How to convert a passed c++ long pointer to java Pointer or array

Question

I have a long pointer that has been passed from c++ to java that refers to an image data, now i want to retrieve the array from this pointer in java ,how can i do this what i have is long ptr in java

i tried this code but i dont know how to make ptr refer to _pointer

long _pointer=Image.GetCptr();
com.sun.jna.Pointer ptr = new com.sun.jna.Memory(2 * 512 * 512);
short testarr[] = new short [512 * 512];
ptr.read(_pointer, testarr, 0, testarr.length);

user59169 · Accepted Answer · 2013-01-06 07:40:49Z

1

According to jna.java.net Documentation read function has the following parameters:

public void read(long offset,
             byte[] buf,
             int index,
             int length)

Indirect the native pointer, copying from memory pointed to by native pointer, into the specified array.

Parameters:
    offset - byte offset from pointer into which data is copied
    buf - byte array into which data is copied
    index - array index from which to start copying
    length - number of elements from native pointer that must be copied

As you can see first parameter is byte offset from the pointer data is copied. in your case 0.
The second parameter is byte array the data is copied. In your case the pointer pointing to the actual image data, or _pointer.
The third parameter is array index in destination which would be 0 again.
and the fourth parameter number of bytes to copy which seems to be 2*512*512.

Hope this helps you.

answered Jan 6, 2013 at 7:40

user59169

1387 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Sara S. Over a year ago

it says that there's not a suitable method that takes int,long,int,int..that happened when i placed _pointer in the second argument :)

user59169 Over a year ago

I really don't know anything about this API. I tried to figure it from the documentation. Sry if I wasted your time :)

Collectives™ on Stack Overflow

How to convert a passed c++ long pointer to java Pointer or array

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related