Specialized string equality based on representation

src/objects-inl.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 101 matching lines @@
     && HeapObject::cast(this)->map()->instance_type() < FIRST_NONSTRING_TYPE;
 }
 
 
 bool Object::IsSeqString() {
   return IsString()
     && (String::cast(this)->representation_tag() == kSeqStringTag);
 }
 
 
-bool Object::IsAsciiString() {
-  return IsString() && (String::cast(this)->is_ascii());
+bool Object::IsSeqAsciiString() {
+  return IsSeqString()
+      && String::cast(this)->IsAsciiRepresentation();
 }
 
 
-bool Object::IsTwoByteString() {
-  return IsString() && (!String::cast(this)->is_ascii());
+bool Object::IsSeqTwoByteString() {
+  return IsSeqString()
+      && !String::cast(this)->IsAsciiRepresentation();
 }
 
 
+bool Object::IsAsciiStringRepresentation() {
+  return IsString() && (String::cast(this)->is_ascii_representation());
+}
+
+
+bool Object::IsTwoByteStringRepresentation() {
+  return IsString() && (!String::cast(this)->is_ascii_representation());
+}
+
+
 bool Object::IsConsString() {
   return IsString()
     && (String::cast(this)->representation_tag() == kConsStringTag);
 }
 
 
 bool Object::IsSlicedString() {
   return IsString()
     && (String::cast(this)->representation_tag() == kSlicedStringTag);
 }
 
 
 bool Object::IsExternalString() {
   return IsString()
     && (String::cast(this)->representation_tag() == kExternalStringTag);
 }
 
 
 bool Object::IsExternalAsciiString() {
-  return IsExternalString() && (String::cast(this)->is_ascii());
+  return IsExternalString() && (String::cast(this)->is_ascii_representation());
 }
 
 
 bool Object::IsExternalTwoByteString() {
-  return IsExternalString() && (!String::cast(this)->is_ascii());
+  return IsExternalString() && (!String::cast(this)->is_ascii_representation());
 }
 
 
 bool Object::IsShortString() {
   return IsString() && (String::cast(this)->size_tag() == kShortStringTag);
 }
 
 
 bool Object::IsMediumString() {
   return IsString() && (String::cast(this)->size_tag() == kMediumStringTag);
@@ skipping 952 matching lines @@
 
 
 CAST_ACCESSOR(FixedArray)
 CAST_ACCESSOR(DescriptorArray)
 CAST_ACCESSOR(Dictionary)
 CAST_ACCESSOR(SymbolTable)
 CAST_ACCESSOR(CompilationCacheTable)
 CAST_ACCESSOR(MapCache)
 CAST_ACCESSOR(String)
 CAST_ACCESSOR(SeqString)
-CAST_ACCESSOR(AsciiString)
-CAST_ACCESSOR(TwoByteString)
+CAST_ACCESSOR(SeqAsciiString)
+CAST_ACCESSOR(SeqTwoByteString)
 CAST_ACCESSOR(ConsString)
 CAST_ACCESSOR(SlicedString)
 CAST_ACCESSOR(ExternalString)
 CAST_ACCESSOR(ExternalAsciiString)
 CAST_ACCESSOR(ExternalTwoByteString)
 CAST_ACCESSOR(JSObject)
 CAST_ACCESSOR(Smi)
 CAST_ACCESSOR(Failure)
 CAST_ACCESSOR(HeapObject)
 CAST_ACCESSOR(HeapNumber)
@@ skipping 86 matching lines @@
   if (str_type != kSeqStringTag && str_type != kExternalStringTag) {
     Flatten();
   }
 }
 
 
 uint16_t String::Get(int index) {
   ASSERT(index >= 0 && index < length());
   switch (representation_tag()) {
     case kSeqStringTag:
-      return is_ascii()
-        ? AsciiString::cast(this)->AsciiStringGet(index)
-        : TwoByteString::cast(this)->TwoByteStringGet(index);
+      return is_ascii_representation()
+        ? SeqAsciiString::cast(this)->AsciiStringGet(index)
+        : SeqTwoByteString::cast(this)->TwoByteStringGet(index);
     case kConsStringTag:
       return ConsString::cast(this)->ConsStringGet(index);
     case kSlicedStringTag:
       return SlicedString::cast(this)->SlicedStringGet(index);
     case kExternalStringTag:
-      return is_ascii()
+      return is_ascii_representation()
         ? ExternalAsciiString::cast(this)->ExternalAsciiStringGet(index)
         : ExternalTwoByteString::cast(this)->ExternalTwoByteStringGet(index);
     default:
       break;
   }
 
   UNREACHABLE();
   return 0;
 }
 
 
 void String::Set(int index, uint16_t value) {
   ASSERT(index >= 0 && index < length());
   ASSERT(IsSeqString());
 
-  return is_ascii()
-      ? AsciiString::cast(this)->AsciiStringSet(index, value)
-      : TwoByteString::cast(this)->TwoByteStringSet(index, value);
+  return is_ascii_representation()
+      ? SeqAsciiString::cast(this)->AsciiStringSet(index, value)
+      : SeqTwoByteString::cast(this)->TwoByteStringSet(index, value);
 }
 
 
-bool String::IsAscii() {
-  return is_ascii();
+bool String::IsAsciiRepresentation() {
+  return is_ascii_representation();
 }
 
 
 bool String::StringIsConsString() {
   return representation_tag() == kConsStringTag;
 }
 
 
 bool String::StringIsSlicedString() {
   return representation_tag() == kSlicedStringTag;
@@ skipping 13 matching lines @@
 bool String::is_symbol() {
   return is_symbol_map(map());
 }
 
 
 bool String::is_symbol_map(Map* map) {
   return (map->instance_type() & kIsSymbolMask) != 0;
 }
 
 
-bool String::is_ascii() {
-  return is_ascii_map(map());
+bool String::is_ascii_representation() {
+  return is_ascii_representation_map(map());
 }
 
 
-bool String::is_ascii_map(Map* map) {
+bool String::is_ascii_representation_map(Map* map) {
   return (map->instance_type() & kStringEncodingMask) != 0;
 }
 
 
 StringRepresentationTag String::representation_tag() {
   return map_representation_tag(map());
 }
 
 
 StringRepresentationTag String::map_representation_tag(Map* map) {
@@ skipping 11 matching lines @@
       String* slice = String::cast(SlicedString::cast(this)->buffer());
       StringRepresentationTag tag = slice->representation_tag();
       return tag == kSeqStringTag || tag == kExternalStringTag;
     }
     default:
       return true;
   }
 }
 
 
-uint16_t AsciiString::AsciiStringGet(int index) {
+uint16_t SeqAsciiString::AsciiStringGet(int index) {
   ASSERT(index >= 0 && index < length());
   return READ_BYTE_FIELD(this, kHeaderSize + index * kCharSize);
 }
 
 
-void AsciiString::AsciiStringSet(int index, uint16_t value) {
+void SeqAsciiString::AsciiStringSet(int index, uint16_t value) {
   ASSERT(index >= 0 && index < length() && value <= kMaxAsciiCharCode);
   WRITE_BYTE_FIELD(this, kHeaderSize + index * kCharSize,
                    static_cast<byte>(value));
 }
 
 
-Address AsciiString::GetCharsAddress() {
+Address SeqAsciiString::GetCharsAddress() {
   return FIELD_ADDR(this, kHeaderSize);
 }
 
 
-Address TwoByteString::GetCharsAddress() {
+Address SeqTwoByteString::GetCharsAddress() {
   return FIELD_ADDR(this, kHeaderSize);
 }
 
 
-uint16_t TwoByteString::TwoByteStringGet(int index) {
+uint16_t SeqTwoByteString::TwoByteStringGet(int index) {
   ASSERT(index >= 0 && index < length());
   return READ_SHORT_FIELD(this, kHeaderSize + index * kShortSize);
 }
 
 
-void TwoByteString::TwoByteStringSet(int index, uint16_t value) {
+void SeqTwoByteString::TwoByteStringSet(int index, uint16_t value) {
   ASSERT(index >= 0 && index < length());
   WRITE_SHORT_FIELD(this, kHeaderSize + index * kShortSize, value);
 }
 
 
-int TwoByteString::TwoByteStringSize(Map* map) {
+int SeqTwoByteString::TwoByteStringSize(Map* map) {
   uint32_t length = READ_INT_FIELD(this, kLengthOffset);
 
   // Use the map (and not 'this') to compute the size tag, since
   // TwoByteStringSize is called during GC when maps are encoded.
   switch (map_size_tag(map)) {
     case kShortStringTag:
       length = length >> kShortLengthShift;
       break;
     case kMediumStringTag:
       length = length >> kMediumLengthShift;
       break;
     case kLongStringTag:
       length = length >> kLongLengthShift;
       break;
     default:
       break;
   }
   return SizeFor(length);
 }
 
 
-int AsciiString::AsciiStringSize(Map* map) {
+int SeqAsciiString::AsciiStringSize(Map* map) {
   uint32_t length = READ_INT_FIELD(this, kLengthOffset);
 
   // Use the map (and not 'this') to compute the size tag, since
   // AsciiStringSize is called during GC when maps are encoded.
   switch (map_size_tag(map)) {
     case kShortStringTag:
       length = length >> kShortLengthShift;
       break;
     case kMediumStringTag:
       length = length >> kMediumLengthShift;
@@ skipping 831 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_