src/mirror/string.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "string.h"

 #include "array.h"
 #include "gc/card_table-inl.h"
 #include "intern_table.h"
 #include "object-inl.h"
 #include "runtime.h"
 #include "sirt_ref.h"
 #include "thread.h"
 #include "utf.h"

 namespace art {
 namespace mirror {

 const CharArray* String::GetCharArray() const {
   return GetFieldObject<const CharArray*>(ValueOffset(), false);
 }

 void String::ComputeHashCode() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   SetHashCode(ComputeUtf16Hash(GetCharArray(), GetOffset(), GetLength()));
 }

 int32_t String::GetUtfLength() const {
   return CountUtf8Bytes(GetCharArray()->GetData() + GetOffset(), GetLength());
 }

 int32_t String::FastIndexOf(int32_t ch, int32_t start) const {
   int32_t count = GetLength();
   if (start < 0) {
     start = 0;
   } else if (start > count) {
     start = count;
   }
   const uint16_t* chars = GetCharArray()->GetData() + GetOffset();
   const uint16_t* p = chars + start;
   const uint16_t* end = chars + count;
   while (p < end) {
     if (*p++ == ch) {
       return (p - 1) - chars;
     }
   }
   return -1;
 }

 void String::SetArray(CharArray* new_array) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   DCHECK(new_array != NULL);
   SetFieldObject(OFFSET_OF_OBJECT_MEMBER(String, array_), new_array, false);
 }

 // TODO: get global references for these
 Class* String::java_lang_String_ = NULL;

 void String::SetClass(Class* java_lang_String) {
   CHECK(java_lang_String_ == NULL);
   CHECK(java_lang_String != NULL);
   java_lang_String_ = java_lang_String;
 }

 void String::ResetClass() {
   CHECK(java_lang_String_ != NULL);
   java_lang_String_ = NULL;
 }

 String* String::Intern() {
   return Runtime::Current()->GetInternTable()->InternWeak(this);
 }

 int32_t String::GetHashCode() {
   int32_t result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), false);
   if (result == 0) {
     ComputeHashCode();
   }
   result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), false);
   DCHECK(result != 0 || ComputeUtf16Hash(GetCharArray(), GetOffset(), GetLength()) == 0)
           << ToModifiedUtf8() << " " << result;
   return result;
 }

 int32_t String::GetLength() const {
   int32_t result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, count_), false);
   DCHECK(result >= 0 && result <= GetCharArray()->GetLength());
   return result;
 }

 uint16_t String::CharAt(int32_t index) const {
   // TODO: do we need this? Equals is the only caller, and could
   // bounds check itself.
   if (index < 0 || index >= count_) {
     Thread* self = Thread::Current();
     self->ThrowNewExceptionF("Ljava/lang/StringIndexOutOfBoundsException;",
         "length=%i; index=%i", count_, index);
     return 0;
   }
   return GetCharArray()->Get(index + GetOffset());
 }

 String* String::AllocFromUtf16(Thread* self,
                                int32_t utf16_length,
                                const uint16_t* utf16_data_in,
                                int32_t hash_code) {
   CHECK(utf16_data_in != NULL || utf16_length == 0);
   String* string = Alloc(self, GetJavaLangString(), utf16_length);
   if (string == NULL) {
     return NULL;
   }
   // TODO: use 16-bit wide memset variant
   CharArray* array = const_cast<CharArray*>(string->GetCharArray());
   if (array == NULL) {
     return NULL;
   }
   for (int i = 0; i < utf16_length; i++) {
     array->Set(i, utf16_data_in[i]);
   }
   if (hash_code != 0) {
     string->SetHashCode(hash_code);
   } else {
     string->ComputeHashCode();
   }
   return string;
 }

   String* String::AllocFromModifiedUtf8(Thread* self, const char* utf) {
   if (utf == NULL) {
     return NULL;
   }
   size_t char_count = CountModifiedUtf8Chars(utf);
   return AllocFromModifiedUtf8(self, char_count, utf);
 }

 String* String::AllocFromModifiedUtf8(Thread* self, int32_t utf16_length,
                                       const char* utf8_data_in) {
   String* string = Alloc(self, GetJavaLangString(), utf16_length);
   if (string == NULL) {
     return NULL;
   }
   uint16_t* utf16_data_out =
       const_cast<uint16_t*>(string->GetCharArray()->GetData());
   ConvertModifiedUtf8ToUtf16(utf16_data_out, utf8_data_in);
   string->ComputeHashCode();
   return string;
 }

 String* String::Alloc(Thread* self, Class* java_lang_String, int32_t utf16_length) {
   SirtRef<CharArray> array(self, CharArray::Alloc(self, utf16_length));
   if (array.get() == NULL) {
     return NULL;
   }
   return Alloc(self, java_lang_String, array.get());
 }

 String* String::Alloc(Thread* self, Class* java_lang_String, CharArray* array) {
   // Hold reference in case AllocObject causes GC.
   SirtRef<CharArray> array_ref(self, array);
   String* string = down_cast<String*>(java_lang_String->AllocObject(self));
   if (string == NULL) {
     return NULL;
   }
   string->SetArray(array);
   string->SetCount(array->GetLength());
   return string;
 }

 bool String::Equals(const String* that) const {
   if (this == that) {
     // Quick reference equality test
     return true;
   } else if (that == NULL) {
     // Null isn't an instanceof anything
     return false;
   } else if (this->GetLength() != that->GetLength()) {
     // Quick length inequality test
     return false;
   } else {
     // Note: don't short circuit on hash code as we're presumably here as the
     // hash code was already equal
     for (int32_t i = 0; i < that->GetLength(); ++i) {
       if (this->CharAt(i) != that->CharAt(i)) {
         return false;
       }
     }
     return true;
   }
 }

 bool String::Equals(const uint16_t* that_chars, int32_t that_offset, int32_t that_length) const {
   if (this->GetLength() != that_length) {
     return false;
   } else {
     for (int32_t i = 0; i < that_length; ++i) {
       if (this->CharAt(i) != that_chars[that_offset + i]) {
         return false;
       }
     }
     return true;
   }
 }

 bool String::Equals(const char* modified_utf8) const {
   for (int32_t i = 0; i < GetLength(); ++i) {
     uint16_t ch = GetUtf16FromUtf8(&modified_utf8);
     if (ch == '\0' || ch != CharAt(i)) {
       return false;
     }
   }
   return *modified_utf8 == '\0';
 }

 bool String::Equals(const StringPiece& modified_utf8) const {
   if (modified_utf8.size() != GetLength()) {
     return false;
   }
   const char* p = modified_utf8.data();
   for (int32_t i = 0; i < GetLength(); ++i) {
     uint16_t ch = GetUtf16FromUtf8(&p);
     if (ch != CharAt(i)) {
       return false;
     }
   }
   return true;
 }

 // Create a modified UTF-8 encoded std::string from a java/lang/String object.
 std::string String::ToModifiedUtf8() const {
   const uint16_t* chars = GetCharArray()->GetData() + GetOffset();
   size_t byte_count = GetUtfLength();
   std::string result(byte_count, static_cast<char>(0));
   ConvertUtf16ToModifiedUtf8(&result[0], chars, GetLength());
   return result;
 }

 #ifdef HAVE__MEMCMP16
 // "count" is in 16-bit units.
 extern "C" uint32_t __memcmp16(const uint16_t* s0, const uint16_t* s1, size_t count);
 #define MemCmp16 __memcmp16
 #else
 static uint32_t MemCmp16(const uint16_t* s0, const uint16_t* s1, size_t count) {
   for (size_t i = 0; i < count; i++) {
     if (s0[i] != s1[i]) {
       return static_cast<int32_t>(s0[i]) - static_cast<int32_t>(s1[i]);
     }
   }
   return 0;
 }
 #endif

 int32_t String::CompareTo(String* rhs) const {
   // Quick test for comparison of a string with itself.
   const String* lhs = this;
   if (lhs == rhs) {
     return 0;
   }
   // TODO: is this still true?
   // The annoying part here is that 0x00e9 - 0xffff != 0x00ea,
   // because the interpreter converts the characters to 32-bit integers
   // *without* sign extension before it subtracts them (which makes some
   // sense since "char" is unsigned).  So what we get is the result of
   // 0x000000e9 - 0x0000ffff, which is 0xffff00ea.
   int lhsCount = lhs->GetLength();
   int rhsCount = rhs->GetLength();
   int countDiff = lhsCount - rhsCount;
   int minCount = (countDiff < 0) ? lhsCount : rhsCount;
   const uint16_t* lhsChars = lhs->GetCharArray()->GetData() + lhs->GetOffset();
   const uint16_t* rhsChars = rhs->GetCharArray()->GetData() + rhs->GetOffset();
   int otherRes = MemCmp16(lhsChars, rhsChars, minCount);
   if (otherRes != 0) {
     return otherRes;
   }
   return countDiff;
 }

 }  // namespace mirror
 }  // namespace art
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "string.h"

	#include "array.h"
	#include "gc/card_table-inl.h"
	#include "intern_table.h"
	#include "object-inl.h"
	#include "runtime.h"
	#include "sirt_ref.h"
	#include "thread.h"
	#include "utf.h"

	namespace art {
	namespace mirror {

	const CharArray* String::GetCharArray() const {
	return GetFieldObject<const CharArray*>(ValueOffset(), false);
	}

	void String::ComputeHashCode() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	SetHashCode(ComputeUtf16Hash(GetCharArray(), GetOffset(), GetLength()));
	}

	int32_t String::GetUtfLength() const {
	return CountUtf8Bytes(GetCharArray()->GetData() + GetOffset(), GetLength());
	}

	int32_t String::FastIndexOf(int32_t ch, int32_t start) const {
	int32_t count = GetLength();
	if (start < 0) {
	start = 0;
	} else if (start > count) {
	start = count;
	}
	const uint16_t* chars = GetCharArray()->GetData() + GetOffset();
	const uint16_t* p = chars + start;
	const uint16_t* end = chars + count;
	while (p < end) {
	if (*p++ == ch) {
	return (p - 1) - chars;
	}
	}
	return -1;
	}

	void String::SetArray(CharArray* new_array) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	DCHECK(new_array != NULL);
	SetFieldObject(OFFSET_OF_OBJECT_MEMBER(String, array_), new_array, false);
	}

	// TODO: get global references for these
	Class* String::java_lang_String_ = NULL;

	void String::SetClass(Class* java_lang_String) {
	CHECK(java_lang_String_ == NULL);
	CHECK(java_lang_String != NULL);
	java_lang_String_ = java_lang_String;
	}

	void String::ResetClass() {
	CHECK(java_lang_String_ != NULL);
	java_lang_String_ = NULL;
	}

	String* String::Intern() {
	return Runtime::Current()->GetInternTable()->InternWeak(this);
	}

	int32_t String::GetHashCode() {
	int32_t result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), false);
	if (result == 0) {
	ComputeHashCode();
	}
	result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), false);
	DCHECK(result != 0 \|\| ComputeUtf16Hash(GetCharArray(), GetOffset(), GetLength()) == 0)
	<< ToModifiedUtf8() << " " << result;
	return result;
	}

	int32_t String::GetLength() const {
	int32_t result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, count_), false);
	DCHECK(result >= 0 && result <= GetCharArray()->GetLength());
	return result;
	}

	uint16_t String::CharAt(int32_t index) const {
	// TODO: do we need this? Equals is the only caller, and could
	// bounds check itself.
	if (index < 0 \|\| index >= count_) {
	Thread* self = Thread::Current();
	self->ThrowNewExceptionF("Ljava/lang/StringIndexOutOfBoundsException;",
	"length=%i; index=%i", count_, index);
	return 0;
	}
	return GetCharArray()->Get(index + GetOffset());
	}

	String* String::AllocFromUtf16(Thread* self,
	int32_t utf16_length,
	const uint16_t* utf16_data_in,
	int32_t hash_code) {
	CHECK(utf16_data_in != NULL \|\| utf16_length == 0);
	String* string = Alloc(self, GetJavaLangString(), utf16_length);
	if (string == NULL) {
	return NULL;
	}
	// TODO: use 16-bit wide memset variant
	CharArray* array = const_cast<CharArray*>(string->GetCharArray());
	if (array == NULL) {
	return NULL;
	}
	for (int i = 0; i < utf16_length; i++) {
	array->Set(i, utf16_data_in[i]);
	}
	if (hash_code != 0) {
	string->SetHashCode(hash_code);
	} else {
	string->ComputeHashCode();
	}
	return string;
	}

	String* String::AllocFromModifiedUtf8(Thread* self, const char* utf) {
	if (utf == NULL) {
	return NULL;
	}
	size_t char_count = CountModifiedUtf8Chars(utf);
	return AllocFromModifiedUtf8(self, char_count, utf);
	}

	String* String::AllocFromModifiedUtf8(Thread* self, int32_t utf16_length,
	const char* utf8_data_in) {
	String* string = Alloc(self, GetJavaLangString(), utf16_length);
	if (string == NULL) {
	return NULL;
	}
	uint16_t* utf16_data_out =
	const_cast<uint16_t*>(string->GetCharArray()->GetData());
	ConvertModifiedUtf8ToUtf16(utf16_data_out, utf8_data_in);
	string->ComputeHashCode();
	return string;
	}

	String* String::Alloc(Thread* self, Class* java_lang_String, int32_t utf16_length) {
	SirtRef<CharArray> array(self, CharArray::Alloc(self, utf16_length));
	if (array.get() == NULL) {
	return NULL;
	}
	return Alloc(self, java_lang_String, array.get());
	}

	String* String::Alloc(Thread* self, Class* java_lang_String, CharArray* array) {
	// Hold reference in case AllocObject causes GC.
	SirtRef<CharArray> array_ref(self, array);
	String* string = down_cast<String*>(java_lang_String->AllocObject(self));
	if (string == NULL) {
	return NULL;
	}
	string->SetArray(array);
	string->SetCount(array->GetLength());
	return string;
	}

	bool String::Equals(const String* that) const {
	if (this == that) {
	// Quick reference equality test
	return true;
	} else if (that == NULL) {
	// Null isn't an instanceof anything
	return false;
	} else if (this->GetLength() != that->GetLength()) {
	// Quick length inequality test
	return false;
	} else {
	// Note: don't short circuit on hash code as we're presumably here as the
	// hash code was already equal
	for (int32_t i = 0; i < that->GetLength(); ++i) {
	if (this->CharAt(i) != that->CharAt(i)) {
	return false;
	}
	}
	return true;
	}
	}

	bool String::Equals(const uint16_t* that_chars, int32_t that_offset, int32_t that_length) const {
	if (this->GetLength() != that_length) {
	return false;
	} else {
	for (int32_t i = 0; i < that_length; ++i) {
	if (this->CharAt(i) != that_chars[that_offset + i]) {
	return false;
	}
	}
	return true;
	}
	}

	bool String::Equals(const char* modified_utf8) const {
	for (int32_t i = 0; i < GetLength(); ++i) {
	uint16_t ch = GetUtf16FromUtf8(&modified_utf8);
	if (ch == '\0' \|\| ch != CharAt(i)) {
	return false;
	}
	}
	return *modified_utf8 == '\0';
	}

	bool String::Equals(const StringPiece& modified_utf8) const {
	if (modified_utf8.size() != GetLength()) {
	return false;
	}
	const char* p = modified_utf8.data();
	for (int32_t i = 0; i < GetLength(); ++i) {
	uint16_t ch = GetUtf16FromUtf8(&p);
	if (ch != CharAt(i)) {
	return false;
	}
	}
	return true;
	}

	// Create a modified UTF-8 encoded std::string from a java/lang/String object.
	std::string String::ToModifiedUtf8() const {
	const uint16_t* chars = GetCharArray()->GetData() + GetOffset();
	size_t byte_count = GetUtfLength();
	std::string result(byte_count, static_cast<char>(0));
	ConvertUtf16ToModifiedUtf8(&result[0], chars, GetLength());
	return result;
	}

	#ifdef HAVE__MEMCMP16
	// "count" is in 16-bit units.
	extern "C" uint32_t __memcmp16(const uint16_t* s0, const uint16_t* s1, size_t count);
	#define MemCmp16 __memcmp16
	#else
	static uint32_t MemCmp16(const uint16_t* s0, const uint16_t* s1, size_t count) {
	for (size_t i = 0; i < count; i++) {
	if (s0[i] != s1[i]) {
	return static_cast<int32_t>(s0[i]) - static_cast<int32_t>(s1[i]);
	}
	}
	return 0;
	}
	#endif

	int32_t String::CompareTo(String* rhs) const {
	// Quick test for comparison of a string with itself.
	const String* lhs = this;
	if (lhs == rhs) {
	return 0;
	}
	// TODO: is this still true?
	// The annoying part here is that 0x00e9 - 0xffff != 0x00ea,
	// because the interpreter converts the characters to 32-bit integers
	// without sign extension before it subtracts them (which makes some
	// sense since "char" is unsigned). So what we get is the result of
	// 0x000000e9 - 0x0000ffff, which is 0xffff00ea.
	int lhsCount = lhs->GetLength();
	int rhsCount = rhs->GetLength();
	int countDiff = lhsCount - rhsCount;
	int minCount = (countDiff < 0) ? lhsCount : rhsCount;
	const uint16_t* lhsChars = lhs->GetCharArray()->GetData() + lhs->GetOffset();
	const uint16_t* rhsChars = rhs->GetCharArray()->GetData() + rhs->GetOffset();
	int otherRes = MemCmp16(lhsChars, rhsChars, minCount);
	if (otherRes != 0) {
	return otherRes;
	}
	return countDiff;
	}

	} // namespace mirror
	} // namespace art