// Copyright 2019 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. namespace string { macro NewJSStringIterator(implicit context: Context)( string: String, nextIndex: Smi): JSStringIterator { return new JSStringIterator{ map: GetInitialStringIteratorMap(), properties_or_hash: kEmptyFixedArray, elements: kEmptyFixedArray, string: string, index: nextIndex }; } // ES6 #sec-string.prototype-@@iterator transitioning javascript builtin StringPrototypeIterator( js-implicit context: NativeContext, receiver: JSAny)(): JSStringIterator { const name: String = ToThisString(receiver, 'String.prototype[Symbol.iterator]'); const index: Smi = 0; return NewJSStringIterator(name, index); } // ES6 #sec-%stringiteratorprototype%.next transitioning javascript builtin StringIteratorPrototypeNext( js-implicit context: NativeContext, receiver: JSAny)(): JSObject { const iterator = Cast<JSStringIterator>(receiver) otherwise ThrowTypeError( MessageTemplate::kIncompatibleMethodReceiver, 'String Iterator.prototype.next', receiver); const string = iterator.string; const position: intptr = SmiUntag(iterator.index); const length: intptr = string.length_intptr; if (position >= length) { return AllocateJSIteratorResult(Undefined, True); } // Move to next codepoint. const encoding = UnicodeEncoding::UTF16; const ch = string::LoadSurrogatePairAt(string, length, position, encoding); const value: String = string::StringFromSingleUTF16EncodedCodePoint(ch); iterator.index = SmiTag(position + value.length_intptr); return AllocateJSIteratorResult(value, False); } }