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      1 /*
      2  * Copyright (C) 2010 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_PRIMITIVE_ARRAY_H_included
     18 #define SCOPED_PRIMITIVE_ARRAY_H_included
     19 
     20 #include "JNIHelp.h"
     21 
     22 // ScopedBooleanArrayRO, ScopedByteArrayRO, ScopedCharArrayRO, ScopedDoubleArrayRO,
     23 // ScopedFloatArrayRO, ScopedIntArrayRO, ScopedLongArrayRO, and ScopedShortArrayRO provide
     24 // convenient read-only access to Java arrays from JNI code. This is cheaper than read-write
     25 // access and should be used by default.
     26 #define INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(PRIMITIVE_TYPE, NAME) \
     27     class Scoped ## NAME ## ArrayRO { \
     28     public: \
     29         Scoped ## NAME ## ArrayRO(JNIEnv* env, PRIMITIVE_TYPE ## Array javaArray) \
     30         : mEnv(env), mJavaArray(javaArray), mRawArray(NULL) { \
     31             if (mJavaArray == NULL) { \
     32                 jniThrowNullPointerException(mEnv, NULL); \
     33             } else { \
     34                 mRawArray = mEnv->Get ## NAME ## ArrayElements(mJavaArray, NULL); \
     35             } \
     36         } \
     37         ~Scoped ## NAME ## ArrayRO() { \
     38             if (mRawArray) { \
     39                 mEnv->Release ## NAME ## ArrayElements(mJavaArray, mRawArray, JNI_ABORT); \
     40             } \
     41         } \
     42         const PRIMITIVE_TYPE* get() const { return mRawArray; } \
     43         const PRIMITIVE_TYPE& operator[](size_t n) const { return mRawArray[n]; } \
     44         size_t size() const { return mEnv->GetArrayLength(mJavaArray); } \
     45     private: \
     46         JNIEnv* mEnv; \
     47         PRIMITIVE_TYPE ## Array mJavaArray; \
     48         PRIMITIVE_TYPE* mRawArray; \
     49         Scoped ## NAME ## ArrayRO(const Scoped ## NAME ## ArrayRO&); \
     50         void operator=(const Scoped ## NAME ## ArrayRO&); \
     51     }
     52 
     53 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jboolean, Boolean);
     54 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jbyte, Byte);
     55 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jchar, Char);
     56 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jdouble, Double);
     57 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jfloat, Float);
     58 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jint, Int);
     59 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jlong, Long);
     60 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jshort, Short);
     61 
     62 #undef INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO
     63 
     64 // ScopedBooleanArrayRW, ScopedByteArrayRW, ScopedCharArrayRW, ScopedDoubleArrayRW,
     65 // ScopedFloatArrayRW, ScopedIntArrayRW, ScopedLongArrayRW, and ScopedShortArrayRW provide
     66 // convenient read-write access to Java arrays from JNI code. These are more expensive,
     67 // since they entail a copy back onto the Java heap, and should only be used when necessary.
     68 #define INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(PRIMITIVE_TYPE, NAME) \
     69     class Scoped ## NAME ## ArrayRW { \
     70     public: \
     71         Scoped ## NAME ## ArrayRW(JNIEnv* env, PRIMITIVE_TYPE ## Array javaArray) \
     72         : mEnv(env), mJavaArray(javaArray), mRawArray(NULL) { \
     73             if (mJavaArray == NULL) { \
     74                 jniThrowNullPointerException(mEnv, NULL); \
     75             } else { \
     76                 mRawArray = mEnv->Get ## NAME ## ArrayElements(mJavaArray, NULL); \
     77             } \
     78         } \
     79         ~Scoped ## NAME ## ArrayRW() { \
     80             if (mRawArray) { \
     81                 mEnv->Release ## NAME ## ArrayElements(mJavaArray, mRawArray, 0); \
     82             } \
     83         } \
     84         const PRIMITIVE_TYPE* get() const { return mRawArray; } \
     85         const PRIMITIVE_TYPE& operator[](size_t n) const { return mRawArray[n]; } \
     86         PRIMITIVE_TYPE* get() { return mRawArray; } \
     87         PRIMITIVE_TYPE& operator[](size_t n) { return mRawArray[n]; } \
     88         size_t size() const { return mEnv->GetArrayLength(mJavaArray); } \
     89     private: \
     90         JNIEnv* mEnv; \
     91         PRIMITIVE_TYPE ## Array mJavaArray; \
     92         PRIMITIVE_TYPE* mRawArray; \
     93         Scoped ## NAME ## ArrayRW(const Scoped ## NAME ## ArrayRW&); \
     94         void operator=(const Scoped ## NAME ## ArrayRW&); \
     95     }
     96 
     97 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jboolean, Boolean);
     98 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jbyte, Byte);
     99 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jchar, Char);
    100 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jdouble, Double);
    101 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jfloat, Float);
    102 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jint, Int);
    103 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jlong, Long);
    104 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jshort, Short);
    105 
    106 #undef INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW
    107 
    108 #endif  // SCOPED_PRIMITIVE_ARRAY_H_included
    109