1 /*
2 * Copyright (c) 2021 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 #include "ecmascript/builtins/builtins_string_iterator.h"
17
18 #include "ecmascript/base/string_helper.h"
19 #include "ecmascript/ecma_macros.h"
20 #include "ecmascript/js_iterator.h"
21 #include "ecmascript/js_string_iterator.h"
22 #include "ecmascript/js_tagged_number.h"
23 #include "ecmascript/js_tagged_value.h"
24 #include "ecmascript/object_factory.h"
25
26 namespace panda::ecmascript::builtins {
Next(EcmaRuntimeCallInfo * argv)27 JSTaggedValue BuiltinsStringIterator::Next(EcmaRuntimeCallInfo *argv)
28 {
29 ASSERT(argv);
30 BUILTINS_API_TRACE(argv->GetThread(), StringIterator, Next);
31 JSThread *thread = argv->GetThread();
32 [[maybe_unused]] EcmaHandleScope handleScope(thread);
33 // 1. Let O be the this value.
34 JSHandle<JSTaggedValue> thisValue = GetThis(argv);
35 // 2. If Type(O) is not Object, throw a TypeError exception.
36 // 3. If O does not have all of the internal slots of an String Iterator Instance (21.1.5.3),
37 // throw a TypeError exception.
38 if (!thisValue->IsStringIterator()) {
39 THROW_TYPE_ERROR_AND_RETURN(thread, "is not StringIterator", JSTaggedValue::Exception());
40 }
41 // 4. Let s be the value of the [[IteratedString]] internal slot of O.
42 JSHandle<JSTaggedValue> string(thread, thisValue.GetObject<JSStringIterator>()->GetIteratedString());
43 // 5. If s is undefined, return CreateIterResultObject(undefined, true).
44 if (string->IsUndefined()) {
45 return JSIterator::CreateIterResultObject(thread, string, true).GetTaggedValue();
46 }
47 // 6. Let position be the value of the [[StringIteratorNextIndex]] internal slot of O.
48 uint32_t position = thisValue.GetObject<JSStringIterator>()->GetStringIteratorNextIndex();
49
50 // 7. Let len be the number of elements in s.
51 uint32_t len = EcmaStringAccessor(string.GetObject<EcmaString>()).GetLength();
52 // If position ≥ len, then
53 // a. Set the value of the [[IteratedString]] internal slot of O to
54 // b. Return CreateIterResultObject(undefined, true).
55 if (position >= len) {
56 thisValue.GetObject<JSStringIterator>()->SetIteratedString(thread, JSTaggedValue::Undefined());
57 JSHandle<JSTaggedValue> result(thread, JSTaggedValue::Undefined());
58 return JSIterator::CreateIterResultObject(thread, result, true).GetTaggedValue();
59 }
60
61 // 9. Let first be the code unit value at index position in s.
62 uint16_t first = EcmaStringAccessor(string.GetObject<EcmaString>()).Get<false>(position);
63 JSMutableHandle<JSTaggedValue> result(thread, JSTaggedValue::Undefined());
64 uint32_t resultSize = 1;
65 // 10. If first < 0xD800 or first > 0xDBFF or position+1 = len, let resultString be the string consisting of the
66 // single code unit first.
67 ObjectFactory *factory = thread->GetEcmaVM()->GetFactory();
68 if (position + 1 == len || first < base::utf_helper::DECODE_LEAD_LOW ||
69 first > base::utf_helper::DECODE_LEAD_HIGH) {
70 std::vector<uint16_t> resultString {first, 0x0};
71 result.Update(factory->NewFromUtf16(resultString.data(), 1).GetTaggedValue());
72 } else {
73 // 11. Else,
74 // a. Let second be the code unit value at index position+1 in the String S.
75 // b. If second < 0xDC00 or second > 0xDFFF, let resultString be the string consisting of the single code unit
76 // first.
77 // c. Else, let resultString be the string consisting of the code unit first followed by the code unit second.
78 uint16_t second = EcmaStringAccessor(string.GetObject<EcmaString>()).Get<false>(position + 1);
79 if (second < base::utf_helper::DECODE_TRAIL_LOW || second > base::utf_helper::DECODE_TRAIL_HIGH) {
80 std::vector<uint16_t> resultString {first, 0x0};
81 result.Update(factory->NewFromUtf16NotCompress(resultString.data(), 1).GetTaggedValue());
82 } else {
83 std::vector<uint16_t> resultString {first, second, 0x0};
84 result.Update(
85 factory->NewFromUtf16NotCompress(resultString.data(), 2).GetTaggedValue()); // 2: two bytes
86 resultSize = 2; // 2: 2 means that two bytes represent a character string
87 }
88 }
89 // 12. Let resultSize be the number of code units in resultString.
90 // 13. Set the value of the [[StringIteratorNextIndex]] internal slot of O to position+ resultSize.
91 thisValue.GetObject<JSStringIterator>()->SetStringIteratorNextIndex(position + resultSize);
92
93 // 14. Return CreateIterResultObject(resultString, false).
94 return JSIterator::CreateIterResultObject(thread, result, false).GetTaggedValue();
95 }
96 } // namespace panda::ecmascript::builtins
97