#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include <jni.h>
#include "it_valueteam_securityutility_KeyJNIBridge.h"

#define SHMSZ     27
//#define KEY     5678
#define KEY     5650
#define PERM     0600

JNIEXPORT jbyteArray JNICALL Java_it_valueteam_securityutility_KeyJNIBridge_readKey
  (JNIEnv * env, jobject obj, jint indirizzo){

    int shmid;
    int i = 0;
    key_t key;
    char *shm, *s;
    jbyteArray result;
    char buffer[24] = "12345123451234512345123";
	 
    //key = KEY;
    key = (key_t)indirizzo;
    
    result = (*env)->NewByteArray(env,24);
    if(result==NULL) {
    	printf("Allocazione fallita.\n");
    }

    if ((shmid = shmget(key, SHMSZ, PERM)) < 0) {
        perror("shmget");
        return NULL;
    }

    if ((shm = shmat(shmid, NULL, 0)) == (char *) -1) {
        perror("shmat");
        return NULL;
    }
    
    for(s = shm; i<24; s++) {
    	buffer[i++] = *s;
    }
    
    (*env)->SetByteArrayRegion(env,result,0,24,buffer);
    return result;
}

JNIEXPORT void JNICALL Java_it_valueteam_securityutility_KeyJNIBridge_writeKey
  (JNIEnv * env, jobject obj, jint indirizzo, jbyteArray chiave) {
  	
    int shmid;
    key_t key;
    char * shm, *s;
    int i;
    jbyte *start;
    
    //key = KEY;
    key = (key_t)indirizzo;
    
    printf("Inizio scrittura.\n");

    /*
     * Create the segment.
     */
    if ((shmid = shmget(key, SHMSZ, IPC_CREAT | PERM)) < 0) {
      perror("shmget");
      exit(1);
    }

    /*
     * Now we attach the segment to our data space.
     */
    if ((shm = shmat(shmid, NULL, 0)) == (char * ) - 1) {
      perror("shmat");
      exit(1);
    }
    
    start = (*env)->GetByteArrayElements(env,chiave,NULL);
    s = shm;
    for(i=0;i<24;i++) {
    	* s++ = start[i];
    }
    (*env)->ReleaseByteArrayElements(env, chiave, start, 0);
    
}