Add trim, trimLeft and trimRight methods to String

src/runtime.cc

 // Copyright 2006-2009 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3566 matching lines @@
 
 static Object* Runtime_StringToLowerCase(Arguments args) {
   return ConvertCase<unibrow::ToLowercase>(args, &to_lower_mapping);
 }
 
 
 static Object* Runtime_StringToUpperCase(Arguments args) {
   return ConvertCase<unibrow::ToUppercase>(args, &to_upper_mapping);
 }
 
+static inline bool IsTrimWhiteSpace(unibrow::uchar c) {
+  return unibrow::WhiteSpace::Is(c) || c == 0x200b;
+}
+
+static Object* Runtime_StringTrim(Arguments args) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 3);
+
+  CONVERT_CHECKED(String, s, args[0]);
+  CONVERT_BOOLEAN_CHECKED(trimLeft, args[1]);
+  CONVERT_BOOLEAN_CHECKED(trimRight, args[2]);
+
+  s->TryFlattenIfNotFlat();
+  int length = s->length();
+
+  int left = 0;
+  if (trimLeft) {
+    while (left < length && IsTrimWhiteSpace(s->Get(left)))
+      left++;
+  }
+
+  int right = length;
+  if (trimRight) {
+    while (right > left && IsTrimWhiteSpace(s->Get(right - 1)))
+      right--;
+  }
+  return s->Slice(left, right);
+}
 
 bool Runtime::IsUpperCaseChar(uint16_t ch) {
   unibrow::uchar chars[unibrow::ToUppercase::kMaxWidth];
   int char_length = to_upper_mapping.get(ch, 0, chars);
   return char_length == 0;
 }
 
 
 static Object* Runtime_NumberToString(Arguments args) {
   NoHandleAllocation ha;
@@ skipping 4125 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal