runtime-strings.cc revision bcf72ee8e3b26f1d0726869c7ddb3921c68b09a8 
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/regexp/jsregexp-inl.h"
9#include "src/string-builder.h"
10#include "src/string-search.h"
11
12namespace v8 {
13namespace internal {
14
15
16// Perform string match of pattern on subject, starting at start index.
17// Caller must ensure that 0 <= start_index <= sub->length(),
18// and should check that pat->length() + start_index <= sub->length().
19int StringMatch(Isolate* isolate, Handle<String> sub, Handle<String> pat,
20                int start_index) {
21  DCHECK(0 <= start_index);
22  DCHECK(start_index <= sub->length());
23
24  int pattern_length = pat->length();
25  if (pattern_length == 0) return start_index;
26
27  int subject_length = sub->length();
28  if (start_index + pattern_length > subject_length) return -1;
29
30  sub = String::Flatten(sub);
31  pat = String::Flatten(pat);
32
33  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
34  // Extract flattened substrings of cons strings before getting encoding.
35  String::FlatContent seq_sub = sub->GetFlatContent();
36  String::FlatContent seq_pat = pat->GetFlatContent();
37
38  // dispatch on type of strings
39  if (seq_pat.IsOneByte()) {
40    Vector<const uint8_t> pat_vector = seq_pat.ToOneByteVector();
41    if (seq_sub.IsOneByte()) {
42      return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
43                          start_index);
44    }
45    return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector,
46                        start_index);
47  }
48  Vector<const uc16> pat_vector = seq_pat.ToUC16Vector();
49  if (seq_sub.IsOneByte()) {
50    return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
51                        start_index);
52  }
53  return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector, start_index);
54}
55
56
57// This may return an empty MaybeHandle if an exception is thrown or
58// we abort due to reaching the recursion limit.
59MaybeHandle<String> StringReplaceOneCharWithString(
60    Isolate* isolate, Handle<String> subject, Handle<String> search,
61    Handle<String> replace, bool* found, int recursion_limit) {
62  StackLimitCheck stackLimitCheck(isolate);
63  if (stackLimitCheck.HasOverflowed() || (recursion_limit == 0)) {
64    return MaybeHandle<String>();
65  }
66  recursion_limit--;
67  if (subject->IsConsString()) {
68    ConsString* cons = ConsString::cast(*subject);
69    Handle<String> first = Handle<String>(cons->first());
70    Handle<String> second = Handle<String>(cons->second());
71    Handle<String> new_first;
72    if (!StringReplaceOneCharWithString(isolate, first, search, replace, found,
73                                        recursion_limit).ToHandle(&new_first)) {
74      return MaybeHandle<String>();
75    }
76    if (*found) return isolate->factory()->NewConsString(new_first, second);
77
78    Handle<String> new_second;
79    if (!StringReplaceOneCharWithString(isolate, second, search, replace, found,
80                                        recursion_limit)
81             .ToHandle(&new_second)) {
82      return MaybeHandle<String>();
83    }
84    if (*found) return isolate->factory()->NewConsString(first, new_second);
85
86    return subject;
87  } else {
88    int index = StringMatch(isolate, subject, search, 0);
89    if (index == -1) return subject;
90    *found = true;
91    Handle<String> first = isolate->factory()->NewSubString(subject, 0, index);
92    Handle<String> cons1;
93    ASSIGN_RETURN_ON_EXCEPTION(
94        isolate, cons1, isolate->factory()->NewConsString(first, replace),
95        String);
96    Handle<String> second =
97        isolate->factory()->NewSubString(subject, index + 1, subject->length());
98    return isolate->factory()->NewConsString(cons1, second);
99  }
100}
101
102
103RUNTIME_FUNCTION(Runtime_StringReplaceOneCharWithString) {
104  HandleScope scope(isolate);
105  DCHECK(args.length() == 3);
106  CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
107  CONVERT_ARG_HANDLE_CHECKED(String, search, 1);
108  CONVERT_ARG_HANDLE_CHECKED(String, replace, 2);
109
110  // If the cons string tree is too deep, we simply abort the recursion and
111  // retry with a flattened subject string.
112  const int kRecursionLimit = 0x1000;
113  bool found = false;
114  Handle<String> result;
115  if (StringReplaceOneCharWithString(isolate, subject, search, replace, &found,
116                                     kRecursionLimit).ToHandle(&result)) {
117    return *result;
118  }
119  if (isolate->has_pending_exception()) return isolate->heap()->exception();
120
121  subject = String::Flatten(subject);
122  if (StringReplaceOneCharWithString(isolate, subject, search, replace, &found,
123                                     kRecursionLimit).ToHandle(&result)) {
124    return *result;
125  }
126  if (isolate->has_pending_exception()) return isolate->heap()->exception();
127  // In case of empty handle and no pending exception we have stack overflow.
128  return isolate->StackOverflow();
129}
130
131
132RUNTIME_FUNCTION(Runtime_StringIndexOf) {
133  HandleScope scope(isolate);
134  DCHECK(args.length() == 3);
135
136  CONVERT_ARG_HANDLE_CHECKED(String, sub, 0);
137  CONVERT_ARG_HANDLE_CHECKED(String, pat, 1);
138  CONVERT_ARG_HANDLE_CHECKED(Object, index, 2);
139
140  uint32_t start_index = 0;
141  if (!index->ToArrayIndex(&start_index)) return Smi::FromInt(-1);
142
143  RUNTIME_ASSERT(start_index <= static_cast<uint32_t>(sub->length()));
144  int position = StringMatch(isolate, sub, pat, start_index);
145  return Smi::FromInt(position);
146}
147
148
149template <typename schar, typename pchar>
150static int StringMatchBackwards(Vector<const schar> subject,
151                                Vector<const pchar> pattern, int idx) {
152  int pattern_length = pattern.length();
153  DCHECK(pattern_length >= 1);
154  DCHECK(idx + pattern_length <= subject.length());
155
156  if (sizeof(schar) == 1 && sizeof(pchar) > 1) {
157    for (int i = 0; i < pattern_length; i++) {
158      uc16 c = pattern[i];
159      if (c > String::kMaxOneByteCharCode) {
160        return -1;
161      }
162    }
163  }
164
165  pchar pattern_first_char = pattern[0];
166  for (int i = idx; i >= 0; i--) {
167    if (subject[i] != pattern_first_char) continue;
168    int j = 1;
169    while (j < pattern_length) {
170      if (pattern[j] != subject[i + j]) {
171        break;
172      }
173      j++;
174    }
175    if (j == pattern_length) {
176      return i;
177    }
178  }
179  return -1;
180}
181
182
183RUNTIME_FUNCTION(Runtime_StringLastIndexOf) {
184  HandleScope scope(isolate);
185  DCHECK(args.length() == 3);
186
187  CONVERT_ARG_HANDLE_CHECKED(String, sub, 0);
188  CONVERT_ARG_HANDLE_CHECKED(String, pat, 1);
189  CONVERT_ARG_HANDLE_CHECKED(Object, index, 2);
190
191  uint32_t start_index = 0;
192  if (!index->ToArrayIndex(&start_index)) return Smi::FromInt(-1);
193
194  uint32_t pat_length = pat->length();
195  uint32_t sub_length = sub->length();
196
197  if (start_index + pat_length > sub_length) {
198    start_index = sub_length - pat_length;
199  }
200
201  if (pat_length == 0) {
202    return Smi::FromInt(start_index);
203  }
204
205  sub = String::Flatten(sub);
206  pat = String::Flatten(pat);
207
208  int position = -1;
209  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
210
211  String::FlatContent sub_content = sub->GetFlatContent();
212  String::FlatContent pat_content = pat->GetFlatContent();
213
214  if (pat_content.IsOneByte()) {
215    Vector<const uint8_t> pat_vector = pat_content.ToOneByteVector();
216    if (sub_content.IsOneByte()) {
217      position = StringMatchBackwards(sub_content.ToOneByteVector(), pat_vector,
218                                      start_index);
219    } else {
220      position = StringMatchBackwards(sub_content.ToUC16Vector(), pat_vector,
221                                      start_index);
222    }
223  } else {
224    Vector<const uc16> pat_vector = pat_content.ToUC16Vector();
225    if (sub_content.IsOneByte()) {
226      position = StringMatchBackwards(sub_content.ToOneByteVector(), pat_vector,
227                                      start_index);
228    } else {
229      position = StringMatchBackwards(sub_content.ToUC16Vector(), pat_vector,
230                                      start_index);
231    }
232  }
233
234  return Smi::FromInt(position);
235}
236
237
238RUNTIME_FUNCTION(Runtime_StringLocaleCompare) {
239  HandleScope handle_scope(isolate);
240  DCHECK(args.length() == 2);
241
242  CONVERT_ARG_HANDLE_CHECKED(String, str1, 0);
243  CONVERT_ARG_HANDLE_CHECKED(String, str2, 1);
244
245  if (str1.is_identical_to(str2)) return Smi::FromInt(0);  // Equal.
246  int str1_length = str1->length();
247  int str2_length = str2->length();
248
249  // Decide trivial cases without flattening.
250  if (str1_length == 0) {
251    if (str2_length == 0) return Smi::FromInt(0);  // Equal.
252    return Smi::FromInt(-str2_length);
253  } else {
254    if (str2_length == 0) return Smi::FromInt(str1_length);
255  }
256
257  int end = str1_length < str2_length ? str1_length : str2_length;
258
259  // No need to flatten if we are going to find the answer on the first
260  // character.  At this point we know there is at least one character
261  // in each string, due to the trivial case handling above.
262  int d = str1->Get(0) - str2->Get(0);
263  if (d != 0) return Smi::FromInt(d);
264
265  str1 = String::Flatten(str1);
266  str2 = String::Flatten(str2);
267
268  DisallowHeapAllocation no_gc;
269  String::FlatContent flat1 = str1->GetFlatContent();
270  String::FlatContent flat2 = str2->GetFlatContent();
271
272  for (int i = 0; i < end; i++) {
273    if (flat1.Get(i) != flat2.Get(i)) {
274      return Smi::FromInt(flat1.Get(i) - flat2.Get(i));
275    }
276  }
277
278  return Smi::FromInt(str1_length - str2_length);
279}
280
281
282RUNTIME_FUNCTION(Runtime_SubString) {
283  HandleScope scope(isolate);
284  DCHECK(args.length() == 3);
285
286  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
287  int start, end;
288  // We have a fast integer-only case here to avoid a conversion to double in
289  // the common case where from and to are Smis.
290  if (args[1]->IsSmi() && args[2]->IsSmi()) {
291    CONVERT_SMI_ARG_CHECKED(from_number, 1);
292    CONVERT_SMI_ARG_CHECKED(to_number, 2);
293    start = from_number;
294    end = to_number;
295  } else {
296    CONVERT_DOUBLE_ARG_CHECKED(from_number, 1);
297    CONVERT_DOUBLE_ARG_CHECKED(to_number, 2);
298    start = FastD2IChecked(from_number);
299    end = FastD2IChecked(to_number);
300  }
301  RUNTIME_ASSERT(end >= start);
302  RUNTIME_ASSERT(start >= 0);
303  RUNTIME_ASSERT(end <= string->length());
304  isolate->counters()->sub_string_runtime()->Increment();
305
306  return *isolate->factory()->NewSubString(string, start, end);
307}
308
309
310RUNTIME_FUNCTION(Runtime_StringAdd) {
311  HandleScope scope(isolate);
312  DCHECK(args.length() == 2);
313  CONVERT_ARG_HANDLE_CHECKED(String, str1, 0);
314  CONVERT_ARG_HANDLE_CHECKED(String, str2, 1);
315  isolate->counters()->string_add_runtime()->Increment();
316  Handle<String> result;
317  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
318      isolate, result, isolate->factory()->NewConsString(str1, str2));
319  return *result;
320}
321
322
323RUNTIME_FUNCTION(Runtime_InternalizeString) {
324  HandleScope handles(isolate);
325  RUNTIME_ASSERT(args.length() == 1);
326  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
327  return *isolate->factory()->InternalizeString(string);
328}
329
330
331RUNTIME_FUNCTION(Runtime_StringMatch) {
332  HandleScope handles(isolate);
333  DCHECK(args.length() == 3);
334
335  CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
336  CONVERT_ARG_HANDLE_CHECKED(JSRegExp, regexp, 1);
337  CONVERT_ARG_HANDLE_CHECKED(JSArray, regexp_info, 2);
338
339  RUNTIME_ASSERT(regexp_info->HasFastObjectElements());
340
341  RegExpImpl::GlobalCache global_cache(regexp, subject, isolate);
342  if (global_cache.HasException()) return isolate->heap()->exception();
343
344  int capture_count = regexp->CaptureCount();
345
346  ZoneScope zone_scope(isolate->runtime_zone());
347  ZoneList<int> offsets(8, zone_scope.zone());
348
349  while (true) {
350    int32_t* match = global_cache.FetchNext();
351    if (match == NULL) break;
352    offsets.Add(match[0], zone_scope.zone());  // start
353    offsets.Add(match[1], zone_scope.zone());  // end
354  }
355
356  if (global_cache.HasException()) return isolate->heap()->exception();
357
358  if (offsets.length() == 0) {
359    // Not a single match.
360    return isolate->heap()->null_value();
361  }
362
363  RegExpImpl::SetLastMatchInfo(regexp_info, subject, capture_count,
364                               global_cache.LastSuccessfulMatch());
365
366  int matches = offsets.length() / 2;
367  Handle<FixedArray> elements = isolate->factory()->NewFixedArray(matches);
368  Handle<String> substring =
369      isolate->factory()->NewSubString(subject, offsets.at(0), offsets.at(1));
370  elements->set(0, *substring);
371  FOR_WITH_HANDLE_SCOPE(isolate, int, i = 1, i, i < matches, i++, {
372    int from = offsets.at(i * 2);
373    int to = offsets.at(i * 2 + 1);
374    Handle<String> substring =
375        isolate->factory()->NewProperSubString(subject, from, to);
376    elements->set(i, *substring);
377  });
378  Handle<JSArray> result = isolate->factory()->NewJSArrayWithElements(elements);
379  result->set_length(Smi::FromInt(matches));
380  return *result;
381}
382
383
384RUNTIME_FUNCTION(Runtime_StringCharCodeAtRT) {
385  HandleScope handle_scope(isolate);
386  DCHECK(args.length() == 2);
387
388  CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
389  CONVERT_NUMBER_CHECKED(uint32_t, i, Uint32, args[1]);
390
391  // Flatten the string.  If someone wants to get a char at an index
392  // in a cons string, it is likely that more indices will be
393  // accessed.
394  subject = String::Flatten(subject);
395
396  if (i >= static_cast<uint32_t>(subject->length())) {
397    return isolate->heap()->nan_value();
398  }
399
400  return Smi::FromInt(subject->Get(i));
401}
402
403
404RUNTIME_FUNCTION(Runtime_StringCompare) {
405  HandleScope handle_scope(isolate);
406  DCHECK_EQ(2, args.length());
407  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
408  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
409  isolate->counters()->string_compare_runtime()->Increment();
410  switch (String::Compare(x, y)) {
411    case ComparisonResult::kLessThan:
412      return Smi::FromInt(LESS);
413    case ComparisonResult::kEqual:
414      return Smi::FromInt(EQUAL);
415    case ComparisonResult::kGreaterThan:
416      return Smi::FromInt(GREATER);
417    case ComparisonResult::kUndefined:
418      break;
419  }
420  UNREACHABLE();
421  return Smi::FromInt(0);
422}
423
424
425RUNTIME_FUNCTION(Runtime_StringBuilderConcat) {
426  HandleScope scope(isolate);
427  DCHECK(args.length() == 3);
428  CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
429  int32_t array_length;
430  if (!args[1]->ToInt32(&array_length)) {
431    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
432  }
433  CONVERT_ARG_HANDLE_CHECKED(String, special, 2);
434
435  size_t actual_array_length = 0;
436  RUNTIME_ASSERT(
437      TryNumberToSize(isolate, array->length(), &actual_array_length));
438  RUNTIME_ASSERT(array_length >= 0);
439  RUNTIME_ASSERT(static_cast<size_t>(array_length) <= actual_array_length);
440
441  // This assumption is used by the slice encoding in one or two smis.
442  DCHECK(Smi::kMaxValue >= String::kMaxLength);
443
444  RUNTIME_ASSERT(array->HasFastElements());
445  JSObject::EnsureCanContainHeapObjectElements(array);
446
447  int special_length = special->length();
448  if (!array->HasFastObjectElements()) {
449    return isolate->Throw(isolate->heap()->illegal_argument_string());
450  }
451
452  int length;
453  bool one_byte = special->HasOnlyOneByteChars();
454
455  {
456    DisallowHeapAllocation no_gc;
457    FixedArray* fixed_array = FixedArray::cast(array->elements());
458    if (fixed_array->length() < array_length) {
459      array_length = fixed_array->length();
460    }
461
462    if (array_length == 0) {
463      return isolate->heap()->empty_string();
464    } else if (array_length == 1) {
465      Object* first = fixed_array->get(0);
466      if (first->IsString()) return first;
467    }
468    length = StringBuilderConcatLength(special_length, fixed_array,
469                                       array_length, &one_byte);
470  }
471
472  if (length == -1) {
473    return isolate->Throw(isolate->heap()->illegal_argument_string());
474  }
475
476  if (one_byte) {
477    Handle<SeqOneByteString> answer;
478    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
479        isolate, answer, isolate->factory()->NewRawOneByteString(length));
480    StringBuilderConcatHelper(*special, answer->GetChars(),
481                              FixedArray::cast(array->elements()),
482                              array_length);
483    return *answer;
484  } else {
485    Handle<SeqTwoByteString> answer;
486    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
487        isolate, answer, isolate->factory()->NewRawTwoByteString(length));
488    StringBuilderConcatHelper(*special, answer->GetChars(),
489                              FixedArray::cast(array->elements()),
490                              array_length);
491    return *answer;
492  }
493}
494
495
496RUNTIME_FUNCTION(Runtime_StringBuilderJoin) {
497  HandleScope scope(isolate);
498  DCHECK(args.length() == 3);
499  CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
500  int32_t array_length;
501  if (!args[1]->ToInt32(&array_length)) {
502    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
503  }
504  CONVERT_ARG_HANDLE_CHECKED(String, separator, 2);
505  RUNTIME_ASSERT(array->HasFastObjectElements());
506  RUNTIME_ASSERT(array_length >= 0);
507
508  Handle<FixedArray> fixed_array(FixedArray::cast(array->elements()));
509  if (fixed_array->length() < array_length) {
510    array_length = fixed_array->length();
511  }
512
513  if (array_length == 0) {
514    return isolate->heap()->empty_string();
515  } else if (array_length == 1) {
516    Object* first = fixed_array->get(0);
517    RUNTIME_ASSERT(first->IsString());
518    return first;
519  }
520
521  int separator_length = separator->length();
522  RUNTIME_ASSERT(separator_length > 0);
523  int max_nof_separators =
524      (String::kMaxLength + separator_length - 1) / separator_length;
525  if (max_nof_separators < (array_length - 1)) {
526    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
527  }
528  int length = (array_length - 1) * separator_length;
529  for (int i = 0; i < array_length; i++) {
530    Object* element_obj = fixed_array->get(i);
531    RUNTIME_ASSERT(element_obj->IsString());
532    String* element = String::cast(element_obj);
533    int increment = element->length();
534    if (increment > String::kMaxLength - length) {
535      STATIC_ASSERT(String::kMaxLength < kMaxInt);
536      length = kMaxInt;  // Provoke exception;
537      break;
538    }
539    length += increment;
540  }
541
542  Handle<SeqTwoByteString> answer;
543  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
544      isolate, answer, isolate->factory()->NewRawTwoByteString(length));
545
546  DisallowHeapAllocation no_gc;
547
548  uc16* sink = answer->GetChars();
549#ifdef DEBUG
550  uc16* end = sink + length;
551#endif
552
553  RUNTIME_ASSERT(fixed_array->get(0)->IsString());
554  String* first = String::cast(fixed_array->get(0));
555  String* separator_raw = *separator;
556
557  int first_length = first->length();
558  String::WriteToFlat(first, sink, 0, first_length);
559  sink += first_length;
560
561  for (int i = 1; i < array_length; i++) {
562    DCHECK(sink + separator_length <= end);
563    String::WriteToFlat(separator_raw, sink, 0, separator_length);
564    sink += separator_length;
565
566    RUNTIME_ASSERT(fixed_array->get(i)->IsString());
567    String* element = String::cast(fixed_array->get(i));
568    int element_length = element->length();
569    DCHECK(sink + element_length <= end);
570    String::WriteToFlat(element, sink, 0, element_length);
571    sink += element_length;
572  }
573  DCHECK(sink == end);
574
575  // Use %_FastOneByteArrayJoin instead.
576  DCHECK(!answer->IsOneByteRepresentation());
577  return *answer;
578}
579
580template <typename sinkchar>
581static void WriteRepeatToFlat(String* src, Vector<sinkchar> buffer, int cursor,
582                              int repeat, int length) {
583  if (repeat == 0) return;
584
585  sinkchar* start = &buffer[cursor];
586  String::WriteToFlat<sinkchar>(src, start, 0, length);
587
588  int done = 1;
589  sinkchar* next = start + length;
590
591  while (done < repeat) {
592    int block = Min(done, repeat - done);
593    int block_chars = block * length;
594    CopyChars(next, start, block_chars);
595    next += block_chars;
596    done += block;
597  }
598}
599
600template <typename Char>
601static void JoinSparseArrayWithSeparator(FixedArray* elements,
602                                         int elements_length,
603                                         uint32_t array_length,
604                                         String* separator,
605                                         Vector<Char> buffer) {
606  DisallowHeapAllocation no_gc;
607  int previous_separator_position = 0;
608  int separator_length = separator->length();
609  DCHECK_LT(0, separator_length);
610  int cursor = 0;
611  for (int i = 0; i < elements_length; i += 2) {
612    int position = NumberToInt32(elements->get(i));
613    String* string = String::cast(elements->get(i + 1));
614    int string_length = string->length();
615    if (string->length() > 0) {
616      int repeat = position - previous_separator_position;
617      WriteRepeatToFlat<Char>(separator, buffer, cursor, repeat,
618                              separator_length);
619      cursor += repeat * separator_length;
620      previous_separator_position = position;
621      String::WriteToFlat<Char>(string, &buffer[cursor], 0, string_length);
622      cursor += string->length();
623    }
624  }
625
626  int last_array_index = static_cast<int>(array_length - 1);
627  // Array length must be representable as a signed 32-bit number,
628  // otherwise the total string length would have been too large.
629  DCHECK(array_length <= 0x7fffffff);  // Is int32_t.
630  int repeat = last_array_index - previous_separator_position;
631  WriteRepeatToFlat<Char>(separator, buffer, cursor, repeat, separator_length);
632  cursor += repeat * separator_length;
633  DCHECK(cursor <= buffer.length());
634}
635
636
637RUNTIME_FUNCTION(Runtime_SparseJoinWithSeparator) {
638  HandleScope scope(isolate);
639  DCHECK(args.length() == 3);
640  CONVERT_ARG_HANDLE_CHECKED(JSArray, elements_array, 0);
641  CONVERT_NUMBER_CHECKED(uint32_t, array_length, Uint32, args[1]);
642  CONVERT_ARG_HANDLE_CHECKED(String, separator, 2);
643  // elements_array is fast-mode JSarray of alternating positions
644  // (increasing order) and strings.
645  RUNTIME_ASSERT(elements_array->HasFastSmiOrObjectElements());
646  // array_length is length of original array (used to add separators);
647  // separator is string to put between elements. Assumed to be non-empty.
648  RUNTIME_ASSERT(array_length > 0);
649
650  // Find total length of join result.
651  int string_length = 0;
652  bool is_one_byte = separator->IsOneByteRepresentation();
653  bool overflow = false;
654  CONVERT_NUMBER_CHECKED(int, elements_length, Int32, elements_array->length());
655  RUNTIME_ASSERT(elements_length <= elements_array->elements()->length());
656  RUNTIME_ASSERT((elements_length & 1) == 0);  // Even length.
657  FixedArray* elements = FixedArray::cast(elements_array->elements());
658  {
659    DisallowHeapAllocation no_gc;
660    for (int i = 0; i < elements_length; i += 2) {
661      String* string = String::cast(elements->get(i + 1));
662      int length = string->length();
663      if (is_one_byte && !string->IsOneByteRepresentation()) {
664        is_one_byte = false;
665      }
666      if (length > String::kMaxLength ||
667          String::kMaxLength - length < string_length) {
668        overflow = true;
669        break;
670      }
671      string_length += length;
672    }
673  }
674
675  int separator_length = separator->length();
676  if (!overflow && separator_length > 0) {
677    if (array_length <= 0x7fffffffu) {
678      int separator_count = static_cast<int>(array_length) - 1;
679      int remaining_length = String::kMaxLength - string_length;
680      if ((remaining_length / separator_length) >= separator_count) {
681        string_length += separator_length * (array_length - 1);
682      } else {
683        // Not room for the separators within the maximal string length.
684        overflow = true;
685      }
686    } else {
687      // Nonempty separator and at least 2^31-1 separators necessary
688      // means that the string is too large to create.
689      STATIC_ASSERT(String::kMaxLength < 0x7fffffff);
690      overflow = true;
691    }
692  }
693  if (overflow) {
694    // Throw an exception if the resulting string is too large. See
695    // https://code.google.com/p/chromium/issues/detail?id=336820
696    // for details.
697    THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
698  }
699
700  if (is_one_byte) {
701    Handle<SeqOneByteString> result = isolate->factory()
702                                          ->NewRawOneByteString(string_length)
703                                          .ToHandleChecked();
704    JoinSparseArrayWithSeparator<uint8_t>(
705        FixedArray::cast(elements_array->elements()), elements_length,
706        array_length, *separator,
707        Vector<uint8_t>(result->GetChars(), string_length));
708    return *result;
709  } else {
710    Handle<SeqTwoByteString> result = isolate->factory()
711                                          ->NewRawTwoByteString(string_length)
712                                          .ToHandleChecked();
713    JoinSparseArrayWithSeparator<uc16>(
714        FixedArray::cast(elements_array->elements()), elements_length,
715        array_length, *separator,
716        Vector<uc16>(result->GetChars(), string_length));
717    return *result;
718  }
719}
720
721
722// Copies Latin1 characters to the given fixed array looking up
723// one-char strings in the cache. Gives up on the first char that is
724// not in the cache and fills the remainder with smi zeros. Returns
725// the length of the successfully copied prefix.
726static int CopyCachedOneByteCharsToArray(Heap* heap, const uint8_t* chars,
727                                         FixedArray* elements, int length) {
728  DisallowHeapAllocation no_gc;
729  FixedArray* one_byte_cache = heap->single_character_string_cache();
730  Object* undefined = heap->undefined_value();
731  int i;
732  WriteBarrierMode mode = elements->GetWriteBarrierMode(no_gc);
733  for (i = 0; i < length; ++i) {
734    Object* value = one_byte_cache->get(chars[i]);
735    if (value == undefined) break;
736    elements->set(i, value, mode);
737  }
738  if (i < length) {
739    DCHECK(Smi::FromInt(0) == 0);
740    memset(elements->data_start() + i, 0, kPointerSize * (length - i));
741  }
742#ifdef DEBUG
743  for (int j = 0; j < length; ++j) {
744    Object* element = elements->get(j);
745    DCHECK(element == Smi::FromInt(0) ||
746           (element->IsString() && String::cast(element)->LooksValid()));
747  }
748#endif
749  return i;
750}
751
752
753// Converts a String to JSArray.
754// For example, "foo" => ["f", "o", "o"].
755RUNTIME_FUNCTION(Runtime_StringToArray) {
756  HandleScope scope(isolate);
757  DCHECK(args.length() == 2);
758  CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
759  CONVERT_NUMBER_CHECKED(uint32_t, limit, Uint32, args[1]);
760
761  s = String::Flatten(s);
762  const int length = static_cast<int>(Min<uint32_t>(s->length(), limit));
763
764  Handle<FixedArray> elements;
765  int position = 0;
766  if (s->IsFlat() && s->IsOneByteRepresentation()) {
767    // Try using cached chars where possible.
768    elements = isolate->factory()->NewUninitializedFixedArray(length);
769
770    DisallowHeapAllocation no_gc;
771    String::FlatContent content = s->GetFlatContent();
772    if (content.IsOneByte()) {
773      Vector<const uint8_t> chars = content.ToOneByteVector();
774      // Note, this will initialize all elements (not only the prefix)
775      // to prevent GC from seeing partially initialized array.
776      position = CopyCachedOneByteCharsToArray(isolate->heap(), chars.start(),
777                                               *elements, length);
778    } else {
779      MemsetPointer(elements->data_start(), isolate->heap()->undefined_value(),
780                    length);
781    }
782  } else {
783    elements = isolate->factory()->NewFixedArray(length);
784  }
785  for (int i = position; i < length; ++i) {
786    Handle<Object> str =
787        isolate->factory()->LookupSingleCharacterStringFromCode(s->Get(i));
788    elements->set(i, *str);
789  }
790
791#ifdef DEBUG
792  for (int i = 0; i < length; ++i) {
793    DCHECK(String::cast(elements->get(i))->length() == 1);
794  }
795#endif
796
797  return *isolate->factory()->NewJSArrayWithElements(elements);
798}
799
800
801static inline bool ToUpperOverflows(uc32 character) {
802  // y with umlauts and the micro sign are the only characters that stop
803  // fitting into one-byte when converting to uppercase.
804  static const uc32 yuml_code = 0xff;
805  static const uc32 micro_code = 0xb5;
806  return (character == yuml_code || character == micro_code);
807}
808
809
810template <class Converter>
811MUST_USE_RESULT static Object* ConvertCaseHelper(
812    Isolate* isolate, String* string, SeqString* result, int result_length,
813    unibrow::Mapping<Converter, 128>* mapping) {
814  DisallowHeapAllocation no_gc;
815  // We try this twice, once with the assumption that the result is no longer
816  // than the input and, if that assumption breaks, again with the exact
817  // length.  This may not be pretty, but it is nicer than what was here before
818  // and I hereby claim my vaffel-is.
819  //
820  // NOTE: This assumes that the upper/lower case of an ASCII
821  // character is also ASCII.  This is currently the case, but it
822  // might break in the future if we implement more context and locale
823  // dependent upper/lower conversions.
824  bool has_changed_character = false;
825
826  // Convert all characters to upper case, assuming that they will fit
827  // in the buffer
828  StringCharacterStream stream(string);
829  unibrow::uchar chars[Converter::kMaxWidth];
830  // We can assume that the string is not empty
831  uc32 current = stream.GetNext();
832  bool ignore_overflow = Converter::kIsToLower || result->IsSeqTwoByteString();
833  for (int i = 0; i < result_length;) {
834    bool has_next = stream.HasMore();
835    uc32 next = has_next ? stream.GetNext() : 0;
836    int char_length = mapping->get(current, next, chars);
837    if (char_length == 0) {
838      // The case conversion of this character is the character itself.
839      result->Set(i, current);
840      i++;
841    } else if (char_length == 1 &&
842               (ignore_overflow || !ToUpperOverflows(current))) {
843      // Common case: converting the letter resulted in one character.
844      DCHECK(static_cast<uc32>(chars[0]) != current);
845      result->Set(i, chars[0]);
846      has_changed_character = true;
847      i++;
848    } else if (result_length == string->length()) {
849      bool overflows = ToUpperOverflows(current);
850      // We've assumed that the result would be as long as the
851      // input but here is a character that converts to several
852      // characters.  No matter, we calculate the exact length
853      // of the result and try the whole thing again.
854      //
855      // Note that this leaves room for optimization.  We could just
856      // memcpy what we already have to the result string.  Also,
857      // the result string is the last object allocated we could
858      // "realloc" it and probably, in the vast majority of cases,
859      // extend the existing string to be able to hold the full
860      // result.
861      int next_length = 0;
862      if (has_next) {
863        next_length = mapping->get(next, 0, chars);
864        if (next_length == 0) next_length = 1;
865      }
866      int current_length = i + char_length + next_length;
867      while (stream.HasMore()) {
868        current = stream.GetNext();
869        overflows |= ToUpperOverflows(current);
870        // NOTE: we use 0 as the next character here because, while
871        // the next character may affect what a character converts to,
872        // it does not in any case affect the length of what it convert
873        // to.
874        int char_length = mapping->get(current, 0, chars);
875        if (char_length == 0) char_length = 1;
876        current_length += char_length;
877        if (current_length > String::kMaxLength) {
878          AllowHeapAllocation allocate_error_and_return;
879          THROW_NEW_ERROR_RETURN_FAILURE(isolate,
880                                         NewInvalidStringLengthError());
881        }
882      }
883      // Try again with the real length.  Return signed if we need
884      // to allocate a two-byte string for to uppercase.
885      return (overflows && !ignore_overflow) ? Smi::FromInt(-current_length)
886                                             : Smi::FromInt(current_length);
887    } else {
888      for (int j = 0; j < char_length; j++) {
889        result->Set(i, chars[j]);
890        i++;
891      }
892      has_changed_character = true;
893    }
894    current = next;
895  }
896  if (has_changed_character) {
897    return result;
898  } else {
899    // If we didn't actually change anything in doing the conversion
900    // we simple return the result and let the converted string
901    // become garbage; there is no reason to keep two identical strings
902    // alive.
903    return string;
904  }
905}
906
907
908static const uintptr_t kOneInEveryByte = kUintptrAllBitsSet / 0xFF;
909static const uintptr_t kAsciiMask = kOneInEveryByte << 7;
910
911// Given a word and two range boundaries returns a word with high bit
912// set in every byte iff the corresponding input byte was strictly in
913// the range (m, n). All the other bits in the result are cleared.
914// This function is only useful when it can be inlined and the
915// boundaries are statically known.
916// Requires: all bytes in the input word and the boundaries must be
917// ASCII (less than 0x7F).
918static inline uintptr_t AsciiRangeMask(uintptr_t w, char m, char n) {
919  // Use strict inequalities since in edge cases the function could be
920  // further simplified.
921  DCHECK(0 < m && m < n);
922  // Has high bit set in every w byte less than n.
923  uintptr_t tmp1 = kOneInEveryByte * (0x7F + n) - w;
924  // Has high bit set in every w byte greater than m.
925  uintptr_t tmp2 = w + kOneInEveryByte * (0x7F - m);
926  return (tmp1 & tmp2 & (kOneInEveryByte * 0x80));
927}
928
929
930#ifdef DEBUG
931static bool CheckFastAsciiConvert(char* dst, const char* src, int length,
932                                  bool changed, bool is_to_lower) {
933  bool expected_changed = false;
934  for (int i = 0; i < length; i++) {
935    if (dst[i] == src[i]) continue;
936    expected_changed = true;
937    if (is_to_lower) {
938      DCHECK('A' <= src[i] && src[i] <= 'Z');
939      DCHECK(dst[i] == src[i] + ('a' - 'A'));
940    } else {
941      DCHECK('a' <= src[i] && src[i] <= 'z');
942      DCHECK(dst[i] == src[i] - ('a' - 'A'));
943    }
944  }
945  return (expected_changed == changed);
946}
947#endif
948
949
950template <class Converter>
951static bool FastAsciiConvert(char* dst, const char* src, int length,
952                             bool* changed_out) {
953#ifdef DEBUG
954  char* saved_dst = dst;
955  const char* saved_src = src;
956#endif
957  DisallowHeapAllocation no_gc;
958  // We rely on the distance between upper and lower case letters
959  // being a known power of 2.
960  DCHECK('a' - 'A' == (1 << 5));
961  // Boundaries for the range of input characters than require conversion.
962  static const char lo = Converter::kIsToLower ? 'A' - 1 : 'a' - 1;
963  static const char hi = Converter::kIsToLower ? 'Z' + 1 : 'z' + 1;
964  bool changed = false;
965  uintptr_t or_acc = 0;
966  const char* const limit = src + length;
967
968  // dst is newly allocated and always aligned.
969  DCHECK(IsAligned(reinterpret_cast<intptr_t>(dst), sizeof(uintptr_t)));
970  // Only attempt processing one word at a time if src is also aligned.
971  if (IsAligned(reinterpret_cast<intptr_t>(src), sizeof(uintptr_t))) {
972    // Process the prefix of the input that requires no conversion one aligned
973    // (machine) word at a time.
974    while (src <= limit - sizeof(uintptr_t)) {
975      const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
976      or_acc |= w;
977      if (AsciiRangeMask(w, lo, hi) != 0) {
978        changed = true;
979        break;
980      }
981      *reinterpret_cast<uintptr_t*>(dst) = w;
982      src += sizeof(uintptr_t);
983      dst += sizeof(uintptr_t);
984    }
985    // Process the remainder of the input performing conversion when
986    // required one word at a time.
987    while (src <= limit - sizeof(uintptr_t)) {
988      const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
989      or_acc |= w;
990      uintptr_t m = AsciiRangeMask(w, lo, hi);
991      // The mask has high (7th) bit set in every byte that needs
992      // conversion and we know that the distance between cases is
993      // 1 << 5.
994      *reinterpret_cast<uintptr_t*>(dst) = w ^ (m >> 2);
995      src += sizeof(uintptr_t);
996      dst += sizeof(uintptr_t);
997    }
998  }
999  // Process the last few bytes of the input (or the whole input if
1000  // unaligned access is not supported).
1001  while (src < limit) {
1002    char c = *src;
1003    or_acc |= c;
1004    if (lo < c && c < hi) {
1005      c ^= (1 << 5);
1006      changed = true;
1007    }
1008    *dst = c;
1009    ++src;
1010    ++dst;
1011  }
1012
1013  if ((or_acc & kAsciiMask) != 0) return false;
1014
1015  DCHECK(CheckFastAsciiConvert(saved_dst, saved_src, length, changed,
1016                               Converter::kIsToLower));
1017
1018  *changed_out = changed;
1019  return true;
1020}
1021
1022
1023template <class Converter>
1024MUST_USE_RESULT static Object* ConvertCase(
1025    Handle<String> s, Isolate* isolate,
1026    unibrow::Mapping<Converter, 128>* mapping) {
1027  s = String::Flatten(s);
1028  int length = s->length();
1029  // Assume that the string is not empty; we need this assumption later
1030  if (length == 0) return *s;
1031
1032  // Simpler handling of ASCII strings.
1033  //
1034  // NOTE: This assumes that the upper/lower case of an ASCII
1035  // character is also ASCII.  This is currently the case, but it
1036  // might break in the future if we implement more context and locale
1037  // dependent upper/lower conversions.
1038  if (s->IsOneByteRepresentationUnderneath()) {
1039    // Same length as input.
1040    Handle<SeqOneByteString> result =
1041        isolate->factory()->NewRawOneByteString(length).ToHandleChecked();
1042    DisallowHeapAllocation no_gc;
1043    String::FlatContent flat_content = s->GetFlatContent();
1044    DCHECK(flat_content.IsFlat());
1045    bool has_changed_character = false;
1046    bool is_ascii = FastAsciiConvert<Converter>(
1047        reinterpret_cast<char*>(result->GetChars()),
1048        reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()),
1049        length, &has_changed_character);
1050    // If not ASCII, we discard the result and take the 2 byte path.
1051    if (is_ascii) return has_changed_character ? *result : *s;
1052  }
1053
1054  Handle<SeqString> result;  // Same length as input.
1055  if (s->IsOneByteRepresentation()) {
1056    result = isolate->factory()->NewRawOneByteString(length).ToHandleChecked();
1057  } else {
1058    result = isolate->factory()->NewRawTwoByteString(length).ToHandleChecked();
1059  }
1060
1061  Object* answer = ConvertCaseHelper(isolate, *s, *result, length, mapping);
1062  if (answer->IsException() || answer->IsString()) return answer;
1063
1064  DCHECK(answer->IsSmi());
1065  length = Smi::cast(answer)->value();
1066  if (s->IsOneByteRepresentation() && length > 0) {
1067    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1068        isolate, result, isolate->factory()->NewRawOneByteString(length));
1069  } else {
1070    if (length < 0) length = -length;
1071    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1072        isolate, result, isolate->factory()->NewRawTwoByteString(length));
1073  }
1074  return ConvertCaseHelper(isolate, *s, *result, length, mapping);
1075}
1076
1077
1078RUNTIME_FUNCTION(Runtime_StringToLowerCase) {
1079  HandleScope scope(isolate);
1080  DCHECK_EQ(args.length(), 1);
1081  CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
1082  return ConvertCase(s, isolate, isolate->runtime_state()->to_lower_mapping());
1083}
1084
1085
1086RUNTIME_FUNCTION(Runtime_StringToUpperCase) {
1087  HandleScope scope(isolate);
1088  DCHECK_EQ(args.length(), 1);
1089  CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
1090  return ConvertCase(s, isolate, isolate->runtime_state()->to_upper_mapping());
1091}
1092
1093
1094RUNTIME_FUNCTION(Runtime_StringTrim) {
1095  HandleScope scope(isolate);
1096  DCHECK(args.length() == 3);
1097
1098  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
1099  CONVERT_BOOLEAN_ARG_CHECKED(trimLeft, 1);
1100  CONVERT_BOOLEAN_ARG_CHECKED(trimRight, 2);
1101
1102  string = String::Flatten(string);
1103  int length = string->length();
1104
1105  int left = 0;
1106  UnicodeCache* unicode_cache = isolate->unicode_cache();
1107  if (trimLeft) {
1108    while (left < length &&
1109           unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(left))) {
1110      left++;
1111    }
1112  }
1113
1114  int right = length;
1115  if (trimRight) {
1116    while (
1117        right > left &&
1118        unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(right - 1))) {
1119      right--;
1120    }
1121  }
1122
1123  return *isolate->factory()->NewSubString(string, left, right);
1124}
1125
1126
1127RUNTIME_FUNCTION(Runtime_TruncateString) {
1128  HandleScope scope(isolate);
1129  DCHECK(args.length() == 2);
1130  CONVERT_ARG_HANDLE_CHECKED(SeqString, string, 0);
1131  CONVERT_INT32_ARG_CHECKED(new_length, 1);
1132  RUNTIME_ASSERT(new_length >= 0);
1133  return *SeqString::Truncate(string, new_length);
1134}
1135
1136
1137RUNTIME_FUNCTION(Runtime_NewString) {
1138  HandleScope scope(isolate);
1139  DCHECK(args.length() == 2);
1140  CONVERT_INT32_ARG_CHECKED(length, 0);
1141  CONVERT_BOOLEAN_ARG_CHECKED(is_one_byte, 1);
1142  if (length == 0) return isolate->heap()->empty_string();
1143  Handle<String> result;
1144  if (is_one_byte) {
1145    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1146        isolate, result, isolate->factory()->NewRawOneByteString(length));
1147  } else {
1148    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
1149        isolate, result, isolate->factory()->NewRawTwoByteString(length));
1150  }
1151  return *result;
1152}
1153
1154
1155RUNTIME_FUNCTION(Runtime_StringLessThan) {
1156  HandleScope handle_scope(isolate);
1157  DCHECK_EQ(2, args.length());
1158  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1159  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1160  switch (String::Compare(x, y)) {
1161    case ComparisonResult::kLessThan:
1162      return isolate->heap()->true_value();
1163    case ComparisonResult::kEqual:
1164    case ComparisonResult::kGreaterThan:
1165      return isolate->heap()->false_value();
1166    case ComparisonResult::kUndefined:
1167      break;
1168  }
1169  UNREACHABLE();
1170  return Smi::FromInt(0);
1171}
1172
1173RUNTIME_FUNCTION(Runtime_StringLessThanOrEqual) {
1174  HandleScope handle_scope(isolate);
1175  DCHECK_EQ(2, args.length());
1176  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1177  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1178  switch (String::Compare(x, y)) {
1179    case ComparisonResult::kEqual:
1180    case ComparisonResult::kLessThan:
1181      return isolate->heap()->true_value();
1182    case ComparisonResult::kGreaterThan:
1183      return isolate->heap()->false_value();
1184    case ComparisonResult::kUndefined:
1185      break;
1186  }
1187  UNREACHABLE();
1188  return Smi::FromInt(0);
1189}
1190
1191RUNTIME_FUNCTION(Runtime_StringGreaterThan) {
1192  HandleScope handle_scope(isolate);
1193  DCHECK_EQ(2, args.length());
1194  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1195  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1196  switch (String::Compare(x, y)) {
1197    case ComparisonResult::kGreaterThan:
1198      return isolate->heap()->true_value();
1199    case ComparisonResult::kEqual:
1200    case ComparisonResult::kLessThan:
1201      return isolate->heap()->false_value();
1202    case ComparisonResult::kUndefined:
1203      break;
1204  }
1205  UNREACHABLE();
1206  return Smi::FromInt(0);
1207}
1208
1209RUNTIME_FUNCTION(Runtime_StringGreaterThanOrEqual) {
1210  HandleScope handle_scope(isolate);
1211  DCHECK_EQ(2, args.length());
1212  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1213  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1214  switch (String::Compare(x, y)) {
1215    case ComparisonResult::kEqual:
1216    case ComparisonResult::kGreaterThan:
1217      return isolate->heap()->true_value();
1218    case ComparisonResult::kLessThan:
1219      return isolate->heap()->false_value();
1220    case ComparisonResult::kUndefined:
1221      break;
1222  }
1223  UNREACHABLE();
1224  return Smi::FromInt(0);
1225}
1226
1227RUNTIME_FUNCTION(Runtime_StringEqual) {
1228  HandleScope handle_scope(isolate);
1229  DCHECK_EQ(2, args.length());
1230  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1231  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1232  return isolate->heap()->ToBoolean(String::Equals(x, y));
1233}
1234
1235RUNTIME_FUNCTION(Runtime_StringNotEqual) {
1236  HandleScope handle_scope(isolate);
1237  DCHECK_EQ(2, args.length());
1238  CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
1239  CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
1240  return isolate->heap()->ToBoolean(!String::Equals(x, y));
1241}
1242
1243RUNTIME_FUNCTION(Runtime_FlattenString) {
1244  HandleScope scope(isolate);
1245  DCHECK(args.length() == 1);
1246  CONVERT_ARG_HANDLE_CHECKED(String, str, 0);
1247  return *String::Flatten(str);
1248}
1249
1250
1251RUNTIME_FUNCTION(Runtime_StringCharFromCode) {
1252  HandleScope handlescope(isolate);
1253  DCHECK_EQ(1, args.length());
1254  if (args[0]->IsNumber()) {
1255    CONVERT_NUMBER_CHECKED(uint32_t, code, Uint32, args[0]);
1256    code &= 0xffff;
1257    return *isolate->factory()->LookupSingleCharacterStringFromCode(code);
1258  }
1259  return isolate->heap()->empty_string();
1260}
1261
1262
1263RUNTIME_FUNCTION(Runtime_StringCharAt) {
1264  SealHandleScope shs(isolate);
1265  DCHECK(args.length() == 2);
1266  if (!args[0]->IsString()) return Smi::FromInt(0);
1267  if (!args[1]->IsNumber()) return Smi::FromInt(0);
1268  if (std::isinf(args.number_at(1))) return isolate->heap()->empty_string();
1269  Object* code = __RT_impl_Runtime_StringCharCodeAtRT(args, isolate);
1270  if (code->IsNaN()) return isolate->heap()->empty_string();
1271  return __RT_impl_Runtime_StringCharFromCode(Arguments(1, &code), isolate);
1272}
1273
1274RUNTIME_FUNCTION(Runtime_ExternalStringGetChar) {
1275  SealHandleScope shs(isolate);
1276  DCHECK_EQ(2, args.length());
1277  CONVERT_ARG_CHECKED(ExternalString, string, 0);
1278  CONVERT_INT32_ARG_CHECKED(index, 1);
1279  return Smi::FromInt(string->Get(index));
1280}
1281
1282RUNTIME_FUNCTION(Runtime_OneByteSeqStringGetChar) {
1283  SealHandleScope shs(isolate);
1284  DCHECK(args.length() == 2);
1285  CONVERT_ARG_CHECKED(SeqOneByteString, string, 0);
1286  CONVERT_INT32_ARG_CHECKED(index, 1);
1287  return Smi::FromInt(string->SeqOneByteStringGet(index));
1288}
1289
1290
1291RUNTIME_FUNCTION(Runtime_OneByteSeqStringSetChar) {
1292  SealHandleScope shs(isolate);
1293  DCHECK(args.length() == 3);
1294  CONVERT_INT32_ARG_CHECKED(index, 0);
1295  CONVERT_INT32_ARG_CHECKED(value, 1);
1296  CONVERT_ARG_CHECKED(SeqOneByteString, string, 2);
1297  string->SeqOneByteStringSet(index, value);
1298  return string;
1299}
1300
1301
1302RUNTIME_FUNCTION(Runtime_TwoByteSeqStringGetChar) {
1303  SealHandleScope shs(isolate);
1304  DCHECK(args.length() == 2);
1305  CONVERT_ARG_CHECKED(SeqTwoByteString, string, 0);
1306  CONVERT_INT32_ARG_CHECKED(index, 1);
1307  return Smi::FromInt(string->SeqTwoByteStringGet(index));
1308}
1309
1310
1311RUNTIME_FUNCTION(Runtime_TwoByteSeqStringSetChar) {
1312  SealHandleScope shs(isolate);
1313  DCHECK(args.length() == 3);
1314  CONVERT_INT32_ARG_CHECKED(index, 0);
1315  CONVERT_INT32_ARG_CHECKED(value, 1);
1316  CONVERT_ARG_CHECKED(SeqTwoByteString, string, 2);
1317  string->SeqTwoByteStringSet(index, value);
1318  return string;
1319}
1320
1321
1322RUNTIME_FUNCTION(Runtime_StringCharCodeAt) {
1323  SealHandleScope shs(isolate);
1324  DCHECK(args.length() == 2);
1325  if (!args[0]->IsString()) return isolate->heap()->undefined_value();
1326  if (!args[1]->IsNumber()) return isolate->heap()->undefined_value();
1327  if (std::isinf(args.number_at(1))) return isolate->heap()->nan_value();
1328  return __RT_impl_Runtime_StringCharCodeAtRT(args, isolate);
1329}
1330
1331}  // namespace internal
1332}  // namespace v8
1333