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