104 lines
4.7 KiB
C++
104 lines
4.7 KiB
C++
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef SCOPED_NULLABLE_PRIMITIVE_ARRAY_H
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#define SCOPED_NULLABLE_PRIMITIVE_ARRAY_H
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#include <jni.h>
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namespace android {
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#define ARRAY_TRAITS(ARRAY_TYPE, POINTER_TYPE, NAME) \
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class NAME ## ArrayTraits { \
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public: \
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static constexpr void getArrayRegion(JNIEnv* env, ARRAY_TYPE array, size_t start, \
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size_t len, POINTER_TYPE out) { \
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env->Get ## NAME ## ArrayRegion(array, start, len, out); \
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} \
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\
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static constexpr POINTER_TYPE getArrayElements(JNIEnv* env, ARRAY_TYPE array) { \
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return env->Get ## NAME ## ArrayElements(array, nullptr); \
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} \
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\
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static constexpr void releaseArrayElements(JNIEnv* env, ARRAY_TYPE array, \
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POINTER_TYPE buffer, jint mode) { \
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env->Release ## NAME ## ArrayElements(array, buffer, mode); \
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} \
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}; \
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ARRAY_TRAITS(jbooleanArray, jboolean*, Boolean)
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ARRAY_TRAITS(jbyteArray, jbyte*, Byte)
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ARRAY_TRAITS(jcharArray, jchar*, Char)
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ARRAY_TRAITS(jdoubleArray, jdouble*, Double)
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ARRAY_TRAITS(jfloatArray, jfloat*, Float)
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ARRAY_TRAITS(jintArray, jint*, Int)
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ARRAY_TRAITS(jlongArray, jlong*, Long)
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ARRAY_TRAITS(jshortArray, jshort*, Short)
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#undef ARRAY_TRAITS
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template<typename JavaArrayType, typename PrimitiveType, class Traits, size_t preallocSize = 10>
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class ScopedArrayRO {
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public:
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ScopedArrayRO(JNIEnv* env, JavaArrayType javaArray) : mEnv(env), mJavaArray(javaArray) {
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if (mJavaArray == nullptr) {
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mSize = 0;
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mRawArray = nullptr;
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} else {
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mSize = mEnv->GetArrayLength(mJavaArray);
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if (mSize <= preallocSize) {
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Traits::getArrayRegion(mEnv, mJavaArray, 0, mSize, mBuffer);
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mRawArray = mBuffer;
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} else {
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mRawArray = Traits::getArrayElements(mEnv, mJavaArray);
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}
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}
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}
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~ScopedArrayRO() {
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if (mRawArray != nullptr && mRawArray != mBuffer) {
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Traits::releaseArrayElements(mEnv, mJavaArray, mRawArray, JNI_ABORT);
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}
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}
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const PrimitiveType* get() const { return mRawArray; }
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const PrimitiveType& operator[](size_t n) const { return mRawArray[n]; }
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size_t size() const { return mSize; }
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private:
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JNIEnv* const mEnv;
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JavaArrayType mJavaArray;
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PrimitiveType* mRawArray;
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size_t mSize;
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PrimitiveType mBuffer[preallocSize];
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DISALLOW_COPY_AND_ASSIGN(ScopedArrayRO);
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};
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// ScopedNullable***ArrayRO provide convenient read-only access to Java array from JNI code.
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// These accept nullptr. In that case, get() returns nullptr and size() returns 0.
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using ScopedNullableBooleanArrayRO = ScopedArrayRO<jbooleanArray, jboolean, BooleanArrayTraits>;
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using ScopedNullableByteArrayRO = ScopedArrayRO<jbyteArray, jbyte, ByteArrayTraits>;
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using ScopedNullableCharArrayRO = ScopedArrayRO<jcharArray, jchar, CharArrayTraits>;
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using ScopedNullableDoubleArrayRO = ScopedArrayRO<jdoubleArray, jdouble, DoubleArrayTraits>;
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using ScopedNullableFloatArrayRO = ScopedArrayRO<jfloatArray, jfloat, FloatArrayTraits>;
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using ScopedNullableIntArrayRO = ScopedArrayRO<jintArray, jint, IntArrayTraits>;
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using ScopedNullableLongArrayRO = ScopedArrayRO<jlongArray, jlong, LongArrayTraits>;
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using ScopedNullableShortArrayRO = ScopedArrayRO<jshortArray, jshort, ShortArrayTraits>;
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} // namespace android
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#endif // SCOPED_NULLABLE_PRIMITIVE_ARRAY_H
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