dispatch.cpp

jni java本地接口编程例子原代码,是java调用本地操作系统代码的接口

  (JNIEnv *env, jobject self, jint boff, jfloatArray arr, jint off, jint n)
{
    jfloat *peer = (jfloat *)
        env->GetLongField(self, FID_CPointer_peer);
    env->GetFloatArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyIn
 * Signature: (I[III)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyIn__I_3III
  (JNIEnv *env, jobject self, jint boff, jintArray arr, jint off, jint n)
{
    jint *peer = (jint *)env->GetLongField(self, FID_CPointer_peer);
    env->GetIntArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyIn
 * Signature: (I[JII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyIn__I_3JII
  (JNIEnv *env, jobject self, jint boff, jlongArray arr, jint off, jint n)
{
    jlong *peer = (jlong *)env->GetLongField(self, FID_CPointer_peer);
    env->GetLongArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyIn
 * Signature: (I[SII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyIn__I_3SII
  (JNIEnv *env, jobject self, jint boff, jshortArray arr, jint off, jint n)
{
    jshort *peer = (jshort *)
        env->GetLongField(self, FID_CPointer_peer);
    env->GetShortArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[BII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3BII
  (JNIEnv *env, jobject self, jint boff, jbyteArray arr, jint off, jint n)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    env->SetByteArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[CII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3CII
  (JNIEnv *env, jobject self, jint boff, jcharArray arr, jint off, jint n)
{
    jchar *peer = (jchar *)env->GetLongField(self, FID_CPointer_peer);
    env->SetCharArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[DII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3DII
  (JNIEnv *env, jobject self, jint boff, jdoubleArray arr, jint off, jint n)
{
    jdouble *peer = (jdouble *)
        env->GetLongField(self, FID_CPointer_peer);
    env->SetDoubleArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[FII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3FII
  (JNIEnv *env, jobject self, jint boff, jfloatArray arr, jint off, jint n)
{
    jfloat *peer = (jfloat *)
        env->GetLongField(self, FID_CPointer_peer);
    env->SetFloatArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[III)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3III
  (JNIEnv *env, jobject self, jint boff, jintArray arr, jint off, jint n)
{
    jint *peer = (jint *)env->GetLongField(self, FID_CPointer_peer);
    env->SetIntArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[JII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3JII
  (JNIEnv *env, jobject self, jint boff, jlongArray arr, jint off, jint n)
{
    jlong *peer = (jlong *)env->GetLongField(self, FID_CPointer_peer);
    env->SetLongArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    copyOut
 * Signature: (I[SII)V
 */
JNIEXPORT void JNICALL Java_CPointer_copyOut__I_3SII
  (JNIEnv *env, jobject self, jint boff, jshortArray arr, jint off, jint n)
{
    jshort *peer = (jshort *)
        env->GetLongField(self, FID_CPointer_peer);
    env->SetShortArrayRegion(arr, off, n, peer + boff);
}

/*
 * Class:     CPointer
 * Method:    getByte
 * Signature: (I)B
 */
JNIEXPORT jbyte JNICALL Java_CPointer_getByte
  (JNIEnv *env, jobject self, jint index)
{
    jbyte res;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&res, peer + index, sizeof(res));
    return res;
}

/*
 * Class:     CPointer
 * Method:    getCPointer
 * Signature: (I)LCPointer;
 */
JNIEXPORT jobject JNICALL Java_CPointer_getCPointer
  (JNIEnv *env, jobject self, jint index)
{
    void *ptr;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&ptr, peer + index, sizeof(ptr));
    return makeCPointer(env, ptr);
}

/*
 * Class:     CPointer
 * Method:    getDouble
 * Signature: (I)D
 */
JNIEXPORT jdouble JNICALL Java_CPointer_getDouble
  (JNIEnv *env, jobject self, jint index)
{
    jdouble res;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&res, peer + index, sizeof(res));
    return res;
}

/*
 * Class:     CPointer
 * Method:    getFloat
 * Signature: (I)F
 */
JNIEXPORT jfloat JNICALL Java_CPointer_getFloat
  (JNIEnv *env, jobject self, jint index)
{
    jfloat res;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&res, peer + index, sizeof(res));
    return res;
}

/*
 * Class:     CPointer
 * Method:    getInt
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_CPointer_getInt
  (JNIEnv *env, jobject self, jint index)
{
    jint res;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&res, peer + index, sizeof(res));
    return res;
}

/*
 * Class:     CPointer
 * Method:    getLong
 * Signature: (I)J
 */
JNIEXPORT jlong JNICALL Java_CPointer_getLong
  (JNIEnv *env, jobject self, jint index)
{
    jlong res;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&res, peer + index, sizeof(res));
    return res;
}

/*
 * Class:     CPointer
 * Method:    getShort
 * Signature: (I)S
 */
JNIEXPORT jshort JNICALL Java_CPointer_getShort
  (JNIEnv *env, jobject self, jint index)
{
    jshort res;
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(&res, peer + index, sizeof(res));
    return res;
}

/*
 * Class:     CPointer
 * Method:    getString
 * Signature: (I)Ljava/lang/String;
 */
JNIEXPORT jstring JNICALL Java_CPointer_getString
  (JNIEnv *env, jobject self, jint index)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    return JNU_NewStringNative(env, (const char *)peer + index);
}

/*
 * Class:     CPointer
 * Method:    setByte
 * Signature: (IB)V
 */
JNIEXPORT void JNICALL Java_CPointer_setByte
  (JNIEnv *env, jobject self, jint index, jbyte value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &value, sizeof(value));
}

/*
 * Class:     CPointer
 * Method:    setCPointer
 * Signature: (ILCPointer;)V
 */
JNIEXPORT void JNICALL Java_CPointer_setCPointer
  (JNIEnv *env, jobject self, jint index, jobject cptr)
{
    void *ptr = (void *)env->GetLongField(cptr, FID_CPointer_peer);
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &ptr, sizeof(ptr));
}

/*
 * Class:     CPointer
 * Method:    setDouble
 * Signature: (ID)V
 */
JNIEXPORT void JNICALL Java_CPointer_setDouble
  (JNIEnv *env, jobject self, jint index, jdouble value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &value, sizeof(value));
}

/*
 * Class:     CPointer
 * Method:    setFloat
 * Signature: (IF)V
 */
JNIEXPORT void JNICALL Java_CPointer_setFloat
  (JNIEnv *env, jobject self, jint index, jfloat value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &value, sizeof(value));
}

/*
 * Class:     CPointer
 * Method:    setInt
 * Signature: (II)V
 */
JNIEXPORT void JNICALL Java_CPointer_setInt
  (JNIEnv *env, jobject self, jint index, jint value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &value, sizeof(value));
}

/*
 * Class:     CPointer
 * Method:    setLong
 * Signature: (IJ)V
 */
JNIEXPORT void JNICALL Java_CPointer_setLong
  (JNIEnv *env, jobject self, jint index, jlong value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &value, sizeof(value));
}

/*
 * Class:     CPointer
 * Method:    setShort
 * Signature: (IS)V
 */
JNIEXPORT void JNICALL Java_CPointer_setShort
  (JNIEnv *env, jobject self, jint index, jshort value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    memcpy(peer + index, &value, sizeof(value));
}

/*
 * Class:     CPointer
 * Method:    setString
 * Signature: (ILjava/lang/String;)V
 */
JNIEXPORT void JNICALL Java_CPointer_setString
  (JNIEnv *env, jobject self, jint index, jstring value)
{
    jbyte *peer = (jbyte *)env->GetLongField(self, FID_CPointer_peer);
    char *str = JNU_GetStringNativeChars(env, value);
    if (str == NULL) return;
    strcpy((char *)peer + index, str);
    free(str);
}


/********************************************************************/
/*		     Native methods of class CMalloc		    */
/********************************************************************/

/*
 * Class:     CMalloc
 * Method:    malloc
 * Signature: (I)J
 */
JNIEXPORT jlong JNICALL Java_CMalloc_malloc
  (JNIEnv *env, jclass cls, jint size)
{
    return (jlong)malloc(size);
}

/*
 * Class:     CMalloc
 * Method:    free
 * Signature: (J)V
 */
JNIEXPORT void JNICALL Java_CMalloc_free
  (JNIEnv *env, jobject self)
{
    long peer = env->GetLongField(self, FID_CPointer_peer);
    free((void *)peer);
}


/********************************************************************/
/*			   Utility functions			    */
/********************************************************************/

/* Throw an exception by name */
static void 
JNU_ThrowByName(JNIEnv *env, const char *name, const char *msg)
{
    jclass cls = env->FindClass(name);

    if (cls != 0) /* Otherwise an exception has already been thrown */
        env->ThrowNew(cls, msg);

    /* It's a good practice to clean up the local references. */
    env->DeleteLocalRef(cls);
}

/* Translates a Java string to a C string using the String.getBytes 
 * method, which uses default local encoding.
 */
static char *
JNU_GetStringNativeChars(JNIEnv *env, jstring jstr)
{
    jbyteArray hab = 0;
    jthrowable exc;
    char *result = 0;

    hab = (jbyteArray)env->CallObjectMethod(jstr, MID_String_getBytes);
    exc = env->ExceptionOccurred();
    if (!exc) {
        jint len = env->GetArrayLength(hab);
        result = (char *)malloc(len + 1);
	if (result == 0) {
	    JNU_ThrowByName(env, "java/lang/OutOfMemoryError", 0);
	    env->DeleteLocalRef(hab);
	    return 0;
	}
	env->GetByteArrayRegion(hab, 0, len, (jbyte *)result);
	result[len] = 0; /* NULL-terminate */
    } else {
        env->DeleteLocalRef(exc);
    }
    env->DeleteLocalRef(hab);
    return result;
}

/* Constructs a Java string from a C array using the String(byte [])
 * constructor, which uses default local encoding.
 */
static jstring
JNU_NewStringNative(JNIEnv *env, const char *str)
{
    jstring result;
    jbyteArray hab = 0;
    int len;

    len = strlen(str);
    hab = env->NewByteArray(len);
    if (hab != 0) {
        env->SetByteArrayRegion(hab, 0, len, (jbyte *)str);
	result = (jstring)env->NewObject(Class_String,
				   MID_String_init, hab);
	env->DeleteLocalRef(hab);
	return result;
    }
    return 0;
}

/* Canonicalize NULL pointers */
static jobject makeCPointer(JNIEnv *env, void *p)
{
    jobject obj;
    if (p == NULL) {
        return NULL;
    }
    obj = env->AllocObject(Class_CPointer);
    if (obj) {
        env->SetLongField(obj, FID_CPointer_peer, (jlong)p);
    }
    return obj;
}