Use direct copy and templates to speed up flattening of strings.

src/utils.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
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 //       disclaimer in the documentation and/or other materials provided
@@ skipping 425 matching lines @@
 
  private:
   Vector<char> buffer_;
   int position_;
 
   bool is_finalized() const { return position_ < 0; }
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(StringBuilder);
 };
 
+
+// Widening copy from ASCII to 16 bit chars.  This is templatized to allow
+// it to be used inside if statements in templatized callers, but it is only
+// usable for sinkchar == uc16.
+template <typename sinkchar>
+static inline void Cpy168(sinkchar* dest, const unsigned char* src, int chars) {

[Christian Plesner Hansen, 2008/10/21 14:16:22]

You may consider copying the first parts of the string in int-size blocks.

[Erik Corry, 2008/10/22 11:59:48]

Can't do this because of alignment issues.

+  ASSERT(sizeof(sinkchar) == 2);

[Christian Plesner Hansen, 2008/10/21 14:16:22]

You can use STATIC_CHECK here to catch this at compiletime.

+  while (chars--) {
+    char c = *src++;
+    *dest++ = c;
+  }
+}
+
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_