jni jnienv GetFloatArrayRegion example c c++ java

Get<PrimitiveType>ArrayRegion Routines - GetFloatArrayRegion

void Get<PrimitiveType>ArrayRegion(JNIEnv *env, ArrayType array,
jsize start, jsize len, NativeType *buf);

A family of functions that copies a region of a primitive array into a buffer.

The following table describes the specific primitive array element accessors. You should do the following substitutions:(GetFloatArrayRegion)

• Replace Get<PrimitiveType>ArrayRegion with one of the actual primitive element accessor routine names from Table 4-12.

• Replace ArrayType with the corresponding array type.

• Replace NativeType with the corresponding native type for that routine.

Table 4-12a Get<PrimitiveType>ArrayRegion Family of Array Accessor Routines

Get<PrimitiveType>ArrayRegion Routine	Array Type	Native Type
GetBooleanArrayRegion()	jbooleanArray	jboolean
GetByteArrayRegion()	jbyteArray	jbyte
GetCharArrayRegion()	jcharArray	jchar
GetShortArrayRegion()	jshortArray	jhort
GetIntArrayRegion()	jintArray	jint
GetLongArrayRegion()	jlongArray	jlong
GetFloatArrayRegion()	jfloatArray	jloat
GetDoubleArrayRegion()	jdoubleArray	jdouble

LINKAGE of GetFloatArrayRegion

Indices in the JNIEnv interface function table.

Table 4-12b Get<PrimitiveType>ArrayRegion Family of Array Accessor Routines

Get<PrimitiveType>ArrayRegion Routine	Index
GetBooleanArrayRegion()	199
GetByteArrayRegion()	200
GetCharArrayRegion()	201
GetShortArrayRegion()	202
GetIntArrayRegion()	203
GetLongArrayRegion()	204
GetFloatArrayRegion()	205
GetDoubleArrayRegion()	206

PARAMETERS of GetFloatArrayRegion

env: the JNI interface pointer.

array: a Java array.

start: the starting index.

len: the number of elements to be copied.

buf: the destination buffer.

THROWS:

ArrayIndexOutOfBoundsException: if one of the indexes in the region is not valid.

Example of GetFloatArrayRegion




        case 'F': {
            m_cmdParser->reply.WriteByte(JDWP_TAG_FLOAT);
            m_cmdParser->reply.WriteInt(length);
            if ( length == 0 ) {
                return;
            }
            jfloat* bufferArray = reinterpret_cast<jfloat*>(AgentBase::GetMemoryManager()
                    .Allocate(sizeof(jfloat)*length JDWP_FILE_LINE));
            AgentAutoFree scavenger(bufferArray JDWP_FILE_LINE);
            jni->GetFloatArrayRegion(static_cast<jfloatArray>(arrayObject), firstIndex, length, bufferArray);
            classManager.CheckOnException(jni);
                        
            for (int i = 0; i < length; i++) {
                value.f = bufferArray[i];
                JDWP_TRACE_DATA("GetValues: send: index=" << i
                    << ", value=(float)" << value.f);
                m_cmdParser->reply.WriteUntaggedValue(jni, JDWP_TAG_FLOAT, value);
            }
            return;
        }