From 46d818df26f3585f9261c735129a606837406875 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Fri, 21 Aug 2020 00:47:09 -0400
Subject: [PATCH] Special-case some of the string walking code

Make variants of FcStrCaseWalkerNext for the two
common cases, delim == NULL and delim == " ", to
speed things up.

These are inner loops, and having the conditions
as simple as possible helps.
---
 src/fcstr.c | 86 ++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 62 insertions(+), 24 deletions(-)

diff --git a/src/fcstr.c b/src/fcstr.c
index 864d4aa..39ecbbb 100644
--- a/src/fcstr.c
+++ b/src/fcstr.c
@@ -160,7 +160,7 @@ FcStrCaseWalkerLong (FcCaseWalker *w, FcChar8 r)
 }
 
 static FcChar8
-FcStrCaseWalkerNext (FcCaseWalker *w, const char *delims)
+FcStrCaseWalkerNextNonDelim (FcCaseWalker *w, const char *delims)
 {
     FcChar8	r;
 
@@ -182,6 +182,50 @@ FcStrCaseWalkerNext (FcCaseWalker *w, const char *delims)
     return r;
 }
 
+static FcChar8
+FcStrCaseWalkerNextNonBlank (FcCaseWalker *w)
+{
+    FcChar8	r;
+
+    if (w->read)
+    {
+	if ((r = *w->read++))
+	    return r;
+	w->read = 0;
+    }
+    do
+    {
+	r = *w->src++;
+    } while (r == ' ');
+
+    if ((r & 0xc0) == 0xc0)
+	return FcStrCaseWalkerLong (w, r);
+    if ('A' <= r && r <= 'Z')
+        r = r - 'A' + 'a';
+    return r;
+}
+
+static FcChar8
+FcStrCaseWalkerNext (FcCaseWalker *w)
+{
+    FcChar8	r;
+
+    if (w->read)
+    {
+	if ((r = *w->read++))
+	    return r;
+	w->read = 0;
+    }
+
+    r = *w->src++;
+
+    if ((r & 0xc0) == 0xc0)
+	return FcStrCaseWalkerLong (w, r);
+    if ('A' <= r && r <= 'Z')
+        r = r - 'A' + 'a';
+    return r;
+}
+
 FcChar8 *
 FcStrDowncase (const FcChar8 *s)
 {
@@ -190,13 +234,13 @@ FcStrDowncase (const FcChar8 *s)
     FcChar8	    *dst, *d;
 
     FcStrCaseWalkerInit (s, &w);
-    while (FcStrCaseWalkerNext (&w, NULL))
+    while (FcStrCaseWalkerNext (&w))
 	len++;
     d = dst = malloc (len + 1);
     if (!d)
 	return 0;
     FcStrCaseWalkerInit (s, &w);
-    while ((*d++ = FcStrCaseWalkerNext (&w, NULL)));
+    while ((*d++ = FcStrCaseWalkerNext (&w)));
     return dst;
 }
 
@@ -213,8 +257,8 @@ FcStrCmpIgnoreCase (const FcChar8 *s1, const FcChar8 *s2)
 
     for (;;)
     {
-	c1 = FcStrCaseWalkerNext (&w1, NULL);
-	c2 = FcStrCaseWalkerNext (&w2, NULL);
+	c1 = FcStrCaseWalkerNext (&w1);
+	c2 = FcStrCaseWalkerNext (&w2);
 	if (!c1 || (c1 != c2))
 	    break;
     }
@@ -223,12 +267,6 @@ FcStrCmpIgnoreCase (const FcChar8 *s1, const FcChar8 *s2)
 
 int
 FcStrCmpIgnoreBlanksAndCase (const FcChar8 *s1, const FcChar8 *s2)
-{
-    return FcStrCmpIgnoreCaseAndDelims (s1, s2, (const FcChar8 *)" ");
-}
-
-int
-FcStrCmpIgnoreCaseAndDelims (const FcChar8 *s1, const FcChar8 *s2, const FcChar8 *delims)
 {
     FcCaseWalker    w1, w2;
     FcChar8	    c1, c2;
@@ -240,8 +278,8 @@ FcStrCmpIgnoreCaseAndDelims (const FcChar8 *s1, const FcChar8 *s2, const FcChar8
 
     for (;;)
     {
-	c1 = FcStrCaseWalkerNext (&w1, (const char *)delims);
-	c2 = FcStrCaseWalkerNext (&w2, (const char *)delims);
+	c1 = FcStrCaseWalkerNextNonBlank (&w1);
+	c2 = FcStrCaseWalkerNextNonBlank (&w2);
 	if (!c1 || (c1 != c2))
 	    break;
     }
@@ -277,7 +315,7 @@ FcStrHashIgnoreCase (const FcChar8 *s)
     FcChar8	    c;
 
     FcStrCaseWalkerInit (s, &w);
-    while ((c = FcStrCaseWalkerNext (&w, NULL)))
+    while ((c = FcStrCaseWalkerNext (&w)))
 	h = ((h << 3) ^ (h >> 3)) ^ c;
     return h;
 }
@@ -297,8 +335,8 @@ FcStrIsAtIgnoreBlanksAndCase (const FcChar8 *s1, const FcChar8 *s2)
 
     for (;;)
     {
-	c1 = FcStrCaseWalkerNext (&w1, " ");
-	c2 = FcStrCaseWalkerNext (&w2, " ");
+	c1 = FcStrCaseWalkerNextNonBlank (&w1);
+	c2 = FcStrCaseWalkerNextNonBlank (&w2);
 	if (!c1 || (c1 != c2))
 	    break;
     }
@@ -356,8 +394,8 @@ FcStrIsAtIgnoreCase (const FcChar8 *s1, const FcChar8 *s2)
 
     for (;;)
     {
-	c1 = FcStrCaseWalkerNext (&w1, NULL);
-	c2 = FcStrCaseWalkerNext (&w2, NULL);
+	c1 = FcStrCaseWalkerNext (&w1);
+	c2 = FcStrCaseWalkerNext (&w2);
 	if (!c1 || (c1 != c2))
 	    break;
     }
@@ -425,8 +463,8 @@ FcStrMatchIgnoreCaseAndDelims (const FcChar8 *s1, const FcChar8 *s2, const FcCha
 
     for (;;)
     {
-	c1 = FcStrCaseWalkerNext (&w1, (const char *)delims);
-	c2 = FcStrCaseWalkerNext (&w2, (const char *)delims);
+	c1 = FcStrCaseWalkerNextNonDelim (&w1, (const char *)delims);
+	c2 = FcStrCaseWalkerNextNonDelim (&w2, (const char *)delims);
 	if (!c1 || (c1 != c2))
 	    break;
     }
@@ -493,12 +531,12 @@ FcStrStrIgnoreCase (const FcChar8 *s1, const FcChar8 *s2)
     FcStrCaseWalkerInit (s1, &w1);
     FcStrCaseWalkerInit (s2, &w2);
 
-    c2 = FcStrCaseWalkerNext (&w2, NULL);
+    c2 = FcStrCaseWalkerNext (&w2);
 
     for (;;)
     {
 	cur = w1.src;
-	c1 = FcStrCaseWalkerNext (&w1, NULL);
+	c1 = FcStrCaseWalkerNext (&w1);
 	if (!c1)
 	    break;
 	if (c1 == c2)
@@ -509,8 +547,8 @@ FcStrStrIgnoreCase (const FcChar8 *s1, const FcChar8 *s2)
 
 	    for (;;)
 	    {
-		c1t = FcStrCaseWalkerNext (&w1t, NULL);
-		c2t = FcStrCaseWalkerNext (&w2t, NULL);
+		c1t = FcStrCaseWalkerNext (&w1t);
+		c2t = FcStrCaseWalkerNext (&w2t);
 
 		if (!c2t)
 		    return cur;