1 /*
2 * Copyright (c) 2021-2024 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/ecma_string-inl.h"
19 #include "ecmascript/ecma_string_table.h"
20 #include "ecmascript/js_iterator.h"
21 #include "ecmascript/js_string_iterator.h"
22
23 namespace panda::ecmascript::builtins {
Next(EcmaRuntimeCallInfo * argv)24 JSTaggedValue BuiltinsStringIterator::Next(EcmaRuntimeCallInfo *argv)
25 {
26 ASSERT(argv);
27 BUILTINS_API_TRACE(argv->GetThread(), StringIterator, Next);
28 JSThread *thread = argv->GetThread();
29 [[maybe_unused]] EcmaHandleScope handleScope(thread);
30 // 1. Let O be the this value.
31 JSHandle<JSTaggedValue> thisValue = GetThis(argv);
32 return NextInternal(thread, thisValue);
33 }
34
NextInternal(JSThread * thread,JSHandle<JSTaggedValue> thisValue)35 JSTaggedValue BuiltinsStringIterator::NextInternal(JSThread *thread, JSHandle<JSTaggedValue> thisValue)
36 {
37 // 2. If Type(O) is not Object, throw a TypeError exception.
38 // 3. If O does not have all of the internal slots of an String Iterator Instance (21.1.5.3),
39 // throw a TypeError exception.
40 if (!thisValue->IsStringIterator()) {
41 THROW_TYPE_ERROR_AND_RETURN(thread, "is not StringIterator", JSTaggedValue::Exception());
42 }
43 // 4. Let s be the value of the [[IteratedString]] internal slot of O.
44 JSHandle<JSTaggedValue> string(thread, thisValue.GetObject<JSStringIterator>()->GetIteratedString(thread));
45 // 5. If s is undefined, return CreateIterResultObject(undefined, true).
46 if (string->IsUndefined()) {
47 return JSIterator::CreateIterResultObject(thread, string, true).GetTaggedValue();
48 }
49 // 6. Let position be the value of the [[StringIteratorNextIndex]] internal slot of O.
50 uint32_t position = thisValue.GetObject<JSStringIterator>()->GetStringIteratorNextIndex();
51
52 // 7. Let len be the number of elements in s.
53 uint32_t len = EcmaStringAccessor(string.GetObject<EcmaString>()).GetLength();
54 // If position ≥ len, then
55 // a. Set the value of the [[IteratedString]] internal slot of O to
56 // b. Return CreateIterResultObject(undefined, true).
57 if (position >= len) {
58 thisValue.GetObject<JSStringIterator>()->SetIteratedString(thread, JSTaggedValue::Undefined());
59 JSHandle<JSTaggedValue> result(thread, JSTaggedValue::Undefined());
60 return JSIterator::CreateIterResultObject(thread, result, true).GetTaggedValue();
61 }
62
63 // 9. Let first be the code unit value at index position in s.
64 uint16_t first = EcmaStringAccessor(string.GetObject<EcmaString>()).Get<false>(thread, position);
65 JSMutableHandle<JSTaggedValue> result(thread, JSTaggedValue::Undefined());
66 uint32_t resultSize = 1;
67 // 10. If first < 0xD800 or first > 0xDBFF or position+1 = len, let resultString be the string consisting of the
68 // single code unit first.
69 ObjectFactory *factory = thread->GetEcmaVM()->GetFactory();
70 if (position + 1 == len || first < common::utf_helper::DECODE_LEAD_LOW ||
71 first > common::utf_helper::DECODE_LEAD_HIGH) {
72 if (EcmaStringAccessor::CanBeCompressed(&first, 1)) {
73 JSHandle<SingleCharTable> singleCharTable(thread, thread->GetSingleCharTable());
74 result.Update(singleCharTable->GetStringFromSingleCharTable(thread, first));
75 } else {
76 std::vector<uint16_t> resultString {first, 0x0};
77 result.Update(factory->NewFromUtf16(resultString.data(), 1).GetTaggedValue());
78 }
79 } else {
80 // 11. Else,
81 // a. Let second be the code unit value at index position+1 in the String S.
82 // b. If second < 0xDC00 or second > 0xDFFF, let resultString be the string consisting of the single code unit
83 // first.
84 // c. Else, let resultString be the string consisting of the code unit first followed by the code unit second.
85 uint16_t second = EcmaStringAccessor(string.GetObject<EcmaString>()).Get<false>(thread, position + 1);
86 if (second < common::utf_helper::DECODE_TRAIL_LOW || second > common::utf_helper::DECODE_TRAIL_HIGH) {
87 std::vector<uint16_t> resultString {first, 0x0};
88 result.Update(factory->NewFromUtf16NotCompress(resultString.data(), 1).GetTaggedValue());
89 } else {
90 std::vector<uint16_t> resultString {first, second, 0x0};
91 result.Update(
92 factory->NewFromUtf16NotCompress(resultString.data(), 2).GetTaggedValue()); // 2: two bytes
93 resultSize = 2; // 2: 2 means that two bytes represent a character string
94 }
95 }
96 // 12. Let resultSize be the number of code units in resultString.
97 // 13. Set the value of the [[StringIteratorNextIndex]] internal slot of O to position+ resultSize.
98 thisValue.GetObject<JSStringIterator>()->SetStringIteratorNextIndex(position + resultSize);
99
100 // 14. Return CreateIterResultObject(resultString, false).
101 return JSIterator::CreateIterResultObject(thread, result, false).GetTaggedValue();
102 }
103 } // namespace panda::ecmascript::builtins
104