Anfügen Byte-Arrays in JNI

Question

Ich habe Probleme bei der Konvertierung der Funktion von Java zu JNI anhängen. Wenn mir jemand helfen kann, würde ich das schätzen.

Java

Anfügen Funktion in Java

/* 
private byte[] append(byte[]... dtIn) { 

    // get dtIn length 
    int length = 0; 
    for (byte[] d : dtIn) { 
     length += d.length; 
    } 

    // allocate memory 
    ByteBuffer b = ByteBuffer.allocate(length); 

    // append dtIn 
    for (int i = 0; i < dtIn.length; i++) { 
     b.put(dtIn[i]); 
    } 
    return b.array(); 
} 
*/ 


private native byte[] append(byte[]... dtIn); 

static { 
    System.loadLibrary("mylibs"); 
} 

JNI

Globale Konstante

const char *CLS_BYTE_BUFFER = "java/nio/ByteBuffer"; 
const char *MID_ALLOCATE = "allocate"; 
const char *SIG_ALLOCATE = "(I)Ljava/nio/ByteBuffer;"; 
const char *MID_PUT= "put"; 
const char *SIG_PUT = "(B)Ljava/nio/ByteBuffer;"; 
const char *MID_ARRAY = "array"; 
const char *SIG_ARRAY = "()[B"; 

Globale Variablen

JavaVM *_jvm; 
jclass _clsByteBuffer; 
jmethodID _midAllocate, _midPut, _midArray; 

Diese Funktion wird aufgerufen, wenn System.loadLibrary ("mylibs") ausgeführt wird.

JNIEXPORT jint JNICALL 
JNI_OnLoad(JavaVM *jvm, void *reserved) { 
    jclass clsByteBuffer; 

    JNIEnv *env; 

    _jvm = jvm; 
    if (jvm->GetEnv((void **) &env, JNI_VERSION_1_6)) { 
     return JNI_ERR; 
    } 

    // ByteBuffer 
    clsByteBuffer = env->FindClass(CLS_BYTE_BUFFER); 
    if (clsByteBuffer == NULL || tryCatch()) { 
     return JNI_ERR; 
    } 

    _clsByteBuffer = (jclass) env->NewWeakGlobalRef(clsByteBuffer); 
    if (_clsByteBuffer == NULL || tryCatch()) { 
     return JNI_ERR; 
    } 

    // allocate 
    _midAllocate = env->GetStaticMethodID(_clsByteBuffer, MID_ALLOCATE, SIG_ALLOCATE); 
    if (_midAllocate == NULL || tryCatch()) { 
     return JNI_ERR; 
    } 

    // put 
    _midPut = env->GetMethodID(_clsByteBuffer, MID_PUT, SIG_PUT); 
    if (_midPut == NULL || tryCatch()) { 
     return JNI_ERR; 
    } 

    // array 
    _midArray = env->GetMethodID(_clsByteBuffer, MID_ARRAY, SIG_ARRAY); 
    if (_midArray == NULL || tryCatch()) { 
     return JNI_ERR; 
    } 

    return JNI_VERSION_1_6; 
} 

Anfügen Funktion (PROBLEM IN HERE !!)

JNIEXPORT jbyteArray JNICALL 
Java_com_company_myapp_activity_test_append(JNIEnv *env, jobject instance, jobjectArray dtIn) { 

    // This works 
    JNIEnv *e = getEnv(); 
    if (e == NULL || instance == NULL || dtIn == NULL) { 
     return NULL; 
    } 

    // This works 
    jint length = 0; 
    for (jint i = 0; i < e->GetArrayLength(dtIn); i++) { 
     jbyteArray item = (jbyteArray) e->GetObjectArrayElement(dtIn, i); 
     length = length + e->GetArrayLength(item); 
    } 

    // Allocate buffers 
    jobject buffer = e->CallStaticObjectMethod(_clsByteBuffer, _midAllocate, length); 
    if (buffer == NULL || tryCatch()) { 
     return NULL; 
    } 

    // This does not worked ??? 
    for (jint i = 0; i < e->GetArrayLength(dtIn); i++) { 
     jbyteArray item = (jbyteArray) e->GetObjectArrayElement(dtIn, i); 

     e->CallVoidMethod(buffer, _midPut, item); 
    } 
    return (jbyteArray) e->CallObjectMethod(buffer, _midArray); 
} 

Answer 1

Mein Problem gelöst wird, tritt der Fehler aufgrund eines konstanten Schreibfehlers für Unterschrift setzen, weniger [ Marke.

ersetzen

const char *SIG_PUT = "(B)Ljava/nio/ByteBuffer;"; 

mit

const char *SIG_PUT = "([B)Ljava/nio/ByteBuffer;";