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| 1 // Copyright 2014 the V8 project authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #include "src/runtime/runtime-utils.h" | 5 #include "src/runtime/runtime-utils.h" |
| 6 | 6 |
| 7 #include "src/arguments.h" | 7 #include "src/arguments.h" |
| 8 #include "src/regexp/jsregexp-inl.h" | 8 #include "src/regexp/jsregexp-inl.h" |
| 9 #include "src/string-builder.h" | 9 #include "src/string-builder.h" |
| 10 #include "src/string-search.h" | 10 #include "src/string-search.h" |
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| 672 return result; | 672 return result; |
| 673 } else { | 673 } else { |
| 674 // If we didn't actually change anything in doing the conversion | 674 // If we didn't actually change anything in doing the conversion |
| 675 // we simple return the result and let the converted string | 675 // we simple return the result and let the converted string |
| 676 // become garbage; there is no reason to keep two identical strings | 676 // become garbage; there is no reason to keep two identical strings |
| 677 // alive. | 677 // alive. |
| 678 return string; | 678 return string; |
| 679 } | 679 } |
| 680 } | 680 } |
| 681 | 681 |
| 682 | |
| 683 static const uintptr_t kOneInEveryByte = kUintptrAllBitsSet / 0xFF; | |
| 684 static const uintptr_t kAsciiMask = kOneInEveryByte << 7; | |
| 685 | |
| 686 // Given a word and two range boundaries returns a word with high bit | |
| 687 // set in every byte iff the corresponding input byte was strictly in | |
| 688 // the range (m, n). All the other bits in the result are cleared. | |
| 689 // This function is only useful when it can be inlined and the | |
| 690 // boundaries are statically known. | |
| 691 // Requires: all bytes in the input word and the boundaries must be | |
| 692 // ASCII (less than 0x7F). | |
| 693 static inline uintptr_t AsciiRangeMask(uintptr_t w, char m, char n) { | |
| 694 // Use strict inequalities since in edge cases the function could be | |
| 695 // further simplified. | |
| 696 DCHECK(0 < m && m < n); | |
| 697 // Has high bit set in every w byte less than n. | |
| 698 uintptr_t tmp1 = kOneInEveryByte * (0x7F + n) - w; | |
| 699 // Has high bit set in every w byte greater than m. | |
| 700 uintptr_t tmp2 = w + kOneInEveryByte * (0x7F - m); | |
| 701 return (tmp1 & tmp2 & (kOneInEveryByte * 0x80)); | |
| 702 } | |
| 703 | |
| 704 | |
| 705 #ifdef DEBUG | |
| 706 static bool CheckFastAsciiConvert(char* dst, const char* src, int length, | |
| 707 bool changed, bool is_to_lower) { | |
| 708 bool expected_changed = false; | |
| 709 for (int i = 0; i < length; i++) { | |
| 710 if (dst[i] == src[i]) continue; | |
| 711 expected_changed = true; | |
| 712 if (is_to_lower) { | |
| 713 DCHECK('A' <= src[i] && src[i] <= 'Z'); | |
| 714 DCHECK(dst[i] == src[i] + ('a' - 'A')); | |
| 715 } else { | |
| 716 DCHECK('a' <= src[i] && src[i] <= 'z'); | |
| 717 DCHECK(dst[i] == src[i] - ('a' - 'A')); | |
| 718 } | |
| 719 } | |
| 720 return (expected_changed == changed); | |
| 721 } | |
| 722 #endif | |
| 723 | |
| 724 | |
| 725 template <class Converter> | |
| 726 static bool FastAsciiConvert(char* dst, const char* src, int length, | |
| 727 bool* changed_out) { | |
| 728 #ifdef DEBUG | |
| 729 char* saved_dst = dst; | |
| 730 const char* saved_src = src; | |
| 731 #endif | |
| 732 DisallowHeapAllocation no_gc; | |
| 733 // We rely on the distance between upper and lower case letters | |
| 734 // being a known power of 2. | |
| 735 DCHECK('a' - 'A' == (1 << 5)); | |
| 736 // Boundaries for the range of input characters than require conversion. | |
| 737 static const char lo = Converter::kIsToLower ? 'A' - 1 : 'a' - 1; | |
| 738 static const char hi = Converter::kIsToLower ? 'Z' + 1 : 'z' + 1; | |
| 739 bool changed = false; | |
| 740 uintptr_t or_acc = 0; | |
| 741 const char* const limit = src + length; | |
| 742 | |
| 743 // dst is newly allocated and always aligned. | |
| 744 DCHECK(IsAligned(reinterpret_cast<intptr_t>(dst), sizeof(uintptr_t))); | |
| 745 // Only attempt processing one word at a time if src is also aligned. | |
| 746 if (IsAligned(reinterpret_cast<intptr_t>(src), sizeof(uintptr_t))) { | |
| 747 // Process the prefix of the input that requires no conversion one aligned | |
| 748 // (machine) word at a time. | |
| 749 while (src <= limit - sizeof(uintptr_t)) { | |
| 750 const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src); | |
| 751 or_acc |= w; | |
| 752 if (AsciiRangeMask(w, lo, hi) != 0) { | |
| 753 changed = true; | |
| 754 break; | |
| 755 } | |
| 756 *reinterpret_cast<uintptr_t*>(dst) = w; | |
| 757 src += sizeof(uintptr_t); | |
| 758 dst += sizeof(uintptr_t); | |
| 759 } | |
| 760 // Process the remainder of the input performing conversion when | |
| 761 // required one word at a time. | |
| 762 while (src <= limit - sizeof(uintptr_t)) { | |
| 763 const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src); | |
| 764 or_acc |= w; | |
| 765 uintptr_t m = AsciiRangeMask(w, lo, hi); | |
| 766 // The mask has high (7th) bit set in every byte that needs | |
| 767 // conversion and we know that the distance between cases is | |
| 768 // 1 << 5. | |
| 769 *reinterpret_cast<uintptr_t*>(dst) = w ^ (m >> 2); | |
| 770 src += sizeof(uintptr_t); | |
| 771 dst += sizeof(uintptr_t); | |
| 772 } | |
| 773 } | |
| 774 // Process the last few bytes of the input (or the whole input if | |
| 775 // unaligned access is not supported). | |
| 776 while (src < limit) { | |
| 777 char c = *src; | |
| 778 or_acc |= c; | |
| 779 if (lo < c && c < hi) { | |
| 780 c ^= (1 << 5); | |
| 781 changed = true; | |
| 782 } | |
| 783 *dst = c; | |
| 784 ++src; | |
| 785 ++dst; | |
| 786 } | |
| 787 | |
| 788 if ((or_acc & kAsciiMask) != 0) return false; | |
| 789 | |
| 790 DCHECK(CheckFastAsciiConvert(saved_dst, saved_src, length, changed, | |
| 791 Converter::kIsToLower)); | |
| 792 | |
| 793 *changed_out = changed; | |
| 794 return true; | |
| 795 } | |
| 796 | |
| 797 | |
| 798 template <class Converter> | 682 template <class Converter> |
| 799 MUST_USE_RESULT static Object* ConvertCase( | 683 MUST_USE_RESULT static Object* ConvertCase( |
| 800 Handle<String> s, Isolate* isolate, | 684 Handle<String> s, Isolate* isolate, |
| 801 unibrow::Mapping<Converter, 128>* mapping) { | 685 unibrow::Mapping<Converter, 128>* mapping) { |
| 802 s = String::Flatten(s); | 686 s = String::Flatten(s); |
| 803 int length = s->length(); | 687 int length = s->length(); |
| 804 // Assume that the string is not empty; we need this assumption later | 688 // Assume that the string is not empty; we need this assumption later |
| 805 if (length == 0) return *s; | 689 if (length == 0) return *s; |
| 806 | 690 |
| 807 // Simpler handling of ASCII strings. | 691 // Simpler handling of ASCII strings. |
| 808 // | 692 // |
| 809 // NOTE: This assumes that the upper/lower case of an ASCII | 693 // NOTE: This assumes that the upper/lower case of an ASCII |
| 810 // character is also ASCII. This is currently the case, but it | 694 // character is also ASCII. This is currently the case, but it |
| 811 // might break in the future if we implement more context and locale | 695 // might break in the future if we implement more context and locale |
| 812 // dependent upper/lower conversions. | 696 // dependent upper/lower conversions. |
| 813 if (s->IsOneByteRepresentationUnderneath()) { | 697 if (s->IsOneByteRepresentationUnderneath()) { |
| 814 // Same length as input. | 698 // Same length as input. |
| 815 Handle<SeqOneByteString> result = | 699 Handle<SeqOneByteString> result = |
| 816 isolate->factory()->NewRawOneByteString(length).ToHandleChecked(); | 700 isolate->factory()->NewRawOneByteString(length).ToHandleChecked(); |
| 817 DisallowHeapAllocation no_gc; | 701 DisallowHeapAllocation no_gc; |
| 818 String::FlatContent flat_content = s->GetFlatContent(); | 702 String::FlatContent flat_content = s->GetFlatContent(); |
| 819 DCHECK(flat_content.IsFlat()); | 703 DCHECK(flat_content.IsFlat()); |
| 820 bool has_changed_character = false; | 704 bool has_changed_character = false; |
| 821 bool is_ascii = FastAsciiConvert<Converter>( | 705 bool is_ascii = FastAsciiConvert<Converter::kIsToLower>( |
| 822 reinterpret_cast<char*>(result->GetChars()), | 706 reinterpret_cast<char*>(result->GetChars()), |
| 823 reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()), | 707 reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()), |
| 824 length, &has_changed_character); | 708 length, &has_changed_character); |
| 825 // If not ASCII, we discard the result and take the 2 byte path. | 709 // If not ASCII, we discard the result and take the 2 byte path. |
| 826 if (is_ascii) return has_changed_character ? *result : *s; | 710 if (is_ascii) return has_changed_character ? *result : *s; |
| 827 } | 711 } |
| 828 | 712 |
| 829 Handle<SeqString> result; // Same length as input. | 713 Handle<SeqString> result; // Same length as input. |
| 830 if (s->IsOneByteRepresentation()) { | 714 if (s->IsOneByteRepresentation()) { |
| 831 result = isolate->factory()->NewRawOneByteString(length).ToHandleChecked(); | 715 result = isolate->factory()->NewRawOneByteString(length).ToHandleChecked(); |
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| 984 SealHandleScope shs(isolate); | 868 SealHandleScope shs(isolate); |
| 985 DCHECK(args.length() == 2); | 869 DCHECK(args.length() == 2); |
| 986 if (!args[0]->IsString()) return isolate->heap()->undefined_value(); | 870 if (!args[0]->IsString()) return isolate->heap()->undefined_value(); |
| 987 if (!args[1]->IsNumber()) return isolate->heap()->undefined_value(); | 871 if (!args[1]->IsNumber()) return isolate->heap()->undefined_value(); |
| 988 if (std::isinf(args.number_at(1))) return isolate->heap()->nan_value(); | 872 if (std::isinf(args.number_at(1))) return isolate->heap()->nan_value(); |
| 989 return __RT_impl_Runtime_StringCharCodeAtRT(args, isolate); | 873 return __RT_impl_Runtime_StringCharCodeAtRT(args, isolate); |
| 990 } | 874 } |
| 991 | 875 |
| 992 } // namespace internal | 876 } // namespace internal |
| 993 } // namespace v8 | 877 } // namespace v8 |
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