149 lines
4.7 KiB
C
149 lines
4.7 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) 2016-2021 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 an internal function that is used to match a Unicode
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extended grapheme sequence. It is used by both pcre2_match() and
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pcre2_def_match(). However, it is called only when Unicode support is being
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compiled. Nevertheless, we provide a dummy function when there is no Unicode
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support, because some compilers do not like functionless source files. */
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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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/* Dummy function */
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#ifndef SUPPORT_UNICODE
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PCRE2_SPTR
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PRIV(extuni)(uint32_t c, PCRE2_SPTR eptr, PCRE2_SPTR start_subject,
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PCRE2_SPTR end_subject, BOOL utf, int *xcount)
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{
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(void)c;
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(void)eptr;
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(void)start_subject;
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(void)end_subject;
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(void)utf;
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(void)xcount;
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return NULL;
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}
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#else
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/*************************************************
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* Match an extended grapheme sequence *
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*************************************************/
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/*
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Arguments:
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c the first character
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eptr pointer to next character
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start_subject pointer to start of subject
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end_subject pointer to end of subject
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utf TRUE if in UTF mode
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xcount pointer to count of additional characters,
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or NULL if count not needed
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Returns: pointer after the end of the sequence
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*/
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PCRE2_SPTR
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PRIV(extuni)(uint32_t c, PCRE2_SPTR eptr, PCRE2_SPTR start_subject,
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PCRE2_SPTR end_subject, BOOL utf, int *xcount)
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{
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int lgb = UCD_GRAPHBREAK(c);
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while (eptr < end_subject)
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{
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int rgb;
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int len = 1;
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if (!utf) c = *eptr; else { GETCHARLEN(c, eptr, len); }
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rgb = UCD_GRAPHBREAK(c);
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if ((PRIV(ucp_gbtable)[lgb] & (1u << rgb)) == 0) break;
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/* Not breaking between Regional Indicators is allowed only if there
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are an even number of preceding RIs. */
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if (lgb == ucp_gbRegional_Indicator && rgb == ucp_gbRegional_Indicator)
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{
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int ricount = 0;
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PCRE2_SPTR bptr = eptr - 1;
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if (utf) BACKCHAR(bptr);
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/* bptr is pointing to the left-hand character */
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while (bptr > start_subject)
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{
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bptr--;
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if (utf)
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{
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BACKCHAR(bptr);
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GETCHAR(c, bptr);
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}
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else
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c = *bptr;
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if (UCD_GRAPHBREAK(c) != ucp_gbRegional_Indicator) break;
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ricount++;
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}
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if ((ricount & 1) != 0) break; /* Grapheme break required */
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}
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/* If Extend or ZWJ follows Extended_Pictographic, do not update lgb; this
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allows any number of them before a following Extended_Pictographic. */
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if ((rgb != ucp_gbExtend && rgb != ucp_gbZWJ) ||
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lgb != ucp_gbExtended_Pictographic)
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lgb = rgb;
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eptr += len;
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if (xcount != NULL) *xcount += 1;
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}
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return eptr;
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}
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#endif /* SUPPORT_UNICODE */
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/* End of pcre2_extuni.c */
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