From d7ef4b7364482c4749537ca35a54bca0956e5709 Mon Sep 17 00:00:00 2001
From: Karl Williamson <public@khwilliamson.com>
Date: Tue, 30 Nov 2010 22:05:25 -0700
Subject: [PATCH] regexec.c: Handle REFFU and NREFFU; refactor

This adds handling of the Unicode folding semantics capture buffer
backreferences.  I've refactored the code so that the case statements
set up the type of folding, to avoid having to test for which in the
common code.

Also, the previous code was confusing fold case and lowercase.  There is
already a routine to handle the fold case, so that simplified things.
---
 regexec.c | 115 +++++++++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 72 insertions(+), 43 deletions(-)

diff --git a/regexec.c b/regexec.c
index ff76c84..ffa2da4 100644
--- a/regexec.c
+++ b/regexec.c
@@ -3927,31 +3927,69 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
 	    break;
             
 	case NREFFL:
-	{
+	{   /* The capture buffer cases.  The ones beginning with N for the
+	       named buffers just convert to the equivalent numbered and
+	       pretend they were called as the corresponding numbered buffer
+	       op.  */
 	    char *s;
 	    char type;
+	    I32 (*folder)() = NULL;	/* NULL assumes will be NREF, REF: no
+					   folding */
+	    const U8 * fold_array = NULL;
+
 	    PL_reg_flags |= RF_tainted;
-	    /* FALL THROUGH */
-	case NREF:
+	    folder = foldEQ_locale;
+	    fold_array = PL_fold_locale;
+	    type = REFFL;
+	    goto do_nref;
+
+	case NREFFU:
+	    folder = foldEQ_latin1;
+	    fold_array = PL_fold_latin1;
+	    type = REFFU;
+	    goto do_nref;
+
 	case NREFF:
-	    type = OP(scan);
+	    folder = foldEQ;
+	    fold_array = PL_fold;
+	    type = REFF;
+	    goto do_nref;
+
+	case NREF:
+	    type = REF;
+	  do_nref:
+
+	    /* For the named back references, find the corresponding buffer
+	     * number */
 	    n = reg_check_named_buff_matched(rex,scan);
 
-            if ( n ) {
-                type = REF + ( type - NREF );
-                goto do_ref;
-            } else {
+            if ( ! n ) {
                 sayNO;
-            }
-            /* unreached */
+	    }
+	    goto do_nref_ref_common;
+
 	case REFFL:
 	    PL_reg_flags |= RF_tainted;
+	    folder = foldEQ_locale;
+	    fold_array = PL_fold_locale;
+	    goto do_ref;
+
+	case REFFU:
+	    folder = foldEQ_latin1;
+	    fold_array = PL_fold_latin1;
+	    goto do_ref;
+
+	case REFF:
+	    folder = foldEQ;
+	    fold_array = PL_fold;
 	    /* FALL THROUGH */
+
         case REF:
-	case REFF: 
-	    n = ARG(scan);  /* which paren pair */
+	  do_ref:
 	    type = OP(scan);
-	  do_ref:  
+	    n = ARG(scan);  /* which paren pair */
+
+	  do_nref_ref_common:
 	    ln = PL_regoffs[n].start;
 	    PL_reg_leftiter = PL_reg_maxiter;		/* Void cache */
 	    if (*PL_reglastparen < n || ln == -1)
@@ -3960,49 +3998,40 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
 		break;
 
 	    s = PL_bostr + ln;
-	    if (utf8_target && type != REF) {	/* REF can do byte comparison */
-		char *l = locinput;
-		const char *e = PL_bostr + PL_regoffs[n].end;
-		/*
-		 * Note that we can't do the "other character" lookup trick as
-		 * in the 8-bit case (no pun intended) because in Unicode we
-		 * have to map both upper and title case to lower case.
-		 */
-		if (type == REFF) {
-		    while (s < e) {
-			STRLEN ulen1, ulen2;
-			U8 tmpbuf1[UTF8_MAXBYTES_CASE+1];
-			U8 tmpbuf2[UTF8_MAXBYTES_CASE+1];
-
-			if (l >= PL_regeol)
-			    sayNO;
-			toLOWER_utf8((U8*)s, tmpbuf1, &ulen1);
-			toLOWER_utf8((U8*)l, tmpbuf2, &ulen2);
-			if (ulen1 != ulen2 || memNE((char *)tmpbuf1, (char *)tmpbuf2, ulen1))
-			    sayNO;
-			s += ulen1;
-			l += ulen2;
-		    }
+	    if (type != REF	/* REF can do byte comparison */
+		&& (utf8_target
+                    || (type == REFFU
+                        && (*s == (char) LATIN_SMALL_LETTER_SHARP_S
+                            || *locinput == (char) LATIN_SMALL_LETTER_SHARP_S))))
+	    { /* XXX handle REFFL better */
+		char * limit = PL_regeol;
+
+		/* This call case insensitively compares the entire buffer
+		    * at s, with the current input starting at locinput, but
+		    * not going off the end given by PL_regeol, and returns in
+		    * limit upon success, how much of the current input was
+		    * matched */
+		if (! foldEQ_utf8(s, NULL, PL_regoffs[n].end - ln, utf8_target,
+				    locinput, &limit, 0, utf8_target))
+		{
+		    sayNO;
 		}
-		locinput = l;
+		locinput = limit;
 		nextchr = UCHARAT(locinput);
 		break;
 	    }
 
-	    /* Inline the first character, for speed. */
+	    /* Not utf8:  Inline the first character, for speed. */
 	    if (UCHARAT(s) != nextchr &&
 		(type == REF ||
-		 (UCHARAT(s) != (type == REFF
-				  ? PL_fold : PL_fold_locale)[nextchr])))
+		 UCHARAT(s) != fold_array[nextchr]))
 		sayNO;
 	    ln = PL_regoffs[n].end - ln;
 	    if (locinput + ln > PL_regeol)
 		sayNO;
 	    if (ln > 1 && (type == REF
 			   ? memNE(s, locinput, ln)
-			   : (type == REFF
-			      ? ! foldEQ(s, locinput, ln)
-			      : ! foldEQ_locale(s, locinput, ln))))
+			   : ! folder(s, locinput, ln)))
 		sayNO;
 	    locinput += ln;
 	    nextchr = UCHARAT(locinput);
-- 
2.7.4