add PIRegularExpression

3rd/pcre2/src/pcre2_extuni.c

@@ -0,0 +1,162 @@
+/*************************************************
+*      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) 2016-2024 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 an internal function that is used to match a Unicode
+extended grapheme sequence. It is used by both pcre2_match() and
+pcre2_dfa_match(). However, it is called only when Unicode support is being
+compiled. Nevertheless, we provide a dummy function when there is no Unicode
+support, because some compilers do not like functionless source files. */
+
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+
+#include "pcre2_internal.h"
+
+
+/* Dummy function */
+
+#ifndef SUPPORT_UNICODE
+PCRE2_SPTR
+PRIV(extuni)(uint32_t c, PCRE2_SPTR eptr, PCRE2_SPTR start_subject,
+  PCRE2_SPTR end_subject, BOOL utf, int *xcount)
+{
+(void)c;
+(void)eptr;
+(void)start_subject;
+(void)end_subject;
+(void)utf;
+(void)xcount;
+return NULL;
+}
+#else
+
+
+/*************************************************
+*      Match an extended grapheme sequence       *
+*************************************************/
+
+/* NOTE: The logic contained in this function is replicated in three special-
+purpose functions in the pcre2_jit_compile.c module. If the logic below is
+changed, they must be kept in step so that the interpreter and the JIT have the
+same behaviour.
+
+Arguments:
+  c              the first character
+  eptr           pointer to next character
+  start_subject  pointer to start of subject
+  end_subject    pointer to end of subject
+  utf            TRUE if in UTF mode
+  xcount         pointer to count of additional characters,
+                   or NULL if count not needed
+
+Returns:         pointer after the end of the sequence
+*/
+
+PCRE2_SPTR
+PRIV(extuni)(uint32_t c, PCRE2_SPTR eptr, PCRE2_SPTR start_subject,
+  PCRE2_SPTR end_subject, BOOL utf, int *xcount)
+{
+BOOL was_ep_ZWJ = FALSE;
+int lgb = UCD_GRAPHBREAK(c);
+
+while (eptr < end_subject)
+  {
+  int rgb;
+  int len = 1;
+  if (!utf) c = *eptr; else { GETCHARLEN(c, eptr, len); }
+  rgb = UCD_GRAPHBREAK(c);
+  if ((PRIV(ucp_gbtable)[lgb] & (1u << rgb)) == 0) break;
+
+  /* ZWJ followed by Extended Pictographic is allowed only if the ZWJ was
+  preceded by Extended Pictographic. */
+
+  if (lgb == ucp_gbZWJ && rgb == ucp_gbExtended_Pictographic && !was_ep_ZWJ)
+    break;
+
+  /* Not breaking between Regional Indicators is allowed only if there
+  are an even number of preceding RIs. */
+
+  if (lgb == ucp_gbRegional_Indicator && rgb == ucp_gbRegional_Indicator)
+    {
+    int ricount = 0;
+    PCRE2_SPTR bptr = eptr - 1;
+    if (utf) BACKCHAR(bptr);
+
+    /* bptr is pointing to the left-hand character */
+
+    while (bptr > start_subject)
+      {
+      bptr--;
+      if (utf)
+        {
+        BACKCHAR(bptr);
+        GETCHAR(c, bptr);
+        }
+      else
+      c = *bptr;
+      if (UCD_GRAPHBREAK(c) != ucp_gbRegional_Indicator) break;
+      ricount++;
+      }
+    if ((ricount & 1) != 0) break;  /* Grapheme break required */
+    }
+
+  /* Set a flag when ZWJ follows Extended Pictographic (with optional Extend in
+  between; see next statement). */
+
+  was_ep_ZWJ = (lgb == ucp_gbExtended_Pictographic && rgb == ucp_gbZWJ);
+
+  /* If Extend follows Extended_Pictographic, do not update lgb; this allows
+  any number of them before a following ZWJ. */
+
+  if (rgb != ucp_gbExtend || lgb != ucp_gbExtended_Pictographic) lgb = rgb;
+
+  eptr += len;
+  if (xcount != NULL) *xcount += 1;
+  }
+
+return eptr;
+}
+
+#endif  /* SUPPORT_UNICODE */
+
+/* End of pcre2_extuni.c */