diff --git a/ChangeLog b/ChangeLog index d5689cb..fbdd85e 100644 --- a/ChangeLog +++ b/ChangeLog @@ -237,6 +237,13 @@ be the result. the internal recursive calls that are used for lookrounds and recursions within the pattern. +37. More refactoring has got rid of the internal could_be_empty_branch() +function (around 400 lines of code, including comments) by keeping track of +could-be-emptiness as the pattern is compiled instead of scanning compiled +groups. (This would have been much harder before the refactoring of #3 above.) +This lifts a restriction on the number of branches in a group (more than about +1100 would give "pattern is too complicated"). + Version 10.22 29-July-2016 -------------------------- diff --git a/src/pcre2_compile.c b/src/pcre2_compile.c index bead86f..3012de9 100644 --- a/src/pcre2_compile.c +++ b/src/pcre2_compile.c @@ -120,7 +120,7 @@ static unsigned int add_list_to_class(uint8_t *, PCRE2_UCHAR **, uint32_t, compile_block *, const uint32_t *, unsigned int); -static BOOL +static int compile_regex(uint32_t, PCRE2_UCHAR **, uint32_t **, int *, uint32_t, uint32_t *, int32_t *, uint32_t *, int32_t *, branch_chain *, compile_block *, PCRE2_SIZE *); @@ -372,10 +372,8 @@ compiler is clever with identical subexpressions. */ /* These flags are used in the groupinfo vector. */ -#define GI_SET_COULD_BE_EMPTY 0x80000000u -#define GI_COULD_BE_EMPTY 0x40000000u -#define GI_NOT_FIXED_LENGTH 0x20000000u -#define GI_SET_FIXED_LENGTH 0x10000000u +#define GI_SET_FIXED_LENGTH 0x80000000u +#define GI_NOT_FIXED_LENGTH 0x40000000u #define GI_FIXED_LENGTH_MASK 0x0000ffffu /* This simple test for a decimal digit works for both ASCII/Unicode and EBCDIC @@ -4134,427 +4132,6 @@ for (;;) -/************************************************* -* Scan compiled branch for non-emptiness * -*************************************************/ - -/* This function scans through a branch of a compiled pattern to see whether it -can match the empty string. It is called at the end of compiling to check the -entire pattern, and from compile_branch() when checking for an unlimited repeat -of a group that can match nothing. In the latter case it is called only when -doing the real compile, not during the pre-compile that measures the size of -the compiled pattern. - -Note that first_significant_code() skips over backward and negative forward -assertions when its final argument is TRUE. If we hit an unclosed bracket, we -return "empty" - this means we've struck an inner bracket whose current branch -will already have been scanned. - -Arguments: - code points to start of search - endcode points to where to stop - utf TRUE if in UTF mode - cb compile data - atend TRUE if being called to check an entire pattern - recurses chain of recurse_check to catch mutual recursion - countptr pointer to count to catch over-complicated pattern - -Returns: 0 if what is matched cannot be empty - 1 if what is matched could be empty - -1 if the pattern is too complicated -*/ - -#define CBE_NOTEMPTY 0 -#define CBE_EMPTY 1 -#define CBE_TOOCOMPLICATED (-1) - - -static int -could_be_empty_branch(PCRE2_SPTR code, PCRE2_SPTR endcode, BOOL utf, - compile_block *cb, BOOL atend, recurse_check *recurses, int *countptr) -{ -uint32_t group = 0; -uint32_t groupinfo = 0; -PCRE2_UCHAR c; -recurse_check this_recurse; - -/* If what we are checking has already been set as "could be empty", we know -the answer. */ - -if (*code >= OP_SBRA && *code <= OP_SCOND) return CBE_EMPTY; - -/* If this is a capturing group, we may have the answer cached, but we can only -use this information if there are no (?| groups in the pattern, because -otherwise group numbers are not unique. */ - -if ((cb->external_flags & PCRE2_DUPCAPUSED) == 0 && - (*code == OP_CBRA || *code == OP_CBRAPOS)) - { - group = GET2(code, 1 + LINK_SIZE); - groupinfo = cb->groupinfo[group]; - if ((groupinfo & GI_SET_COULD_BE_EMPTY) != 0) - return ((groupinfo & GI_COULD_BE_EMPTY) != 0)? CBE_EMPTY : CBE_NOTEMPTY; - } - -/* A large and/or complex regex can take too long to process. We have to assume -it can match an empty string. This can happen more often when (?| groups are -present in the pattern and the caching is disabled. Setting the cap at 1100 -allows the test for more than 1023 capturing patterns to work. */ - -if ((*countptr)++ > 1100) return CBE_TOOCOMPLICATED; - -/* Scan the opcodes for this branch. */ - -for (code = first_significant_code(code + PRIV(OP_lengths)[*code], TRUE); - code < endcode; - code = first_significant_code(code + PRIV(OP_lengths)[c], TRUE)) - { - PCRE2_SPTR ccode; - - c = *code; - - /* Skip over forward assertions; the other assertions are skipped by - first_significant_code() with a TRUE final argument. */ - - if (c == OP_ASSERT) - { - do code += GET(code, 1); while (*code == OP_ALT); - c = *code; - continue; - } - - /* For a recursion/subroutine call we can scan the recursion when this - function is called at the end, to check a complete pattern. Before then, - recursions just have the group number as their argument and in any case may - be forward references. In that situation, we return CBE_EMPTY, just in case. - It means that unlimited repeats of groups that contain recursions are always - treated as "could be empty" - which just adds a bit more processing time - because of the runtime check. */ - - if (c == OP_RECURSE) - { - PCRE2_SPTR scode, endgroup; - BOOL empty_branch; - - if (!atend) goto ISTRUE; - scode = cb->start_code + GET(code, 1); - endgroup = scode; - - /* We need to detect whether this is a recursive call, as otherwise there - will be an infinite loop. If it is a recursion, just skip over it. Simple - recursions are easily detected. For mutual recursions we keep a chain on - the stack. */ - - do endgroup += GET(endgroup, 1); while (*endgroup == OP_ALT); - if (code >= scode && code <= endgroup) continue; /* Simple recursion */ - else - { - recurse_check *r = recurses; - for (r = recurses; r != NULL; r = r->prev) - if (r->group == scode) break; - if (r != NULL) continue; /* Mutual recursion */ - } - - /* Scan the referenced group, remembering it on the stack chain to detect - mutual recursions. */ - - empty_branch = FALSE; - this_recurse.prev = recurses; - this_recurse.group = scode; - - do - { - int rc = could_be_empty_branch(scode, endcode, utf, cb, atend, - &this_recurse, countptr); - if (rc < 0) return rc; - if (rc > 0) - { - empty_branch = TRUE; - break; - } - scode += GET(scode, 1); - } - while (*scode == OP_ALT); - - if (!empty_branch) goto ISFALSE; /* All branches are non-empty */ - continue; - } - - /* Groups with zero repeats can of course be empty; skip them. */ - - if (c == OP_BRAZERO || c == OP_BRAMINZERO || c == OP_SKIPZERO || - c == OP_BRAPOSZERO) - { - code += PRIV(OP_lengths)[c]; - do code += GET(code, 1); while (*code == OP_ALT); - c = *code; - continue; - } - - /* A nested group that is already marked as "could be empty" can just be - skipped. */ - - if (c == OP_SBRA || c == OP_SBRAPOS || - c == OP_SCBRA || c == OP_SCBRAPOS) - { - do code += GET(code, 1); while (*code == OP_ALT); - c = *code; - continue; - } - - /* For other groups, scan the branches. */ - - if (c == OP_BRA || c == OP_BRAPOS || - c == OP_CBRA || c == OP_CBRAPOS || - c == OP_ONCE || c == OP_ONCE_NC || - c == OP_COND || c == OP_SCOND) - { - BOOL empty_branch; - if (GET(code, 1) == 0) goto ISTRUE; /* Hit unclosed bracket */ - - /* If a conditional group has only one branch, there is a second, implied, - empty branch, so just skip over the conditional, because it could be empty. - Otherwise, scan the individual branches of the group. */ - - if (c == OP_COND && code[GET(code, 1)] != OP_ALT) - code += GET(code, 1); - else - { - empty_branch = FALSE; - do - { - if (!empty_branch) - { - int rc = could_be_empty_branch(code, endcode, utf, cb, atend, - recurses, countptr); - if (rc < 0) return rc; - if (rc > 0) empty_branch = TRUE; - } - code += GET(code, 1); - } - while (*code == OP_ALT); - if (!empty_branch) goto ISFALSE; /* All branches are non-empty */ - } - - c = *code; - continue; - } - - /* Handle the other opcodes */ - - switch (c) - { - /* Check for quantifiers after a class. XCLASS is used for classes that - cannot be represented just by a bit map. This includes negated single - high-valued characters. The length in PRIV(OP_lengths)[] is zero; the - actual length is stored in the compiled code, so we must update "code" - here. */ - -#if defined SUPPORT_UNICODE || PCRE2_CODE_UNIT_WIDTH != 8 - case OP_XCLASS: - ccode = code += GET(code, 1); - goto CHECK_CLASS_REPEAT; -#endif - - case OP_CLASS: - case OP_NCLASS: - ccode = code + PRIV(OP_lengths)[OP_CLASS]; - -#if defined SUPPORT_UNICODE || PCRE2_CODE_UNIT_WIDTH != 8 - CHECK_CLASS_REPEAT: -#endif - - switch (*ccode) - { - case OP_CRSTAR: /* These could be empty; continue */ - case OP_CRMINSTAR: - case OP_CRQUERY: - case OP_CRMINQUERY: - case OP_CRPOSSTAR: - case OP_CRPOSQUERY: - break; - - default: /* Non-repeat => class must match */ - case OP_CRPLUS: /* These repeats aren't empty */ - case OP_CRMINPLUS: - case OP_CRPOSPLUS: - goto ISFALSE; - - case OP_CRRANGE: - case OP_CRMINRANGE: - case OP_CRPOSRANGE: - if (GET2(ccode, 1) > 0) goto ISFALSE; /* Minimum > 0 */ - break; - } - break; - - /* Opcodes that must match a character */ - - case OP_ANY: - case OP_ALLANY: - case OP_ANYBYTE: - - case OP_PROP: - case OP_NOTPROP: - case OP_ANYNL: - - case OP_NOT_HSPACE: - case OP_HSPACE: - case OP_NOT_VSPACE: - case OP_VSPACE: - case OP_EXTUNI: - - case OP_NOT_DIGIT: - case OP_DIGIT: - case OP_NOT_WHITESPACE: - case OP_WHITESPACE: - case OP_NOT_WORDCHAR: - case OP_WORDCHAR: - - case OP_CHAR: - case OP_CHARI: - case OP_NOT: - case OP_NOTI: - - case OP_PLUS: - case OP_PLUSI: - case OP_MINPLUS: - case OP_MINPLUSI: - - case OP_NOTPLUS: - case OP_NOTPLUSI: - case OP_NOTMINPLUS: - case OP_NOTMINPLUSI: - - case OP_POSPLUS: - case OP_POSPLUSI: - case OP_NOTPOSPLUS: - case OP_NOTPOSPLUSI: - - case OP_EXACT: - case OP_EXACTI: - case OP_NOTEXACT: - case OP_NOTEXACTI: - - case OP_TYPEPLUS: - case OP_TYPEMINPLUS: - case OP_TYPEPOSPLUS: - case OP_TYPEEXACT: - goto ISFALSE; - - /* These are going to continue, as they may be empty, but we have to - fudge the length for the \p and \P cases. */ - - case OP_TYPESTAR: - case OP_TYPEMINSTAR: - case OP_TYPEPOSSTAR: - case OP_TYPEQUERY: - case OP_TYPEMINQUERY: - case OP_TYPEPOSQUERY: - if (code[1] == OP_PROP || code[1] == OP_NOTPROP) code += 2; - break; - - /* Same for these */ - - case OP_TYPEUPTO: - case OP_TYPEMINUPTO: - case OP_TYPEPOSUPTO: - if (code[1 + IMM2_SIZE] == OP_PROP || code[1 + IMM2_SIZE] == OP_NOTPROP) - code += 2; - break; - - /* End of branch */ - - case OP_KET: - case OP_KETRMAX: - case OP_KETRMIN: - case OP_KETRPOS: - case OP_ALT: - goto ISTRUE; - - /* In UTF-8 or UTF-16 mode, STAR, MINSTAR, POSSTAR, QUERY, MINQUERY, - POSQUERY, UPTO, MINUPTO, and POSUPTO and their caseless and negative - versions may be followed by a multi-code-unit character. */ - -#ifdef MAYBE_UTF_MULTI - case OP_STAR: - case OP_STARI: - case OP_NOTSTAR: - case OP_NOTSTARI: - - case OP_MINSTAR: - case OP_MINSTARI: - case OP_NOTMINSTAR: - case OP_NOTMINSTARI: - - case OP_POSSTAR: - case OP_POSSTARI: - case OP_NOTPOSSTAR: - case OP_NOTPOSSTARI: - - case OP_QUERY: - case OP_QUERYI: - case OP_NOTQUERY: - case OP_NOTQUERYI: - - case OP_MINQUERY: - case OP_MINQUERYI: - case OP_NOTMINQUERY: - case OP_NOTMINQUERYI: - - case OP_POSQUERY: - case OP_POSQUERYI: - case OP_NOTPOSQUERY: - case OP_NOTPOSQUERYI: - if (utf && HAS_EXTRALEN(code[1])) code += GET_EXTRALEN(code[1]); - break; - - case OP_UPTO: - case OP_UPTOI: - case OP_NOTUPTO: - case OP_NOTUPTOI: - - case OP_MINUPTO: - case OP_MINUPTOI: - case OP_NOTMINUPTO: - case OP_NOTMINUPTOI: - - case OP_POSUPTO: - case OP_POSUPTOI: - case OP_NOTPOSUPTO: - case OP_NOTPOSUPTOI: - if (utf && HAS_EXTRALEN(code[1 + IMM2_SIZE])) code += GET_EXTRALEN(code[1 + IMM2_SIZE]); - break; -#endif /* MAYBE_UTF_MULTI */ - - /* MARK, and PRUNE/SKIP/THEN with an argument must skip over the argument - string. */ - - case OP_MARK: - case OP_PRUNE_ARG: - case OP_SKIP_ARG: - case OP_THEN_ARG: - code += code[1]; - break; - - /* None of the remaining opcodes are required to match a character. */ - - default: - break; - } - } - -ISTRUE: -groupinfo |= GI_COULD_BE_EMPTY; - -ISFALSE: -if (group > 0) cb->groupinfo[group] = groupinfo | GI_SET_COULD_BE_EMPTY; - -return ((groupinfo & GI_COULD_BE_EMPTY) != 0)? CBE_EMPTY : CBE_NOTEMPTY; -} - - - #ifdef SUPPORT_UNICODE /************************************************* * Get othercase range * @@ -4948,17 +4525,20 @@ Arguments: lengthptr NULL during the real compile phase points to length accumulator during pre-compile phase -Returns: TRUE on success - FALSE, with *errorcodeptr set non-zero on error +Returns: 0 There's been an error, *errorcodeptr is non-zero + +1 Success, this branch must match at least one character + -1 Success, this branch may match an empty string */ -static BOOL +static int compile_branch(uint32_t *optionsptr, PCRE2_UCHAR **codeptr, uint32_t **pptrptr, int *errorcodeptr, uint32_t *firstcuptr, int32_t *firstcuflagsptr, uint32_t *reqcuptr, int32_t *reqcuflagsptr, branch_chain *bcptr, compile_block *cb, PCRE2_SIZE *lengthptr) { int bravalue = 0; +int okreturn = -1; +int group_return = 0; uint32_t repeat_min = 0, repeat_max = 0; /* To please picky compilers */ uint32_t greedy_default, greedy_non_default; uint32_t repeat_type, op_type; @@ -4980,6 +4560,8 @@ PCRE2_UCHAR *tempcode; PCRE2_UCHAR *previous = NULL; PCRE2_UCHAR op_previous; BOOL groupsetfirstcu = FALSE; +BOOL matched_char = FALSE; +BOOL previous_matched_char = FALSE; const uint8_t *cbits = cb->cbits; uint8_t classbits[32]; @@ -5040,6 +4622,7 @@ for (;; pptr++) BOOL should_flip_negation; BOOL match_all_or_no_wide_chars; BOOL possessive_quantifier; + BOOL note_group_empty; int class_has_8bitchar; int i; uint32_t mclength; @@ -5067,7 +4650,7 @@ for (;; pptr++) { *errorcodeptr = (code >= cb->start_workspace + cb->workspace_size)? ERR52 : ERR86; - return FALSE; + return 0; } /* There is at least one situation where code goes backwards: this is the @@ -5087,7 +4670,7 @@ for (;; pptr++) if (OFLOW_MAX - *lengthptr < (PCRE2_SIZE)(code - orig_code)) { *errorcodeptr = ERR20; /* Integer overflow */ - return FALSE; + return 0; } *lengthptr += (PCRE2_SIZE)(code - orig_code); code = orig_code; @@ -5104,9 +4687,16 @@ for (;; pptr++) Checking for the legality of quantifiers happens in parse_regex(), except for a quantifier after an assertion that is a condition. */ - if (meta < META_ASTERISK || meta > META_MINMAX_QUERY) previous = code; + if (meta < META_ASTERISK || meta > META_MINMAX_QUERY) + { + previous = code; + if (matched_char) okreturn = 1; + } - skipunits = 0; /* Default value for most subgroups */ + previous_matched_char = matched_char; + matched_char = FALSE; + note_group_empty = FALSE; + skipunits = 0; /* Default value for most subgroups */ switch(meta) { @@ -5122,7 +4712,7 @@ for (;; pptr++) *reqcuflagsptr = reqcuflags; *codeptr = code; *pptrptr = pptr; - return TRUE; + return okreturn; /* ===================================================================*/ @@ -5147,6 +4737,7 @@ for (;; pptr++) repeats. The value of reqcu doesn't change either. */ case META_DOT: + matched_char = TRUE; if (firstcuflags == REQ_UNSET) firstcuflags = REQ_NONE; zerofirstcu = firstcu; zerofirstcuflags = firstcuflags; @@ -5164,6 +4755,7 @@ for (;; pptr++) case META_CLASS_EMPTY: case META_CLASS_EMPTY_NOT: + matched_char = TRUE; *code++ = (meta == META_CLASS_EMPTY_NOT)? OP_ALLANY : OP_FAIL; if (firstcuflags == REQ_UNSET) firstcuflags = REQ_NONE; zerofirstcu = firstcu; @@ -5186,6 +4778,7 @@ for (;; pptr++) case META_CLASS_NOT: case META_CLASS: + matched_char = TRUE; negate_class = meta == META_CLASS_NOT; /* We can optimize the case of a single character in a class by generating @@ -5406,7 +4999,7 @@ for (;; pptr++) "in character class", meta); #endif *errorcodeptr = ERR89; /* Internal error - unrecognized. */ - return FALSE; + return 0; } escape = META_DATA(meta); @@ -5840,7 +5433,7 @@ for (;; pptr++) PUT2(code, 2+LINK_SIZE, ng->number); if (ng->number > cb->top_backref) cb->top_backref = ng->number; skipunits = 1+IMM2_SIZE; - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; } break; /* Found a duplicated name */ } @@ -5862,7 +5455,7 @@ for (;; pptr++) { *errorcodeptr = ERR61; cb->erroroffset = offset + i; - return FALSE; + return 0; } } } @@ -5871,7 +5464,7 @@ for (;; pptr++) { *errorcodeptr = ERR15; cb->erroroffset = offset; - return FALSE; + return 0; } /* (?Rdigits) treated as a recursion reference by number. A value of @@ -5882,7 +5475,7 @@ for (;; pptr++) code[1+LINK_SIZE] = OP_RREF; PUT2(code, 2+LINK_SIZE, groupnumber); skipunits = 1+IMM2_SIZE; - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; } /* A duplicated name was found. Note that if an R name is found @@ -5896,7 +5489,7 @@ for (;; pptr++) count = 0; /* Values for first pass (avoids compiler warning) */ index = 0; if (lengthptr == NULL && !find_dupname_details(name, length, &index, - &count, errorcodeptr, cb)) return FALSE; + &count, errorcodeptr, cb)) return 0; /* Add one to the opcode to change CREF/RREF into DNCREF/DNRREF and insert appropriate data values. */ @@ -5906,9 +5499,11 @@ for (;; pptr++) PUT2(code, 2+LINK_SIZE, index); PUT2(code, 2+LINK_SIZE+IMM2_SIZE, count); } - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; - /* The DEFINE condition is always false. */ + /* The DEFINE condition is always false. It's internal groups may never + be called, so matched_char must remain false, hence the jump to + GROUP_PROCESS rather than GROUP_PROCESS_NOTE_EMPTY. */ case META_COND_DEFINE: bravalue = OP_COND; @@ -5927,14 +5522,14 @@ for (;; pptr++) { *errorcodeptr = ERR15; cb->erroroffset = offset; - return FALSE; + return 0; } if (groupnumber > cb->top_backref) cb->top_backref = groupnumber; offset -= 2; /* Point at initial ( for too many branches error */ code[1+LINK_SIZE] = OP_CREF; skipunits = 1+IMM2_SIZE; PUT2(code, 2+LINK_SIZE, groupnumber); - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; /* Test for the PCRE2 version. */ @@ -5949,13 +5544,13 @@ for (;; pptr++) OP_TRUE : OP_FALSE; skipunits = 1; pptr += 3; - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; /* The condition is an assertion, possibly preceded by a callout. */ case META_COND_ASSERT: bravalue = OP_COND; - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; /* ===================================================================*/ @@ -6000,7 +5595,7 @@ for (;; pptr++) case META_ATOMIC: bravalue = OP_ONCE; - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; case META_NOCAPTURE: bravalue = OP_BRA; @@ -6008,7 +5603,12 @@ for (;; pptr++) /* Process nested bracketed regex. The nesting depth is maintained for the benefit of the stackguard function. The test for too deep nesting is now - done in parse_regex(). */ + done in parse_regex(). Assertion and DEFINE groups come to GROUP_PROCESS; + others come to GROUP_PROCESS_NOTE_EMPTY, to indicate that we need to take + note of whether or not they may match an empty string. */ + + GROUP_PROCESS_NOTE_EMPTY: + note_group_empty = TRUE; GROUP_PROCESS: cb->parens_depth += 1; @@ -6019,7 +5619,8 @@ for (;; pptr++) templastcapture = cb->lastcapture; /* Save value before group */ length_prevgroup = 0; /* Initialize for pre-compile phase */ - if (!compile_regex( + if ((group_return = + compile_regex( options, /* The option state */ &tempcode, /* Where to put code (updated) */ &pptr, /* Input pointer (updated) */ @@ -6033,11 +5634,19 @@ for (;; pptr++) cb, /* Compile data block */ (lengthptr == NULL)? NULL : /* Actual compile phase */ &length_prevgroup /* Pre-compile phase */ - )) - return FALSE; + )) == 0) + return 0; /* Error */ + cb->parens_depth -= 1; - /* If this was an atomic group and there are no capturing groups within it, + /* If that was a non-conditional significant group (not an assertion, not a + DEFINE) that matches at least one character, then the current item matches + a character. Conditionals are handled below. */ + + if (note_group_empty && bravalue != OP_COND && group_return > 0) + matched_char = TRUE; + + /* If that was an atomic group and there are no capturing groups within it, generate OP_ONCE_NC instead of OP_ONCE. */ if (bravalue == OP_ONCE && cb->lastcapture <= templastcapture) @@ -6067,7 +5676,7 @@ for (;; pptr++) tc += GET(tc,1); } while (*tc != OP_KET); - + /* A DEFINE group is never obeyed inline (the "condition" is always false). It must have only one branch. Having checked this, change the opcode to OP_FALSE. */ @@ -6078,7 +5687,7 @@ for (;; pptr++) { cb->erroroffset = offset; *errorcodeptr = ERR54; - return FALSE; + return 0; } code[LINK_SIZE+1] = OP_FALSE; bravalue = OP_DEFINE; /* A flag to suppress char handling below */ @@ -6086,7 +5695,8 @@ for (;; pptr++) /* A "normal" conditional group. If there is just one branch, we must not make use of its firstcu or reqcu, because this is equivalent to an - empty second branch. */ + empty second branch. Also, it may match an empty string. If there are two + branches, this item must match a character if the group must. */ else { @@ -6094,9 +5704,10 @@ for (;; pptr++) { cb->erroroffset = offset; *errorcodeptr = ERR27; - return FALSE; + return 0; } if (condcount == 1) subfirstcuflags = subreqcuflags = REQ_NONE; + else if (group_return > 0) matched_char = TRUE; } } @@ -6110,7 +5721,7 @@ for (;; pptr++) if (OFLOW_MAX - *lengthptr < length_prevgroup - 2 - 2*LINK_SIZE) { *errorcodeptr = ERR20; - return FALSE; + return 0; } *lengthptr += length_prevgroup - 2 - 2*LINK_SIZE; code++; /* This already contains bravalue */ @@ -6269,7 +5880,7 @@ for (;; pptr++) { *errorcodeptr = ERR15; cb->erroroffset = offset; - return FALSE; + return 0; } /* If a back reference name is not duplicated, we can handle it as @@ -6288,7 +5899,7 @@ for (;; pptr++) count = 0; /* Values for first pass (avoids compiler warning) */ index = 0; if (lengthptr == NULL && !find_dupname_details(name, length, &index, - &count, errorcodeptr, cb)) return FALSE; + &count, errorcodeptr, cb)) return 0; if (firstcuflags == REQ_UNSET) firstcuflags = REQ_NONE; *code++ = ((options & PCRE2_CASELESS) != 0)? OP_DNREFI : OP_DNREF; @@ -6407,6 +6018,7 @@ for (;; pptr++) repeat_max = 1; REPEAT: + if (previous_matched_char && repeat_min > 0) matched_char = TRUE; /* Remember whether this is a variable length repeat, and default to single-char opcodes. */ @@ -6475,6 +6087,7 @@ for (;; pptr++) PUT(previous, 3 + 2*LINK_SIZE, 2 + 2*LINK_SIZE); code += 2 + 2 * LINK_SIZE; length_prevgroup = 3 + 3*LINK_SIZE; + group_return = -1; /* Set "may match empty string" */ } /* Now handle repetition for the different types of item. */ @@ -6689,7 +6302,7 @@ for (;; pptr++) OFLOW_MAX - *lengthptr < delta) { *errorcodeptr = ERR20; - return FALSE; + return 0; } *lengthptr += delta; } @@ -6742,7 +6355,7 @@ for (;; pptr++) OFLOW_MAX - *lengthptr < delta) { *errorcodeptr = ERR20; - return FALSE; + return 0; } *lengthptr += delta; } @@ -6831,34 +6444,14 @@ for (;; pptr++) else { - /* In the compile phase, check whether the group could match an - empty string. */ + /* In the compile phase, adjust the opcode if the group can match + an empty string. For a conditional group with only one branch, the + value of group_return will not show "could be empty", so we must + check that separately. */ if (lengthptr == NULL) { - PCRE2_UCHAR *scode = bracode; - do - { - int count = 0; - int rc = could_be_empty_branch(scode, ketcode, utf, cb, FALSE, - NULL, &count); - if (rc < 0) - { - *errorcodeptr = ERR86; - return FALSE; - } - if (rc > 0) - { - *bracode += OP_SBRA - OP_BRA; - break; - } - scode += GET(scode, 1); - } - while (*scode == OP_ALT); - - /* A conditional group with only one branch has an implicit empty - alternative branch. */ - + if (group_return < 0) *bracode += OP_SBRA - OP_BRA; if (*bracode == OP_COND && bracode[GET(bracode,1)] != OP_ALT) *bracode = OP_SCOND; } @@ -6917,7 +6510,7 @@ for (;; pptr++) if (op_previous >= OP_EODN) /* Not a character type - internal error */ { *errorcodeptr = ERR10; - return FALSE; + return 0; } else { @@ -7188,7 +6781,7 @@ for (;; pptr++) { cb->erroroffset = offset; *errorcodeptr = ERR15; /* Non-existent subpattern */ - return FALSE; + return 0; } /* Come here from named backref handling when the reference is to a @@ -7241,7 +6834,7 @@ for (;; pptr++) { cb->erroroffset = offset; *errorcodeptr = ERR15; /* Non-existent subpattern */ - return FALSE; + return 0; } HANDLE_NUMERICAL_RECURSION: *code = OP_RECURSE; @@ -7261,7 +6854,7 @@ for (;; pptr++) skipunits = IMM2_SIZE; PUT2(code, 1+LINK_SIZE, meta_arg); cb->lastcapture = meta_arg; - goto GROUP_PROCESS; + goto GROUP_PROCESS_NOTE_EMPTY; /* ===============================================================*/ @@ -7279,12 +6872,15 @@ for (;; pptr++) case META_ESCAPE: /* We can test for escape sequences that consume a character because their - values lie between ESC_b and ESC_Z for the latter; this may have to change - if any new ones are ever created. For these sequences, we disable the - setting of a first character if it hasn't already been set. */ + values lie between ESC_b and ESC_Z; this may have to change if any new ones + are ever created. For these sequences, we disable the setting of a first + character if it hasn't already been set. */ - if (firstcuflags == REQ_UNSET && meta_arg > ESC_b && meta_arg < ESC_Z) - firstcuflags = REQ_NONE; + if (meta_arg > ESC_b && meta_arg < ESC_Z) + { + matched_char = TRUE; + if (firstcuflags == REQ_UNSET) firstcuflags = REQ_NONE; + } /* Set values to reset to if this is followed by a zero repeat. */ @@ -7341,7 +6937,7 @@ for (;; pptr++) fprintf(stderr, "** Unrecognized parsed pattern item 0x%.8x\n", *pptr); #endif *errorcodeptr = ERR89; /* Internal error - unrecognized. */ - return FALSE; + return 0; } /* Handle a literal character. We come here by goto in the case of a @@ -7350,6 +6946,7 @@ for (;; pptr++) NORMAL_CHAR: meta = *pptr; /* Get the full 32 bits */ NORMAL_CHAR_SET: /* Character is already in meta */ + matched_char = TRUE; /* For caseless UTF mode, check whether this character has more than one other case. If so, generate a special OP_PROP item instead of OP_CHARI. */ @@ -7471,10 +7068,12 @@ Arguments: lengthptr NULL during the real compile phase points to length accumulator during pre-compile phase -Returns: TRUE on success -*/ +Returns: 0 There has been an error + +1 Success, this group must match at least one character + -1 Success, this group may match an empty string +*/ -static BOOL +static int compile_regex(uint32_t options, PCRE2_UCHAR **codeptr, uint32_t **pptrptr, int *errorcodeptr, uint32_t skipunits, uint32_t *firstcuptr, int32_t *firstcuflagsptr, uint32_t *reqcuptr,int32_t *reqcuflagsptr, @@ -7486,6 +7085,7 @@ PCRE2_UCHAR *start_bracket = code; BOOL lookbehind; open_capitem capitem; int capnumber = 0; +int okreturn = 1; uint32_t *pptr = *pptrptr; uint32_t firstcu, reqcu; uint32_t lookbehindlength; @@ -7501,7 +7101,7 @@ if (cb->cx->stack_guard != NULL && cb->cx->stack_guard(cb->parens_depth, cb->cx->stack_guard_data)) { *errorcodeptr= ERR33; - return FALSE; + return 0; } /* Miscellaneous initialization */ @@ -7555,6 +7155,8 @@ code += 1 + LINK_SIZE + skipunits; for (;;) { + int branch_return; + /* Insert OP_REVERSE if this is as lookbehind assertion. */ if (lookbehind && lookbehindlength > 0) @@ -7567,10 +7169,15 @@ for (;;) /* Now compile the branch; in the pre-compile phase its length gets added into the length. */ - if (!compile_branch(&options, &code, &pptr, errorcodeptr, &branchfirstcu, - &branchfirstcuflags, &branchreqcu, &branchreqcuflags, &bc, - cb, (lengthptr == NULL)? NULL : &length)) - return FALSE; + if ((branch_return = + compile_branch(&options, &code, &pptr, errorcodeptr, &branchfirstcu, + &branchfirstcuflags, &branchreqcu, &branchreqcuflags, &bc, + cb, (lengthptr == NULL)? NULL : &length)) == 0) + return 0; + + /* If a branch can match an empty string, so can the whole group. */ + + if (branch_return < 0) okreturn = -1; /* In the real compile phase, there is some post-processing to be done. */ @@ -7697,11 +7304,12 @@ for (;;) if (OFLOW_MAX - *lengthptr < length) { *errorcodeptr = ERR20; - return FALSE; + return 0; } *lengthptr += length; } - return TRUE; +// if (lengthptr == NULL) fprintf(stderr, "~~group returns %d\n", okreturn); + return okreturn; } /* Another branch follows. In the pre-compile phase, we can move the code @@ -9041,6 +8649,7 @@ uint32_t limit_recursion = UINT32_MAX; int newline = 0; /* Unset; can be set by the pattern */ int bsr = 0; /* Unset; can be set by the pattern */ int errorcode = 0; /* Initialize to avoid compiler warn */ +int regexrc; /* Return from compile */ uint32_t i; /* Local loop counter */ @@ -9518,9 +9127,9 @@ of the function here. */ pptr = cb.parsed_pattern; code = (PCRE2_UCHAR *)codestart; *code = OP_BRA; -(void)compile_regex(re->overall_options, &code, &pptr, &errorcode, 0, &firstcu, - &firstcuflags, &reqcu, &reqcuflags, NULL, &cb, NULL); - +regexrc = compile_regex(re->overall_options, &code, &pptr, &errorcode, 0, + &firstcu, &firstcuflags, &reqcu, &reqcuflags, NULL, &cb, NULL); +if (regexrc < 0) re->flags |= PCRE2_MATCH_EMPTY; re->top_bracket = cb.bracount; re->top_backref = cb.top_backref; re->max_lookbehind = cb.max_lookbehind; @@ -9716,27 +9325,6 @@ if (reqcuflags >= 0 && } } -/* Check for a pattern than can match an empty string, so that this information -can be provided to applications. */ - -do - { - int count = 0; - int rc = could_be_empty_branch(codestart, code, utf, &cb, TRUE, NULL, &count); - if (rc < 0) - { - errorcode = ERR86; - goto HAD_CB_ERROR; - } - if (rc > 0) - { - re->flags |= PCRE2_MATCH_EMPTY; - break; - } - codestart += GET(codestart, 1); - } -while (*codestart == OP_ALT); - /* Finally, unless PCRE2_NO_START_OPTIMIZE is set, study the compiled pattern to set up information such as a bitmap of starting code units and a minimum matching length. */ diff --git a/testdata/testinput2 b/testdata/testinput2 index aafb4ea..5e7da5f 100644 --- a/testdata/testinput2 +++ b/testdata/testinput2 @@ -4651,7 +4651,7 @@ B)x/alt_verbnames,mark /abcdef/hex,max_pattern_length=3 -# These two patterns used to take a long time to compile +# These patterns used to take a long time to compile "(.*) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) @@ -4664,9 +4664,6 @@ B)x/alt_verbnames,mark ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) a)"xI -# When (?| is used and groups of the same number may be different, -# we have to rely on a count to catch overly complicated patterns. - "(?|()|())(.*) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) @@ -4941,4 +4938,10 @@ a)"xI "()X|((((((((()))))))((((())))))\2())((((((\2\2)))\2)(\22((((\2\2)2))\2)))(2\ZZZ)+:)Z^|91ZiZZnter(ZZ |91Z(ZZ ZZ(\r2Z( or#(\Z2(Z\Z(\2\2)2))\2Z)Z(\22Z((\Z2(Z\Z(\2\2)2))\2Z+:)Z|91Z(ZZ ZZ(\r2Z( or#(\Z2(Z\Z((Z*(\2(Z\':))\0)i|||||||||||||||loZ\2\2)2))\2Z)Z(\22Z((\Z2(Z\Z(\2\2)2))\2Z)))int \)\0nte!rnal errpr\2\\21r(2\ZZZ)+:)Z!|91Z(ZZ ZZ(\r2Z( or#(\Z2(Z\Z(\2\2)2))\2Z)Z(\22Z((\Z2(Z\Z(\2\2)2))\2Z)))int \)\0(2\ZZZ)+:)Z^|91ZiZZnter(ZZ |91Z(ZZ ZZ(\r2Z( or#(\Z2(Z\Z(\2\2)2))\2Z)Z(\22Z((\Z2(Z\Z(\2\2)2))\2Z)))int \)\0(2\ZZZ)+:)Z^)))int \)\0(2\ZZZ)+:)Z^|91ZiZZnter(ZZernZal ZZ(\r2Z( or#(\Z2(Z\Z(\2\2)2))\2Z)Z(\22Z((\Z2(Z\Z(\2\2)2))\2Z)))int \))\ZZ(\r2Z( or#(\Z2(Z\Z(\2\2)2))\2Z)Z(\22Z((\Z2(Z\Z(\2\2)))\2))))((((((\2\2))))))"I +# This checks that new code for handling groups that may match an empty string +# works on a very large number of alternatives. This pattern used to provoke a +# complaint that it was too complicated. + +/(?:\[A|B|C|D|E|F|G|H|I|J|]{200}Z)/expand + # End of testinput2 diff --git a/testdata/testoutput2 b/testdata/testoutput2 index c934be4..1141fc2 100644 --- a/testdata/testoutput2 +++ b/testdata/testoutput2 @@ -10741,7 +10741,8 @@ Matched, but too many substrings /(?(DEFINE)(a(?2)|b)(b(?1)|a))(?:(?1)|(?2))/I Capturing subpattern count = 2 -Subject length lower bound = 1 +May match empty string +Subject length lower bound = 0 /(a(?2)|b)(b(?1)|a)(?:(?1)|(?2))/I Capturing subpattern count = 2 @@ -14759,7 +14760,7 @@ Failed: error 188 at offset 0: pattern string is longer than the limit set by th /abcdef/hex,max_pattern_length=3 -# These two patterns used to take a long time to compile +# These patterns used to take a long time to compile "(.*) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) @@ -14782,14 +14783,14 @@ May match empty string Options: extended Subject length lower bound = 0 -# When (?| is used and groups of the same number may be different, -# we have to rely on a count to catch overly complicated patterns. - "(?|()|())(.*) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))"xI -Failed: error 186 at offset 148: regular expression is too complicated +Capturing subpattern count = 13 +May match empty string +Options: extended +Subject length lower bound = 0 "(?|()|())(?<=a() ((?-2)(?-2))((?-2)(?-2))((?-2)(?-2))((?-2)(?-2)) @@ -15417,6 +15418,12 @@ Max back reference = 22 Contains explicit CR or LF match Subject length lower bound = 0 +# This checks that new code for handling groups that may match an empty string +# works on a very large number of alternatives. This pattern used to provoke a +# complaint that it was too complicated. + +/(?:\[A|B|C|D|E|F|G|H|I|J|]{200}Z)/expand + # End of testinput2 Error -63: PCRE2_ERROR_BADDATA (unknown error number) Error -62: bad serialized data