Move the core of NS_ConvertUCS2toUTF8 into character sinks in nsUTF8Utils.h, and use them to make ToNewUTF8String faster. Fix bug in surrogate handling in the moved code. Make various tweaks to improve performance of conversion between UCS2 and UTF-8 (both ways). b=206682 r=jag sr=jst

git-svn-id: svn://10.0.0.236/trunk@143570 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/string/src/nsReadableUtils.cpp

@@ -245,24 +245,18 @@ NS_COM
 char*
 ToNewUTF8String( const nsAString& aSource )
   {
-    // XXX The conversion code in NS_ConvertUCS2toUTF8 needs to be
-    // refactored so that we can use it here without a double-copy.
-    NS_ConvertUCS2toUTF8 temp(aSource);
+    nsAString::const_iterator start, end;
+    CalculateUTF8Size calculator;
+    copy_string(aSource.BeginReading(start), aSource.EndReading(end),
+                calculator);
 
-    char* result;
-    if (temp.GetOwnsBuffer()) {
-      // We allocated. Trick the string into not freeing its buffer to
-      // avoid an extra allocation.
-      result = temp.mStr;
+    char *result = NS_STATIC_CAST(char*,
+        nsMemory::Alloc(calculator.Size() + 1));
 
-      temp.mStr=0;
-      temp.SetOwnsBuffer(PR_FALSE);
-    }
-    else {
-      // We didn't allocate a buffer, so we need to copy it out of the
-      // nsCAutoString's storage.
-      result = ToNewCString(temp);
-    }
+    ConvertUCS2toUTF8 converter(result);
+    copy_string(aSource.BeginReading(start), aSource.EndReading(end),
+                converter).write_terminator();
+    NS_ASSERTION(calculator.Size() == converter.Size(), "length mismatch");
 
     return result;
   }