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Diffstat (limited to 'include')
-rw-r--r-- | include/ScopedBytes.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/include/ScopedBytes.h b/include/ScopedBytes.h new file mode 100644 index 0000000..cb2614b --- /dev/null +++ b/include/ScopedBytes.h @@ -0,0 +1,80 @@ +/* + * 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. + */ + +#ifndef SCOPED_BYTES_H_included +#define SCOPED_BYTES_H_included + +#include "JNIHelp.h" + +/** + * ScopedBytesRO and ScopedBytesRW attempt to paper over the differences between byte[]s and + * ByteBuffers. This in turn helps paper over the differences between non-direct ByteBuffers backed + * by byte[]s, direct ByteBuffers backed by bytes[]s, and direct ByteBuffers not backed by byte[]s. + * (On Android, this last group only contains MappedByteBuffers.) + */ +template<bool readOnly> +class ScopedBytes { +public: + ScopedBytes(JNIEnv* env, jobject object) + : mEnv(env), mObject(object), mByteArray(NULL), mPtr(NULL) + { + if (mObject == NULL) { + jniThrowNullPointerException(mEnv, NULL); + } else if (mEnv->IsInstanceOf(mObject, JniConstants::byteArrayClass)) { + mByteArray = reinterpret_cast<jbyteArray>(mObject); + mPtr = mEnv->GetByteArrayElements(mByteArray, NULL); + } else { + mPtr = reinterpret_cast<jbyte*>(mEnv->GetDirectBufferAddress(mObject)); + } + } + + ~ScopedBytes() { + if (mByteArray != NULL) { + mEnv->ReleaseByteArrayElements(mByteArray, mPtr, readOnly ? JNI_ABORT : 0); + } + } + +private: + JNIEnv* mEnv; + jobject mObject; + jbyteArray mByteArray; + +protected: + jbyte* mPtr; + +private: + // Disallow copy and assignment. + ScopedBytes(const ScopedBytes&); + void operator=(const ScopedBytes&); +}; + +class ScopedBytesRO : public ScopedBytes<true> { +public: + ScopedBytesRO(JNIEnv* env, jobject object) : ScopedBytes<true>(env, object) {} + const jbyte* get() const { + return mPtr; + } +}; + +class ScopedBytesRW : public ScopedBytes<false> { +public: + ScopedBytesRW(JNIEnv* env, jobject object) : ScopedBytes<false>(env, object) {} + jbyte* get() { + return mPtr; + } +}; + +#endif // SCOPED_BYTES_H_included |