runtime/native/libcore_util_CharsetUtils.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2010 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 "jni_internal.h"
 #include "mirror/string.h"
 #include "mirror/string-inl.h"
 #include "native/libcore_util_CharsetUtils.h"
 #include "scoped_fast_native_object_access.h"
 #include "ScopedPrimitiveArray.h"
 #include "unicode/utf16.h"

 #include <string.h>

 namespace art {

 /**
  * Approximates java.lang.UnsafeByteSequence so we don't have to pay the cost of calling back into
  * Java when converting a char[] to a UTF-8 byte[]. This lets us have UTF-8 conversions slightly
  * faster than ICU for large char[]s without paying for the NIO overhead with small char[]s.
  *
  * We could avoid this by keeping the UTF-8 bytes on the native heap until we're done and only
  * creating a byte[] on the Java heap when we know how big it needs to be, but one shouldn't lie
  * to the garbage collector (nor hide potentially large allocations from it).
  *
  * Because a call to append might require an allocation, it might fail. Callers should always
  * check the return value of append.
  */
 class NativeUnsafeByteSequence {
  public:
   explicit NativeUnsafeByteSequence(JNIEnv* env)
     : mEnv(env), mJavaArray(nullptr), mRawArray(nullptr), mSize(-1), mOffset(0) {
   }

   ~NativeUnsafeByteSequence() {
     // Release our pointer to the raw array, copying changes back to the Java heap.
     if (mRawArray != nullptr) {
       mEnv->ReleaseByteArrayElements(mJavaArray, mRawArray, 0);
     }
   }

   bool append(jbyte b) {
     if (mOffset == mSize && !resize(mSize * 2)) {
       return false;
     }
     mRawArray[mOffset++] = b;
     return true;
   }

   bool resize(int newSize) {
     if (newSize == mSize) {
       return true;
     }

     // Allocate a new array.
     jbyteArray newJavaArray = mEnv->NewByteArray(newSize);
     if (newJavaArray == nullptr) {
       return false;
     }
     jbyte* newRawArray = mEnv->GetByteArrayElements(newJavaArray, nullptr);
     if (newRawArray == nullptr) {
       return false;
     }

     // Copy data out of the old array and then let go of it.
     // Note that we may be trimming the array.
     if (mRawArray != nullptr) {
       memcpy(newRawArray, mRawArray, mOffset);
       mEnv->ReleaseByteArrayElements(mJavaArray, mRawArray, JNI_ABORT);
       mEnv->DeleteLocalRef(mJavaArray);
     }

     // Point ourselves at the new array.
     mJavaArray = newJavaArray;
     mRawArray = newRawArray;
     mSize = newSize;
     return true;
   }

   jbyteArray toByteArray() {
     // Trim any unused space, if necessary.
     bool okay = resize(mOffset);
     return okay ? mJavaArray : nullptr;
   }

  private:
   JNIEnv* mEnv;
   jbyteArray mJavaArray;
   jbyte* mRawArray;
   jint mSize;
   jint mOffset;

   // Disallow copy and assignment.
   NativeUnsafeByteSequence(const NativeUnsafeByteSequence&);
   void operator=(const NativeUnsafeByteSequence&);
 };

 static void CharsetUtils_asciiBytesToChars(JNIEnv* env, jclass, jbyteArray javaBytes, jint offset,
                                            jint length, jcharArray javaChars) {
   ScopedByteArrayRO bytes(env, javaBytes);
   if (bytes.get() == nullptr) {
     return;
   }
   ScopedCharArrayRW chars(env, javaChars);
   if (chars.get() == nullptr) {
     return;
   }

   const jbyte* src = &bytes[offset];
   jchar* dst = &chars[0];
   static const jchar REPLACEMENT_CHAR = 0xfffd;
   for (int i = length - 1; i >= 0; --i) {
     jchar ch = static_cast<jchar>(*src++ & 0xff);
     *dst++ = (ch <= 0x7f) ? ch : REPLACEMENT_CHAR;
   }
 }

 static void CharsetUtils_isoLatin1BytesToChars(JNIEnv* env, jclass, jbyteArray javaBytes,
                                                jint offset, jint length, jcharArray javaChars) {
   ScopedByteArrayRO bytes(env, javaBytes);
   if (bytes.get() == nullptr) {
     return;
   }
   ScopedCharArrayRW chars(env, javaChars);
   if (chars.get() == nullptr) {
     return;
   }

   const jbyte* src = &bytes[offset];
   jchar* dst = &chars[0];
   for (int i = length - 1; i >= 0; --i) {
     *dst++ = static_cast<jchar>(*src++ & 0xff);
   }
 }

 /**
  * Translates the given characters to US-ASCII or ISO-8859-1 bytes, using the fact that
  * Unicode code points between U+0000 and U+007f inclusive are identical to US-ASCII, while
  * U+0000 to U+00ff inclusive are identical to ISO-8859-1.
  */
 static jbyteArray charsToBytes(JNIEnv* env, jstring java_string, jint offset, jint length,
                                jchar maxValidChar) {
   ScopedObjectAccess soa(env);
   StackHandleScope<1> hs(soa.Self());
   Handle<mirror::String> string(hs.NewHandle(soa.Decode<mirror::String*>(java_string)));
   if (string.Get() == nullptr) {
     return nullptr;
   }

   jbyteArray javaBytes = env->NewByteArray(length);
   ScopedByteArrayRW bytes(env, javaBytes);
   if (bytes.get() == nullptr) {
     return nullptr;
   }

   const jchar* src = &(string->GetValue()[offset]);
   jbyte* dst = &bytes[0];
   for (int i = length - 1; i >= 0; --i) {
     jchar ch = *src++;
     if (ch > maxValidChar) {
       ch = '?';
     }
     *dst++ = static_cast<jbyte>(ch);
   }

   return javaBytes;
 }

 static jbyteArray CharsetUtils_toAsciiBytes(JNIEnv* env, jclass, jstring java_string, jint offset,
                                             jint length) {
     return charsToBytes(env, java_string, offset, length, 0x7f);
 }

 static jbyteArray CharsetUtils_toIsoLatin1Bytes(JNIEnv* env, jclass, jstring java_string,
                                                 jint offset, jint length) {
     return charsToBytes(env, java_string, offset, length, 0xff);
 }

 static jbyteArray CharsetUtils_toUtf8Bytes(JNIEnv* env, jclass, jstring java_string, jint offset,
                                            jint length) {
   ScopedObjectAccess soa(env);
   StackHandleScope<1> hs(soa.Self());
   Handle<mirror::String> string(hs.NewHandle(soa.Decode<mirror::String*>(java_string)));
   if (string.Get() == nullptr) {
     return nullptr;
   }

   NativeUnsafeByteSequence out(env);
   if (!out.resize(length)) {
     return nullptr;
   }

   const int end = offset + length;
   for (int i = offset; i < end; ++i) {
     jint ch = string->CharAt(i);
     if (ch < 0x80) {
       // One byte.
       if (!out.append(ch)) {
         return nullptr;
       }
     } else if (ch < 0x800) {
       // Two bytes.
       if (!out.append((ch >> 6) | 0xc0) || !out.append((ch & 0x3f) | 0x80)) {
         return nullptr;
       }
     } else if (U16_IS_SURROGATE(ch)) {
       // A supplementary character.
       jchar high = static_cast<jchar>(ch);
       jchar low = (i + 1 != end) ? string->CharAt(i + 1) : 0;
       if (!U16_IS_SURROGATE_LEAD(high) || !U16_IS_SURROGATE_TRAIL(low)) {
         if (!out.append('?')) {
           return nullptr;
         }
         continue;
       }
       // Now we know we have a *valid* surrogate pair, we can consume the low surrogate.
       ++i;
       ch = U16_GET_SUPPLEMENTARY(high, low);
       // Four bytes.
       jbyte b1 = (ch >> 18) | 0xf0;
       jbyte b2 = ((ch >> 12) & 0x3f) | 0x80;
       jbyte b3 = ((ch >> 6) & 0x3f) | 0x80;
       jbyte b4 = (ch & 0x3f) | 0x80;
       if (!out.append(b1) || !out.append(b2) || !out.append(b3) || !out.append(b4)) {
         return nullptr;
       }
     } else {
       // Three bytes.
       jbyte b1 = (ch >> 12) | 0xe0;
       jbyte b2 = ((ch >> 6) & 0x3f) | 0x80;
       jbyte b3 = (ch & 0x3f) | 0x80;
       if (!out.append(b1) || !out.append(b2) || !out.append(b3)) {
         return nullptr;
       }
     }
   }
   return out.toByteArray();
 }

 static JNINativeMethod gMethods[] = {
   NATIVE_METHOD(CharsetUtils, asciiBytesToChars, "!([BII[C)V"),
   NATIVE_METHOD(CharsetUtils, isoLatin1BytesToChars, "!([BII[C)V"),
   NATIVE_METHOD(CharsetUtils, toAsciiBytes, "!(Ljava/lang/String;II)[B"),
   NATIVE_METHOD(CharsetUtils, toIsoLatin1Bytes, "!(Ljava/lang/String;II)[B"),
   NATIVE_METHOD(CharsetUtils, toUtf8Bytes, "!(Ljava/lang/String;II)[B"),
 };

 void register_libcore_util_CharsetUtils(JNIEnv* env) {
   REGISTER_NATIVE_METHODS("libcore/util/CharsetUtils");
 }

 }  // namespace art
	/*
	* Copyright (C) 2010 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 "jni_internal.h"
	#include "mirror/string.h"
	#include "mirror/string-inl.h"
	#include "native/libcore_util_CharsetUtils.h"
	#include "scoped_fast_native_object_access.h"
	#include "ScopedPrimitiveArray.h"
	#include "unicode/utf16.h"

	#include <string.h>

	namespace art {

	/**
	* Approximates java.lang.UnsafeByteSequence so we don't have to pay the cost of calling back into
	* Java when converting a char[] to a UTF-8 byte[]. This lets us have UTF-8 conversions slightly
	* faster than ICU for large char[]s without paying for the NIO overhead with small char[]s.
	*
	* We could avoid this by keeping the UTF-8 bytes on the native heap until we're done and only
	* creating a byte[] on the Java heap when we know how big it needs to be, but one shouldn't lie
	* to the garbage collector (nor hide potentially large allocations from it).
	*
	* Because a call to append might require an allocation, it might fail. Callers should always
	* check the return value of append.
	*/
	class NativeUnsafeByteSequence {
	public:
	explicit NativeUnsafeByteSequence(JNIEnv* env)
	: mEnv(env), mJavaArray(nullptr), mRawArray(nullptr), mSize(-1), mOffset(0) {
	}

	~NativeUnsafeByteSequence() {
	// Release our pointer to the raw array, copying changes back to the Java heap.
	if (mRawArray != nullptr) {
	mEnv->ReleaseByteArrayElements(mJavaArray, mRawArray, 0);
	}
	}

	bool append(jbyte b) {
	if (mOffset == mSize && !resize(mSize * 2)) {
	return false;
	}
	mRawArray[mOffset++] = b;
	return true;
	}

	bool resize(int newSize) {
	if (newSize == mSize) {
	return true;
	}

	// Allocate a new array.
	jbyteArray newJavaArray = mEnv->NewByteArray(newSize);
	if (newJavaArray == nullptr) {
	return false;
	}
	jbyte* newRawArray = mEnv->GetByteArrayElements(newJavaArray, nullptr);
	if (newRawArray == nullptr) {
	return false;
	}

	// Copy data out of the old array and then let go of it.
	// Note that we may be trimming the array.
	if (mRawArray != nullptr) {
	memcpy(newRawArray, mRawArray, mOffset);
	mEnv->ReleaseByteArrayElements(mJavaArray, mRawArray, JNI_ABORT);
	mEnv->DeleteLocalRef(mJavaArray);
	}

	// Point ourselves at the new array.
	mJavaArray = newJavaArray;
	mRawArray = newRawArray;
	mSize = newSize;
	return true;
	}

	jbyteArray toByteArray() {
	// Trim any unused space, if necessary.
	bool okay = resize(mOffset);
	return okay ? mJavaArray : nullptr;
	}

	private:
	JNIEnv* mEnv;
	jbyteArray mJavaArray;
	jbyte* mRawArray;
	jint mSize;
	jint mOffset;

	// Disallow copy and assignment.
	NativeUnsafeByteSequence(const NativeUnsafeByteSequence&);
	void operator=(const NativeUnsafeByteSequence&);
	};

	static void CharsetUtils_asciiBytesToChars(JNIEnv* env, jclass, jbyteArray javaBytes, jint offset,
	jint length, jcharArray javaChars) {
	ScopedByteArrayRO bytes(env, javaBytes);
	if (bytes.get() == nullptr) {
	return;
	}
	ScopedCharArrayRW chars(env, javaChars);
	if (chars.get() == nullptr) {
	return;
	}

	const jbyte* src = &bytes[offset];
	jchar* dst = &chars[0];
	static const jchar REPLACEMENT_CHAR = 0xfffd;
	for (int i = length - 1; i >= 0; --i) {
	jchar ch = static_cast<jchar>(*src++ & 0xff);
	*dst++ = (ch <= 0x7f) ? ch : REPLACEMENT_CHAR;
	}
	}

	static void CharsetUtils_isoLatin1BytesToChars(JNIEnv* env, jclass, jbyteArray javaBytes,
	jint offset, jint length, jcharArray javaChars) {
	ScopedByteArrayRO bytes(env, javaBytes);
	if (bytes.get() == nullptr) {
	return;
	}
	ScopedCharArrayRW chars(env, javaChars);
	if (chars.get() == nullptr) {
	return;
	}

	const jbyte* src = &bytes[offset];
	jchar* dst = &chars[0];
	for (int i = length - 1; i >= 0; --i) {
	dst++ = static_cast<jchar>(src++ & 0xff);
	}
	}

	/**
	* Translates the given characters to US-ASCII or ISO-8859-1 bytes, using the fact that
	* Unicode code points between U+0000 and U+007f inclusive are identical to US-ASCII, while
	* U+0000 to U+00ff inclusive are identical to ISO-8859-1.
	*/
	static jbyteArray charsToBytes(JNIEnv* env, jstring java_string, jint offset, jint length,
	jchar maxValidChar) {
	ScopedObjectAccess soa(env);
	StackHandleScope<1> hs(soa.Self());
	Handle<mirror::String> string(hs.NewHandle(soa.Decode<mirror::String*>(java_string)));
	if (string.Get() == nullptr) {
	return nullptr;
	}

	jbyteArray javaBytes = env->NewByteArray(length);
	ScopedByteArrayRW bytes(env, javaBytes);
	if (bytes.get() == nullptr) {
	return nullptr;
	}

	const jchar* src = &(string->GetValue()[offset]);
	jbyte* dst = &bytes[0];
	for (int i = length - 1; i >= 0; --i) {
	jchar ch = *src++;
	if (ch > maxValidChar) {
	ch = '?';
	}
	*dst++ = static_cast<jbyte>(ch);
	}

	return javaBytes;
	}

	static jbyteArray CharsetUtils_toAsciiBytes(JNIEnv* env, jclass, jstring java_string, jint offset,
	jint length) {
	return charsToBytes(env, java_string, offset, length, 0x7f);
	}

	static jbyteArray CharsetUtils_toIsoLatin1Bytes(JNIEnv* env, jclass, jstring java_string,
	jint offset, jint length) {
	return charsToBytes(env, java_string, offset, length, 0xff);
	}

	static jbyteArray CharsetUtils_toUtf8Bytes(JNIEnv* env, jclass, jstring java_string, jint offset,
	jint length) {
	ScopedObjectAccess soa(env);
	StackHandleScope<1> hs(soa.Self());
	Handle<mirror::String> string(hs.NewHandle(soa.Decode<mirror::String*>(java_string)));
	if (string.Get() == nullptr) {
	return nullptr;
	}

	NativeUnsafeByteSequence out(env);
	if (!out.resize(length)) {
	return nullptr;
	}

	const int end = offset + length;
	for (int i = offset; i < end; ++i) {
	jint ch = string->CharAt(i);
	if (ch < 0x80) {
	// One byte.
	if (!out.append(ch)) {
	return nullptr;
	}
	} else if (ch < 0x800) {
	// Two bytes.
	if (!out.append((ch >> 6) \| 0xc0) \|\| !out.append((ch & 0x3f) \| 0x80)) {
	return nullptr;
	}
	} else if (U16_IS_SURROGATE(ch)) {
	// A supplementary character.
	jchar high = static_cast<jchar>(ch);
	jchar low = (i + 1 != end) ? string->CharAt(i + 1) : 0;
	if (!U16_IS_SURROGATE_LEAD(high) \|\| !U16_IS_SURROGATE_TRAIL(low)) {
	if (!out.append('?')) {
	return nullptr;
	}
	continue;
	}
	// Now we know we have a valid surrogate pair, we can consume the low surrogate.
	++i;
	ch = U16_GET_SUPPLEMENTARY(high, low);
	// Four bytes.
	jbyte b1 = (ch >> 18) \| 0xf0;
	jbyte b2 = ((ch >> 12) & 0x3f) \| 0x80;
	jbyte b3 = ((ch >> 6) & 0x3f) \| 0x80;
	jbyte b4 = (ch & 0x3f) \| 0x80;
	if (!out.append(b1) \|\| !out.append(b2) \|\| !out.append(b3) \|\| !out.append(b4)) {
	return nullptr;
	}
	} else {
	// Three bytes.
	jbyte b1 = (ch >> 12) \| 0xe0;
	jbyte b2 = ((ch >> 6) & 0x3f) \| 0x80;
	jbyte b3 = (ch & 0x3f) \| 0x80;
	if (!out.append(b1) \|\| !out.append(b2) \|\| !out.append(b3)) {
	return nullptr;
	}
	}
	}
	return out.toByteArray();
	}

	static JNINativeMethod gMethods[] = {
	NATIVE_METHOD(CharsetUtils, asciiBytesToChars, "!([BII[C)V"),
	NATIVE_METHOD(CharsetUtils, isoLatin1BytesToChars, "!([BII[C)V"),
	NATIVE_METHOD(CharsetUtils, toAsciiBytes, "!(Ljava/lang/String;II)[B"),
	NATIVE_METHOD(CharsetUtils, toIsoLatin1Bytes, "!(Ljava/lang/String;II)[B"),
	NATIVE_METHOD(CharsetUtils, toUtf8Bytes, "!(Ljava/lang/String;II)[B"),
	};

	void register_libcore_util_CharsetUtils(JNIEnv* env) {
	REGISTER_NATIVE_METHODS("libcore/util/CharsetUtils");
	}

	} // namespace art