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         explicit Scoped ## NAME ## ArrayRO(JNIEnv* env) \
30         : mEnv(env), mJavaArray(NULL), mRawArray(NULL), mSize(0) {} \
31         Scoped ## NAME ## ArrayRO(JNIEnv* env, PRIMITIVE_TYPE ## Array javaArray) \
32         : mEnv(env) { \
33             if (javaArray == NULL) { \
34                 mJavaArray = NULL; \
35                 mSize = 0; \
36                 mRawArray = NULL; \
37                 jniThrowNullPointerException(mEnv, NULL); \
38             } else { \
39                 reset(javaArray); \
40             } \
41         } \
42         ~Scoped ## NAME ## ArrayRO() { \
43             if (mRawArray != NULL && mRawArray != mBuffer) { \
44                 mEnv->Release ## NAME ## ArrayElements(mJavaArray, mRawArray, JNI_ABORT); \
45             } \
46         } \
47         void reset(PRIMITIVE_TYPE ## Array javaArray) { \
48             mJavaArray = javaArray; \
49             mSize = mEnv->GetArrayLength(mJavaArray); \
50             if (mSize <= buffer_size) { \
51                 mEnv->Get ## NAME ## ArrayRegion(mJavaArray, 0, mSize, mBuffer); \
52                 mRawArray = mBuffer; \
53             } else { \
54                 mRawArray = mEnv->Get ## NAME ## ArrayElements(mJavaArray, NULL); \
55             } \
56         } \
57         const PRIMITIVE_TYPE* get() const { return mRawArray; } \
58         PRIMITIVE_TYPE ## Array getJavaArray() const { return mJavaArray; } \
59         const PRIMITIVE_TYPE& operator[](size_t n) const { return mRawArray[n]; } \
60         size_t size() const { return mSize; } \
61     private: \
62         static const jsize buffer_size = 1024; \
63         JNIEnv* const mEnv; \
64         PRIMITIVE_TYPE ## Array mJavaArray; \
65         PRIMITIVE_TYPE* mRawArray; \
66         jsize mSize; \
67         PRIMITIVE_TYPE mBuffer[buffer_size]; \
68         DISALLOW_COPY_AND_ASSIGN(Scoped ## NAME ## ArrayRO); \
69     }
70 
71 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jboolean, Boolean);
72 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jbyte, Byte);
73 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jchar, Char);
74 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jdouble, Double);
75 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jfloat, Float);
76 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jint, Int);
77 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jlong, Long);
78 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO(jshort, Short);
79 
80 #undef INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RO
81 
82 // ScopedBooleanArrayRW, ScopedByteArrayRW, ScopedCharArrayRW, ScopedDoubleArrayRW,
83 // ScopedFloatArrayRW, ScopedIntArrayRW, ScopedLongArrayRW, and ScopedShortArrayRW provide
84 // convenient read-write access to Java arrays from JNI code. These are more expensive,
85 // since they entail a copy back onto the Java heap, and should only be used when necessary.
86 #define INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(PRIMITIVE_TYPE, NAME) \
87     class Scoped ## NAME ## ArrayRW { \
88     public: \
89         explicit Scoped ## NAME ## ArrayRW(JNIEnv* env) \
90         : mEnv(env), mJavaArray(NULL), mRawArray(NULL) {} \
91         Scoped ## NAME ## ArrayRW(JNIEnv* env, PRIMITIVE_TYPE ## Array javaArray) \
92         : mEnv(env), mJavaArray(javaArray), mRawArray(NULL) { \
93             if (mJavaArray == NULL) { \
94                 jniThrowNullPointerException(mEnv, NULL); \
95             } else { \
96                 mRawArray = mEnv->Get ## NAME ## ArrayElements(mJavaArray, NULL); \
97             } \
98         } \
99         ~Scoped ## NAME ## ArrayRW() { \
100             if (mRawArray) { \
101                 mEnv->Release ## NAME ## ArrayElements(mJavaArray, mRawArray, 0); \
102             } \
103         } \
104         void reset(PRIMITIVE_TYPE ## Array javaArray) { \
105             mJavaArray = javaArray; \
106             mRawArray = mEnv->Get ## NAME ## ArrayElements(mJavaArray, NULL); \
107         } \
108         const PRIMITIVE_TYPE* get() const { return mRawArray; } \
109         PRIMITIVE_TYPE ## Array getJavaArray() const { return mJavaArray; } \
110         const PRIMITIVE_TYPE& operator[](size_t n) const { return mRawArray[n]; } \
111         PRIMITIVE_TYPE* get() { return mRawArray; } \
112         PRIMITIVE_TYPE& operator[](size_t n) { return mRawArray[n]; } \
113         size_t size() const { return mEnv->GetArrayLength(mJavaArray); } \
114     private: \
115         JNIEnv* const mEnv; \
116         PRIMITIVE_TYPE ## Array mJavaArray; \
117         PRIMITIVE_TYPE* mRawArray; \
118         DISALLOW_COPY_AND_ASSIGN(Scoped ## NAME ## ArrayRW); \
119     }
120 
121 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jboolean, Boolean);
122 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jbyte, Byte);
123 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jchar, Char);
124 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jdouble, Double);
125 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jfloat, Float);
126 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jint, Int);
127 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jlong, Long);
128 INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW(jshort, Short);
129 
130 #undef INSTANTIATE_SCOPED_PRIMITIVE_ARRAY_RW
131 
132 #endif  // SCOPED_PRIMITIVE_ARRAY_H_included
133