arn-e

cc     test.c   -o test
my_var     : 15
my_ptr     : 15
my_ptr_ptr : 15

arn-e

#include <stdio.h>
#include <stdlib.h>

// struct with a common interface for varying data types
struct poly_struct
{
	void (*value)();
	void (*print)(struct poly_struct);
};

arn-e

void ptr_sample()
{
  int my_var = 15;
  int *my_ptr = &my_var;
  int **my_ptr_ptr = &my_ptr;

  printf("my_var     : %i\n", my_var);
  printf("my_ptr     : %i\n", *my_ptr);
  printf("my_ptr_ptr : %i\n", **my_ptr_ptr);
}

arn-e

int main(int argc, char const *argv[])
{
  struct jintArray jvm_array;
  jvm_array = create_jintArray(5);
  struct env_type env_struct = create_env_structure();
  struct env_type *env_ptr = &env_struct;
  struct env_type **env = &env_ptr;
  
  int *native_array;

arn-e

struct env_type create_env_structure() 
{
  struct env_type env_struct, *env_ptr;

  env_struct.GetIntArrayElements = &GetIntArrayElementsFunc;
  env_struct.ReleaseIntArrayElements = &ReleaseIntArrayElementsFunc;
  return env_struct;
}

arn-e

struct jintArray create_jintArray(int size)
{
  struct jintArray jvm_array;

  jvm_array.size = size;
  jvm_array.elements = malloc(size * sizeof(int));

  for (int i = 0; i < (jvm_array.size); i ++){
    jvm_array.elements[i] = i;
  }

arn-e

int *ReleaseIntArrayElementsFunc(struct jintArray jvm_array, int *native_array)
{ 
  free(jvm_array.elements);
  return 0;
}

arn-e

struct env_type 
{
  int *(*GetIntArrayElements)(struct jintArray);
  int *(*ReleaseIntArrayElements)(struct jintArray, int *native_array);  
};

arn-e

int *GetIntArrayElementsFunc(struct jintArray jvm_array)
{
  int size = jvm_array.size;
  int *native_array = malloc(size * sizeof(int));

  for (int i = 0; i < size; i ++){
    native_array[i] = jvm_array.elements[i];
  }
  return native_array;
}

arn-e

#include <stdio.h>
#include <stdlib.h>

struct jintArray
{
  int size;
  int *elements;
};