (1<<b); + } + } + /* Prefer next over scan for minimal matching. */ if (cc->minmod) { |