Bug 729952 - Part 2: Use a better hash function in nsCRT, nsTHashtable, and pldhash. r=bz

xpcom/ds/nsCRT.cpp

@@ -54,11 +54,10 @@
 #include "nsCRT.h"
 #include "nsIServiceManager.h"
 #include "nsCharTraits.h"
-#include "prbit.h"
 #include "nsUTF8Utils.h"
+#include "mozilla/HashFunctions.h"
 
-#define ADD_TO_HASHVAL(hashval, c) \
-    hashval = PR_ROTATE_LEFT32(hashval, 4) ^ (c);
+using namespace mozilla;
 
 //----------------------------------------------------------------------
 
@@ -221,11 +220,13 @@ PRUint32 nsCRT::HashCode(const char* str, PRUint32* resultingStrLen)
   if (!str) return h;
 
   unsigned char c;
-  while ( (c = *s++) )
-    ADD_TO_HASHVAL(h, c);
+  while ( (c = *s++) ) {
+    h = AddToHash(h, c);
+  }
 
   if ( resultingStrLen )
     *resultingStrLen = (s-str)-1;
+
   return h;
 }
 
@@ -238,7 +239,7 @@ PRUint32 nsCRT::HashCode(const char* start, PRUint32 length)
   unsigned char c;
   while ( s < end ) {
     c = *s++;
-    ADD_TO_HASHVAL(h, c);
+    h = AddToHash(h, c);
   }
 
   return h;
@@ -253,10 +254,11 @@ PRUint32 nsCRT::HashCode(const PRUnichar* str, PRUint32* resultingStrLen)
 
   PRUnichar c;
   while ( (c = *s++) )
-    ADD_TO_HASHVAL(h, c);
+    h = AddToHash(h, c);
 
   if ( resultingStrLen )
     *resultingStrLen = (s-str)-1;
+
   return h;
 }
 
@@ -269,7 +271,7 @@ PRUint32 nsCRT::HashCode(const PRUnichar* start, PRUint32 length)
   PRUnichar c;
   while ( s < end ) {
     c = *s++;
-    ADD_TO_HASHVAL(h, c);
+    h = AddToHash(h, c);
   }
 
   return h;
@@ -292,11 +294,10 @@ PRUint32 nsCRT::HashCodeAsUTF16(const char* start, PRUint32 length,
       }
 
       if (ucs4 < PLANE1_BASE) {
-        ADD_TO_HASHVAL(h, ucs4);
+        h = AddToHash(h, ucs4);
       }
       else {
-        ADD_TO_HASHVAL(h, H_SURROGATE(ucs4));
-        ADD_TO_HASHVAL(h, L_SURROGATE(ucs4));
+        h = AddToHash(h, H_SURROGATE(ucs4), L_SURROGATE(ucs4));
       }
     }
 

xpcom/glue/nsTHashtable.cpp

@@ -38,6 +38,9 @@
 #include "nsTHashtable.h"
 #include "nsHashKeys.h"
 #include "prbit.h"
+#include "mozilla/HashFunctions.h"
+
+using namespace mozilla;
 
 PRUint32
 HashString( const nsAString& aStr )
@@ -55,7 +58,7 @@ HashString( const nsAString& aStr )
 #endif
 
   while (begin != end) {
-    code = PR_ROTATE_LEFT32(code, 4) ^ PRUint32(*begin);
+    code = AddToHash(code, *begin);
     ++begin;
   }
 
@@ -78,7 +81,7 @@ HashString( const nsACString& aStr )
 #endif
 
   while (begin != end) {
-    code = PR_ROTATE_LEFT32(code, 4) ^ PRUint32(*begin);
+    code = AddToHash(code, *begin);
     ++begin;
   }
 
@@ -89,9 +92,10 @@ PRUint32
 HashString(const char *str)
 {
   PRUint32 code = 0;
+  const char *origStr = str;
 
   while (*str) {
-    code = PR_ROTATE_LEFT32(code, 4) ^ PRUint32(*str);
+    code = AddToHash(code, *str);
     ++str;
   }
 
@@ -102,9 +106,10 @@ PRUint32
 HashString(const PRUnichar *str)
 {
   PRUint32 code = 0;
+  const PRUnichar *origStr = str;
 
   while (*str) {
-    code = PR_ROTATE_LEFT32(code, 4) ^ PRUint32(*str);
+    code = AddToHash(code, *str);
     ++str;
   }
 

xpcom/glue/pldhash.cpp

@@ -48,6 +48,7 @@
 #include <string.h>
 #include "prbit.h"
 #include "pldhash.h"
+#include "mozilla/HashFunctions.h"
 #include "nsDebug.h"     /* for PR_ASSERT */
 
 #ifdef PL_DHASHMETER
@@ -108,6 +109,8 @@
 
 #endif /* defined(DEBUG) */
 
+using namespace mozilla;
+
 void *
 PL_DHashAllocTable(PLDHashTable *table, PRUint32 nbytes)
 {
@@ -128,7 +131,7 @@ PL_DHashStringKey(PLDHashTable *table, const void *key)
 
     h = 0;
     for (s = (const unsigned char *) key; *s != '\0'; s++)
-        h = PR_ROTATE_LEFT32(h, 4) ^ *s;
+        h = AddToHash(h, *s);
     return h;
 }