1// Copyright 2014 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "src/runtime/runtime-utils.h"
6
7#include "src/arguments.h"
8#include "src/conversions-inl.h"
9#include "src/isolate-inl.h"
10#include "src/regexp/jsregexp-inl.h"
11#include "src/regexp/jsregexp.h"
12#include "src/string-builder.h"
13#include "src/string-search.h"
14
15namespace v8 {
16namespace internal {
17
18
19// Perform string match of pattern on subject, starting at start index.
20// Caller must ensure that 0 <= start_index <= sub->length(),
21// and should check that pat->length() + start_index <= sub->length().
22int StringMatch(Isolate* isolate, Handle<String> sub, Handle<String> pat,
23                int start_index) {
24  DCHECK(0 <= start_index);
25  DCHECK(start_index <= sub->length());
26
27  int pattern_length = pat->length();
28  if (pattern_length == 0) return start_index;
29
30  int subject_length = sub->length();
31  if (start_index + pattern_length > subject_length) return -1;
32
33  sub = String::Flatten(sub);
34  pat = String::Flatten(pat);
35
36  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
37  // Extract flattened substrings of cons strings before getting encoding.
38  String::FlatContent seq_sub = sub->GetFlatContent();
39  String::FlatContent seq_pat = pat->GetFlatContent();
40
41  // dispatch on type of strings
42  if (seq_pat.IsOneByte()) {
43    Vector<const uint8_t> pat_vector = seq_pat.ToOneByteVector();
44    if (seq_sub.IsOneByte()) {
45      return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
46                          start_index);
47    }
48    return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector,
49                        start_index);
50  }
51  Vector<const uc16> pat_vector = seq_pat.ToUC16Vector();
52  if (seq_sub.IsOneByte()) {
53    return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
54                        start_index);
55  }
56  return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector, start_index);
57}
58
59
60// This may return an empty MaybeHandle if an exception is thrown or
61// we abort due to reaching the recursion limit.
62MaybeHandle<String> StringReplaceOneCharWithString(
63    Isolate* isolate, Handle<String> subject, Handle<String> search,
64    Handle<String> replace, bool* found, int recursion_limit) {
65  StackLimitCheck stackLimitCheck(isolate);
66  if (stackLimitCheck.HasOverflowed() || (recursion_limit == 0)) {
67    return MaybeHandle<String>();
68  }
69  recursion_limit--;
70  if (subject->IsConsString()) {
71    ConsString* cons = ConsString::cast(*subject);
72    Handle<String> first = Handle<String>(cons->first());
73    Handle<String> second = Handle<String>(cons->second());
74    Handle<String> new_first;
75    if (!StringReplaceOneCharWithString(isolate, first, search, replace, found,
76                                        recursion_limit).ToHandle(&new_first)) {
77      return MaybeHandle<String>();
78    }
79    if (*found) return isolate->factory()->NewConsString(new_first, second);
80
81    Handle<String> new_second;
82    if (!StringReplaceOneCharWithString(isolate, second, search, replace, found,
83                                        recursion_limit)
84             .ToHandle(&new_second)) {
85      return MaybeHandle<String>();
86    }
87    if (*found) return isolate->factory()->NewConsString(first, new_second);
88
89    return subject;
90  } else {
91    int index = StringMatch(isolate, subject, search, 0);
92    if (index == -1) return subject;
93    *found = true;
94    Handle<String> first = isolate->factory()->NewSubString(subject, 0, index);
95    Handle<String> cons1;
96    ASSIGN_RETURN_ON_EXCEPTION(
97        isolate, cons1, isolate->factory()->NewConsString(first, replace),
98        String);
99    Handle<String> second =
100        isolate->factory()->NewSubString(subject, index + 1, subject->length());
101    return isolate->factory()->NewConsString(cons1, second);
102  }
103}
104
105
106RUNTIME_FUNCTION(Runtime_StringReplaceOneCharWithString) {
107  HandleScope scope(isolate);
108  DCHECK(args.length() == 3);
109  CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
110  CONVERT_ARG_HANDLE_CHECKED(String, search, 1);
111  CONVERT_ARG_HANDLE_CHECKED(String, replace, 2);
112
113  // If the cons string tree is too deep, we simply abort the recursion and
114  // retry with a flattened subject string.
115  const int kRecursionLimit = 0x1000;
116  bool found = false;
117  Handle<String> result;
118  if (StringReplaceOneCharWithString(isolate, subject, search, replace, &found,
119                                     kRecursionLimit).ToHandle(&result)) {
120    return *result;
121  }
122  if (isolate->has_pending_exception()) return isolate->heap()->exception();
123
124  subject = String::Flatten(subject);
125  if (StringReplaceOneCharWithString(isolate, subject, search, replace, &found,
126                                     kRecursionLimit).ToHandle(&result)) {
127    return *result;
128  }
129  if (isolate->has_pending_exception()) return isolate->heap()->exception();
130  // In case of empty handle and no pending exception we have stack overflow.
131  return isolate->StackOverflow();
132}
133
134
135RUNTIME_FUNCTION(Runtime_StringIndexOf) {
136  HandleScope scope(isolate);
137  DCHECK(args.length() == 3);
138
139  CONVERT_ARG_HANDLE_CHECKED(String, sub, 0);
140  CONVERT_ARG_HANDLE_CHECKED(String, pat, 1);
141  CONVERT_ARG_HANDLE_CHECKED(Object, index, 2);
142
143  uint32_t start_index = 0;
144  if (!index->ToArrayIndex(&start_index)) return Smi::FromInt(-1);
145
146  RUNTIME_ASSERT(start_index <= static_cast<uint32_t>(sub->length()));
147  int position = StringMatch(isolate, sub, pat, start_index);
148  return Smi::FromInt(position);
149}
150
151
152template <typename schar, typename pchar>
153static int StringMatchBackwards(Vector<const schar> subject,
154                                Vector<const pchar> pattern, int idx) {
155  int pattern_length = pattern.length();
156  DCHECK(pattern_length >= 1);
157  DCHECK(idx + pattern_length <= subject.length());
158
159  if (sizeof(schar) == 1 && sizeof(pchar) > 1) {
160    for (int i = 0; i < pattern_length; i++) {
161      uc16 c = pattern[i];
162      if (c > String::kMaxOneByteCharCode) {
163        return -1;
164      }
165    }
166  }
167
168  pchar pattern_first_char = pattern[0];
169  for (int i = idx; i >= 0; i--) {
170    if (subject[i] != pattern_first_char) continue;
171    int j = 1;
172    while (j < pattern_length) {
173      if (pattern[j] != subject[i + j]) {
174        break;
175      }
176      j++;
177    }
178    if (j == pattern_length) {
179      return i;
180    }
181  }
182  return -1;
183}
184
185
186RUNTIME_FUNCTION(Runtime_StringLastIndexOf) {
187  HandleScope scope(isolate);
188  DCHECK(args.length() == 3);
189
190  CONVERT_ARG_HANDLE_CHECKED(String, sub, 0);
191  CONVERT_ARG_HANDLE_CHECKED(String, pat, 1);
192  CONVERT_ARG_HANDLE_CHECKED(Object, index, 2);
193
194  uint32_t start_index = 0;
195  if (!index->ToArrayIndex(&start_index)) return Smi::FromInt(-1);
196
197  uint32_t pat_length = pat->length();
198  uint32_t sub_length = sub->length();
199
200  if (start_index + pat_length > sub_length) {
201    start_index = sub_length - pat_length;
202  }
203
204  if (pat_length == 0) {
205    return Smi::FromInt(start_index);
206  }
207
208  sub = String::Flatten(sub);
209  pat = String::Flatten(pat);
210
211  int position = -1;
212  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
213
214  String::FlatContent sub_content = sub->GetFlatContent();
215  String::FlatContent pat_content = pat->GetFlatContent();
216
217  if (pat_content.IsOneByte()) {
218    Vector<const uint8_t> pat_vector = pat_content.ToOneByteVector();
219    if (sub_content.IsOneByte()) {
220      position = StringMatchBackwards(sub_content.ToOneByteVector(), pat_vector,
221                                      start_index);
222    } else {
223      position = StringMatchBackwards(sub_content.ToUC16Vector(), pat_vector,
224                                      start_index);
225    }
226  } else {
227    Vector<const uc16> pat_vector = pat_content.ToUC16Vector();
228    if (sub_content.IsOneByte()) {
229      position = StringMatchBackwards(sub_content.ToOneByteVector(), pat_vector,
230                                      start_index);
231    } else {
232      position = StringMatchBackwards(sub_content.ToUC16Vector(), pat_vector,
233                                      start_index);
234    }
235  }
236
237  return Smi::FromInt(position);
238}
239
240
241RUNTIME_FUNCTION(Runtime_StringLocaleCompare) {
242  HandleScope handle_scope(isolate);
243  DCHECK(args.length() == 2);
244
245  CONVERT_ARG_HANDLE_CHECKED(String, str1, 0);
246  CONVERT_ARG_HANDLE_CHECKED(String, str2, 1);
247
248  if (str1.is_identical_to(str2)) return Smi::FromInt(0);  // Equal.
249  int str1_length = str1->length();
250  int str2_length = str2->length();
251
252  // Decide trivial cases without flattening.
253  if (str1_length == 0) {
254    if (str2_length == 0) return Smi::FromInt(0);  // Equal.
255    return Smi::FromInt(-str2_length);
256  } else {
257    if (str2_length == 0) return Smi::FromInt(str1_length);
258  }
259
260  int end = str1_length < str2_length ? str1_length : str2_length;
261
262  // No need to flatten if we are going to find the answer on the first
263  // character.  At this point we know there is at least one character
264  // in each string, due to the trivial case handling above.
265  int d = str1->Get(0) - str2->Get(0);
266  if (d != 0) return Smi::FromInt(d);
267
268  str1 = String::Flatten(str1);
269  str2 = String::Flatten(str2);
270
271  DisallowHeapAllocation no_gc;
272  String::FlatContent flat1 = str1->GetFlatContent();
273  String::FlatContent flat2 = str2->GetFlatContent();
274
275  for (int i = 0; i < end; i++) {
276    if (flat1.Get(i) != flat2.Get(i)) {
277      return Smi::FromInt(flat1.Get(i) - flat2.Get(i));
278    }
279  }
280
281  return Smi::FromInt(str1_length - str2_length);
282}
283
284
285RUNTIME_FUNCTION(Runtime_SubString) {
286  HandleScope scope(isolate);
287  DCHECK(args.length() == 3);
288
289  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
290  int start, end;
291  // We have a fast integer-only case here to avoid a conversion to double in
292  // the common case where from and to are Smis.
293  if (args[1]->IsSmi() && args[2]->IsSmi()) {
294    CONVERT_SMI_ARG_CHECKED(from_number, 1);
295    CONVERT_SMI_ARG_CHECKED(to_number, 2);
296    start = from_number;
297    end = to_number;
298  } else {
299    CONVERT_DOUBLE_ARG_CHECKED(from_number, 1);
300    CONVERT_DOUBLE_ARG_CHECKED(to_number, 2);
301    start = FastD2IChecked(from_number);
302    end = FastD2IChecked(to_number);
303  }
304  RUNTIME_ASSERT(end >= start);
305  RUNTIME_ASSERT(start >= 0);
306  RUNTIME_ASSERT(end <= string->length());
307  isolate->counters()->sub_string_runtime()->Increment();
308
309  return *isolate->factory()->NewSubString(string, start, end);
310}
311
312
313RUNTIME_FUNCTION(Runtime_StringAdd) {
314  HandleScope scope(isolate);
315  DCHECK(args.length() == 2);
316  CONVERT_ARG_HANDLE_CHECKED(String, str1, 0);
317  CONVERT_ARG_HANDLE_CHECKED(String, str2, 1);
318  isolate->counters()->string_add_runtime()->Increment();
319  Handle<String> result;
320  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
321      isolate, result, isolate->factory()->NewConsString(str1, str2));
322  return *result;
323}
324
325
326RUNTIME_FUNCTION(Runtime_InternalizeString) {
327  HandleScope handles(isolate);
328  RUNTIME_ASSERT(args.length() == 1);
329  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
330  return *isolate->factory()->InternalizeString(string);
331}
332
333
334RUNTIME_FUNCTION(Runtime_StringMatch) {
335  HandleScope handles(isolate);
336  DCHECK(args.length() == 3);
337
338  CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
339  CONVERT_ARG_HANDLE_CHECKED(JSRegExp, regexp, 1);
340  CONVERT_ARG_HANDLE_CHECKED(JSArray, regexp_info, 2);
341
342  RUNTIME_ASSERT(regexp_info->HasFastObjectElements());
343
344  RegExpImpl::GlobalCache global_cache(regexp, subject, true, isolate);
345  if (global_cache.HasException()) return isolate->heap()->exception();
346
347  int capture_count = regexp->CaptureCount();
348
349  ZoneScope zone_scope(isolate->runtime_zone());
350  ZoneList<int> offsets(8, zone_scope.zone());
351
352  while (true) {
353    int32_t* match = global_cache.FetchNext();
354    if (match == NULL) break;
355    offsets.Add(match[0], zone_scope.zone());  // start
356    offsets.Add(match[1], zone_scope.zone());  // end
357  }
358
359  if (global_cache.HasException()) return isolate->heap()->exception();
360
361  if (offsets.length() == 0) {
362    // Not a single match.
363    return isolate->heap()->null_value();
364  }
365
366  RegExpImpl::SetLastMatchInfo(regexp_info, subject, capture_count,
367                               global_cache.LastSuccessfulMatch());
368
369  int matches = offsets.length() / 2;
370  Handle<FixedArray> elements = isolate->factory()->NewFixedArray(matches);
371  Handle<String> substring =
372      isolate->factory()->NewSubString(subject, offsets.at(0), offsets.at(1));
373  elements->set(0, *substring);
374  for (int i = 1; i < matches; i++) {
375    HandleScope temp_scope(isolate);
376    int from = offsets.at(i * 2);
377    int to = offsets.at(i * 2 + 1);
378    Handle<String> substring =
379        isolate->factory()->NewProperSubString(subject, from, to);
380    elements->set(i, *substring);
381  }
382  Handle<JSArray> result = isolate->factory()->NewJSArrayWithElements(elements);
383  result->set_length(Smi::FromInt(matches));
384  return *result;
385}
386
387
388RUNTIME_FUNCTION(Runtime_StringCharCodeAtRT) {
389  HandleScope handle_scope(isolate);
390  DCHECK(args.length() == 2);
391
392  CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
393  CONVERT_NUMBER_CHECKED(uint32_t, i, Uint32, args[1]);
394
395  // Flatten the string.  If someone wants to get a char at an index
396  // in a cons string, it is likely that more indices will be
397  // accessed.
398  subject = String::Flatten(subject);
399
400  if (i >= static_cast<uint32_t>(subject->length())) {
401    return isolate->heap()->nan_value();
402  }
403
404  return Smi::FromInt(subject->Get(i));
405}
406
407
408RUNTIME_FUNCTION(Runtime_StringCompare) {
409  HandleScope handle_scope(isolate);
410  DCHECK_EQ(2, args.length());
411  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
412  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
413  isolate->counters()->string_compare_runtime()->Increment();
414  switch (String::Compare(x, y)) {
415    case ComparisonResult::kLessThan:
416      return Smi::FromInt(LESS);
417    case ComparisonResult::kEqual:
418      return Smi::FromInt(EQUAL);
419    case ComparisonResult::kGreaterThan:
420      return Smi::FromInt(GREATER);
421    case ComparisonResult::kUndefined:
422      break;
423  }
424  UNREACHABLE();
425  return Smi::FromInt(0);
426}
427
428
429RUNTIME_FUNCTION(Runtime_StringBuilderConcat) {
430  HandleScope scope(isolate);
431  DCHECK(args.length() == 3);
432  CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
433  int32_t array_length;
434  if (!args[1]->ToInt32(&array_length)) {
435    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
436  }
437  CONVERT_ARG_HANDLE_CHECKED(String, special, 2);
438
439  size_t actual_array_length = 0;
440  RUNTIME_ASSERT(
441      TryNumberToSize(isolate, array->length(), &actual_array_length));
442  RUNTIME_ASSERT(array_length >= 0);
443  RUNTIME_ASSERT(static_cast<size_t>(array_length) <= actual_array_length);
444
445  // This assumption is used by the slice encoding in one or two smis.
446  DCHECK(Smi::kMaxValue >= String::kMaxLength);
447
448  RUNTIME_ASSERT(array->HasFastElements());
449  JSObject::EnsureCanContainHeapObjectElements(array);
450
451  int special_length = special->length();
452  if (!array->HasFastObjectElements()) {
453    return isolate->Throw(isolate->heap()->illegal_argument_string());
454  }
455
456  int length;
457  bool one_byte = special->HasOnlyOneByteChars();
458
459  {
460    DisallowHeapAllocation no_gc;
461    FixedArray* fixed_array = FixedArray::cast(array->elements());
462    if (fixed_array->length() < array_length) {
463      array_length = fixed_array->length();
464    }
465
466    if (array_length == 0) {
467      return isolate->heap()->empty_string();
468    } else if (array_length == 1) {
469      Object* first = fixed_array->get(0);
470      if (first->IsString()) return first;
471    }
472    length = StringBuilderConcatLength(special_length, fixed_array,
473                                       array_length, &one_byte);
474  }
475
476  if (length == -1) {
477    return isolate->Throw(isolate->heap()->illegal_argument_string());
478  }
479
480  if (one_byte) {
481    Handle<SeqOneByteString> answer;
482    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
483        isolate, answer, isolate->factory()->NewRawOneByteString(length));
484    StringBuilderConcatHelper(*special, answer->GetChars(),
485                              FixedArray::cast(array->elements()),
486                              array_length);
487    return *answer;
488  } else {
489    Handle<SeqTwoByteString> answer;
490    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
491        isolate, answer, isolate->factory()->NewRawTwoByteString(length));
492    StringBuilderConcatHelper(*special, answer->GetChars(),
493                              FixedArray::cast(array->elements()),
494                              array_length);
495    return *answer;
496  }
497}
498
499
500RUNTIME_FUNCTION(Runtime_StringBuilderJoin) {
501  HandleScope scope(isolate);
502  DCHECK(args.length() == 3);
503  CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
504  int32_t array_length;
505  if (!args[1]->ToInt32(&array_length)) {
506    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
507  }
508  CONVERT_ARG_HANDLE_CHECKED(String, separator, 2);
509  RUNTIME_ASSERT(array->HasFastObjectElements());
510  RUNTIME_ASSERT(array_length >= 0);
511
512  Handle<FixedArray> fixed_array(FixedArray::cast(array->elements()));
513  if (fixed_array->length() < array_length) {
514    array_length = fixed_array->length();
515  }
516
517  if (array_length == 0) {
518    return isolate->heap()->empty_string();
519  } else if (array_length == 1) {
520    Object* first = fixed_array->get(0);
521    RUNTIME_ASSERT(first->IsString());
522    return first;
523  }
524
525  int separator_length = separator->length();
526  RUNTIME_ASSERT(separator_length > 0);
527  int max_nof_separators =
528      (String::kMaxLength + separator_length - 1) / separator_length;
529  if (max_nof_separators < (array_length - 1)) {
530    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
531  }
532  int length = (array_length - 1) * separator_length;
533  for (int i = 0; i < array_length; i++) {
534    Object* element_obj = fixed_array->get(i);
535    RUNTIME_ASSERT(element_obj->IsString());
536    String* element = String::cast(element_obj);
537    int increment = element->length();
538    if (increment > String::kMaxLength - length) {
539      STATIC_ASSERT(String::kMaxLength < kMaxInt);
540      length = kMaxInt;  // Provoke exception;
541      break;
542    }
543    length += increment;
544  }
545
546  Handle<SeqTwoByteString> answer;
547  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
548      isolate, answer, isolate->factory()->NewRawTwoByteString(length));
549
550  DisallowHeapAllocation no_gc;
551
552  uc16* sink = answer->GetChars();
553#ifdef DEBUG
554  uc16* end = sink + length;
555#endif
556
557  RUNTIME_ASSERT(fixed_array->get(0)->IsString());
558  String* first = String::cast(fixed_array->get(0));
559  String* separator_raw = *separator;
560  int first_length = first->length();
561  String::WriteToFlat(first, sink, 0, first_length);
562  sink += first_length;
563
564  for (int i = 1; i < array_length; i++) {
565    DCHECK(sink + separator_length <= end);
566    String::WriteToFlat(separator_raw, sink, 0, separator_length);
567    sink += separator_length;
568
569    RUNTIME_ASSERT(fixed_array->get(i)->IsString());
570    String* element = String::cast(fixed_array->get(i));
571    int element_length = element->length();
572    DCHECK(sink + element_length <= end);
573    String::WriteToFlat(element, sink, 0, element_length);
574    sink += element_length;
575  }
576  DCHECK(sink == end);
577
578  // Use %_FastOneByteArrayJoin instead.
579  DCHECK(!answer->IsOneByteRepresentation());
580  return *answer;
581}
582
583template <typename Char>
584static void JoinSparseArrayWithSeparator(FixedArray* elements,
585                                         int elements_length,
586                                         uint32_t array_length,
587                                         String* separator,
588                                         Vector<Char> buffer) {
589  DisallowHeapAllocation no_gc;
590  int previous_separator_position = 0;
591  int separator_length = separator->length();
592  int cursor = 0;
593  for (int i = 0; i < elements_length; i += 2) {
594    int position = NumberToInt32(elements->get(i));
595    String* string = String::cast(elements->get(i + 1));
596    int string_length = string->length();
597    if (string->length() > 0) {
598      while (previous_separator_position < position) {
599        String::WriteToFlat<Char>(separator, &buffer[cursor], 0,
600                                  separator_length);
601        cursor += separator_length;
602        previous_separator_position++;
603      }
604      String::WriteToFlat<Char>(string, &buffer[cursor], 0, string_length);
605      cursor += string->length();
606    }
607  }
608  if (separator_length > 0) {
609    // Array length must be representable as a signed 32-bit number,
610    // otherwise the total string length would have been too large.
611    DCHECK(array_length <= 0x7fffffff);  // Is int32_t.
612    int last_array_index = static_cast<int>(array_length - 1);
613    while (previous_separator_position < last_array_index) {
614      String::WriteToFlat<Char>(separator, &buffer[cursor], 0,
615                                separator_length);
616      cursor += separator_length;
617      previous_separator_position++;
618    }
619  }
620  DCHECK(cursor <= buffer.length());
621}
622
623
624RUNTIME_FUNCTION(Runtime_SparseJoinWithSeparator) {
625  HandleScope scope(isolate);
626  DCHECK(args.length() == 3);
627  CONVERT_ARG_HANDLE_CHECKED(JSArray, elements_array, 0);
628  CONVERT_NUMBER_CHECKED(uint32_t, array_length, Uint32, args[1]);
629  CONVERT_ARG_HANDLE_CHECKED(String, separator, 2);
630  // elements_array is fast-mode JSarray of alternating positions
631  // (increasing order) and strings.
632  RUNTIME_ASSERT(elements_array->HasFastSmiOrObjectElements());
633  // array_length is length of original array (used to add separators);
634  // separator is string to put between elements. Assumed to be non-empty.
635  RUNTIME_ASSERT(array_length > 0);
636
637  // Find total length of join result.
638  int string_length = 0;
639  bool is_one_byte = separator->IsOneByteRepresentation();
640  bool overflow = false;
641  CONVERT_NUMBER_CHECKED(int, elements_length, Int32, elements_array->length());
642  RUNTIME_ASSERT(elements_length <= elements_array->elements()->length());
643  RUNTIME_ASSERT((elements_length & 1) == 0);  // Even length.
644  FixedArray* elements = FixedArray::cast(elements_array->elements());
645  for (int i = 0; i < elements_length; i += 2) {
646    RUNTIME_ASSERT(elements->get(i)->IsNumber());
647    CONVERT_NUMBER_CHECKED(uint32_t, position, Uint32, elements->get(i));
648    RUNTIME_ASSERT(position < array_length);
649    RUNTIME_ASSERT(elements->get(i + 1)->IsString());
650  }
651
652  {
653    DisallowHeapAllocation no_gc;
654    for (int i = 0; i < elements_length; i += 2) {
655      String* string = String::cast(elements->get(i + 1));
656      int length = string->length();
657      if (is_one_byte && !string->IsOneByteRepresentation()) {
658        is_one_byte = false;
659      }
660      if (length > String::kMaxLength ||
661          String::kMaxLength - length < string_length) {
662        overflow = true;
663        break;
664      }
665      string_length += length;
666    }
667  }
668
669  int separator_length = separator->length();
670  if (!overflow && separator_length > 0) {
671    if (array_length <= 0x7fffffffu) {
672      int separator_count = static_cast<int>(array_length) - 1;
673      int remaining_length = String::kMaxLength - string_length;
674      if ((remaining_length / separator_length) >= separator_count) {
675        string_length += separator_length * (array_length - 1);
676      } else {
677        // Not room for the separators within the maximal string length.
678        overflow = true;
679      }
680    } else {
681      // Nonempty separator and at least 2^31-1 separators necessary
682      // means that the string is too large to create.
683      STATIC_ASSERT(String::kMaxLength < 0x7fffffff);
684      overflow = true;
685    }
686  }
687  if (overflow) {
688    // Throw an exception if the resulting string is too large. See
689    // https://code.google.com/p/chromium/issues/detail?id=336820
690    // for details.
691    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
692  }
693
694  if (is_one_byte) {
695    Handle<SeqOneByteString> result = isolate->factory()
696                                          ->NewRawOneByteString(string_length)
697                                          .ToHandleChecked();
698    JoinSparseArrayWithSeparator<uint8_t>(
699        FixedArray::cast(elements_array->elements()), elements_length,
700        array_length, *separator,
701        Vector<uint8_t>(result->GetChars(), string_length));
702    return *result;
703  } else {
704    Handle<SeqTwoByteString> result = isolate->factory()
705                                          ->NewRawTwoByteString(string_length)
706                                          .ToHandleChecked();
707    JoinSparseArrayWithSeparator<uc16>(
708        FixedArray::cast(elements_array->elements()), elements_length,
709        array_length, *separator,
710        Vector<uc16>(result->GetChars(), string_length));
711    return *result;
712  }
713}
714
715
716// Copies Latin1 characters to the given fixed array looking up
717// one-char strings in the cache. Gives up on the first char that is
718// not in the cache and fills the remainder with smi zeros. Returns
719// the length of the successfully copied prefix.
720static int CopyCachedOneByteCharsToArray(Heap* heap, const uint8_t* chars,
721                                         FixedArray* elements, int length) {
722  DisallowHeapAllocation no_gc;
723  FixedArray* one_byte_cache = heap->single_character_string_cache();
724  Object* undefined = heap->undefined_value();
725  int i;
726  WriteBarrierMode mode = elements->GetWriteBarrierMode(no_gc);
727  for (i = 0; i < length; ++i) {
728    Object* value = one_byte_cache->get(chars[i]);
729    if (value == undefined) break;
730    elements->set(i, value, mode);
731  }
732  if (i < length) {
733    DCHECK(Smi::FromInt(0) == 0);
734    memset(elements->data_start() + i, 0, kPointerSize * (length - i));
735  }
736#ifdef DEBUG
737  for (int j = 0; j < length; ++j) {
738    Object* element = elements->get(j);
739    DCHECK(element == Smi::FromInt(0) ||
740           (element->IsString() && String::cast(element)->LooksValid()));
741  }
742#endif
743  return i;
744}
745
746
747// Converts a String to JSArray.
748// For example, "foo" => ["f", "o", "o"].
749RUNTIME_FUNCTION(Runtime_StringToArray) {
750  HandleScope scope(isolate);
751  DCHECK(args.length() == 2);
752  CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
753  CONVERT_NUMBER_CHECKED(uint32_t, limit, Uint32, args[1]);
754
755  s = String::Flatten(s);
756  const int length = static_cast<int>(Min<uint32_t>(s->length(), limit));
757
758  Handle<FixedArray> elements;
759  int position = 0;
760  if (s->IsFlat() && s->IsOneByteRepresentation()) {
761    // Try using cached chars where possible.
762    elements = isolate->factory()->NewUninitializedFixedArray(length);
763
764    DisallowHeapAllocation no_gc;
765    String::FlatContent content = s->GetFlatContent();
766    if (content.IsOneByte()) {
767      Vector<const uint8_t> chars = content.ToOneByteVector();
768      // Note, this will initialize all elements (not only the prefix)
769      // to prevent GC from seeing partially initialized array.
770      position = CopyCachedOneByteCharsToArray(isolate->heap(), chars.start(),
771                                               *elements, length);
772    } else {
773      MemsetPointer(elements->data_start(), isolate->heap()->undefined_value(),
774                    length);
775    }
776  } else {
777    elements = isolate->factory()->NewFixedArray(length);
778  }
779  for (int i = position; i < length; ++i) {
780    Handle<Object> str =
781        isolate->factory()->LookupSingleCharacterStringFromCode(s->Get(i));
782    elements->set(i, *str);
783  }
784
785#ifdef DEBUG
786  for (int i = 0; i < length; ++i) {
787    DCHECK(String::cast(elements->get(i))->length() == 1);
788  }
789#endif
790
791  return *isolate->factory()->NewJSArrayWithElements(elements);
792}
793
794
795static inline bool ToUpperOverflows(uc32 character) {
796  // y with umlauts and the micro sign are the only characters that stop
797  // fitting into one-byte when converting to uppercase.
798  static const uc32 yuml_code = 0xff;
799  static const uc32 micro_code = 0xb5;
800  return (character == yuml_code || character == micro_code);
801}
802
803
804template <class Converter>
805MUST_USE_RESULT static Object* ConvertCaseHelper(
806    Isolate* isolate, String* string, SeqString* result, int result_length,
807    unibrow::Mapping<Converter, 128>* mapping) {
808  DisallowHeapAllocation no_gc;
809  // We try this twice, once with the assumption that the result is no longer
810  // than the input and, if that assumption breaks, again with the exact
811  // length.  This may not be pretty, but it is nicer than what was here before
812  // and I hereby claim my vaffel-is.
813  //
814  // NOTE: This assumes that the upper/lower case of an ASCII
815  // character is also ASCII.  This is currently the case, but it
816  // might break in the future if we implement more context and locale
817  // dependent upper/lower conversions.
818  bool has_changed_character = false;
819
820  // Convert all characters to upper case, assuming that they will fit
821  // in the buffer
822  StringCharacterStream stream(string);
823  unibrow::uchar chars[Converter::kMaxWidth];
824  // We can assume that the string is not empty
825  uc32 current = stream.GetNext();
826  bool ignore_overflow = Converter::kIsToLower || result->IsSeqTwoByteString();
827  for (int i = 0; i < result_length;) {
828    bool has_next = stream.HasMore();
829    uc32 next = has_next ? stream.GetNext() : 0;
830    int char_length = mapping->get(current, next, chars);
831    if (char_length == 0) {
832      // The case conversion of this character is the character itself.
833      result->Set(i, current);
834      i++;
835    } else if (char_length == 1 &&
836               (ignore_overflow || !ToUpperOverflows(current))) {
837      // Common case: converting the letter resulted in one character.
838      DCHECK(static_cast<uc32>(chars[0]) != current);
839      result->Set(i, chars[0]);
840      has_changed_character = true;
841      i++;
842    } else if (result_length == string->length()) {
843      bool overflows = ToUpperOverflows(current);
844      // We've assumed that the result would be as long as the
845      // input but here is a character that converts to several
846      // characters.  No matter, we calculate the exact length
847      // of the result and try the whole thing again.
848      //
849      // Note that this leaves room for optimization.  We could just
850      // memcpy what we already have to the result string.  Also,
851      // the result string is the last object allocated we could
852      // "realloc" it and probably, in the vast majority of cases,
853      // extend the existing string to be able to hold the full
854      // result.
855      int next_length = 0;
856      if (has_next) {
857        next_length = mapping->get(next, 0, chars);
858        if (next_length == 0) next_length = 1;
859      }
860      int current_length = i + char_length + next_length;
861      while (stream.HasMore()) {
862        current = stream.GetNext();
863        overflows |= ToUpperOverflows(current);
864        // NOTE: we use 0 as the next character here because, while
865        // the next character may affect what a character converts to,
866        // it does not in any case affect the length of what it convert
867        // to.
868        int char_length = mapping->get(current, 0, chars);
869        if (char_length == 0) char_length = 1;
870        current_length += char_length;
871        if (current_length > String::kMaxLength) {
872          AllowHeapAllocation allocate_error_and_return;
873          THROW_NEW_ERROR_RETURN_FAILURE(isolate,
874                                         NewInvalidStringLengthError());
875        }
876      }
877      // Try again with the real length.  Return signed if we need
878      // to allocate a two-byte string for to uppercase.
879      return (overflows && !ignore_overflow) ? Smi::FromInt(-current_length)
880                                             : Smi::FromInt(current_length);
881    } else {
882      for (int j = 0; j < char_length; j++) {
883        result->Set(i, chars[j]);
884        i++;
885      }
886      has_changed_character = true;
887    }
888    current = next;
889  }
890  if (has_changed_character) {
891    return result;
892  } else {
893    // If we didn't actually change anything in doing the conversion
894    // we simple return the result and let the converted string
895    // become garbage; there is no reason to keep two identical strings
896    // alive.
897    return string;
898  }
899}
900
901
902static const uintptr_t kOneInEveryByte = kUintptrAllBitsSet / 0xFF;
903static const uintptr_t kAsciiMask = kOneInEveryByte << 7;
904
905// Given a word and two range boundaries returns a word with high bit
906// set in every byte iff the corresponding input byte was strictly in
907// the range (m, n). All the other bits in the result are cleared.
908// This function is only useful when it can be inlined and the
909// boundaries are statically known.
910// Requires: all bytes in the input word and the boundaries must be
911// ASCII (less than 0x7F).
912static inline uintptr_t AsciiRangeMask(uintptr_t w, char m, char n) {
913  // Use strict inequalities since in edge cases the function could be
914  // further simplified.
915  DCHECK(0 < m && m < n);
916  // Has high bit set in every w byte less than n.
917  uintptr_t tmp1 = kOneInEveryByte * (0x7F + n) - w;
918  // Has high bit set in every w byte greater than m.
919  uintptr_t tmp2 = w + kOneInEveryByte * (0x7F - m);
920  return (tmp1 & tmp2 & (kOneInEveryByte * 0x80));
921}
922
923
924#ifdef DEBUG
925static bool CheckFastAsciiConvert(char* dst, const char* src, int length,
926                                  bool changed, bool is_to_lower) {
927  bool expected_changed = false;
928  for (int i = 0; i < length; i++) {
929    if (dst[i] == src[i]) continue;
930    expected_changed = true;
931    if (is_to_lower) {
932      DCHECK('A' <= src[i] && src[i] <= 'Z');
933      DCHECK(dst[i] == src[i] + ('a' - 'A'));
934    } else {
935      DCHECK('a' <= src[i] && src[i] <= 'z');
936      DCHECK(dst[i] == src[i] - ('a' - 'A'));
937    }
938  }
939  return (expected_changed == changed);
940}
941#endif
942
943
944template <class Converter>
945static bool FastAsciiConvert(char* dst, const char* src, int length,
946                             bool* changed_out) {
947#ifdef DEBUG
948  char* saved_dst = dst;
949  const char* saved_src = src;
950#endif
951  DisallowHeapAllocation no_gc;
952  // We rely on the distance between upper and lower case letters
953  // being a known power of 2.
954  DCHECK('a' - 'A' == (1 << 5));
955  // Boundaries for the range of input characters than require conversion.
956  static const char lo = Converter::kIsToLower ? 'A' - 1 : 'a' - 1;
957  static const char hi = Converter::kIsToLower ? 'Z' + 1 : 'z' + 1;
958  bool changed = false;
959  uintptr_t or_acc = 0;
960  const char* const limit = src + length;
961
962  // dst is newly allocated and always aligned.
963  DCHECK(IsAligned(reinterpret_cast<intptr_t>(dst), sizeof(uintptr_t)));
964  // Only attempt processing one word at a time if src is also aligned.
965  if (IsAligned(reinterpret_cast<intptr_t>(src), sizeof(uintptr_t))) {
966    // Process the prefix of the input that requires no conversion one aligned
967    // (machine) word at a time.
968    while (src <= limit - sizeof(uintptr_t)) {
969      const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
970      or_acc |= w;
971      if (AsciiRangeMask(w, lo, hi) != 0) {
972        changed = true;
973        break;
974      }
975      *reinterpret_cast<uintptr_t*>(dst) = w;
976      src += sizeof(uintptr_t);
977      dst += sizeof(uintptr_t);
978    }
979    // Process the remainder of the input performing conversion when
980    // required one word at a time.
981    while (src <= limit - sizeof(uintptr_t)) {
982      const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
983      or_acc |= w;
984      uintptr_t m = AsciiRangeMask(w, lo, hi);
985      // The mask has high (7th) bit set in every byte that needs
986      // conversion and we know that the distance between cases is
987      // 1 << 5.
988      *reinterpret_cast<uintptr_t*>(dst) = w ^ (m >> 2);
989      src += sizeof(uintptr_t);
990      dst += sizeof(uintptr_t);
991    }
992  }
993  // Process the last few bytes of the input (or the whole input if
994  // unaligned access is not supported).
995  while (src < limit) {
996    char c = *src;
997    or_acc |= c;
998    if (lo < c && c < hi) {
999      c ^= (1 << 5);
1000      changed = true;
1001    }
1002    *dst = c;
1003    ++src;
1004    ++dst;
1005  }
1006
1007  if ((or_acc & kAsciiMask) != 0) return false;
1008
1009  DCHECK(CheckFastAsciiConvert(saved_dst, saved_src, length, changed,
1010                               Converter::kIsToLower));
1011
1012  *changed_out = changed;
1013  return true;
1014}
1015
1016
1017template <class Converter>
1018MUST_USE_RESULT static Object* ConvertCase(
1019    Handle<String> s, Isolate* isolate,
1020    unibrow::Mapping<Converter, 128>* mapping) {
1021  s = String::Flatten(s);
1022  int length = s->length();
1023  // Assume that the string is not empty; we need this assumption later
1024  if (length == 0) return *s;
1025
1026  // Simpler handling of ASCII strings.
1027  //
1028  // NOTE: This assumes that the upper/lower case of an ASCII
1029  // character is also ASCII.  This is currently the case, but it
1030  // might break in the future if we implement more context and locale
1031  // dependent upper/lower conversions.
1032  if (s->IsOneByteRepresentationUnderneath()) {
1033    // Same length as input.
1034    Handle<SeqOneByteString> result =
1035        isolate->factory()->NewRawOneByteString(length).ToHandleChecked();
1036    DisallowHeapAllocation no_gc;
1037    String::FlatContent flat_content = s->GetFlatContent();
1038    DCHECK(flat_content.IsFlat());
1039    bool has_changed_character = false;
1040    bool is_ascii = FastAsciiConvert<Converter>(
1041        reinterpret_cast<char*>(result->GetChars()),
1042        reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()),
1043        length, &has_changed_character);
1044    // If not ASCII, we discard the result and take the 2 byte path.
1045    if (is_ascii) return has_changed_character ? *result : *s;
1046  }
1047
1048  Handle<SeqString> result;  // Same length as input.
1049  if (s->IsOneByteRepresentation()) {
1050    result = isolate->factory()->NewRawOneByteString(length).ToHandleChecked();
1051  } else {
1052    result = isolate->factory()->NewRawTwoByteString(length).ToHandleChecked();
1053  }
1054
1055  Object* answer = ConvertCaseHelper(isolate, *s, *result, length, mapping);
1056  if (answer->IsException() || answer->IsString()) return answer;
1057
1058  DCHECK(answer->IsSmi());
1059  length = Smi::cast(answer)->value();
1060  if (s->IsOneByteRepresentation() && length > 0) {
1061    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1062        isolate, result, isolate->factory()->NewRawOneByteString(length));
1063  } else {
1064    if (length < 0) length = -length;
1065    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1066        isolate, result, isolate->factory()->NewRawTwoByteString(length));
1067  }
1068  return ConvertCaseHelper(isolate, *s, *result, length, mapping);
1069}
1070
1071
1072RUNTIME_FUNCTION(Runtime_StringToLowerCase) {
1073  HandleScope scope(isolate);
1074  DCHECK(args.length() == 1);
1075  CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
1076  return ConvertCase(s, isolate, isolate->runtime_state()->to_lower_mapping());
1077}
1078
1079
1080RUNTIME_FUNCTION(Runtime_StringToUpperCase) {
1081  HandleScope scope(isolate);
1082  DCHECK(args.length() == 1);
1083  CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
1084  return ConvertCase(s, isolate, isolate->runtime_state()->to_upper_mapping());
1085}
1086
1087
1088RUNTIME_FUNCTION(Runtime_StringTrim) {
1089  HandleScope scope(isolate);
1090  DCHECK(args.length() == 3);
1091
1092  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
1093  CONVERT_BOOLEAN_ARG_CHECKED(trimLeft, 1);
1094  CONVERT_BOOLEAN_ARG_CHECKED(trimRight, 2);
1095
1096  string = String::Flatten(string);
1097  int length = string->length();
1098
1099  int left = 0;
1100  UnicodeCache* unicode_cache = isolate->unicode_cache();
1101  if (trimLeft) {
1102    while (left < length &&
1103           unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(left))) {
1104      left++;
1105    }
1106  }
1107
1108  int right = length;
1109  if (trimRight) {
1110    while (
1111        right > left &&
1112        unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(right - 1))) {
1113      right--;
1114    }
1115  }
1116
1117  return *isolate->factory()->NewSubString(string, left, right);
1118}
1119
1120
1121RUNTIME_FUNCTION(Runtime_TruncateString) {
1122  HandleScope scope(isolate);
1123  DCHECK(args.length() == 2);
1124  CONVERT_ARG_HANDLE_CHECKED(SeqString, string, 0);
1125  CONVERT_INT32_ARG_CHECKED(new_length, 1);
1126  RUNTIME_ASSERT(new_length >= 0);
1127  return *SeqString::Truncate(string, new_length);
1128}
1129
1130
1131RUNTIME_FUNCTION(Runtime_NewString) {
1132  HandleScope scope(isolate);
1133  DCHECK(args.length() == 2);
1134  CONVERT_INT32_ARG_CHECKED(length, 0);
1135  CONVERT_BOOLEAN_ARG_CHECKED(is_one_byte, 1);
1136  if (length == 0) return isolate->heap()->empty_string();
1137  Handle<String> result;
1138  if (is_one_byte) {
1139    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1140        isolate, result, isolate->factory()->NewRawOneByteString(length));
1141  } else {
1142    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1143        isolate, result, isolate->factory()->NewRawTwoByteString(length));
1144  }
1145  return *result;
1146}
1147
1148
1149RUNTIME_FUNCTION(Runtime_StringEquals) {
1150  HandleScope handle_scope(isolate);
1151  DCHECK(args.length() == 2);
1152
1153  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1154  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1155
1156  bool not_equal = !String::Equals(x, y);
1157  // This is slightly convoluted because the value that signifies
1158  // equality is 0 and inequality is 1 so we have to negate the result
1159  // from String::Equals.
1160  DCHECK(not_equal == 0 || not_equal == 1);
1161  STATIC_ASSERT(EQUAL == 0);
1162  STATIC_ASSERT(NOT_EQUAL == 1);
1163  return Smi::FromInt(not_equal);
1164}
1165
1166
1167RUNTIME_FUNCTION(Runtime_FlattenString) {
1168  HandleScope scope(isolate);
1169  DCHECK(args.length() == 1);
1170  CONVERT_ARG_HANDLE_CHECKED(String, str, 0);
1171  return *String::Flatten(str);
1172}
1173
1174
1175RUNTIME_FUNCTION(Runtime_StringCharFromCode) {
1176  HandleScope handlescope(isolate);
1177  DCHECK_EQ(1, args.length());
1178  if (args[0]->IsNumber()) {
1179    CONVERT_NUMBER_CHECKED(uint32_t, code, Uint32, args[0]);
1180    code &= 0xffff;
1181    return *isolate->factory()->LookupSingleCharacterStringFromCode(code);
1182  }
1183  return isolate->heap()->empty_string();
1184}
1185
1186
1187RUNTIME_FUNCTION(Runtime_StringCharAt) {
1188  SealHandleScope shs(isolate);
1189  DCHECK(args.length() == 2);
1190  if (!args[0]->IsString()) return Smi::FromInt(0);
1191  if (!args[1]->IsNumber()) return Smi::FromInt(0);
1192  if (std::isinf(args.number_at(1))) return isolate->heap()->empty_string();
1193  Object* code = __RT_impl_Runtime_StringCharCodeAtRT(args, isolate);
1194  if (code->IsNaN()) return isolate->heap()->empty_string();
1195  return __RT_impl_Runtime_StringCharFromCode(Arguments(1, &code), isolate);
1196}
1197
1198
1199RUNTIME_FUNCTION(Runtime_OneByteSeqStringGetChar) {
1200  SealHandleScope shs(isolate);
1201  DCHECK(args.length() == 2);
1202  CONVERT_ARG_CHECKED(SeqOneByteString, string, 0);
1203  CONVERT_INT32_ARG_CHECKED(index, 1);
1204  return Smi::FromInt(string->SeqOneByteStringGet(index));
1205}
1206
1207
1208RUNTIME_FUNCTION(Runtime_OneByteSeqStringSetChar) {
1209  SealHandleScope shs(isolate);
1210  DCHECK(args.length() == 3);
1211  CONVERT_INT32_ARG_CHECKED(index, 0);
1212  CONVERT_INT32_ARG_CHECKED(value, 1);
1213  CONVERT_ARG_CHECKED(SeqOneByteString, string, 2);
1214  string->SeqOneByteStringSet(index, value);
1215  return string;
1216}
1217
1218
1219RUNTIME_FUNCTION(Runtime_TwoByteSeqStringGetChar) {
1220  SealHandleScope shs(isolate);
1221  DCHECK(args.length() == 2);
1222  CONVERT_ARG_CHECKED(SeqTwoByteString, string, 0);
1223  CONVERT_INT32_ARG_CHECKED(index, 1);
1224  return Smi::FromInt(string->SeqTwoByteStringGet(index));
1225}
1226
1227
1228RUNTIME_FUNCTION(Runtime_TwoByteSeqStringSetChar) {
1229  SealHandleScope shs(isolate);
1230  DCHECK(args.length() == 3);
1231  CONVERT_INT32_ARG_CHECKED(index, 0);
1232  CONVERT_INT32_ARG_CHECKED(value, 1);
1233  CONVERT_ARG_CHECKED(SeqTwoByteString, string, 2);
1234  string->SeqTwoByteStringSet(index, value);
1235  return string;
1236}
1237
1238
1239RUNTIME_FUNCTION(Runtime_StringCharCodeAt) {
1240  SealHandleScope shs(isolate);
1241  DCHECK(args.length() == 2);
1242  if (!args[0]->IsString()) return isolate->heap()->undefined_value();
1243  if (!args[1]->IsNumber()) return isolate->heap()->undefined_value();
1244  if (std::isinf(args.number_at(1))) return isolate->heap()->nan_value();
1245  return __RT_impl_Runtime_StringCharCodeAtRT(args, isolate);
1246}
1247
1248}  // namespace internal
1249}  // namespace v8
1250