Create string efficiently from Uint16List/View.

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 18647 matching lines @@
 
 RawTwoByteString* TwoByteString::New(const String& str,
                                      Heap::Space space) {
   intptr_t len = str.Length();
   const String& result = String::Handle(TwoByteString::New(len, space));
   String::Copy(result, 0, str, 0, len);
   return TwoByteString::raw(result);
 }
 
 
+RawTwoByteString* TwoByteString::New(const TypedData& other_typed_data,
+                                     intptr_t other_start_index,
+                                     intptr_t other_len,
+                                     Heap::Space space) {
+  const String& result = String::Handle(TwoByteString::New(other_len, space));
+  if (other_len > 0) {
+    NoGCScope no_gc;
+    memmove(TwoByteString::CharAddr(result, 0),
+            other_typed_data.DataAddr(other_start_index),
+            other_len * sizeof(uint16_t));
+  }
+  return TwoByteString::raw(result);
+}
+
+
+RawTwoByteString* TwoByteString::New(const ExternalTypedData& other_typed_data,
+                                     intptr_t other_start_index,
+                                     intptr_t other_len,
+                                     Heap::Space space) {
+  const String& result = String::Handle(TwoByteString::New(other_len, space));
+  if (other_len > 0) {
+    NoGCScope no_gc;
+    memmove(TwoByteString::CharAddr(result, 0),
+            other_typed_data.DataAddr(other_start_index),
+            other_len * sizeof(uint16_t));
+  }
+  return TwoByteString::raw(result);
+}
+
+
 RawTwoByteString* TwoByteString::Concat(const String& str1,
                                         const String& str2,
                                         Heap::Space space) {
   intptr_t len1 = str1.Length();
   intptr_t len2 = str2.Length();
   intptr_t len = len1 + len2;
   const String& result = String::Handle(TwoByteString::New(len, space));
   String::Copy(result, 0, str1, 0, len1);
   String::Copy(result, len1, str2, 0, len2);
   return TwoByteString::raw(result);
@@ skipping 1852 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart