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/*
* Copyright (C) 2017 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_NULLABLE_PRIMITIVE_ARRAY_H
#define SCOPED_NULLABLE_PRIMITIVE_ARRAY_H
#include <jni.h>
namespace android {
#define ARRAY_TRAITS(ARRAY_TYPE, POINTER_TYPE, NAME) \
class NAME ## ArrayTraits { \
public: \
static constexpr void getArrayRegion(JNIEnv* env, ARRAY_TYPE array, size_t start, \
size_t len, POINTER_TYPE out) { \
env->Get ## NAME ## ArrayRegion(array, start, len, out); \
} \
\
static constexpr POINTER_TYPE getArrayElements(JNIEnv* env, ARRAY_TYPE array) { \
return env->Get ## NAME ## ArrayElements(array, nullptr); \
} \
\
static constexpr void releaseArrayElements(JNIEnv* env, ARRAY_TYPE array, \
POINTER_TYPE buffer, jint mode) { \
env->Release ## NAME ## ArrayElements(array, buffer, mode); \
} \
}; \
ARRAY_TRAITS(jbooleanArray, jboolean*, Boolean)
ARRAY_TRAITS(jbyteArray, jbyte*, Byte)
ARRAY_TRAITS(jcharArray, jchar*, Char)
ARRAY_TRAITS(jdoubleArray, jdouble*, Double)
ARRAY_TRAITS(jfloatArray, jfloat*, Float)
ARRAY_TRAITS(jintArray, jint*, Int)
ARRAY_TRAITS(jlongArray, jlong*, Long)
ARRAY_TRAITS(jshortArray, jshort*, Short)
#undef ARRAY_TRAITS
template<typename JavaArrayType, typename PrimitiveType, class Traits, size_t preallocSize = 10>
class ScopedArrayRO {
public:
ScopedArrayRO(JNIEnv* env, JavaArrayType javaArray) : mEnv(env), mJavaArray(javaArray) {
if (mJavaArray == nullptr) {
mSize = 0;
mRawArray = nullptr;
} else {
mSize = mEnv->GetArrayLength(mJavaArray);
if (mSize <= preallocSize) {
Traits::getArrayRegion(mEnv, mJavaArray, 0, mSize, mBuffer);
mRawArray = mBuffer;
} else {
mRawArray = Traits::getArrayElements(mEnv, mJavaArray);
}
}
}
~ScopedArrayRO() {
if (mRawArray != nullptr && mRawArray != mBuffer) {
Traits::releaseArrayElements(mEnv, mJavaArray, mRawArray, JNI_ABORT);
}
}
const PrimitiveType* get() const { return mRawArray; }
const PrimitiveType& operator[](size_t n) const { return mRawArray[n]; }
size_t size() const { return mSize; }
private:
JNIEnv* const mEnv;
JavaArrayType mJavaArray;
PrimitiveType* mRawArray;
size_t mSize;
PrimitiveType mBuffer[preallocSize];
DISALLOW_COPY_AND_ASSIGN(ScopedArrayRO);
};
// ScopedNullable***ArrayRO provide convenient read-only access to Java array from JNI code.
// These accept nullptr. In that case, get() returns nullptr and size() returns 0.
using ScopedNullableBooleanArrayRO = ScopedArrayRO<jbooleanArray, jboolean, BooleanArrayTraits>;
using ScopedNullableByteArrayRO = ScopedArrayRO<jbyteArray, jbyte, ByteArrayTraits>;
using ScopedNullableCharArrayRO = ScopedArrayRO<jcharArray, jchar, CharArrayTraits>;
using ScopedNullableDoubleArrayRO = ScopedArrayRO<jdoubleArray, jdouble, DoubleArrayTraits>;
using ScopedNullableFloatArrayRO = ScopedArrayRO<jfloatArray, jfloat, FloatArrayTraits>;
using ScopedNullableIntArrayRO = ScopedArrayRO<jintArray, jint, IntArrayTraits>;
using ScopedNullableLongArrayRO = ScopedArrayRO<jlongArray, jlong, LongArrayTraits>;
using ScopedNullableShortArrayRO = ScopedArrayRO<jshortArray, jshort, ShortArrayTraits>;
} // namespace android
#endif // SCOPED_NULLABLE_PRIMITIVE_ARRAY_H
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