Improve performance of string buffer by modifying concatAll native to allow growable array and an i…

runtime/vm/object.h

 // 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.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 4756 matching lines @@
                    intptr_t src_offset,
                    intptr_t len);
 
   static RawString* EscapeSpecialCharacters(const String& str);
 
   static RawString* Concat(const String& str1,
                            const String& str2,
                            Heap::Space space = Heap::kNew);
   static RawString* ConcatAll(const Array& strings,
                               Heap::Space space = Heap::kNew);
+  // Concat all strings in 'strings' from 'start' to 'end' (excluding).
+  static RawString* ConcatAllRange(const Array& strings,
+                                   intptr_t start,
+                                   intptr_t end,
+                                   Heap::Space space = Heap::kNew);
 
   static RawString* SubString(const String& str,
                               intptr_t begin_index,
                               Heap::Space space = Heap::kNew);
   static RawString* SubString(const String& str,
                               intptr_t begin_index,
                               intptr_t length,
                               Heap::Space space = Heap::kNew);
 
   static RawString* Transform(int32_t (*mapping)(int32_t ch),
@@ skipping 100 matching lines @@
   // 'other' must be OneByteString.
   static RawOneByteString* New(const String& other_one_byte_string,
                                intptr_t other_start_index,
                                intptr_t other_len,
                                Heap::Space space);
 
   static RawOneByteString* Concat(const String& str1,
                                   const String& str2,
                                   Heap::Space space);
   static RawOneByteString* ConcatAll(const Array& strings,
+                                     intptr_t start,
+                                     intptr_t end,
                                      intptr_t len,
                                      Heap::Space space);
 
   static RawOneByteString* Transform(int32_t (*mapping)(int32_t ch),
                                      const String& str,
                                      Heap::Space space);
 
   // High performance version of substring for one-byte strings.
   // "str" must be OneByteString.
   static RawOneByteString* SubStringUnchecked(const String& str,
@@ skipping 76 matching lines @@
                                const int32_t* characters,
                                intptr_t len,
                                Heap::Space space);
   static RawTwoByteString* New(const String& str,
                                Heap::Space space);
 
   static RawTwoByteString* Concat(const String& str1,
                                   const String& str2,
                                   Heap::Space space);
   static RawTwoByteString* ConcatAll(const Array& strings,
+                                     intptr_t start,
+                                     intptr_t end,
                                      intptr_t len,
                                      Heap::Space space);
 
   static RawTwoByteString* Transform(int32_t (*mapping)(int32_t ch),
                                      const String& str,
                                      Heap::Space space);
 
   static void SetPeer(const String& str,
                       void* peer,
                       Dart_PeerFinalizer cback);
@@ skipping 1212 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_