[webkit-changes] [160954] trunk/Source/WTF

Fri, 20 Dec 2013 18:22:44 -0800

Title: [160954] trunk/Source/WTF
Revision
160954
Author
ander...@apple.com
Date
2013-12-20 18:25:19 -0800 (Fri, 20 Dec 2013)

Log Message

Speed up case folding for 8-bit strings
https://bugs.webkit.org/show_bug.cgi?id=126098

Reviewed by Geoffrey Garen.

Add a case folding lookup table for 8-bit strings and use it instead of calling down to u_foldCase.
On a simple microbenchmark using a lookup table is about 15x faster.

* wtf/text/StringHash.h:
(WTF::CaseFoldingHash::foldCase):
* wtf/text/StringImpl.cpp:
(WTF::equalIgnoringCase):
* wtf/text/StringImpl.h:

Modified Paths

Diff

Modified: trunk/Source/WTF/ChangeLog (160953 => 160954)


--- trunk/Source/WTF/ChangeLog	2013-12-21 02:15:19 UTC (rev 160953)
+++ trunk/Source/WTF/ChangeLog	2013-12-21 02:25:19 UTC (rev 160954)
@@ -1,3 +1,19 @@
+2013-12-20  Anders Carlsson  <ander...@apple.com>
+
+        Speed up case folding for 8-bit strings
+        https://bugs.webkit.org/show_bug.cgi?id=126098
+
+        Reviewed by Geoffrey Garen.
+
+        Add a case folding lookup table for 8-bit strings and use it instead of calling down to u_foldCase.
+        On a simple microbenchmark using a lookup table is about 15x faster.
+
+        * wtf/text/StringHash.h:
+        (WTF::CaseFoldingHash::foldCase):
+        * wtf/text/StringImpl.cpp:
+        (WTF::equalIgnoringCase):
+        * wtf/text/StringImpl.h:
+
 2013-12-20  Myles C. Maxfield  <mmaxfi...@apple.com>
 
         Faster implementation of text-decoration-skip: ink

Modified: trunk/Source/WTF/wtf/text/StringHash.h (160953 => 160954)


--- trunk/Source/WTF/wtf/text/StringHash.h	2013-12-21 02:15:19 UTC (rev 160953)
+++ trunk/Source/WTF/wtf/text/StringHash.h	2013-12-21 02:25:19 UTC (rev 160954)
@@ -75,6 +75,9 @@
     public:
         template<typename T> static inline UChar foldCase(T character)
         {
+            if (std::is_same<T, LChar>::value)
+                return StringImpl::latin1CaseFoldTable[character];
+            
             return u_foldCase(character, U_FOLD_CASE_DEFAULT);
         }

Modified: trunk/Source/WTF/wtf/text/StringImpl.cpp (160953 => 160954)


--- trunk/Source/WTF/wtf/text/StringImpl.cpp	2013-12-21 02:15:19 UTC (rev 160953)
+++ trunk/Source/WTF/wtf/text/StringImpl.cpp	2013-12-21 02:25:19 UTC (rev 160954)
@@ -953,7 +953,7 @@
 bool equalIgnoringCase(const LChar* a, const LChar* b, unsigned length)
 {
     while (length--) {
-        if (u_foldCase(*a++, U_FOLD_CASE_DEFAULT) != u_foldCase(*b++, U_FOLD_CASE_DEFAULT))
+        if (StringImpl::latin1CaseFoldTable[*a++] != StringImpl::latin1CaseFoldTable[*b++])
             return false;
     }
     return true;
@@ -962,7 +962,7 @@
 bool equalIgnoringCase(const UChar* a, const LChar* b, unsigned length)
 {
     while (length--) {
-        if (u_foldCase(*a++, U_FOLD_CASE_DEFAULT) != u_foldCase(*b++, U_FOLD_CASE_DEFAULT))
+        if (u_foldCase(*a++, U_FOLD_CASE_DEFAULT) != StringImpl::latin1CaseFoldTable[*b++])
             return false;
     }
     return true;
@@ -2133,4 +2133,25 @@
     return utf8ForRange(0, length(), mode);
 }
 
+// Table is based on ftp://ftp.unicode.org/Public/UNIDATA/CaseFolding.txt
+const UChar StringImpl::latin1CaseFoldTable[256] = {
+    0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f,
+    0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017, 0x0018, 0x0019, 0x001a, 0x001b, 0x001c, 0x001d, 0x001e, 0x001f, 
+    0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f, 
+    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f,
+    0x0040, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f,
+    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x005b, 0x005c, 0x005d, 0x005e, 0x005f,
+    0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f,
+    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x007b, 0x007c, 0x007d, 0x007e, 0x007f,
+    0x0080, 0x0081, 0x0082, 0x0083, 0x0084, 0x0085, 0x0086, 0x0087, 0x0088, 0x0089, 0x008a, 0x008b, 0x008c, 0x008d, 0x008e, 0x008f,
+    0x0090, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096, 0x0097, 0x0098, 0x0099, 0x009a, 0x009b, 0x009c, 0x009d, 0x009e, 0x009f,
+    0x00a0, 0x00a1, 0x00a2, 0x00a3, 0x00a4, 0x00a5, 0x00a6, 0x00a7, 0x00a8, 0x00a9, 0x00aa, 0x00ab, 0x00ac, 0x00ad, 0x00ae, 0x00af,
+    0x00b0, 0x00b1, 0x00b2, 0x00b3, 0x00b4, 0x03bc, 0x00b6, 0x00b7, 0x00b8, 0x00b9, 0x00ba, 0x00bb, 0x00bc, 0x00bd, 0x00be, 0x00bf,
+    0x00e0, 0x00e1, 0x00e2, 0x00e3, 0x00e4, 0x00e5, 0x00e6, 0x00e7, 0x00e8, 0x00e9, 0x00ea, 0x00eb, 0x00ec, 0x00ed, 0x00ee, 0x00ef,
+    0x00f0, 0x00f1, 0x00f2, 0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00d7, 0x00f8, 0x00f9, 0x00fa, 0x00fb, 0x00fc, 0x00fd, 0x00fe, 0x00df,
+    0x00e0, 0x00e1, 0x00e2, 0x00e3, 0x00e4, 0x00e5, 0x00e6, 0x00e7, 0x00e8, 0x00e9, 0x00ea, 0x00eb, 0x00ec, 0x00ed, 0x00ee, 0x00ef,
+    0x00f0, 0x00f1, 0x00f2, 0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7, 0x00f8, 0x00f9, 0x00fa, 0x00fb, 0x00fc, 0x00fd, 0x00fe, 0x00ff, 
+};
+
+
 } // namespace WTF

Modified: trunk/Source/WTF/wtf/text/StringImpl.h (160953 => 160954)


--- trunk/Source/WTF/wtf/text/StringImpl.h	2013-12-21 02:15:19 UTC (rev 160953)
+++ trunk/Source/WTF/wtf/text/StringImpl.h	2013-12-21 02:25:19 UTC (rev 160954)
@@ -760,6 +760,8 @@
     ALWAYS_INLINE static StringStats& stringStats() { return m_stringStats; }
 #endif
 
+    WTF_EXPORT_STRING_API static const UChar latin1CaseFoldTable[256];
+
 private:
     bool requiresCopy() const
     {

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