jni

출처

• JNI 헤더 만들기 :: CheatSheet
• How to pass C structs back and forth to Java code in JNI? - Stack Overflow
• JNI Types and Data Structures - Oracle Docs
• double 데이터형 값 주고 받기 | JNI Tutorial - skyfe79
• JNI(Java Native Interface) 이용 방법 (2/6) - 3.1~3.2 - Daum 블로그
• 강좌와 팁 - JNI programming - (2) 기본 변수형 다루기 - 임베디드 리눅스 시스템 포럼 embedded linux system
• Hwp 수식을 latex로(hml Equation Parser) – Wonno's Note – Daily Study Note
• GitHub - johnhuang-cn/jpserve: Calling Python from JAVA

py_pwm.h

typedef struct
{
    //PyObject_HEAD
    unsigned int gpio;
    float freq;
    float dutycycle;
} PWMObject;

int PWM_init(PWMObject *self, int channel, float frequency);
void PWM_start(PWMObject *self, float dutycycle);
int PWM_ChangeDutyCycle(PWMObject *self, float dutycycle);

PWMObject.java

package com.pi4j.wiringpi;

public class PWMObject {

	public int gpio;
	public float freq;
	public float dutycycle;

	public PWMObject() {

	}

	public int getGpio() {
		return gpio;
	}

	public void setGpio(int gpio) {
		this.gpio = gpio;
	}

	public float getFreq() {
		return freq;
	}

	public void setFreq(float freq) {
		this.freq = freq;
	}

	public float getDutycycle() {
		return dutycycle;
	}

	public void setDutycycle(float dutycycle) {
		this.dutycycle = dutycycle;
	}

}

com_pi4j_wiringpi_ASUSGpio.h

#include <jni.h>
/* Header for class com_pi4j_wiringpi_ASUSGpio */

#ifndef _Included_com_pi4j_wiringpi_ASUSGpio
#define _Included_com_pi4j_wiringpi_ASUSGpio
#ifdef __cplusplus
extern "C" {
#endif

#undef com_pi4j_wiringpi_ASUSGpio_ASUS
#define com_pi4j_wiringpi_ASUSGpio_ASUS 13L
#undef com_pi4j_wiringpi_ASUSGpio_OUTPUT
#define com_pi4j_wiringpi_ASUSGpio_OUTPUT 1L

JNIEXPORT jint JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pySetmode
  (JNIEnv *, jclass, jint);

JNIEXPORT jint JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pySetupChannel
  (JNIEnv *, jclass, jint, jint);

JNIEXPORT jobject JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pwmInit
  (JNIEnv *, jclass, jint, jfloat);

JNIEXPORT void JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pwmStart
  (JNIEnv *, jclass, jobject, jfloat);

JNIEXPORT jint JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pwmChangeDutyCycle
  (JNIEnv *, jclass, jobject, jfloat);

#ifdef __cplusplus
}
#endif
#endif

com_pi4j_wiringpi_ASUSGpio.c

#include <stdio.h>
#include <jni.h>
#include <wiringPi.h>
#include <RKIO.h>
#include <wiringTB.h>
#include <constants.h>
#include <common.h>
#include <c_gpio.h>
#include <py_gpio.h>
#include <py_pwm.h>
#include "com_pi4j_wiringpi_ASUSGpio.h"

void setPwmObject(JNIEnv *env, jclass targetClass, jobject newObject, PWMObject pwm) {
	
	jfieldID fid;
	
	// JniObject 객체의 intField 필드값 설정
	fid = (*env)->GetFieldID(env, targetClass, "gpio", "I");
	(*env)->SetIntField(env, newObject, fid, pwm.gpio);
	
	// JniObject 객체의 intField 필드값 설정
	fid = (*env)->GetFieldID(env, targetClass, "freq", "F");
	(*env)->SetFloatField(env, newObject, fid, pwm.freq);
	
	// JniObject 객체의 intField 필드값 설정
	fid = (*env)->GetFieldID(env, targetClass, "dutycycle", "F");
	(*env)->SetFloatField(env, newObject, fid, pwm.dutycycle);
}

void getPwmObject(JNIEnv *env, jclass targetClass, jobject newObject, PWMObject *pwm) {
	
	jfieldID fid;
	
	// JniObject 객체의 intField 필드값 설정
	fid = (*env)->GetFieldID(env, targetClass, "gpio", "I");
	pwm->gpio = (*env)->GetIntField(env, newObject, fid);
	
	// JniObject 객체의 intField 필드값 설정
	fid = (*env)->GetFieldID(env, targetClass, "freq", "F");
	pwm->freq = (*env)->GetFloatField(env, newObject, fid);
	
	// JniObject 객체의 intField 필드값 설정
	fid = (*env)->GetFieldID(env, targetClass, "dutycycle", "F");
	pwm->dutycycle = (*env)->GetFloatField(env, newObject, fid);
}

JNIEXPORT jint JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pySetmode
(JNIEnv *env, jclass obj, jint new_mode)
{
	return py_setmode(new_mode);
}

JNIEXPORT jint JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pySetupChannel
(JNIEnv *env, jclass obj, jint channel, jint direction)
{
	return py_setup_channel(channel, direction);
}

JNIEXPORT jobject JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pwmInit
(JNIEnv *env, jclass obj, jint channel, jfloat frequency)
{
	//pwm = GPIO.PWM(myservo,50) # 50hz yani 20mslik periyod
	PWMObject pwm;
	PWM_init(&pwm, channel, frequency);
	//printf("pwm.gpio = %d\n", pwm.gpio);
	
	//
	jclass targetClass = (*env)->FindClass(env, "com/pi4j/wiringpi/PWMObject");
	
	// 생성자 찾기
	jmethodID mid = (*env)->GetMethodID(env, targetClass, "<init>", "()V");

	// 객체 생성(객체 레퍼런스 반환)
	jobject newObject = (*env)->NewObject(env, targetClass, mid, "()V");
	
	setPwmObject(env, targetClass, newObject, pwm);
	
	return newObject;
}

JNIEXPORT void JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pwmStart
(JNIEnv *env, jclass obj, jobject thiz, jfloat dutycycle)
{
	PWMObject pwm;
	
	//
	jclass targetClass = (*env)->FindClass(env, "com/pi4j/wiringpi/PWMObject");
	getPwmObject(env, targetClass, thiz, &pwm);
	
	PWM_start(&pwm, dutycycle);
	setPwmObject(env, targetClass, thiz, pwm);
}

JNIEXPORT jint JNICALL Java_com_pi4j_wiringpi_ASUSGpio_pwmChangeDutyCycle
(JNIEnv *env, jclass obj, jobject thiz, jfloat dutycycle)
{
	PWMObject pwm;
	
	//
	jclass targetClass = (*env)->FindClass(env, "com/pi4j/wiringpi/PWMObject");
	getPwmObject(env, targetClass, thiz, &pwm);
	
	int result = PWM_ChangeDutyCycle(&pwm, dutycycle);
	setPwmObject(env, targetClass, thiz, pwm);
	
	return result;
}

ASUSGpio.java

package com.pi4j.wiringpi;

import com.pi4j.util.NativeLibraryLoader;

public class ASUSGpio {

  // private constructor
  private ASUSGpio()  {
    // forbid object construction
  }

  public static final int ASUS = 13;

  public static final int OUTPUT = 1;

  static {
    // Load the platform library
    NativeLibraryLoader.load("libpi4j.so");
  }

  public static native int pySetmode(int new_mode);

  public static native int pySetupChannel(int channel, int direction);

  public static native PWMObject pwmInit(int channel, float frequency);

  public static native void pwmStart(PWMObject self, float dutycycle);

  public static native int pwmChangeDutyCycle(PWMObject self, float dutycycle);
}

빌드

$ export SimulatedPlatform="TinkerBoard GPIO Provider"
$ mvn clean install

-----------------

hml-equation-parser 패키지를 설치

$ sudo apt-get install pandoc
$ sudo pip3 install typing
$ sudo pip3 install hml_equation_parser

jpserve 패키지를 설치

$ sudo pip install jpserve

jython 설치

$ java -jar jython-installer-2.7.0.jar