Seigo Nonaka | beb1640 | 2017-11-22 12:07:16 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef SCOPED_NULLABLE_PRIMITIVE_ARRAY_H |
| 18 | #define SCOPED_NULLABLE_PRIMITIVE_ARRAY_H |
| 19 | |
| 20 | #include <jni.h> |
| 21 | |
| 22 | namespace android { |
| 23 | |
| 24 | #define ARRAY_TRAITS(ARRAY_TYPE, POINTER_TYPE, NAME) \ |
| 25 | class NAME ## ArrayTraits { \ |
| 26 | public: \ |
| 27 | static constexpr void getArrayRegion(JNIEnv* env, ARRAY_TYPE array, size_t start, \ |
| 28 | size_t len, POINTER_TYPE out) { \ |
| 29 | env->Get ## NAME ## ArrayRegion(array, start, len, out); \ |
| 30 | } \ |
| 31 | \ |
| 32 | static constexpr POINTER_TYPE getArrayElements(JNIEnv* env, ARRAY_TYPE array) { \ |
| 33 | return env->Get ## NAME ## ArrayElements(array, nullptr); \ |
| 34 | } \ |
| 35 | \ |
| 36 | static constexpr void releaseArrayElements(JNIEnv* env, ARRAY_TYPE array, \ |
| 37 | POINTER_TYPE buffer, jint mode) { \ |
| 38 | env->Release ## NAME ## ArrayElements(array, buffer, mode); \ |
| 39 | } \ |
| 40 | }; \ |
| 41 | |
| 42 | ARRAY_TRAITS(jbooleanArray, jboolean*, Boolean) |
| 43 | ARRAY_TRAITS(jbyteArray, jbyte*, Byte) |
| 44 | ARRAY_TRAITS(jcharArray, jchar*, Char) |
| 45 | ARRAY_TRAITS(jdoubleArray, jdouble*, Double) |
| 46 | ARRAY_TRAITS(jfloatArray, jfloat*, Float) |
| 47 | ARRAY_TRAITS(jintArray, jint*, Int) |
| 48 | ARRAY_TRAITS(jlongArray, jlong*, Long) |
| 49 | ARRAY_TRAITS(jshortArray, jshort*, Short) |
| 50 | |
| 51 | #undef ARRAY_TRAITS |
| 52 | |
| 53 | template<typename JavaArrayType, typename PrimitiveType, class Traits, size_t preallocSize = 10> |
| 54 | class ScopedArrayRO { |
| 55 | public: |
| 56 | ScopedArrayRO(JNIEnv* env, JavaArrayType javaArray) : mEnv(env), mJavaArray(javaArray) { |
| 57 | if (mJavaArray == nullptr) { |
| 58 | mSize = 0; |
| 59 | mRawArray = nullptr; |
| 60 | } else { |
| 61 | mSize = mEnv->GetArrayLength(mJavaArray); |
| 62 | if (mSize <= preallocSize) { |
| 63 | Traits::getArrayRegion(mEnv, mJavaArray, 0, mSize, mBuffer); |
| 64 | mRawArray = mBuffer; |
| 65 | } else { |
| 66 | mRawArray = Traits::getArrayElements(mEnv, mJavaArray); |
| 67 | } |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | ~ScopedArrayRO() { |
| 72 | if (mRawArray != nullptr && mRawArray != mBuffer) { |
| 73 | Traits::releaseArrayElements(mEnv, mJavaArray, mRawArray, JNI_ABORT); |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | const PrimitiveType* get() const { return mRawArray; } |
| 78 | const PrimitiveType& operator[](size_t n) const { return mRawArray[n]; } |
| 79 | size_t size() const { return mSize; } |
| 80 | |
| 81 | private: |
| 82 | JNIEnv* const mEnv; |
| 83 | JavaArrayType mJavaArray; |
| 84 | PrimitiveType* mRawArray; |
| 85 | size_t mSize; |
| 86 | PrimitiveType mBuffer[preallocSize]; |
| 87 | DISALLOW_COPY_AND_ASSIGN(ScopedArrayRO); |
| 88 | }; |
| 89 | |
| 90 | // ScopedNullable***ArrayRO provide convenient read-only access to Java array from JNI code. |
| 91 | // These accept nullptr. In that case, get() returns nullptr and size() returns 0. |
| 92 | using ScopedNullableBooleanArrayRO = ScopedArrayRO<jbooleanArray, jboolean, BooleanArrayTraits>; |
| 93 | using ScopedNullableByteArrayRO = ScopedArrayRO<jbyteArray, jbyte, ByteArrayTraits>; |
| 94 | using ScopedNullableCharArrayRO = ScopedArrayRO<jcharArray, jchar, CharArrayTraits>; |
| 95 | using ScopedNullableDoubleArrayRO = ScopedArrayRO<jdoubleArray, jdouble, DoubleArrayTraits>; |
| 96 | using ScopedNullableFloatArrayRO = ScopedArrayRO<jfloatArray, jfloat, FloatArrayTraits>; |
| 97 | using ScopedNullableIntArrayRO = ScopedArrayRO<jintArray, jint, IntArrayTraits>; |
| 98 | using ScopedNullableLongArrayRO = ScopedArrayRO<jlongArray, jlong, LongArrayTraits>; |
| 99 | using ScopedNullableShortArrayRO = ScopedArrayRO<jshortArray, jshort, ShortArrayTraits>; |
| 100 | |
| 101 | } // namespace android |
| 102 | |
| 103 | #endif // SCOPED_NULLABLE_PRIMITIVE_ARRAY_H |