/************************************************* * Perl-Compatible Regular Expressions * *************************************************/ /* PCRE is a library of functions to support regular expressions whose syntax and semantics are as close as possible to those of the Perl 5 language. Written by Philip Hazel Original API code Copyright (c) 1997-2012 University of Cambridge New API code Copyright (c) 2016-2018 University of Cambridge ----------------------------------------------------------------------------- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the University of Cambridge nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ----------------------------------------------------------------------------- */ /* This module contains a single function that scans through a compiled pattern until it finds a capturing bracket with the given number, or, if the number is negative, an instance of OP_REVERSE for a lookbehind. The function is called from pcre2_compile.c and also from pcre2_study.c when finding the minimum matching length. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "pcre2_internal.h" /************************************************* * Scan compiled regex for specific bracket * *************************************************/ /* Arguments: code points to start of expression utf TRUE in UTF mode number the required bracket number or negative to find a lookbehind Returns: pointer to the opcode for the bracket, or NULL if not found */ PCRE2_SPTR PRIV(find_bracket)(PCRE2_SPTR code, BOOL utf, int number) { for (;;) { PCRE2_UCHAR c = *code; if (c == OP_END) return NULL; /* XCLASS is used for classes that cannot be represented just by a bit map. This includes negated single high-valued characters. CALLOUT_STR is used for callouts with string arguments. In both cases the length in the table is zero; the actual length is stored in the compiled code. */ if (c == OP_XCLASS) code += GET(code, 1); else if (c == OP_CALLOUT_STR) code += GET(code, 1 + 2*LINK_SIZE); /* Handle lookbehind */ else if (c == OP_REVERSE) { if (number < 0) return (PCRE2_UCHAR *)code; code += PRIV(OP_lengths)[c]; } /* Handle capturing bracket */ else if (c == OP_CBRA || c == OP_SCBRA || c == OP_CBRAPOS || c == OP_SCBRAPOS) { int n = (int)GET2(code, 1+LINK_SIZE); if (n == number) return (PCRE2_UCHAR *)code; code += PRIV(OP_lengths)[c]; } /* Otherwise, we can get the item's length from the table, except that for repeated character types, we have to test for \p and \P, which have an extra two bytes of parameters, and for MARK/PRUNE/SKIP/THEN with an argument, we must add in its length. */ else { switch(c) { case OP_TYPESTAR: case OP_TYPEMINSTAR: case OP_TYPEPLUS: case OP_TYPEMINPLUS: case OP_TYPEQUERY: case OP_TYPEMINQUERY: case OP_TYPEPOSSTAR: case OP_TYPEPOSPLUS: case OP_TYPEPOSQUERY: if (code[1] == OP_PROP || code[1] == OP_NOTPROP) code += 2; break; case OP_TYPEUPTO: case OP_TYPEMINUPTO: case OP_TYPEEXACT: case OP_TYPEPOSUPTO: if (code[1 + IMM2_SIZE] == OP_PROP || code[1 + IMM2_SIZE] == OP_NOTPROP) code += 2; break; case OP_MARK: case OP_COMMIT_ARG: case OP_PRUNE_ARG: case OP_SKIP_ARG: case OP_THEN_ARG: code += code[1]; break; } /* Add in the fixed length from the table */ code += PRIV(OP_lengths)[c]; /* In UTF-8 and UTF-16 modes, opcodes that are followed by a character may be followed by a multi-byte character. The length in the table is a minimum, so we have to arrange to skip the extra bytes. */ #ifdef MAYBE_UTF_MULTI if (utf) switch(c) { case OP_CHAR: case OP_CHARI: case OP_NOT: case OP_NOTI: case OP_EXACT: case OP_EXACTI: case OP_NOTEXACT: case OP_NOTEXACTI: 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: 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_PLUS: case OP_PLUSI: case OP_NOTPLUS: case OP_NOTPLUSI: case OP_MINPLUS: case OP_MINPLUSI: case OP_NOTMINPLUS: case OP_NOTMINPLUSI: case OP_POSPLUS: case OP_POSPLUSI: case OP_NOTPOSPLUS: case OP_NOTPOSPLUSI: 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 (HAS_EXTRALEN(code[-1])) code += GET_EXTRALEN(code[-1]); break; } #else (void)(utf); /* Keep compiler happy by referencing function argument */ #endif /* MAYBE_UTF_MULTI */ } } } /* End of pcre2_find_bracket.c */