1/*************************************************
2* Perl-Compatible Regular Expressions *
3*************************************************/
4
5/* PCRE is a library of functions to support regular expressions whose syntax
6and semantics are as close as possible to those of the Perl 5 language.
7
8 Written by Philip Hazel
9 Original API code Copyright (c) 1997-2012 University of Cambridge
10 New API code Copyright (c) 2016-2021 University of Cambridge
11
12-----------------------------------------------------------------------------
13Redistribution and use in source and binary forms, with or without
14modification, are permitted provided that the following conditions are met:
15
16 * Redistributions of source code must retain the above copyright notice,
17 this list of conditions and the following disclaimer.
18
19 * Redistributions in binary form must reproduce the above copyright
20 notice, this list of conditions and the following disclaimer in the
21 documentation and/or other materials provided with the distribution.
22
23 * Neither the name of the University of Cambridge nor the names of its
24 contributors may be used to endorse or promote products derived from
25 this software without specific prior written permission.
26
27THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
28AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
31LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37POSSIBILITY OF SUCH DAMAGE.
38-----------------------------------------------------------------------------
39*/
40
41/* This module contains an internal function that is used to match a Unicode
42extended grapheme sequence. It is used by both pcre2_match() and
43pcre2_def_match(). However, it is called only when Unicode support is being
44compiled. Nevertheless, we provide a dummy function when there is no Unicode
45support, because some compilers do not like functionless source files. */
46
47
48#ifdef HAVE_CONFIG_H
49#include "config.h"
50#endif
51
52
53#include "pcre2_internal.h"
54
55
56/* Dummy function */
57
58#ifndef SUPPORT_UNICODE
59PCRE2_SPTR
60PRIV(extuni)(uint32_t c, PCRE2_SPTR eptr, PCRE2_SPTR start_subject,
61 PCRE2_SPTR end_subject, BOOL utf, int *xcount)
62{
63(void)c;
64(void)eptr;
65(void)start_subject;
66(void)end_subject;
67(void)utf;
68(void)xcount;
69return NULL;
70}
71#else
72
73
74/*************************************************
75* Match an extended grapheme sequence *
76*************************************************/
77
78/*
79Arguments:
80 c the first character
81 eptr pointer to next character
82 start_subject pointer to start of subject
83 end_subject pointer to end of subject
84 utf TRUE if in UTF mode
85 xcount pointer to count of additional characters,
86 or NULL if count not needed
87
88Returns: pointer after the end of the sequence
89*/
90
91PCRE2_SPTR
92PRIV(extuni)(uint32_t c, PCRE2_SPTR eptr, PCRE2_SPTR start_subject,
93 PCRE2_SPTR end_subject, BOOL utf, int *xcount)
94{
95int lgb = UCD_GRAPHBREAK(c);
96
97while (eptr < end_subject)
98 {
99 int rgb;
100 int len = 1;
101 if (!utf) c = *eptr; else { GETCHARLEN(c, eptr, len); }
102 rgb = UCD_GRAPHBREAK(c);
103 if ((PRIV(ucp_gbtable)[lgb] & (1u << rgb)) == 0) break;
104
105 /* Not breaking between Regional Indicators is allowed only if there
106 are an even number of preceding RIs. */
107
108 if (lgb == ucp_gbRegional_Indicator && rgb == ucp_gbRegional_Indicator)
109 {
110 int ricount = 0;
111 PCRE2_SPTR bptr = eptr - 1;
112 if (utf) BACKCHAR(bptr);
113
114 /* bptr is pointing to the left-hand character */
115
116 while (bptr > start_subject)
117 {
118 bptr--;
119 if (utf)
120 {
121 BACKCHAR(bptr);
122 GETCHAR(c, bptr);
123 }
124 else
125 c = *bptr;
126 if (UCD_GRAPHBREAK(c) != ucp_gbRegional_Indicator) break;
127 ricount++;
128 }
129 if ((ricount & 1) != 0) break; /* Grapheme break required */
130 }
131
132 /* If Extend or ZWJ follows Extended_Pictographic, do not update lgb; this
133 allows any number of them before a following Extended_Pictographic. */
134
135 if ((rgb != ucp_gbExtend && rgb != ucp_gbZWJ) ||
136 lgb != ucp_gbExtended_Pictographic)
137 lgb = rgb;
138
139 eptr += len;
140 if (xcount != NULL) *xcount += 1;
141 }
142
143return eptr;
144}
145
146#endif /* SUPPORT_UNICODE */
147
148/* End of pcre2_extuni.c */
149